International Journal of Application or Innovation in Engineering & Management (IJAIEM)
Web Site: www.ijaiem.org Email: editor@ijaiem.org
Volume 03, Issue 09, September 2014
ISSN 2319 - 4847
REMOVAL OF TRACE METAL (As) FROM
GROUNDWATER USING: LOW COST
ADSORBENT USEFUL IN RURAL SECTOR
Ram Karan Singh
Department of Civil Engineering, King Khalid University
Abha City, Kingdom of Saudi Arabia
ABSTRACT
The problem of trace metals in the water is becoming the major source of contamination specially Arsenic. This is a most
commonly trace metal found on the earth. The presence of Arsenic in ground water may originate from chemical reactions,
due to weathering of rocks, due to mining activities, industrial effluents or use in agricultural sectors as a insecticides or a
pesticides. Arsenic levels above permissible limits of 50 ppb in groundwater have been reported from many parts of the world. It
has been an unforeseen consequence of a large-scale programme of replacing contaminated surface water sources by ‘safe’
groundwater. Arsenic in groundwater was first detected in 1983 following reports of many people suffering from arsenical skin
diseases. In Bangladesh, West Bengal region of India [1] inner Mangolia region in China, Thailand, Argentina, Ghana, Japan,
Chile, Mexico, Hungary, Romania, U.S.A. [2] and Taiwan [3], millions of people are suffering from ill effects of excess arsenic
intake. The permissible limit of arsenic in drinking water is 50 ppb [4, 5], but arsenic up to 3.4 mg/l has been reported in some
regions of the world. Chronic poisoning of Arsenic is manifested by General muscular weakness, loss of appetite, nausea,
inflammation of mucous membranes in the eyes, nose and larynx, skin lesions, gastrointestinal injuries, kidney damage,
circulatory collapse, respiratory failure and neurological disorders [6] vascular system damage, gangrene, lung, bladder, lymph
glands, prostate, kidney and liver cancers. The skin lesions caused by Arsenicosis are confused with leprosy. Affected villages
are treated much like isolated leper colonies. Sufferers are barred from social activities and often face rejection, even by
immediate family members. Thus, it is urgently needed to find alternate sources of safe drinking water or to develop some
feasible technique for Arsenic removal from contaminated water.
Keywords:-Trace metals, Arsenic, Groundwater, Adsorption.
1. INTRODUCTION
Chemistry of Arsenic
The As is stable in the four oxidation states under different re-dox condition (+5, +3, 0 and -3). The most common
oxidation states of As in water are Oxidized As (V) or Arsenate (H2AsO4, H3AsO4, HAsO4) and reduced As (III) or
Arsenite (H2AsO3, H3AsO3, HAsO3) forms [7]. The former is less toxic, easy to be removed and is main species in
natural waters. Generally As (V) is more prevalent in aerobic surface water while As (III) is more likely to occur in
anaerobic ground waters. However, actual valence states depend on the redox environment in water systems and may
vary from place to place [8]. Removal of As (III) from aqueous solutions is usually poor as compared to that of As (V)
by most (almost all) treatment technologies evaluated because in the pH range of 4 to 10, As (V) exists in water as
monovalent or bivalent anions having negative charge, whereas As (III) exists predominantly as a neutral species. For
ease of removal of arsenic, oxidative pretreatment of As (III) bearing water is usually done using chemical oxidants.
Oxidizing agents being used for this purpose are manganese oxide [9], ozone [10] and iron [11], chlorine, pure oxygen,
hypochlorite, hydrogen peroxide, Fenton’s reagent (H2O2/Fe2+), permanganate, UV light, Ferric Chloride and
sonication etc. A variety of technologies have been used for the treatment of arsenic in water, including conventional
co-precipitation with ferric chloride, lime softening, Ion exchange resins, adsorption, electro dialysis reