A study of the suspension effect observed in a Dowex-50 - water system
by John Edward Robbins
A THESIS Submitted to the Graduate Faculty in partial fulfillment of the requirements for the degree
of Master of Science in Chemistry
Montana State University
© Copyright by John Edward Robbins (1961)
Abstract:
In this investigation, the distribution of ions in a Dowex-50-Water System, was considered. Within the
limits of experimental error, the data support the ’’bound-water theory" as it relates to ion distribution.
The actual distribution of Cl as determined with Cl36 was compared with the apparent distribution as
determined potentiometrically with a Ag,AgCl-reference electrode pair. The discrepancy
(corresponding to as much as 93 millivolts) was attributed to a liquid junction potential at the resin-salt
bridge interface. The data are shown to provide qualitative, and to some extent quantitative, support to
a theory proposed by Overbeek.
Any potentiometric measurement made in an exchanger-water system and employing reference
electrode with salt bridge is considered to be subject to error from this source. A STUDY OF THE SUSPENSION EFFECT
OBSERVED IN A DOWEX-50 - WATER SYSTEM
i
by
Jo h n E .R obbins
A THESIS
Subm it,ted to the. G ra d u a te F acu ljty
in
p a r t i a l f u l f i l l m e n t o f th e r e q u ir e m e n ts
fo r. th e d e g re e o f
M a s te r o f S c ie n c e i n C h em istry
at
M ontana S t a t e C o lle g e
A pproved:
H ead, M ajor DepdrEment
/
Bozeman, M ontana
A u g u st, 1961
-3 -
ACKNOWLEDGEMENT
I w ish to e x p r e s s my s i n c e r e th a n k s to D r. R. A. O lse n f o r h i s
g u id a n c e and h i s p a t i e n c e th ro u g h o u t t h i s w ork.
I w ould l i k e to e x p r e s s my a p p r e c i a t i o n to Anaconda Copper
Company f o r th e fu n d s to c a r r y on my r e s e a r c h and a l s o to th e chem­
i s t r y d e p a rtm e n t f o r th e a s s i s t a n t s h i p w hich e n a b le d me to c o n tin u e
my w ork.
I w ould a l s o l i k e to e x p re s s th a n k s to D r. Graeme B aker and D r.
B ruce M urray f o r th e h e l p f u l c r i t i c i s m , and a l s o th e g r a d u a te s t u ­
d e n ts who gave h e l p f u l s u g g e s tio n s .
To my w if e , P a t r i c i a , a h ig h n o te o f a p p r e c i a t i o n f o r h e r h e lp
th ro u g h o u t t h i s tim e .
-4-
TAfiLE OF CONTENTS
Page
LIST OF TABLES............................................................
5
LIST OF FIGURES. . . . ................................................... .............................................6
ABSTRACT ........................
I.
II.
III.
INTRODUCTION ...................
V I.
..............................................
i . . . . . . . . . . .
EXPERIMENTAL....................................
B.
C.
D.
E.
V.
. . . . . . . . .
LITERATURE REVIEW. . . . . . . . . . .
A.
IV.
7
8
10
17
C h a r a c t e r i s t i c S u sp e n sio n E f f e c t s o f S e le c te d Io n
E xchange R e s in s .........................................................................
17. .
Io n D i s t r i b u t i o n i n Dowex-50 - W ater S y s t e m ......................... 20
D i s t r i b u t i o n o f' C1^6 i n a Dowex-50 - W ater System . . .. 2 7
S tu d y o f 3^+ by E s t e r H y d ro ly s is R a te s .......................
29
P o te n tio m e tr ic D e te r m in a tio n i n Exch a n g e r-W a te r System . . 33
OVERfiEEK' S TREATMENT.................................................................................
CALCULATION OFE j
. . 36
...............................................................................
.4 3
SUMMARY AND CONCLUSIONS............................ ...................... .... ................................46
V II.
SUGGESTION FOR FUTURE RESEARCH . . . . . . . . . . . . . . . .
47
V III,
APPENDIX . ........... ......................................................................................... . . . .
48
A.
B.
C.
D.
IX.
D e f i n i t i o n s and S y m b o l i s m .......................................... ... . . . . .
T h ree P h ase S y s t e m ...........................
Donnan S ystem ............................................................ . . . . . . . .
P ro c e d u re s . . . . . . .
................... . ............................
LITERATURE CITED ......................
48
49
50
51
.5 8
-5-
LIST OF TABLES
T a b le
I.
Page
C h a r a c t e r i s t i c s o f Io n Exchange R e s in s - . . i , ............................ 19
ll a .
"Bound W ater" D a ta .......................................................................... i . . . .
ll b .
"Bound W ater" D ata ( c o u n tin g d a t a ) ............................................................ 25
III.
D i s t r i b u t i o n o f C l" ^ . . . ......................................................... ...................... 31
IV.
C o n c e n tr a tio n o f C l 1 C o r r e c te d f o r "Bound W a te r" ............................ 32
V.
V I.
V II.
V III.
24
C o m p a rativ e R a te s o f E s te r H y d r o ly s is o f E q u iv a le n t
Amounts o f H+ P e r U n it V o lu m e ................... ..........................
32
.C om parisoh o f AEc a l and E0 o n n an ............................................................. 3 7
C om parison o f V a lu e s f o r E j w ith D i f f e r e n t E le c tr o d e P a i r s . . 44
Volumes o f th e S e p a r a t e .P h a s e s . ............................................................... 54
-6-
LIST OF FIGURES
F ig u r e
Page
1.
E l e c tr o m e tr ic O b s e rv a tio n s Made by D a v is .............................................. 12
2.
C om parison o f th e S u s p e n sio n E f f e c t Between S tro n g A cid
and Bash R e s in s and Weak A cid and B ase R e s in ..................................... 18
3.
"Bound W ater" Theory* ................................. . . . . . . . . . . . .
4.
H y d ro ly s is o f M eth y l A c e ta te H+- C a ta ly z e d .......................................... 30
5.
S a l t C o n c e n tr a tio n v s . pH. .... ............................................................................ 38
6.
C om parison o f 4 E c a l w ith- E
U sin g 2.42% H+
M o n tm o r illo h ite . . . . . . . ? . . . . . .
................... ....
26
39
7.
C om parison o f
i w ith EDonnan U sin g 2.42% Na+
M o n tm o r illo n ite . . . . . 7 . . . .................................................................. 40
8.
C om parison o f S E , w ith Evwiriar, U sing 5.86% Ca++ F o r t
C o ll in s C la y . . . . . . . . D? n" a? . . . . . . . . . . . . . .
9."
C om parison o f 2S1E , w ith Ennririari U sin g 2.42% Ca++ F o r t
CojLlins C la y . . / . . . . . D?n? a ? ............................................................ 42
10 .
C o m p o sitio n o f
11.
T h ree P h ase S ystem .
' 12, '
41
AEc a l o f Dowex-50 - W ater S ystem . . . . . . .
45
49
Donnan S ystem ..............................................................................................................50
13.
The E f f e c t o f ■% R e s in on S u sp e n sio n E f f e c t . . . . . . . . . .
53
14.
C l3 6 S e l f T A b s o r p t i o n . ............................ .... ....................................
56
. . . .
ABSTRACT
In t h i s i n v e s t i g a t i o n , th e d i s t r i b u t i o n o f io n s in a Dowex-SG-Water
S ystem , was c o n s id e r e d . W ith in th e l i m i t s o f e x p e r im e n ta l e r r o r , th e
d a ta s u p p o r t th e ’’b o u n d -w a te r th e o ry " a s i t r e l a t e s to io n d i s t r i b u t i o n .
The a c t u a l d i s t r i b u t i o n o f C l a s d e te rm in e d w ith C l ^ was com pared
w ith th e a p p a r e n t d i s t r i b u t i o n a s d e te rm in e d p o t e n t i o m e t r i c a l l y w ith a
Ag1A g C l - r e f e r e n c e e l e c t r o d e p a i r . The d is c r e p a n c y (c o r r e s p o n d in g to
a s much a s 93 m i l l i v o l t s ) was a t t r i b u t e d to a l i q u i d . j u n c t i o n p o t e n t i a l
a t th e r e s i n - s a l t b r id g e i n t e r f a c e . The d a ta a r e shown to p r o v id e
q u a l i t a t i v e , and to some e x t e n t q u a n t i t a t i v e , s u p p o r t to a th e o ry p r o ­
p o se d by O v erb eek .
Any p o te n tio m e tr ic m easurem ent made i n an e x c h a n g e r-w a te r sy stem
and em ploying r e f e r e n c e e l e c t r o d e w ith s a l t b r id g e i s c o n s id e r e d to be
s u b j e c t to e r r o r from t h i s s o u r c e .
-8 -
INTRODUCTION
The c o n v e n ie n c e ' and a c c u ra c y o f th e e l e c t r o m e t r i c m ethod h as le d to
i t s w id e s p re a d u s e f o r d e te r m in a tio n o f pH o f aqueous s o l u t i o n s .
For th is
p u rp o s e , th e g la s s e l e c t r o d e i s commonly u s e d w ith a r e f e r e n c e calo m el
e le c tro d e .
The p o t e n t i a l d i f f e r e n c e b etw een t h i s e l e c t r o d e p a i r i s
r e l a t e d to th e pH by fh e e x p r e s s io n Eg l - Er e f = 0 .0 5 9 1 pH,
E le c tric a l
c o n t a c t b etw een th e c a lo m e l e l e c t r o d e and s o l u t i o n i s commonly made by
means o f a KCl s a l t b r id g e .
Inasm uch a s th e e q u i v a le n t c o n d u c ta n c e o f
K+ and C l" a r e n e a r l y th e same (76 vs 79 m ho), th e l i q u i d j u n c t i o n p o te n t
t i a l ( E j ) a t th e c a l o m e l - s o l u tio n i n t e r f a c e i s c o n s id e r e d to b e n e g l i g i b l y
s m a ll (< 2 m v .).
The o b s e rv e d p o t e n t i a l d i f f e r e n c e i s t h e r e f o r e c o n s id e r e d
to b e a r e l i a b l e q u a n t i t a t i v e m easu re o f th e pH o f th e s o l u t i o n .
The q u e s tio n o f a p p l i c a b i l i t y o f th e e l e c t r o m e t r i c m ethod to e x c h a n g e r-w a te r sy stem s h a s r e c e iv e d a t t e n t i o n i n r e c e n t y e a r s ,
A d iffe r­
en ce o f o p in io n s t i l l p e r s i s t s - r s o m e c o n te n d in g t h a t E 1 i n th e s e sy stem s
i s n e g l i g i b l y s m a ll a s i t i s in t r u e s o l u t i o n s —o th e r s c o n te n d in g t h a t
th e E j may be so l a r g e a s to c o m p le te ly i n v a l i d a t e th e d e te r m in a tio n .
i s s u e may be b r i e f l y o u t l i n e d a s f o llo w s :
The
I f th e pH o f an a l i q u o t o f
th e e q u i lib r i u m aqueous p h a s e o f an e x c h a n g e r i s d e te rm in e d e l e c t r o m e t r i c a l l y , i t i s commonly fou n d to d i f f e r from th e pH o f th e s l u r r y .
phenomenon h a s b een term ed th e " s u s p e n s io n e f f e c t " .
The
In m a g n itu d e , it 'm a y
ra n g e from z e ro to a s h ig h a s 4 pH u n i t s , d ep en d in g upon th e ty p e o f e x ­
c h a n g e r, e l e c t r o l y t e c o n te n t and o th e r c h e m ic a l p r o p e r t i e s o f th e sy stem .
W ith r e s p e c t to th e aqueous p h a s e , th e pH o f th e r e s i n may be low er ( p o s i ­
t i v e s u s p e n s io n e f f e c t ) o r may be h ig h e r ( n e g a tiv e s u s p e n s io n e f f e c t ) .
-9-
The o r i g i n a l , and s t i l l p o p u la r , e x p l a n a tio n f o r th e p o s i t i v e su sp en d
s io n e f f e c t a t t r i b u t e s th e low er pH o f th e r e s i n to th e e x i s t e n c e o f H+
io n "sw arm s" a t th e s u r f a c e o f th e p a r t i c l e s .
B eing c o n s tr a i n e d f r o m '
f r e e d i f f u s i o n th r o u g h o u t th e e n t i r e s y ste m by th e o p p o s ite ly ch a rg e d
exchange s i t e s , th e y a r e n e v e r t h e le s s c o n s id e r e d to be e f f e c t i v e i n i n ­
c r e a s i n g th e a c t i v i t y o f th e H+ io n n e a r th e p a r t i c l e s u r f a c e .
A g la s s
e l e c t r o d e p la c e d n e a r th e s u r f a c e o f th e p a r t i c l e a c c o r d in g ly i s exposed
t o s o l u t i o n o f low er pH.
•
■y
R e c e n tly , e v id e n c e h a s b een p u b lis h e d w hich i s i n t e r p r e t e d to mean
t h a t th e s u s p e n s io n e f f e c t may b e due to an e r r o r in h e r e n t i n th e e l e c t r o ­
m e tr ic m eth o d .
A c c o rd in g to t h i s v ie w p o in t, an a p p r e c ia b le Ej a r i s e s a t
th e c a lo m e l- s u s p e n s io n i n t e r f a c e upon b r in g i n g th e c a lo m e l i n c l o s e
p ro x im ity to th e c h a rg e d p a r t i c l e s .
Er e £ a c c o r d in g ly c a n n o t b e c o n s id e r e d
a c o n s t a n t and E g i - Er e f i s a c c o r d in g ly n o t a r e l i a b l e m easu re o f th e pH
i n e x c h a n g e r-w a te r s y s te m s .
As i s r e a d i l y a p p a r e n t, t h e .m a t t e r o f d e te rm in in g th e o r d e r o f
m a g n itu d e o f E j i s a c r u c i a l p ro b lem .
I f i t a c c o u n ts f o r a l l o f th e s u s ­
p e n s io n e f f e c t , i t may b e l a r g e enough i n so m e-sy stem s t o c o m p le te ly i n ­
v a l i d a t e any e l e c t r o m e t r i c m easurem ents r e q u i r i n g th e u s e o f a s a l t b r id g e .
I f E j i s low ( o f th e o r d e r o f m a g n itu d e o f s e v e r a l m i l l i v o l t s o r l e s s ) i t
w i l l n o t b e o b j e c t i o n a b l e i n m ost e l e c t r o m e t r i c d e t e r m in a tio n s .
m ary o b j e c t i v e s o f th e p r e s e n t i n v e s t i g a t i o n w ere to
d e te rm in e E j i n a p a r t i c u l a r sy ste m and
The p r i ­
(a ) q u a n t i t a t i v e l y
(b ) t o s tu d y th e e f f e c t o f
s e v e r a l c h e m ic a l p r o p e r t i e s o f th e s y ste m upon i t s m a g n itu d e .
LITERATURE REVIEW
The s u s p e n s io n e f f e c t was f i r s t r e p o r te d in d e p e n d e n tly by B r a d f ie ld
(9) and W iegner (28) i n 1931.
B r a d f ie ld o b s e rv e d t h a t th e p o te n tio m e tri* ?
.
c a I Iy m easu red pH o f a Hr -C la y s u s p e n s io n was a s much as 3 pH u n i t s low er
th a n th e pH o f th e e q u i lib r i u m s u p e r n a ta n t s o l u t i o n .
The s u s p e n s io n
e f f e c t was o b s e rv e d r e g a r d l e s s o f w h e th e r a g l a s s , a h y d ro g en o r a
q u in h y d ro n e e l e c t r o d e was u s e d ,
B r a d f ie ld s u g g e s te d t h a t th e c h e m ic a l p r o p e r t i e s o f th e H+-C la y w ere
s i m i l a r to th o s e o f a weak a c i d .
Inasm uch as th e n e g a t i v e l y c h a rg e d c la y
p a r t i c l e s s e t t l e d o u t , th e a s s o c i a t e d H+ io n s a l s o s e t t l e d o u t i n o r d e r
to m a in ta in e l e c t r i c a l n e u t r a l i t y th ro u g h o u t th e sy ste m .
The c l a y s , b e in g
weak a c i d s , a llo w e d some d i s s o c i a t i o n o f H+ io n s and e f f e c t i v e l y low ered
th e pH o f th e s u s p e n s io n .
The e x p l a n a ti o n by B r a d f ie ld was w id e ly a c c e p te d w ith l i t t l e m o d if i­
c a t i o n u n t i l a b o u t 1950.
D u rin g t h i s tim e i n t e r v a l , Ej was c o n s id e r e d to
b e n e g l i g i b l y s m a ll, as i t r e p o r t e d l y i s , i n t r u e s o l u t i o n s ( 1 9 ) .
Jen n y e t a l ,
I n 195.0,
( 20) p u b lis h e d e v id e n c e w h ich was i n t e r p r e t e d to mean t h a t
t h e s u s p e n s io n e f f e c t i s s o l e l y due t o E j .
They i n t e r p r e t e d t h e i r r e s u l t s
to mean t h a t th e m o b i l i t i e s o f K+ and C l" a r e changed ( in c r e a s e d and d e ­
c r e a s e d r e s p e c t i v e l y ) by t h e p r e s e n c e o f th e n e g a t iv e l y c h a rg e d ex ch an g er
p a rtic le s .
As. a r e s u l t , an a p p r e c ia b le d i f f u s i o n p o t e n t i a l a r o s e a t
th e s u s p e n s i o n - s a l t b r id g e i n t e r f a c e .
D avis (32) arid’ Du R e itz (33) hav e shown t h a t th e o b s e rv e d pH o f com par­
a b l e s u s p e n s io n s does n o t depend upon th e p o s i t i o n o f th e g l a s s e l e c t r o d e
b u t r a t h e r upon th e p o s i t i o n o f th e c a lo m e l e l e c t r o d e .
T h e ir o b s e r v a tio n s
-11-
a r e d e p ic te d i n F ig u r e I .
s e n t in v e s tig a tio n .
C o n firm a to ry o b s e r v a tio n s w ere made i n th e p r e ­
F o llo w in g th e p u b l i c a t i o n s o f D av is (3 2 ) and D ujR eijte
( 3 3 ) , how ev er, a c o n tr o v e r s y a r o s e r e g a r d in g , th e i n t e r p r e t a t i o n o f th e s e
o b s e r v a ti o n s .
(1 )
The i n t e r p r e t a t i o n o f Jen n y e t a l . a p p e a rs to be a s f o llo w s :
I f a g la s s - c a l o m e l e l e c t r o d e p a i r i s im m ersed i n th e s u p e r ­
n a t a n t l i q u i d a s i n ( a ) , th e Ej a t th e c a l o m e l - s o l u tio n i n t e r f a c e i s
n e g l i g i b l y s m a ll ,(<2 m i l l i v o l t ) and th e o b s e rv e d pH i s a v a l i d i n d i c a t i o n
o f th e ajj+ i n th e medium.
(2)
Em = 0 .
,
As shown i n ( c ) , th e ajj+ i n b o th p h a s e s i s e q u a l, assum ing t h a t
(Em,. th e membrane p o t e n t i a l , r e p r e s e n t s t h e p o t e n t i a l d if f e r e n c e
a c r o s s th e i n t e r f a c e b etw een s l u r r y and s u p e r n a ta n t s o l u t i o n .
(See Appen­
d ix page ..4 9 .)
(3)
I f Em = 0 th e n , a s shown i n ( d ) , am . Ej o f 240 m i l l i v o l t s a r i s e s
a t th e c a lo m e l- s u s p e n s io n i n t e r f a c e upon im m ersing th e c a lo m e l i n t o th e
s u s p e n s io n .
(4 )
The o b s e rv e d pH s h o u ld t h e r e f o r e depend o n ly upon th e p o s i t i o n ,
o f th e c a lo m e l e l e c t r o d e and i s u n a f f e c t e d by th e p o s i t i o n o f th e g la s s
e le c tro d e .
(f).
T h is i s shown to be t r u e by o b s e r v a tio n s ( a ) , (b )» (e ) and
A c c o rd in g to t h i s v ie w p o in t, th e o b s e rv e d EMF. f o r e a c h c e l l w ould
be g iv e n by th e f o llo w in g :
E(a ) =
- E°a l + 0 .0 5 9 1 lo g
E(W - EI l " Ec a l + 0 .0 5 9 1 lo g 4 +
E(o ) = Eg l ‘ 0 .0 5 9 1 lo g a^+ - E ° !
E(d ) “ Ec a l - Ec a l + Ej = Ej
+ Ej '
+ 0 .0 5 9 1 lo g a " +
= 0
-1 2 -
t
f
D.
O mv
240 mv
pH 2 .0
pH 6 .0
pH = 4 .0
Key;
|
Ui
240 mv.
I
e q u ilib r iu m s o l u t i o n
s u s p e n s io n ( c o l l o i d a l p a r t i c l e s )
F ig u r e I .
g la s s e l e c tr o d e
IiJ c a lo m e l e l e c tr o d e
E l e c tr o m e tr ic o b s e r v a tio n s made by D av is
-1 3 -
Il I
E(e ) = Eg l - Ec a l + 0 '0 5 9 1 lo g aH+
Il
lo g
E ( f ) = Eg l ’ Ec a l + 0 .0 5 9 1
aH+
If
III
aH+ = a H+ .
E r ik s s o n (17) and o th e r s have s u g g e s te d an a l t e r n a t i v e e x p la n a tio n o f
th e o b s e r v a tio n s d e p ic te d p r e v io u s l y . From th e Donnan (15) th e o r y , ( s e e
/
1A p pendix, p ag e 4 9 ) , one c a n o b ta in th e r e l a t i o n s h i p :
V
If
m
Em = 0.0591, lo g a H+ / a^+ .
I n c lu d in g t h i s te rm i n th e e x p r e s s io n s f o r . th e c e l l p o t e n t i a l s w here
n e c e s s a r y , we o b ta in f o r c e l l s a , b , c , d , e , and f th e f o llo w in g :
E(a )
eI i
" Ec a l
+ 0 .0 5 9 1 log. aH+
V )
E: i " Ec a l
+ 0 .0 5 9 1 lo g a " +
E (c)
=
E(d)
=
EBl - Eg l
+ 0 .0 5 9 1 lo g a^+ /
Ec a l “ Ec a l + Ej
E(e )
Eg l
" Ec a l
E( f )
Eg l
" Ec a l
+ Ej
- Em
+Em
III
+ 0 .0 5 9 1 lo g a H+
+ E.
, + 0 .0 5 9 1 lo g a^+
- Em
+Em
Now i f we- s u b s t i t u t e i n t o th e above e x p r e s s io n s th e v a lu e o f Em, and
m aking th e a ssu m p tio n th e E j = 0 w e'h av e:
E(a )
Eg l
- E°
cal
E (b)
= Egl
Ec a l
E(c )
= 0
E(d)
- Em
E(e )
= Eg l
E( f )
= Eg l
- Ec a l
“ Ec a l
+
0 .0 5 9 1 lo g a™+
+
0 .0 5 9 1 !o g
+
0 .0 5 9 1 lo g a H+
+
III
0 .0 5 9 1 lo g aH+
-14-
T h is tr e a tm e n t p r o v id e s an a l t e r n a t i v e e x p l a n a tio n f o r th e o b s e r v a tio n s
made by Jen n y e t a l . , D av is (32) and Du R e itz ( 3 3 ) .
They p o i n t o u t t h a t
th e o b s e r v a tio n s can be e x p la in e d s a t i s f a c t o r i l y by assu m in g t h a t Ej i s
n e g l i g i b l y s m a ll and Em c o r r e s p o n d in g ly l a r g e .
The o b s e r v a tio n s may be
e x p la in e d e q u a lly w e ll by th e e x i s t e n c e o f an Em o r a l t e r n a t i v e l y by th e
e x i s t e n c e o f an E 1.
I n 1952, M. P eech , G. H. B o lt and R. A. O lsen (27) r e p o r te d some
a n o m a lie s t h a t th e y a t t r i b u t e d to a l i q u i d ju n c tio n p o t e n t i a l b etw een
th e s a t u r a t e d KCl and c l a y s u s p e n s io n i n t e r f a c e .
They m easu red th e
membrane p o t e n t i a l o f s e v e r a l c la y s u s p e n s io n s by u s e o f two s a t u r a t e d
c a lo m e l e l e c t r o d e s u s in g th e Donnan (1 4 ) e q u i lib r i u m m ethod f o r m e a su rin g
io n a c t i v i t i e s i n s u s p e n s io n s . & Ec a ^ was g iv e n a p o s i t i v e s ig n when th e
e l e c t r o d e i n th e d i a l y z a t e was p o s i t i v e w ith r e s p e c t to th e e l e c t r o d e i n
s u s p e n s io n .
T h is i s i n a c c o rd a n c e f o r a membrane p o t e n t i a l o f a n e g a ­
t i v e l y c h a rg e d c o l l o i d .
A ^ ca r ="%n + E j.
The s ig n o f A E ^ ^ was found to b e p o s i t i v e f o r s u s p e n s io n s o f many
d i f f e r e n t c la y s s a t u r a t e d w ith H+ , Na+ and K+.
However, when c e r t a i n
c la y s w ere s a t u r a t e d w ith Ca"!"*", th e AEc a ^ was n e g a t iv e .
One p o s s i b l e e x ­
p l a n a t i o n s f o r t h i s o b s e r v a tio n w ould b e th e r e v e r s a l o f s ig n on th e col"?
I o id p a r t i c l e . ' T h is p o s s i b i l i t y was ch ec k ed in d e p e n d e n tly by z e t a p o te n ­
t i a l m e asu re m en ts.
I t was found t h a t th e s ig n o f th e c h a rg e on th e p a r ­
t i c l e s h ad n o t b e e n r e v e r s e d .
The r e v e r s a l o f s ig n was t h e r e f o r e a t t r i ­
b u te d to a n e g a t iv e Ej..
I n c o n ju n c tio n w ith th e above w ork, th e o sm o tic p r e s s u r e o f th e c la y
-1 5 -
s u s p e n s io n was d e te rm in e d by e x p e r im e n ta l m easurem ents and a l s o by
c a lc u la tio n .
The a c t i v i t i e s d e te rm in e d th e Dohnan m ethod w ere u se d i n
c a l c u l a t i n g o sm o tic p r e s s u r e , Tf , by th e e q u a tio n :
V = RT (Z + 2Y - 2X)
'
Z = Na+ c o n c e n tr a ti o n ( d i s s o c i a t e d from c la y )
Y = NaA s a l t c o n c e n tr a ti o n i s th e s u s p e n s io n
X = NaA c o n c e n tr a ti o n i n th e d i a l y z a t e .
T hese v a lu e s w ere c a l c u l a t e d from th e fo llo w in g r e l a t i o n t o A Ec a p
A Ec a l = RT In X
F
Y
=
F
RT In Z + Y
X
The o sm o tic p r e s s u r e t h a t was c a l c u l a t e d showed s e r io u s d e v i a t i o n from
th e o sm o tic p r e s s u r e t h a t was m e asu re d .
The d is c r e p a n c y was a t t r i b u t e d
to th e e r r o r in tr o d u c e d i n th e e x p e r im e n ta l e v a l u a ti o n o f Em, and th e
r e s u l t a n t e r r o r i n c a l c u l a t i o n o f o sm o tic p r e s s u r e .
I n 1953, O verbeek (26) p u b lis h e d a t h e o r e t i c a l tr e a tm e n t o f th e
s u s p e n s io n e f f e c t .
He c o n s id e r e d th e s u s p e n s io n e f f e c t and th e Donnan
p o t e n t i a l to be i d e n t i c a l and made up o f th e sum o f E j and Em.
A tte m p ts
a t s e p a r a t e l y e v a l u a ti n g Ej and E ^ w ere c o n s id e r e d to ,be u n s a t i s f a c t o r y
b e c a u se o f th e n e c e s s i t y o f a r b i t r a r y a s s u m p tio n s .
He showed t h a t th e
s u s p e n s io n e f f e c t ( r e f e r r e d to as Eq ) c a n be c a l c u l a t e d a p p ro x im a te ly
from th e c o m p o s itio n o f th e sy ste m by th e r e l a t i o n s h i p :
Eq =
RTi In c o n d u c ta n c e o f e x ch a n g er
F
c o n d u c ta n c e o f e q u i lib r i u m l i q u i d
O v e rb e e k 's tr e a tm e n t was t e s t e d e x p e r im e n ta lly by Bloksma ( 2 ) , u s in g
m o b i l i t i e s o f th e a d s o rb e d io n s .
He c o n c lu d e d t h a t th e ag ree m en t was
s u f f i c i e n t l y good to be c o n f ir m a tiv e .
—16"
R e c e n tly , Bower ( 5 ) ( 6) s tu d ie d th e s u s p e n s io n e f f e c t w ith a g la s s
e l e c t r o d e w hich i s s e l e c t i v e f o r Na+ .
b e e k ’s th e o r y .
Bower found good s u p p o r t f o r O v er-
He a l s o ch eck ed th e e f f e c t o f th e c o n c e n tr a ti o n o f th e
s a l t b r id g e on th e m a g n itu d e o f th e s u s p e n s io n h f f e c t .
I t was found
t h a t th e s u s p e n s io n e f f e c t became n e g l i g i b l e when th e c o n c e n tr a ti o n s
o f s a l t i n th e s a l t b r id g e and e q u i lib r i u m l i q u i d a r e th e sam e.
A t th e p r e s e n t tim e , t h e r e seems to b e , ju d g in g from th e p u b lis h e d
in f o r m a tio n , two s c h o o ls o f th o u g h t r e g a r d in g E j i n c o l l o i d a l s y ste m s.
I
One s c h o o l (24) i s a p p a r e n tly o f th e o p in io n th e Ej i s n e g l i g i b l e . The
o th e r ( 2 0 ) , i s a p p a r e n tly o f th e o p in io n th e Ej i s o f s u f f i c i e n t m agni­
tu d e to e n t i r e l y a c c o u n t f o r th e s u s p e n s io n e f f e c t .
In th is in v e s tig a ­
t i o n , an a tte m p t h a s b een made to o b ta in a m ore r e l i a b l e e s ti m a t e o f
E j th a n i s c u r r e n t l y a v a i l a b l e and th e re b y c o n t r i b u t e to o u r u n d e r ­
s ta n d in g o f th e s u s p e n s io n e f f e c t .
-17"
EXPERIMENTAL
C h a r a c t e r i s t i c S u s p e n sio n E f f e c t s o f S e le c te d Io n Exchange R e sin s
The i n i t i a l o b j e c t i v e was to s e l e c t an e x ch a n g er w h ich e x h i b ite d a
l a r g e s u s p e n s io n e f f je c t.
I t was r e a s o n e d t h a t i f th e e x ch a n g er
ex­
h i b i t e d o n ly a s m a ll s u s p e n s io n e f f e c t , th e a c c u ra c y w ith w hich Ej c o u ld
■ be m easu red w ould b e c o r r e s p o n d in g ly low .
So f a r a s i s knowny th e
l a r g e s t s u s p e n s io n e f f e c t r e p o r te d in th e l i t e r a t u r e i s th e v a lu e o f 4 pH
u n i t s r e p o r te d by Jen n y (20) f o r a Dow p r o d u c t c a l l e d lo n -X .
A c c o rd in g ly ,
s e v e r a l s y n t h e t i c c a t i o n and a n io n e x c h a n g e rs w ere s e l e c t e d f o r c o m p ari­
so n .
A ll r e s i n s w ere t r e a t e d i n th e f o llo w in g way:
(1 )
A sam ple o f a p p ro x im a te ly 20 g . was p la c e d i n a B uchner f u n n e l
under s u c tio n .
(2 )
C a tio n e x c h a n g e rs w ere w ashed w ith 0 .1 N HCl and th e a n io n e x ­
c h a n g e rs w ere w ashed w ith 0 .1 N NaOH.
(3 )
The r e s i n s w ere t r a n s f e r r e d to 500 m l. E rlen m ey e r f l a s k s and
w ere e q u i l i b r a t e d w ith e x c e ss a c id o r b a s e f o r one h a l f h o u r on a w r i s t
a c tio n sh a k e r.
(4 )
The sam p les w ere th e n w ashed i n th e B uchner f u n n e l w ith o u t s u c ­
t i o n u n t i l i n d i c a t o r p a p e r in d i c a t e d t h a t th e e f f l u e n t h ad become a p p r o x i­
m a te ly n e u t r a l .
P r i o r to th e d e te r m in a tio n o f th e s u s p e n s io n e f f e c t , t e n
m i l l i l i t e r s o f w a te r w ere added to a p p ro x im a te ly two gram s o f r e s i n .
The
f l a s k was sh a k e n p e r i o d i c a l l y f o r t h r e e h o u rs and th e n a llo w e d to s ta n d
over n ig h t.
The s u s p e n s io n e f f e c t was m easu red w ith a g l a s s e l e c t r o d e and
a s a t u r a t e d c a lo m e l e l e c t r o d e .
V a lu e s , o b ta in e d f o r th e s u s p e n s io n e f f e c t
-1 8 f o r th e v a r io u s r e s i n s , a r e shown i n T a b le I (p ag e 1 9 ) .
t e r i s t i c s a r e a l s o l i s t e d in th e t a b l e .
O th e r c h a r a c ­
T hese w i l l be d is c u s s e d l a t e r ,
As a r e s u l t o f th e f in d in g s h e r e , Dowex-50 was s e l e c t e d a s th e r e s i n to
be u se d i n th e i n v e s t i g a t i o n .
T h is p a r t i c u l a r r e s i n i s c h a r a c t e r i z e d by
th e fo llo w in g ; 8% c r o s s - l i n k a g e ; p a r t i c l e s i z e 100-200 m esh.
I n th e H+
form , i t was found to e x h i b i t a s u s p e n s io n e f f e c t o f a p p ro x im a te ly 3 pH
u n i t s ; w hich was b e l ie v e d s a t i s f a c t o r y f o r th e p u rp o s e s o f t h i s i n v e s t i ­
g a tio n .
A co m p ariso n o f th e s u s p e n s io n e f f e c t f o r a weak a c id and a
s tr o n g a c id and o f a weak b a s e and s tr o n g b a s e i s d e p ic te d in f ig u r e 2 .
A cid
0
Base
F ig u re 2:
C om parison o f th e S u sp e n sio n E f f e c t b etw een S tro n g A cid
and Base R e s in s and Weak A cid and B ase R e sin s
"19TABLE I
C h a r a c t e r i s t i c s o f Io n E xchange R e s in s
E x ch a n g ers
. Wet R e s in
C a p a c ity *
S u s p e n sio n E f f e c t .
A q u eo u s-R esin
A cid o r Base
S tr e n g th
C a tio n
Dowex-50
1 .7 meq/ml
3 .2 6 pH u n i t s
s tr o n g
Dowex-SOM
1 .7 meq/ml
2.6A pH u n i t s
s tr o n g
A m b e rlite IR -120
1 .9 meq/ml .
3 .0 5 pH u n i t s
s tr o n g
A m b e rlite IRC-SO
3 .5 meq/ml
0 .8 1 pH u n i t s
weak
0 .5 5 meq/ml
2 .8 8 pH u n i t s
D owex-I
•1^33 meq/ml
- 2 .7 9 pH u n i t s
s tr o n g
Dowex-2
1 .3 3 m eq/m l
- 2 .0 5 pH u n i t s
s tr o n g
IR -45
2 .0 0 meq/ml
- 0 . 7 0 , pH u n i t s
weak
!ER-400
1 .0 0 meq/ml
- 3 ,0 7 pH u n i t s
s tr o n g
IRr-410
1 .2 0 meq/ml
-2 .A 6 p H u n i t s
s tr o n g
D u o lite A-AO
I . AO meq/ml
- 3 .3 0 pH u n i t s
s tr o n g
D u o lite A2
1 .3 0 meq/ml
- 2 ,5 3 pH u n i t s
s tr o n g
Mixed bed
IR MB-3
A nion
.
*A11 ex ch an g e c a p a c i t i e s a r e r e p o r te d a s m i l l i e q u i v a l e n t s p e r m i l l i
l i t e r o f w et r e s i n , w ith th e c a t i o n e x c h a n g e r in th e H+ form ; th e a n io n
e x c h a n g e rs i n th e C l” form . F o r th e s u s p e n s io n e f f e c t , th e H+ and OH”
form s w ere u s e d .
-2 0 -
Io n D i s t r i b u t i o n i n a Dowex-50 - W ater System
A.
Donnan T heory v e r s u s "Bound W ater" T heory
In a r e c e n t l y p u b lis h e d t h e s i s , Moreno (34) h as c o n s id e r e d th e r e l a ­
t i v e m e r i ts o f th e Donnan th e o ry and o f th e "bound w a te r" th e o r y (15) f o r
d e s c r ib i n g io n d i s t r i b u t i o n i n an e x c h a n g e r-w a te r sy stem .
i s b a se d upon h i s tr e a tm e n t o f th e two t h e o r i e s .
The fo llo w in g
I n th e "bound w a te r"
th e o r y , i t i s p o s t u l a t e d t h a t a c e r t a i n volum e o f w a te r , V^ 1
-
is tig h tly
a d so rb e d a t th e s u r f a c e o f an ex c h a n g e r so t h a t i t does n o t f u n c tio n as
a s o lv e n t f o r an e l e c t r o l y t e .
By m aking t h i s a s s u m p tio n , one c a n form u­
l a t e th e fo llo w in g :
L e t X = am ount o f C l"
*
[ C l- - ) = c o n c e n tr a ti o n o f C l"
Vb , Vr j Vt = volum e o f bound w a te r , volum e o f re m a in d e r o f w a te r ,
and th e t o t a l volum e o f w a te r r e s p e c t i v e l y .
Then Xr
V[ =
Xt
Vt - Vb
:
. and m u ltip l y in g by Vt we o b ta in ,
^ tvt
_
Vt (Vt -Vb ) ™ v r
,
t h i s may a l s o be w r i t t e n a s f c l T . = (Vt -V^) [ c l \j
— ^
T hus, by k e e p in g Vt , Vr , Vb c o n s ta n t and v a r y in g Xt , we sh o u ld g e t
a p l o t o f Xt /Vt v e r s u s Xr /Vr a s a s t r a i g h t l i n e w hich p a s s e s th ro u g h th e .
o r i g i n and h as a s lo p e o f (Vt - Vb ) /V fc.
d e te rm in e d from th e s lo p e .
S in c e Vfc i s known, Vb can be
(S ee f i g u r e 3, p ag e 26 ) .
*C l was ch o se n b e c a u se i t can be a n a ly z e d f o r by p o t e n t i o m e t r i c ,
r a d i o m e t r i c , and v o lu m e tr ic m eth o d s.
-
If
th e
Dohnan
th e o r y
p r o v id e s
21 th e
m ost
s a tis fa c to ry -
■
tr e a tm e n t o f c h l o r i d e d i s t r i b u t i o n in ah e x c h a n g e r-w a te r sy ste m , th e n
t h e r e i s n o t a d e f i n i t e r e g io n i n w hich Cl™ i s e x c lu d e d , b u t r a t h e r an
e x p o n e n tia l r e l a t i o n s h i p b etw een th e e l e c t r i c a l p o t e n t i a l and Cl™.
A ppendix C, p ag e 4 9 ) .
(S ec
The n e a r e r one a p p ro a c h e s t h e ^ r e s i n s u r f a c e , th e
low er th e (^C lwJ becom es.
The one th e o ry r e q u i r e s a d i f f u s e d o u b le la y e r
th e o th e r a d i s t i n c t d o u b le la y e r .
i
,
A cc o rd in g to th e Donnan tr e a tm e n t f o r u n i - u n i v a l e n t e l e c t r o l y t e
a'
M+
x
=
a'
G l­
and a l s o
(a '
+
X
a"
M+
x a"
C l"
,
(1)
a' . ) (a' )
Cl
C l"
( 2)
(ac i - y
Where a" i s th e a c t i v i t y o f an io n i n th e s u p e r n a ta n t and a ' r e f e r s to th e
s l u r r y and w here a x i s th e a c t i v i t y o f th e a d so rb e d c a t i o n .
T h a t th e
t o t a l c h l o r i d e in th e sy ste m e q u a ls th e sum o f th e c h l o r i d e i n th e p a r t s
re q u ire s th a t,
Xt
= LCl"l'
v'
[c r j.
M t
(3 )
£ c i ~ ] " V"
V'
+ qf
crl
"
(4)
S in c e V1
y' [c r n
Vt
and
[C l" ] ’
' _ fc i" I .
L
=
[cl^ l'
-
- F c r l " V"
Vfc
[ c l" ] " V"
^
• = Fc l I t v t
-
(vt - v")
[C l']-" '7"
Vt
(V ^ V nT
(5 )
-2 2 ”
A c c o rd in g to (2 )
( a ^ - X a ^ .) + ( a ^ J 2 = (a ^ . ) 2
(» 6 i - ) 2 ♦ (= C l-) ( V
and
(%a x
+
a C l- ) 2
th u s
(%a x
+
= S i-)"
and
+ 4=x
=
=
( = S l- ) 2
(7 )
( 8)
( = S i- ) 2 + « = * ) 2
+
(9 )
%(=x) 2
( 10)
( = S i- ) 2 + K = x ) 2
( a " ) 2 + %(a ) 2 - %a
Cl
x
x
( = c i- ) =
( 11)
I f we assum e t h a t a ^ „ = C l" ' th e n we e q u a te (11) and ( 6) .
( a C l- ) 2
+
X ax>2 - %ax =
[ C l - J t Vfc -
|c iJ " V "
(Vt - V")
Ca"
(
r
+
- %a
Cag1- ) 2 + %(axr
f 31" ! = (
+
"V"
Ji
(Vt - V")
- %ax)(V t - V")
+
(13)
P 1"]
V")
C l- InV"
fi t t
( aC i- ) 2 + %(*x ) 2 “ %&J >(y t ~ vM) + Lc l ~ l "V"
(
( aC I- ) 2 + t ( a , ) 2 - %ax)(V fc - V")
WJ'
F
V"
(14)
(15)
(16)
T
As shown by e q u a tio n (16) one w ould n o t e x p e c t a l i n e a r r e l a t i o n s h i p b e ­
tw een [ C l J t and [ c r j "
i f th e Donnan th e o r y i s a p p l i c a b l e to th e sy stem . ■
To ch e c k th e a p p l i c a b i l i t y o f th e s e two th e o r i e s to c h l o r i d e d i s t r i ­
b u ti o n i n a Dowex r e s i n - w a t e r sy ste m , a s e r i e s o f sam ples w ere e q u i l i ­
b r a te d f o r tw e n ty -f o u r h o u r s , w ith c o n c e n tr a ti o n o f H C l^ b e in g th e in d e ­
pendent v a ria b le .
A one m i l l i l i t e r sam ple o f th e s u p e r n a ta n t s o l u t i o n was
p i p e t t e d o u t, n e u t r a l i z e d w ith sodium h y d ro x id e , e v a p o ra te d to d ry n e s s and
-23-
c o u n te d w ith a G e ig e r-M u e lle r c o u n te r .
S o lu tio n s o f e q u a l volum es o f w a te r
and e q u a l am ounts o f c h l o r i d e b u t w ith no r e s i n w ere p r e p a r e d f o r eac h
c o n c e n tr a ti o n and c o u n te d i n th e same m anner.
The fo rm er m easurem ents
w ere u se d a s a m easu re o f (X "/V ") and th e l a t t e r a s (XfcZVfc) .
th e s e two v a lu e s was th e n made; ( s e e f i g u r e 3 , p a g e £ 6 ) .
A p lo t of
The l i n e a r i t y
o b s e rv e d betw een (X11ZVm) and (XfcZVfc) i s c o n s id e r e d to c o n s t i t u t e e v id e n c e
o f th e a p p l i c a b i l i t y o f th e "bound w a te r" th e o r y .
A n o th er s u p p o r tin g p ie c e o f e v id e n c e f o r th e "bound w a te r" th e o ry
was p u b lis h e d r e c e n t l y by A nderson and Low ( I ) .
T h e ir s t u d i e s d e a l w ith
th e d e n s it y o f w a te r n e a r th e s u r f a c e o f c la y p a r t i c l e s .
They found t h a t
w ith i n 10£ o f th e s u r f a c e o f a c la y p a r t i c l e t h a t th e d e n s it y d e c re a s e d
c o n tin u o u s ly .
The d e n s i t i e s a p p ro ac h ed 0 .9 7 gZcc. a s a lo w er l i m i t .
T h is
w ould s u g g e s t t h a t th e w a te r m o le c u le s a r e ta k in g on some ty p e o f o rd e re d
a rra n g e m e n t p resu m ab ly s i m i l a r to w a te r o f h y d r a tio n .
w a te r w ould p ro b a b ly c e a s e t o f u n c ti o n a s a s o lv e n t .
T h is volum e o f
The p r e s e n t i n ­
v e s t i g a t o r s f e e l t h a t t h i s i s th e same volum e ele m e n t t h a t i s o cc u p ie d by
th e "bound w a te r " .
-24-
TABLE I I a
Bound W ater D ata
•• \
Sample
W eight
Volume
o f H C l 36 .
Volume
o f H2O
T o ta l
Volume
•la
1.0000 g.
5 m l.
' 5 m l.
10 m l.
lb
0 .9 9 9 9 g.
5 m l.
5 m l.
10 m l.
5 m l..
5 m l.
10 ml.
b la n k
-
2a
0 .9 9 9 6 g.
4 m l.
6 m l.
10 m l.
2b
1.0 0 0 3 g . .
4 m l.
6 m l.
10 m l."
4 m l.
6 m l.
10 m l.
b la n k
3a
1.0001 g.
2 m l.
8 m l.
10 m l.
3b
0 .9 9 9 9 g.
2 m l.
8 m l.
10 m l.
2 m l.
8 m l.
10 m l.
b la n k
4a
0 .9 9 9 7 g.
I m l.
9 m l.
10 m l.
4b
0 .9 9 9 7 g.
I m l.
9 m l.
10 m l.
I m l.
9 m l.
10 m l.
b la n k
-5a*
*
1 .0000 g .
.5 m l.
5 m l.
10 m l.
5b
1.0000 g.
5 m l.
5 m l.
10 m l.
5 m l.
5 m l.
10 m l.
b la n k
Of:
*The HCl
u se d i n th e f i r s t f o u r sam p les was a 0 .0 0 7 6 9 N s o lu ti o n
w h ereas th e H C l^ u se d f o r th e l a s t sam ple was a t e n f o l d d i l u t i o n o f
th i s a c id .
z
I
-2 5 TABLE I I b
I
"Bound W ater" D ata ( c o u n tin g d a ta from C l ^ )
Xt Zvt ,
c o u n ts Zmin.
meqZml. x 1(H
Xr Zvr
c o u n t s Zmin.
Xr Zv
, meqZmin
XH
Xt Zvt
Sam ple
la
13,677
4 .1 0
lb
13,6 7 4
4 .1 1
2a
10,848
3 .3 5
2b
10,615
3 .2 8
3a
5 ,8 6 5
1 .7 8
3b
5,719
1 .7 4
4a
2,719
0 .8 3
4b
2 ,5 8 4
0 .7 8
5a
1,4 5 2
0 .4 4
5b
1,4 3 2
0 .4 3
b la n k
b la n k
b la n k
b la n k
b la n k
12,795
3 .8 4
9 ,9 6 7
3 .0 8
5 ,0 8 4
1 .5 4
2,-529
0 .7 7
1 ,3 4 5
0 .4 0
A l l c o u n ts a r e c o r r e c t e d f o r b ack g ro u n d .
Sam ple c a l c u l a t i o n :
Xr ZVr = 13,667 £
m in
Xt ZVt = 5 .x 0.00769Z10 = 0 .0 0384 meqZml
x 0 .3 0 0 1 meq min
" m l c o u n ts
x ' 1 0 =
C a l c u la t io n s f o r V^ from th e s lo p e i n f i g u r e 3
= 0 .9 2 7 =
— k \and Vt = 10 m l.
s o lv in g f o r V^
Vb = 0 .7 3 m l.
0 .0 0 4 1 meqZml;
x 10
-26-
C
I
2
3
x 10
F ig u r e 3:
+3
Bound W ater T heory
4
-27
D is trib u tio n of C
6 i n a Dowex-50 - W ater System .
The o b j e c t i v e o f t h i s s e c t i o n was to d e te rm in e th e a c t u a l d i s t r i ­
b u ti o n o f C l" i n th e r e s i n - w a t e r sy ste m .
The v a lu e s o b ta in e d a r e l a t e r
com pared w ith th e a p p a r e n t d i s t r i b u t i o n o f C l" a s d e te rm in e d p o t e n t i o m e tric a lly .
Any d is c r e p a n c y b etw een th e a p p a r e n t and a c t u a l d i s t r i b u ­
t i o n w i l l be a t t r i b u t e d to an Ej a t th e c a l o m e l - r e s i n i n t e r f a c e .
The r e s i n - w a t e r sy ste m i s d iv id e d i n t o th r e e a r b i t r a r y d i v i s i o n s
w hich w i l l be r e f e r r e d to a s p h a s e s .
s o lu tio n .
P h a s e 1" r e f e r s to th e e q u ilib r iu m
P h ase" r e f e r s to th e i n t e r s t i t i a l s o l u t i o n , i . e . ,
t i o n b etw een th e p a r t i c l e s .
th e s o l u ­
P h a s e 1 r e f e r s to th e s o l u t i o n i n th e i n ­
t e r i o r o f th e r e s i n p a r t i c l e s .
H+ r e s i n sam p les w ere e q u i l i b r a t e d w ith a l i q u o t s o f d i l u t e HCl
,tag g ed w ith C l ^ .
A f te r e q u ilib r iu m was a t t a i n e d , th e t h r e e p h a se s
w ere p h y s i c a l l y s e p a r a t e d u s in g th e te c h n iq u e s u g g e s te d by G re g o re t a l.
(18) as s t a t e d i n A ppendix D, page 5 1 .
The c o n c e n tr a ti o n o f C l"
i n th e t h r e e p h a s e s was d e te rm in e d by means o f s ta n d a r d c o u n tin g te c h ­
n iq u e s .
R e s u lts o b ta in e d f o r a s e r i e s o f 1.0 0 0 gram sam p les a r e l i s t ­
ed i n T a b le I I I .
The mean v a lu e o b ta in e d f o r J jC l" ] " ' / [ c l^ ] " was 1 .3 2 and 1 .3 4 f o r
th e 1.0000 gm. and 2 .0 0 0 0 gm. sam p les r e s p e c t i v e l y .
The c o rre s p o n d in g
v a lu e s o f [ c l 3 " ' [ 7 c l 3 ' w ere 6 .7 and 6 .4 .
An a tte m p t was made to d o u b le ch eck th e s e v a lu e s in th e fo llo w in g
way:
u s in g a lambda p i p e t t e and c o v e r in g th e t i p w ith a t i s s u e (sw ip e)
w hich was im perm eable to th e r e s i n p a r t i c l e s , a sam ple o f p h a s e ’"
w ith d raw n from t h r e e d i f f e r e n t sa m p le s.
was
P h a s e " 1 was e x t r a c t e d w ith a
-28-
p ip e tte .
[ C l ] '"
T h ese w ere c o u n te d and th e r a t i o s com pared.
The mean v a lu e f o r
/ [ C l ] " was 1 .1 7 , i n d i c a t i n g a r e l a t i v e l y s m a ll d i f f e r e n c e i n c h l o ­
r i d e c o n c e n tr a ti o n betw een th e s e two p h a s e s .
W hether o r n o t th e la c k o f
ag ree m en t ( 1 .3 2 and 1 .3 4 v s 1 .1 7 ) i s a t t r i b u t a b l e to e x p e r im e n ta l e r r o r
i s n o t known.
A cc o rd in g to th e "bound w a te r" th e o r y , c h l o r i d e i s e x c lu d e d from th e
"bound
w a te r "
a t th e p a r t i c l e s u r f a c e ; th e [ c l" " ] th ro u g h o u t th e r e ­
m a in d er o f th e sy ste m i s c o n s t a n t .
I f we now th in k o f t h i s d i s t r i b u t i o n
a p p lie d to th e sy ste m d e p ic te d i n A ppendix B, page 4 9 , th e n i t would
seem a s tho u g h
'
= I C l" ] "
= ^ C l f l ' p ro v id e d p h a s e " and p h a s e '
a r e c o r r e c t e d f o r th e lo s s o f s o lv e n t to "bound w a te r " .
We have s e e n t h a t
[c l]
T h e r e f o re one
_ | ] l ] N " a c c o r d in g to th e r a d io m e tr i c d a ta .
m ig h t e x p e c t th e "bound w a te r " to a f f e c t th e amount o f w a te r a v a i la b l e , as
s o l v e n t i n p h a s e ' to th e g r e a t e s t e x t e n t .
'A c o r r e c t i o n c a n be made f o r
th e volum e o f w a te r a c t i n g a s a s o lv e n t f o r C l" i n p h a s e 1 i f we assum e a l l
th e "bound w a te r" volum e, V^, to b e c o n ta in e d i n t h i s p h a s e .
[ c l]
The a c t u a l
1 w ould be c a l c u l a t e d by s u b t r a c t i n g V^, a s d e te rm in e d from f i g u r e
3, p a g e f r o m
th e t o t a l volum e o f. p h a s e 1.
A c tu a l [ c l ]
1
=
a p p a r e n t f c l~ J ] 1 x volum e o f phase*
volum e o f p h ase" - V j 3. ,
U sing th e v a lu e s from T a b le I I I th e a c t u a l [ c l ] 1 was c a l c u l a t e d f o r
ea c h sam ple.
T hese v a lu e s a r e l i s t e d i n T a b le IV a lo n g w ith th e co n ce n ­
t r a t i o n s f o r p h a s e 1" .
S t a t i s t i c a l tr e a tm e n t o f th e d a ta i n d i c a t e s no
s i g n i f i c a n t d i f f e r e n c e a t th e 5% l e v e l b etw een ^ C l ] '"
when c o r r e c t e d f o r "bound w a te r " .
and j j l l " ] '
The r e s u l t s , t h e r e f o r e , p ro v id e
-2 9 -
s u p p o r tin g e v id e n c e f o r th e a p p l i c a b i l i t y o f th e bound w a te r th e o ry to th e
r e s i n - w a t e r sy stem u n d e r c o n s i d e r a t i o n .
S tu d y o f a^.+ By E s te r H y d ro ly s is R a te s
The r a t e o f h y d r o ly s is o f an e s t e r i s r e p o r t e d l y a f u n c tio n o f th e
a ^ + in th e medium ( 2 2 ) .
P resu m ab ly th e m easu red r a t e o f h y d r o ly s is o f
an e s t e r c o u ld t h e r e f o r e be u se d to d e te rm in e a^,+.
The p u rp o s e o f th e
s tu d y r e p o r te d h e r e was to d e te rm in e a^+ i n Dowex-50 r e s i n i n t h i s way.
The v a lu e o b ta in e d c o u ld th e n be com pared w ith th e a p p a r e n t a + a s d e t e r H
X
m ined p o t e n t i o m e t r i c a l l y . Any d is c r e p a n c y c o u ld be a t t r i b u t e d to th e E .
•
J
in v o lv e d i n th e pH d e te r m in a tio n .
W ith t h i s o b j e c t i v e i n m ind, a s e r i e s o f h y d r o c h lo r ic a c id s o l u t i o n s
o f v a r y in g pH w ere u se d to s tu d y th e r e l a t i o n betw een pH and r a t e o f h y ­
d ro ly s is .
F o r a m ore d e t a i l e d a c c o u n t o f th e e x p e r im e n ta l p ro c e d u re se e
A ppendix D, pag e 57.
page 30.
The r e s u l t s from t h i s s tu d y a r e p l o t t e d i n f i g u r e 4 ,
R e s in sam p les w ere e q u i l i b r a t e d w ith enough w a te r to make th e
volum es o f th e s o l u t i o n s c o m p arab le.
th e s e sam ples was m e asu re d .
Then th e r a t e o f h y d r o ly s is f o r
The t r i a n g u l a r p o i n t on th e g ra p h i n f i g u r e
4 shows th e r e s t i l t s , o f th e s e d e te r m in a tio n s .
A second s e t o f d e te rm in a ­
ti o n s was made u s in g HCl s o l u t i o n s and Dowex-50 o f co m p arab le e q u iv a le n ts
o f H+ p e r u n i t volum e o f s o l u t i o n .
T hese d e te r m in a tio n s in d i c a t e d t h a t
th e H+ r e s i n was s l i g h t l y more e f f e c t i v e th a n HCl c o n t a in in g e q u a l
p e r u n i t volum e i n c a t a l y z i n g th e h y d r o ly s is r e a c t i o n .
l i s t e d v i n T a b le V, page 32.
meq H+
The r e s u l t s a r e
From th e s e o b s e r v a tio n s i t seems a s th o u g h th e
r a t e o f h y d r o ly s is i s in f lu e n c e d by o th e r f a c t o r s , p o s s i b ly th e a b s o r p tio n
o f th e e s t e r by th e r e s i n .
I t was c o n c lu d e d t h a t . t h e r a t e b f . h y d r o ly s is
-3 0 -
c o u Id n o t be u se d ps a r e l i a b l e m easu re o f a ^ + in th e r e s i n - w a t e r sy stem .
The r e s u l t s o f M cA u liffe and Coleman (22) a l s o h e lp s u b s t a n t i a t e t h i s c o n ­
pH u n i t s
c lu sio n .
R esin
R ate (m eq/m in) x 10*
F ig u r e 4:
H y d ro ly s is o f M e th y l- a c e ta te
H+ c a ta ly z e d
-3 1 -.
TABLE I I I
D is trib u tio n of C l^
.
Sam ple
W eight
(gram s)
la
1.0002
c/m in
(C orr« f o r B ,G .)
c /m in /m l
1260
810
132
1219
853
180
1352
914
184
1269
857
165
1305
851
174
1260
900
152
1219
948
206
1352
1013
212
1269
956
190
1305
946
201
7 .8 4
5 .6 0
0 .9 5
7 .5 8
5 .9 0
1 .2 8
8 .4 3
6 .3 0
1 .3 3
7 .8 0
5 .8 7
1.1 7
8 ; 02
5 .8 3
1 .2 3
1123
6 .9 9
1410
1085
211
1350
1060
225
1341
978
216
1401
1021
204
1392
1063
211
1419
993
230
8 .3 4
6 .4 3
1 .2 6
8 .0 0
6 .2 8
1.3 3
7 .9 2
5 .7 8
1 .2 8 ,
8 .1 2
5 .9 0
1 .1 8
8 .0 6
6 .1 7
1.22
8 .2 1
5 .7 5
1 .3 3
B lank f o r sam ples l"i3
1188
6 .9 9
B lank f o r sam p les 4 -6
1207
6 .9 9
P h ase
Ift
It
I
1.0006
2a
I I I
rt
■ I
3a
■
M
1
. 0
0
0
I
0
Tl
I ‘
4a
1.0003
I Il
'
, If
I
5a
1 .0 0 0 4
I I
I
M
I
B lank
2 .0011
lb
I 11
ft
I
2.0 0 0 6
2b
f I I
M
I
3b
2.0001
-
‘
T ft
Il
I
4b
'
2 .0 0 0 4
I I
I
If
I
5b
2.0001
I I I
ft
I
6b
2 .0 0 0 3
M
l 1
Il
I
1410
1846
367
1350
1808
391
1341
1679
376
1401
1787
355
1392
1809
367
1419
1688
400
C o n c e n tr a tio n
meq/ml x IO^
-32-
TABLE IV
C o n c e n tr a tio n o f
C l'
C o r r e c te d f o r "Bound W ater"
[crj
Sample
x IO4 i n p h a s e '"
as d e te rm in e d from
Cl^G d a ta
[ C l - ] ' x 10^ in p h a s e 1 a s
c a l c u l a t e d by c o r r e c t i n g
f o r "bound w a te r"
la
7 .8 4 meq/ml
5 .9 0 meq/ml
2a
7 .5 8
7 .9 5
3a
8 .4 3
8 .2 6
4a
7 .8 0
7 .3 0
5a
8 .0 2
7 .7 7
8 .3 4
7 .8 4
2b
8 .0 0
8 .2 6
3b
7 .9 2
7 .9 7
4b
8 .1 2
7 .3 4
5b
8 .0 6
7 .5 9
6b
8 .2 1
8 .2 6
mean
7 .9 0 *
7 .6 8 *
lb
. '
*No s i g n i f i c a n t d i f f e r e n c e a t 5% l e v e l .
TABLE
V
-
C o m p arativ e R a te s o f E s te r H y d ro ly s is
of
E q u iv a le n t am ounts o f H* P er U n it Volume
HCl
Dowex-50
1 .0 2 8 x lO '^rneq/m in.
1.263 x IC ^ rn e q /m in .
1.1 1 3 x 10"^m eq/m in.
1.2 3 3 x IO- ^meqZmin.
*
--33-
P o te n t io m e tr ic D e te r m in a tio n i n E x ch an g er-W ater System
t
Some o f th e c e l l s to be c o n s id e r e d i n t h i s s e c t i o n a r e d e p ic te d below
C e ll #1.
g la s s e l .
/ H C l ^ / K C l ^ ^ ^ H g 2C l2 , Hg
C e ll #2.
g la s s e l .
/H C l^
C e ll #3.
Ag, AgCI / H G I / /NH4NO3 (10% )//K C I ( s a t . ) A g C l ( s a t . ) / AgCI , Ag
C e ll #4.
Ag, AgCI/H G I^
and r e s i n / / K C l ( s a t . ) / Hg2C lg , Hg
and r e s i n / /NH^NO^CIO?.) / /K C l ( s a t .) A g C l( s a t.) / /
AgCI , Ag
C e ll #5.
/
Hg, H g g C lg /K C lC sa t.)/ / H C l ^ / HCl and r e s i n / / K C l ( s a t . ) /
/
Hg2C l2 , Hg
See f i g u r e I . D, page 12.
/
C e l l # 6 . g l a s s e l./H C l( m ) / H C l(m ), r e s i n / g l a s s e l .
J
-
See f i g u r e I . C, p a g e ,12. Where / / i n d i c a t e s a l i q u i d j u n c t i o n ,
/
‘.
and / i n d i c a t e s a membrane o r o th e r m e c h a n ic a l means o f s e p a r a t i o n . The
/
p o t e n t i a l s o f th e c e l l s , a s d e p i c te d , w i l l b e r e f e r r e d to a s E^.
\
E2 , Eg e t c . T hese p o t e n t i a l s may b e e x p r e s s e d by th e f o llo w in g ;
E1 = E°1 - e C=I - e JX1KCD - ° - 0591 l ° s ='%
E2 - EgX ' Ec a l - e JCKCD ' ° - 0591 loE
'll.
E3 = EAg9AgCl
“ Er e f ‘ Ej (NH4NO3)
E- = E.
4 "A g,AgCI
“re f
EL = E
E
6
, + E "'
- E"
^j(NH4NO3)
- E__! + E'!
= E0 1 - 0 .0 5 9 1 lo g a '
gi .
I
+ 0 .0 5 9 1 lo g a ^ .
+ 0 .0 5 9 1 lo g a 1'
Cl
* E„
Et 1 + 0 .0 5 9 1 lo g a"+ - E11
S
As r e p o r te d i n m o st p h y s ic a l c h e m is tr y t e x t s , Ej a t a r e f e r e n c e
- 34-
e l e c tr o d e - s o l u t i o n i n t e r f a c e i s n e g l ig ib l y , s m a ll ( x ( 2 m i l l i v o l t s ) .
cause of t h i s ,
and E j ^nh
Be­
^ w i l l be n e g le c te d and we s h a l l r e ­
f e r to EY a s E 1.
J
j
The s u s p e n s io n e f f e c t , i s d e f in e d by th e d if f e r e n c e betw een E1 and
Eg.
E1 - Eg = E j(K c l) “ 0 .0 5 9 1 lo g a ”^ / a " + .
Now i f th e
. e J(NH4NO3) , Ej(KQ1) ' th e n El , " E2 = E3 ‘ E4 ‘
E3 " E4 = e J(NH4NO3) * 0 .0 5 9 1 lo g a ^ „
E5 r e p r e s e n t s
/ a^ .
Efia l = Ej (KQ1) + Em
E , = -0 .0 5 9 1 lo g - a " - E
6
H+
m
I f a " ' x a M _ = a " , x a" _ , a s e x p e c te d from t h e iDonnan th e o ry (14) and
H+
Cl
HT
Cl
s i n c e , Em = 0 .0 5 9 1 lo g a^'+ = 0 .0 5 9 1 lo g a j ^ _ / a ^ _ , th e . above e x p r e s s io n s
become
e I " e 2 “ e J(K C I) + Em
E3 " E4 = e J(NH4NO3) * Em
E5 = e J(K C I) + Em
E6 = 0
The e x i s t i n g l i t e r a t u r e i n d i c a t e s t h a t t h e r e a r e two s c h o o ls o f
th o u g h t on th e e x p la n a tio n o f th e s u s p e n s io n e f f e c t .
One s c h o o l i s o f
th e o p in io n t h a t Ej i s n e g l i g i b l y s m a ll ( ^ 2 m v.) ( 4 ) ( 2 3 ) ( 2 4 ) ( 2 5 ) and
th e o th e r i s o f th e o p in io n t h a t Ej may be la r g e enough to. c o n s t i t u t e a
s e r i o u s e r r o r ( a s g r e a t a s 240 m v.) ( 2 ) ( 3 ) ( 5 ) ( 6 ) ( 2 6 ) ( 2 7 ) .
Some f e e l
t h a t Ej a c c o u n ts f o r th e e n t i r e s u s p e n s io n e f f e c t ( 2 0 ) .
I n t h i s s e c t i o n o f th e t h e s i s , i t was p ro p o se d t h a t th e s i z e o f Ej
=35-
b e q u a n t i t a t i v e l y d e te rm in e d f o r Dowex-50 - w a te r s y s te m s .
To do t h i s , '
a s p r e v io u s l y m e n tio n e d , we h av e s t u d i e d th e d i s t r i b u t i o n o f HCl-30
th ro u g h o u t th e s y ste m by two in d e p e n d e n t m eans.
The a c t u a l d i s t r i b u t i o n
i s c o n s id e r e d t o b e th e d i s t r i b u t i o n a s d e te rm in e d by C l* ^ .
The p o t e n t i -
o m e tric m easurem ents a r e ta k e n a s m easu res o f th e a p p a r e n t d i s t r i b u t i o n .
The d i f f e r e n c e b etw een th e a p p a r e n t and th e a c t u a l d i s t r i b u t i o n makes
p o s s ib le a c a lc u la tio n o f Ej.
I n o r d e r to c o n s id e r th e r a d i o l o g i c a l
d a ta as th e a c t u a l d i s t r i b u t i o n , th e a s s u m p tio n i s made t h a t th e a c t i v i t y
c o e f f i c i e n t f o r C l" i s th e same i n a l l p h a s e s .
The a ssu m p tio n t h a t th e
a c t i v i t y c o e f f i c i e n t o f th e a d so rb e d c a t i o n and t h a t o f th e c a t i o n i n
s o l u t i o n w ere th e same h a s p r e v io u s l y b e e n s u g g e s te d a s b e in g v a l i d (13)
' '. i
( 3 ) . The a s s u m p tio n made f o r th e C l a c t i v i t y c o e f f i c i e n t s i s e q u a lly
re a s o n a b le .
The a ss u m p tio n t h a t th e r a d i o l o g i c a l d a ta r e p r e s e n t s th e
a c t u a l d i s t r i b u t i o n e n a b le s u s to c a l c u l a t e a v a lu e f o r Em.
The a s s u m p tio n o f a c t i v i t y c o e f f i c i e n t o f C l
b e in g th e same i n a l l
p h a s e s means t h a t th e a c t i v i t y c o e f f i c i e n t i s one f o r d i l u t e s o l u t i o n s ,
i . e , i n th e o r d e r o f 10“% .
T h is a ss u m p tio n a p p e a rs to b e c o n s i s t e n t
w ith th e "bound w a te r " th e o r y .
th e n
Q c r ] ,M
[C l-]
=
ac l - .
th e n
=
^C l ]
"
I f th e "bound w a te r" d i s t r i b u t i o n h o ld s ,
= Q C l ^ J 1.
T h e r e f o re a'** - . = a ^
=
i f th e s o l u t i o n s a r e d i l u t e , th e n
= a^«
and s i n c e a g ^ - = )f„ ^ p l ] j
&V.
U sing th e above e x p r e s s io n g iv e n f o r Em, th e s e a s s u m p tio n s i n d i c a t e
I
t h a t Em = 0 ,
From th e r a d i o l o g i c a l d a t a i t i s s e e n t h a t Em a s c a l c u l a t e d
h as a maximum v a lu e o f a p p ro x im a te ly 7 m i l l i v o l t s .
-3 6 O v erb eek 1s T re a tm e n t (26)
O verbeek t h e o r e t i c a l l y t r e a t e d th e fo llo w in g c e l l ;
I
II
/
III
Hg, HggClg / K C l(s a t) / e q u ilib r iu m s o l u t i o n / c o l l o i d s l u r r y /
/ 2
K C L (sat) / HggCIg, Hg.
The e .m .f . , E, o f th e c e l l i s g iv e n by
-EF =
d^ i
(17)
By m a n ip u la tio n o f t h i s e q u a tio n i n o r d e r to a v o id s i n g l e io n a c t i v i t i e s
and in c lu d in g th e membrane p o t e n t i a l , O verbeek o b ta in e d th e e q u a tio n
E =
S
i C -->■
ti
4£i
Zl
+ ^ r 11- zY r 111
f
^
V:______ R______ V
V
B
i
(18)
J
■~v
C
E q u a tio n (18) now in c lu d e s
E = Ej ( l )
+ E ^(2 ) + R j ( 3 ) ’ an<^ a s shown by O v erb eek 1 th e p o t e n t i a l
may b e e x p re s s e d a p p ro x im a te ly by th e fo llo w in g e q u a tio n :
E_ = RT In c o n d u c ta n c e o f s u s p e n s io n
S
—
c o ----------------------------------------n d u c ta n c e o f e q u i lib r i u m s o l u t i o n
(19)
T a b le I p ro v id e s some i n t e r e s t i n g f a c t s th a t,s h o w m e r i t i n e q u a tio n
(1 9 ).
The s tr o n g a c i d e x c h a n g e rs hav e a muph g r e a t e r s u s p e n s io n e f f e c t
th a n weak a c i d e x c h a n g e rs .
The s tr o n g b a s e ex c h a n g e rs hav e a much g r e a t e r
n e g a tiv e s u s p e n s io n e f f e c t th a n th e weak b a s e e x c h a n g e rs .
T h is i s as
e x p e c te d a c c o r d in g to e q u a tio n ( 1 9 ) , s i n c e th e c o n d u c ta n c e o f th e d o u b le
la y e r o f a s tr o n g a c id o r b a s e e x ch a n g er is. much g r e a t e r th a n t h a t o f
th e weak a c id o r b a s e ex c h a n g e r ( s e e T a b le I , page 19 and f i g u r e 2,
page 1 8 ) .
“
37
“
The c o n d u c ta n c e o f th e d o u b le la y e r o f th e c o l l o i d p a r t i c l e s does
n o t i n c r e a s e s i g n i f i c a n t l y w ith i n c r e a s i n g c o n c e n tr a ti o n o f e q u ilib r iu m
e le c tro ly te .
Thus one w ould e x p e c t from e q u a tio n (19) t h a t th e conduct=
a n c e o f th e e q u i lib r i u m e l e c t r o l y t e , a s i t s c o n c e n tr a ti o n was in c r e a s e d ,
w ould become e q u a l to t h a t o f th e s l u r r y .
P eech e t a l .
T h is o b s e r v a tio n was made by
( 2 7 ) , Bower (5 ) ( 6) f o r c l a y - w a te r sy stem s and by th e p r e ­
s e n t i n v e s t i g a t o r s f o r Dowex-50 - w a te r s y s te m s .
(S ee F ig u r e 5 , page5 / )
A number o f r e s i n sam p les w ere e q u i l i b r a t e d w ith s o l u t i o n s o f NaCl
f o r . tw e n ty - f o u r h o u r s .
0 .0 0 0 5 N t o 0 .2 N,
The c o n c e n tr a ti o n o f th e s o l u t i o n s v a r ie d from
The ApH o r AEc a ^ o f e a c h sam ple was d e te rm in e d and
th e v a lu e p l o t t e d v e r s u s c o n c e n tr a ti o n o f NaCI .
Some c o n d u c ta n c e s t u d ­
i e s made on c l a y - w a te r sy ste m s (35) a r e a l s o in c lu d e d .
T hese
4uchranbe4vai^|§/Lw.e^e'':iised^to;;c a !d e la te J%^n]i^n '^f-6qua:tidh)
-lBfoese.-Yalu£sv @ 'fi% 0- ^ a ^ ;:a n 4 j - ^ E e a d g mp a r e ^ . .
a r e d e p ic te d by F ig u r e s 6 , 7 , 8 , and 9.
T h ese co m p ariso n s
A s i m i l a r s tu d y was made by th e
p r e s e n t i n v e s t i g a t o r s f o r Dowex-50, Dowex-SOW and Dowex-I .
s u l t s a r e l i s t e d i n T a b le V I. Tmi f-*;
I" „ ,I-.
",
T hese r e ­
.
TABLE VI
C om parison o f ^ E c a l and EDonnan
E 1
cal
./•®Donnan -
Dowex-50
125 mv.
80
Dowex-SOW
160 mv.
79
74 mv.
68
D o w ex -I
C o n c e n t r a t i o n NaCI .
0 .0 1
0.02
0 .0 3
0 .0 4
0 .0 5
F ig u re 5.
0 .0 6
0 .0 7
e q / l i t e r of so lu tio n
0 .0 8
0 .0 9
S a l t C o n c e n tr a tio n v s .
0 .1
pH
D ia ly z a te
Poharrhltil
-
-Log S p e c i f i c C onductance
C la y -S lu rry
Donnan — ^
Legend:
Q — D ia ly z a te
+ — C lay S lu r ty
& ~ ^E cal
0 “
- l o g K+C l -
F ig u r e 6 .
C om p arison o f
V nnan
m o le s/lite r
A E c g l w it h E0on n an u s i n g 2 .4 2 7 , H+ M o n t m o r illo n it e
Legend:
Q
+
A
A B caI
^Donnan
PoV enfiaI
- lo g S p e c i f i c C on d u ctan ce
®
D ia ly z a te
C lay S lu r r y
F ig u r e 7 .
C om p arison o f
A E c a l w it h E0on n an u s i n g 2.42% Na+ M o n t m o r illo n it e
Legend: Q
-f-
■ 70
D ia ly z a te
C lay S lu r r y
"Fol-BTvt-V
pecif ic
ConJa<-4dnce.
Donnan
-lo g
F ig u r e 8 .
(jCaCl^j m o l e s / l i t e r
C om p arison o f A E c g l w it h Elj0n r5n u s i n g 5.86% Ca
F o r t C o l l i n s C la y
Legend:
q
D ia ly z a te
+
C lay S lu r r y
^
^ Er a l
Po+ er\+ \a.|
- lo g S p e c i f i c C on d u ctan ce
onnan
-lo g
F ig u r e 9 .
CaClg
m o le s/lite r
C om p arison o f A E c g l w it h E0on ngn u s in g 2.42% Ca"*+ M o n t m o r illo n it e
-4 3 The r e s u l t s o b ta in e d q u a l i t a t i v e l y s u p p o r t O v erb eek ' s th e o ry a l ­
th o u g h th e v a lu e s a r e n o t i n good q u a n t i t a t i v e ag re e m e n t.
The same co n ­
c l u s i o n was r e a c h e d by Bloksma (2 ) and more q u a n t i t a t i v e s u b s t a n t i a t i o n
was. o b ta in e d by Bower ( 6) ,
I t i s i n t e r e s t i n g to n o te th e v a lu e s o b ta in e d f o r th e Ca++-M ontm o ri I I o n i t e and th e Ca-^+ - F o r t C o ll in s c l a y s .
A n e g a tiv e
AEc a ^ (27)
i s o b s e rv e d and a n e g a t iv e Donnah i s c a l c u l a t e d by e q u a tio n ( 1 9 ) .
Com­
p a r is o n o f th e m o b i l i t i e s and th e c o n d u c ta n c e s o f H"1", K+ , Na+ and Ca++
r e v e a l s no a p p a r e n t r e a s o n f o r th e ch an g e i n s ig n o f th e p o t e n t i a l .
The
s u s p e n s io n e f f e c t a p p a r e n tly c a n n o t be a f u n c ti o n o f c o n d u c ta n c e a lo n e ,
b u t o th e r f a c t o r s m u st be in v o lv e d .
C a l c u l a t i o n o f Ej
To c a l c u l a t e E j th e f o llo w in g e q u a tio n was u se d ;
■E; + E_
1C a l - - J
w here Ejn = ,5 9 .1 lo g a ^ _ / a " ^ _ and
No. I and No. 2.
AEc a ^ was d e te rm in e d a s i n c e l l s
The d a ta f o r Em w ere ta k e n from T a b le I I I .
I t was
p o in te d o u t p r e v io u s l y t h a t i f th e "bound w a te r" th e o ry h e ld th e n Em
w ould e q u a l z e r o .
Thus th e v a lu e s c a l c u l a t e d f o r Em w ould b e a
maximum v a lu e and t h e r e f o r e th e v a lu e o b ta in e d f o r E . by th e above
'
J ■
e x p r e s s io n w ould be a minimum. A E re j^
was a l s o u s e d .
d e te rm in e d by c e l l s l i k e No. 3 and No. 4 .
The v a lu e s w ere
A n o th e r e l e c t r o d e c o m b in a tio n
u s e d was an A g,AgCI i n c o n ju n c tio n w ith a s a t u r a t e d c a lo m e l e l e c t r o d e .
The Ag9AgCl e l e c t r o d e was p r e p a r e d by th e m ethod o f Brown ( 1 1 ) .
A ll o f
th e s e d a ta a r e l i s t e d i n T a b le V I I 9 p ag e 4 4 , s e e a l s o f i g u r e IO9 page 45.
!I '.
io
■, I". ■
^
L
'
'
v.
. : •; j.
•'>.
; „•
-4 4 -
I t s h o u ld be n o te d t h a t AEr g f
and th e p o t e n t i a l a s m easu red by
th e A g ,A g C l-s a tu ra te d c a lo m e l p a i r d i f f e r i n t h a t th e r e f e r e n c e e l e c ­
tr o d e s a r e d i f f e r e n t and th e s a l t b r id g e s o l u t i o n s a r e d i f f e r e n t co n A
c e n t r a t i o n s . The fo rm er h a v in g a more d i l u t e b r id g e s o l u t i o n . The
d i f f e r e n c e o b ta in e d i n E . i s a t t r i b u t e d to two f a c t o r s :
J .
(a ) th e
m o b i l i t i e s o f th e NH^+ and NO^" a r e more n e a r l y e q u a l th a n th o s e o f
K+ and Cl"", and
(b ) th e d i f f e r e n t c o n c e n tr a ti o n s o f s a l t b r id g e
s o lu tio n (3 ).
TABLE V II
C om parison o f V alu es f o r Ej w ith D i f f e r e n t E le c tr o d e P a ir s
Sample ' AEc a l
la
9 8 .0 *
AEr e f
Em
fj
8.6
8 9 .4
102
9 3 .4
fj
(EAg1AgCl Ec a l )
!i
2a
100.0
6.1
9 3 .9
103
9 6 .9
3a
112.0
7 .4
1 0 5 .6
108
100.6
4a
9 5 .8
7 .3
8 8 .5
82
7 4 .7
5a
88.6
8.0 •
8 0 .6
77
6 9 .0
lb
7 7 .5
6.6
7 0 .9
82
7 5 .4
8 4 .0
6.2
7 7 .8
81
7 5 .8
i
:
2b .
I
3b
9 7 .5
8.0
8 9 .5
79
7 1 .0
4b
11 8 .2
8.0
110.2
80
7 2 .0
5b
12 4 .0
6.8
1 1 7 .2
83
7 6 .2
6b
10 1 .5
9 .1
9 2 .4
*A11 r e a d in g s a r e i n m i l l i v o l t s
r.
-4 5 -
L
1 20 HO-
eH,
100EI»
EJ
\ \ w
w
\ \ \ % ,\\\ s s
\ \W
f
90-
X
I
I
I
I
I I I
Ej
X
/
X
m
X
E
j
0
X
X
X
3a
4a
5a
Sam ples
□
F ig u r e 10.
C o m p o sitio n o f AEc y l o f Dowex-50 - W ater System
-4 6 “-
SUMMARY and conclusions
The d i s t r i b u t i o n o f HCl i n a Dowex-50 - w a te r s y ste m r e c e iv e d a t t e n ­
tio n in th is in v e s tig a tio n .
The d i s t r i b u t i o n c o u ld b e a d e q u a te ly d i s -
c r i b e d , w i t h i n l i m i t s o f e x p e r im e n ta l e r r o r , by th e s o - c a l l e d "bound
w a te r" th e o r y .
A c c o rd in g to t h i s th e o r y , th e r e s i n p a r t i c l e s a r e c o a te d
w ith a t h i n f i l m o f "bound w a te r " ( I ) .
T h is w a te r h a s a c h a r a c t e r i s e :1 - ...Lj
t i c a l l y low d e n s it y and i s presum ed to h av e s t r u c t u r a l c h a r a c t e r i s t i c s
s i m i l a r to i c e .
T h is th e o ry demands t h a t f r e e io n s b e e x c lu d e d from
t h i s "bound w a te r " , w h ich a c c o u n ts f o r n e g a t iv e a d s o r p ti o n o f a n io n s ( 1 5 ) .
D a ta o b ta in e d i n t h i s i n v e s t i g a t i o n i s c o n s i s t e n t w ith , and p r o v id e s some
s u p p o r tin g e v id e n c e f o r th e "bound w a te r" th e o r y .
The e l e c t r i c a l d o u b le
l a y e r a t th e r e s i n s u r f a c e i s t h e r e f o r e v i s u a l i s e d a s a d i s t i n c t r a t h e r
th a n a d i f f u s e l a y e r .
The s o l u t i o n i n th e Dowex-50 - w a te r s y ste m b e ­
yond th e "bound w a te r " f i l m i s a c c o r d in g ly c o n s id e r e d to b e hom ogeneous.
I n an e q u i l i b r a t e d Dowex-50 - w a te r s y s te m , th e p o t e n t i o m e t r i c a l l y
m easu red pH o f th e s l u r r y was fo u n d td d i f f e r from th e c o r r e s p o n d in g
pH o f th e s u p e r n a ta n t s o l u t i o n by a s much a s 3 .2 6 pH u n i t s .
T h is s o -
c a l l e d s u s p e n s io n e f f e c t i s commonly a t t r i b u t e d e i t h e r to an a c t u a l
d i f f e r e n c e i n Sg+ i n th e s y ste m o r to th e e x i s t e n c e o f a l i q u i d ju n c tio n
p o t e n t i a l (E 4) a t th e r e f e r e n c e e l e c t r o d e - r e s i n i n t e r f a c e .
J
’
'
In th is in -
v e s t i g a t i o n , a c o m p a riso n ,w a s made b etw ee n th e a c t u a l d i s t r i b u t i o n o f
C l” i n th e s y s te m , a s d e te rm in e d by C l ^ , and th e a p p a r e n t d i s t r i b u t i o n
o f C l” i n th e s y ste m a s d e te rm in e d p o t e n t i o m e t r i c a l l y .
The r e s u l t s i n d i ­
c a t e d a n E j w h ich c o u ld b e a s h ig h a s 93 m i l l i v o l t s , d ep e n d in g upon
=47"
c e r t a i n c h e m ic a l c h a r a c t e r i s t i c s o f th e sy stem .
T h is E .
c o n s titu te s a
p o t e n t i a l s o u r c e o f e r r o r i n p o te n tio m e tr ic d e te r m in a tio n s made i n e x ­
c h a n g e r -w a te r sy stem s w hich may be l a r g e enough to c o m p le te ly i n v a l i d a t e ,
th e r e s u l t s .
D ata o b ta in e d r e l a t i v e to Ej a r e q u a l i t a t i v e l y c o n s i s t e n t w ith t h 6
t h e o r e t i c a l tr e a tm e n t o f O verbeek ( 2 6 ) .
B o th c a t i o n and a n io n exchange
r e s i n s , e x h i b i t th e s u s p e n s io n e f f e c t : th e fo rm er b e in g p o s i t i v e i n s ig n
and th e l a t t e r b e in g n e g a t iv e i n s ig n .
The E j was a s e n s i t i v e f u n c tio n
o f e l e c t r o l y t e c o n t e n t , a p p ro a c h in g z e ro a p p a r e n tly a s a l i m i t as th e
e l e c t r o l y t e c o n te n t ap p ro a c h e d 0 .2 N.
SUGGESTION FOR FUTURE RESEARCH
I t seems t h a t in f o r m a tio n r e g a r d in g th e fu n d am e n tal c a u s e ( s ) o f
'
"
■
/
l i q u i d j u n c t i o n p o t e n t i a l s i n c o l l o i d a l - w a t e r sy stem s w ould be d e s i r a b l e .
I f th e c a u s e ( s ) w ere known, th e n one w ould p resu m ab ly be a b le to p r e d i c t
w h ich sy ste m w ould g iv e r i s e to l i q u i d j u n c t i o n p o t e n t i a l s .
S tu d ie s c o u ld be made co m p arin g th e e f f e c t on th e m a g n itu d e o f Ej
r e s u l t i n g from r e s i n s a t u r a t e d w ith d i f f e r e n t c a t i o n s .
From th e s e
s t u d i e s p o s s i b ly c o r r e l a t i o n s c o u ld be made c o n c e rn in g th e m a g n itu d e o f
Ej as/, a '.,fu n c tio n '.o f su ^.'^aK to r# '''& A , i o n i e ^ a d i i ^ h y d r a t i o n r a d i i and
v a le n c e .
-4 8 APPENDIX A
I.
D e f i n i t i o n s and Sym bolism
1.
S u s p e n sio n E f f e c t — th e o b se rv e d d i f f e r e n c e betw een th e
d i a l y z a t e pH and th e s u s p e n s io n pH.
2.
E j — l i q u i d j u n c t i o n p o t e n t i a l - - t h e p o t e n t i a l c r e a t e d a t th e
d i f f u s i o n b o u n d ary o f a r e f e r e n c e e l e c t r o d e .
3.
Em—membrane p o t e n t i a l - - w o r k r e q u i r e d to b r in g a p o i n t c h a rg e
from one s i d e o f th e membrane to th e o t h e r .
E = (^ fm - ^
4 . . yV - - e l e c t r i c a l p o t e n t i a l
5.
—c h e m ic a l p o t e n t i a l
6.
— th e e l e c t r o c h e m ic a l p o t e n t i a l .
e l e c t r i c a l and c h e m ic a l p o t e n t i a l s .
-Y i =
+ RTjn a . ' + ZF
v
w here R—u n i v e r s a l gas c o n s ta n t
! - - t e m p e r a t u r e a b s o lu te
—a c t i v i t y
Z—v a le n c e o f io n s p e c ie s
F —F a ra d a y s
T h is i s th e sum o f th e
-4 9 APPENDIX B
P hase"
P hase"
P h a se '
P h a s e '" i s th e d i a l y z a t e .
P hase" i s th e i n t e r s t i t i a l e l e c t r o l y t e .
P h a s e ' i s th e s o lv e n t o r s o l u t i o n ta k e n up by th e c o l l o i d p a r t i c l e s .
F ig u r e 11:
T h ree P hase System
-5 0
APPENDIX C
Membrane P o t e n t i a l and Donnan E q u ilib r iu m
S u sp e n sio n (p h a s e " )
D ia ly z a te ( p h a s e " ')
S em iperm eable Membrane
F ig u r e 12:
A t e q u ilib r iu m A /±" = X ^ '"
Donnan System
f o r a u n iv a le n t c a t io n
I . y y 0 + RTlnaJJ+ + ZF Ijt"
+ R T ln a '^
+ Z F ^ '"
upon r e a r r a n g i n g
2.
RTlna^
=
ZF (
" 1 -V ^") and by d e f i n i t i o n E^ = ( ^
- y/")
a+
3.
"m * B
ln
g o in g back now to e q u a tio n I . and w r i t i n g th e e x p r e s s io n f o r an a n io n
and r e a r r a n g i n g
4 . y</Q + RT In a" - ZF
5.
-RT In
ZF
6.
RT In
ZF
In a l "
aT~
a-: =
am
a l"
a "
_
=
=XJq + RT In a I" - Z F ^ " '
( Y "
- Y '" )
or
( f "
- y )
Now e q u a tin g 2. and 6
in a V
a"'
T h is i s th e e x p r e s s io n d e r iv e d by Donnan (14) w hich r e l a t e s th e
a c t i v i t i e s o f u n i v a l e n t io n s in th e two p h a s e s .
-5 1 APPENDIX D
W ater C o n te n t D e te rm in a tio n
The m e th o d , o f G reg o r e t a l .
c o n t e n t o f th e r e s i n s .
firs t,
(17) was u s e d to d e te rm in e th e w a te r
The r e s i n was e q u i l i b r a t e d w ith e x c e s s w a te r
th e n p la c e d i n a s i n t e r e d g l a s s f i l t e r f u n n e l, u n d e r s u c ti o n ,
f o r l i t t l e more th a n t h r e e m in u te s .
As was shown by G reg o r e t a l . ,
a f t e r t h r e e m in u te s , th e r e s i n m a in ta in e d a r e l a t i v e c o n s ta n t w e ig h t.
>
■
T h is i s b e l i e v e d . t o i n d i c a t e t h a t th e i n t e r s t i t i a l w a te r had b een r e ­
.
moved, and t h a t any a d d i t i o n a l lo s s o f w e ig h t, a f t e r t h i s tim e , would
be due to a i r d r y in g .
The r e s i n was p la c e d i n w eig h in g b o t t l e s , w eighed and p la c e d i n a
vacuum d e s s i c a t p r .
The sam p les w ere w eig h ed p e r i o d i c a l l y u n t i l no f u r t h e r
lo s s i n w e ig h t was shown.
T h is was ta k e n a s th e d ry w e ig h t o f th e r e s i n .
By t r a n s f e r r i n g sam p les to th e w e ig h in g b o t t l e s w ith tim in g and c a r e ,
good p r e c i s i o n was o b ta in e d .
The r e s i n was fou n d to c o n t a in 46%.w a te r ,
by w e ig h t.
A n o th er m ethod, u s e d by G regor e t a l . , was c e n t r i f u g a t i o n .
The
sam p les w ere p la c e d i n s i n t e r e d g l a s s f u n n e ls w hich s a t i n s p e c i a l c e n t r i ­
fu g e f l a s k s .
They w ere c e n t r if u g e d f o r t h i r t y m in u te s a t 1500 g ' s .
T h is
was found to be a d e q u a te to e x t r a c t n e a r l y a l l o f th e i n t e r s t i t i a l w a te r .
The E f f e c t o f P e r c e n t R e s in in S u sp e n sio n
upon th e A p p a re n t pH o f th e S u sp e n sio n
A s e r i e s o f sa m p le s, c o n ta in in g tw e n ty m i l l i l i t e r s o f d i s t i l l e d
w a te r and v a r y in g am ounts o f r e s i n from 1 .5 gms. to 5 .5 gms. d ry w e ig h t,
w ere m easured f o r s u s p e n s io n pH.
The pH o f th e r e s i n was p l o t t e d v e rs u s
-5 2 -
th e am ount o f d ry w e ig h t o f r e s i n .
(S ee f i g u r e 1 3 .)
I t was fou n d t h a t th e pH v a r ie d b u t v e r y l i t t l e , g o in g from 3 .6 to
2 .9 .
The r e l a t i v e l y h ig h pH v a l u e s , o b s e rv e d h e r e , a r e due to th e f a c t
t h a t , w h ile m e a su rin g th e pH, th e r e s i n was s t i r r e d c o n s t a n t l y .
s e ttlin g ,
Upon
th e pH o f th e r e s i n sam p les was a l l 1+0.1 pH.
D e te r m in a tio n o f th e Volume O ccupied by Wet R e sin
A colum n o f r e s i n was p r e p a r e d i n a 50 m i l l i l i t e r b u r e t .
The c o l ­
umn was th o ro u g h ly w e tte d w ith w a te r and th e w a te r l e v e l was above th e
r e s in le v e l.
Some o f th e w a te r was a llo w e d to d r a i n down, w e ll below th e
r e s i n l e v e l . , and th e n so m e.o f th e r e s i n was sco o p ed o u t and p la c e d i n a
w eighing, b o t t l e .
The am ount o f r e s i n t h a t was ta k e n o u t was alw ays
a p p ro x im a te ly a h a l f in c h l a y e r .
th e e x t r a c t i o n .
r e s i n volum e.
The b u r e t was r e f i l l e d w ith w a te r a f t e r
The d i f f e r e n c e in r e s i n l e v e l s was ta k e n , a s th e w et
T h is m ethod was r e p e a te d f o r s e v e r a l s a m p le s.
The r e s i n
sam p les w ere w eighed r e p e a t e d l y , u n t i l no f u r t h e r lo s s o f w ie g h t was
’
d e t e c te d w ith a d d i t i o n a l d r y in g
'
Method- o f S e p a r a tio n o f P h a s e m , P hase" and Phase*
Two m ethods w ere u s e d f o r s e p a r a t i o n o f p h a s e 1" .
re s u lts .
B o th gave s i m i l a r
P h a s e "1 may b e e f f e c t i v e l y s e p a r a t e d e i t h e r by d e c a n tin g th e
d i a l y z a t e o r by f o r c in g th e d i a l y z a t e o u t th ro u g h a s i n t e r e d g la s s f u n n e l.
The r e s i n , p h a s e " , and ,.,phase1 a r e l e f t b e h in d .
C o n s id e rin g p h a s e 1 an d th e w a te r c o n t e n t o f th e w et r e s i n to be id e n ­
t i c a l , th e s e p a r a t i o n o f p h a s e " was s i m i l a r to th e e x p e rim e n ts f o r d e t e r ­
m in in g th e w a te r c o n t e n t.
The s i n t e r e d g l a s s f u n n e l was c e n t r if u g e d f o r
t h i r t y m in u te s a t 1500 g 's to remove p h a s e " .
C h lo r id e s i n p h a s e ’ was
pH o f R e sin
-5 3 -
Amount o f R e sin
g ram s/20 m i l l i t e r s
o f d i s t i l l e d w a te r
F ig u r e 13.
The E f f e c t o f 7» R esin on S u sp e n sio n E f f e c t
-5 4 -
w ashed o u t o f th e r e s i n sam ple w ith d i s t i l l e d w a te r .
D e te r m in a tio n o f th e Volume o f P h a s e '" , P h ase" and P h a s e '
. The r e s i n was e q u i l i b r a t e d w ith 11 m l. o f d i s t i l l e d w a te r .
was d e c a n te d and p la c e d i n a w eig h in g b o t t l e and w eig h ed .
P hase"'
From th e
d e n s it y o f w a te r a t 2 7 ° C ., th e volum e o f p h a s e '" was c a l c u l a t e d .
The
volum e o f p h a s e ' was c a l c u l a t e d from th e w a te r c o n te n t and th e d e n s ity
v a lu e .
The volum e o f p h a s e " was c o n s id e r e d t o be th e d i f f e r e n c e o f th e
t o t a l volum e and th e sum o f p h a s e '"
and p h a s e '.
TABLE V I I I
Volumes o f th e S e p a r a te P h ases
P hase
I g . Sam ples
2 g . Sam ples
9 .2 3 c c .
7 .5 7 c c .
. "
0 .9 0 c c .
1 .7 0 c c .
i
0 .8 7 c c .
1 .7 3 c c .
m
D e te r m in a tio n o f C h lo r id e D i s t r i b u t i o n
by R a d io lo g ic a l M ethods
F o r d e te r m in a tio n o f th e C l ^ d i s t r i b u t i o n , a r e s i n sam p le was
e q u i l i b r a t e d w ith one m i l l i l i t e r o f 0 .0 0 7 6 9 N H C l^ and te n m i l l i l i t e r s
o f d i s t i l l e d w a te r .
The sam ple was s t i r r e d o c c a s i o n a ll y and th e n a l ­
lowed to e q u i l i b r a t e o v e r n i g h t .
l e a s t 24 h o u r s .
The t o t a l e q u i l i b r a t i o n p e r io d was a t
The pH o f th e s u p e r n a ta n t d id n o t change s i g n i f i c a n t l y
a f t e r t h i s tim e .
The t h r e e p h a s e s w ere s e p a r a te d a s d e s c r ib e d on p ag e 5 2 .
The s e p a r ­
a t e p o r t i o n s w ere n e u t r a l i z e d w ith e x c e s s HaOH and th e n e v a p o r a te d to
d ry n e s s i n s t a i n l e s s s t e e l p la n c h e ts ,
The sam p les w ere c o u n te d i n a G e ig e r-M u e lle r c o u n te r .
Each sam ple
was c o u n te d f o r a- f i v e m in u te p e r io d .
C l36 S e lf - A b s o r p tio n
A number o f NaCl3 ^ s o l u t i o n s w ere e v a p o ra te d to d ry n e s s i n s t a i n l e s s
s t e e l p la n c h e ts i n o r d e r to a s c e r t a i n w h e th e r o r n o t any s e l f a b s o r p tio n
was ta k in g p la c e i n th e sam p les u se d i n th e s tu d y o f C l” d i s t r i b u t i o n .
The am ount o f s a l t was v a r i e d from 0 .2 mg. t o 90 mg. and th e c o u n t r a t e
was d e te rm in e d .
f i g u r e 14.
From th e s e d a ta a p l o t was..made; th e r e s u l t s a p p e a r i n
From th e g ra p h i t i s e a s i l y s e e n t h a t s e l f a b s o r p ti o n would
b e o f no c o n c e rn f o r th e sam p les u se d i n t h i s i n v e s t i g a t i o n .
The sam ples
u s e d i n th e i n v e s t i g a t i o n w eig h a p p ro x im a te ly 0 .2 m illig r a m .
A cco rd in g
to f i g u r e 14 no a p p r e c ia b le a b s o r p tio n ta k e s p la c e f o r sam p les o f t h i s
w e ig h t.
D e te r m in a tio n o f C h lo r id e by P o te n io m e tr ic M easurem ent
F o r d e te r m in in g th e c h l o r i d e a c t i v i t y , a Beckman s i l v e r b i l l e t comb i n a t i q n e l e c t r o d e #39187 was u se d a s a A g,AgCl e l e c t r o d e .
T h is e l e c ­
tr o d e i s d e s ig n e d to be u se d w ith th e . Beckman Model G pH m e te r .
T his
e l e c t r o d e i s two e l e c t r o d e s i n one u n i t , c o n t a in in g an A g,AgCI e l e c tr o d e
and an A g,AgCI r e f e r e n c e . e l e c t r o d e i n a s o l u t i o n t h a t i s s a t u r a t e d w ith
r e s p e c t to b o th KCl and AgCI .
Betw een th e r e f e r e n c e e l e c t r o d e and th e sam ple s o l u t i o n , t h e r e . i s .
a r e s e r v o i r c o n t a in in g a 10% s o l u t i o n o f
c o n n e c ts th e sam ple w ith th e r e f e r e n c e e l e c t r o d e .
T h is b r id g e s o l u t i o n
T h is p r e v e n ts c h l o r i d e
io n s from th e r e f e r e n c e e l e c t r o d e from c o n ta m in a tin g th e sam p le.
A
l i n e n f i b e r c o n n e c ts th e r e f e r e n c e e l e c t r o d e to th e b r id g e s o lu ti o n .a n d
-5 6 -
C o u n ts/m in u te
Back S c a t t e r i n g E f f e c t
from S t a i n l e s s S t e e l .
M illig ra m s o f S o lid
F ig u r e 14:
C l"^ S e l f A b so rp tio n
/
-5 7 -
th e b r id g e s o l u t i o n to the, sam p le.
Some e l e c t r o d e s , p r e p a r e d by th e m ethod o f Brown ( 1 1 ) , w ere a l s o
used.
T hese e l e c t r o d e s w ere u s e d i n c o n ju n c tio n w ith a S .C .E .
An A tte m p t to D eterm in e a„*. by R a te s
o f E s te r H y d ro ly s is
The am ount o f r e s i n to be u se d f o r e a c h sam ple was w eighed i n a
50 m i l l i l i t e r E rlen m ey e r f l a s k .
Enough w a te r was added to th e sy stem
to occupy a l l o f p h a s e 1 and p h a s e ” .
i n volum e.
The am ount o f a c id was co m p arab le
The a c i d s o l u t i o n s v a r ie d from .0 .0 to 2 .1 2 i n pH.
o f th e r e s i n was m easu red a t a te m p e r a tu r e o f 35°C.
The pH
The r e s i n and a c id
sam p les w ere p la c e d i n a c o n s t a n t te m p e r a tu r e b a t h , sh ak en and allo w ed
t o r e a c h 35° C.
sam p le.
One m i l l i l i t e r o f p u re m e th y ! a c e ta te was added to each
The z e ro tim e was ta k e n a t t h i s p o i n t .
The r e a c t i o n was s to p p e d
by a d d in g j u s t enough NaOH to t i t r a t e th e t o t a l e q u i v a le n t s o f H+ i i n th e
sy ste m .
The sam p les w ere im m e d ia te ly b ack t i t r a t e d w ith a s ta n d a r d HGl
s o l u t i o n and p h e n o lp h th a le in .
-5 8 -
LITERATURE CITED
P e rio d ic a ls
I.
A n d e rso n 3 D. M. and Low3 P. F . 3 S o i l S c i . S oc, Amer. P r o c . 22:
(1958)
2.
B loksm a3 A .H ., J . C o ll . S c i, ,
3.
B o l t 3 G. H ., J . P hys. Chem.
4.
B o n n er3 0 . D. and S m ith 3 L. L ., J . P hys. Chem.
5.
Bower3 C. A ., S o i l S c i. S oc. Amer, P r o c .
23:29 (1959)
6.
Bower3 C. A ., S o i l S c i . Soc. Amer. P r o c .
2 5 :18 (1961)
7.
Boyd3 G. E . , J . Amer. Chem. S oc.
69,:2818 (1947)
8.
Boyd, G. E . , J . Amer. Chem. S oc.
6 9 :2 8 3 6 (1947)
9.
B r a d f i e l d , R . , . J . , P h y s. , Chem ..3 5 :3 6 0 (1931)
12:135 (1957)
61: 1166 (1957) '
6 4 :2 6 1 (1960)
10.
B r e i t e n , M. J . , J . Amer. Chem. S oc.
19:5111 (1958)
11.
Brown, J . , J . Amer. Chem. Soc.
12.
Colem an, N. T ., S o i l s S c i. Soc. Amer. P r o c . j j ; 106 (1951)
.13.
D obry-D ucla u x . A ., J . Polym er S c i.
14.
Donnan, F . G ., Chem. Rev. I ; 80 (1924)
15.
E a to n and S o k o lo f f 3 S o i l S c i. 4 0 :2 3 7 (1935)
16.
E r i k s s o n 3 E.., KungI . L a n tb r u k s -H o g s k o la n A n n a le r 17 :9 2
17.
E r i k s s o n 3 E . ,- S c i e n c e
18.
G re g o r3 H. P . , H eld , K. M. and B e l la n 3 J 63 A n al. Chem, 2 3 :620 (1951)
19.
G uggehheim 3 E. A ., J , P hys. Chem. 3 3 :8 4 2 (1929)
20.
J e n n y 3 H ., N e ils o n 3 T. R ., Colem an, N. T. and W illia m s , D. E .,
S c ie n c e 112:164 (1950)
21.
K ra u s 3 K, A, and M oore3 G ., J . Amer. Chem, S oc. 75,: 1457 (1953)
5 6 :6 4 6 (1934)
2 3 :499 (1957)
113:4 1 8 (1951)
-5 9 -
P e r i o d i c a l s ( C e n t.)
22.
M c A u liffe , A. and Colem an, N. T ., S o i l S c i . S oc. Am. P r o c .
19: 156 (1955)
23.
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M acIn n es, D. A ., THE PRINCIPLES OF ELECTROCHEMISTRY
P u b lis h in g C o r p ., New Y ork p . 221 (1939)
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K u n in , K, ION EXCHANGE RESIN
2nd E d i t i o n (1950)
31 .
N achod, F . C.
ION EXCHANGE
R e in h o ld
W iley & Sons I n c . , New Y ork
A cadem ic P r e s s , New Y ork
p . 45 (1949)
T heses
32 .
D a v is , L. E . , U n iv e r s it y o f C a l i f o r n i a
(1941) Ph.D . t h e s i s
33.
Du R e i t z , C ., Tekn H ogskola n , S to ck h o lm (1938) Ph.D . t h e s i s
34 .
Moreno Camacho, E d g a r d ,. U n iv e r s ity o f C a l i f o r p i a (1957)
35 .
O ls e n , R. A ., C o r n e ll U n iv e r s it y
(1953) Ph.D . t h e s i s
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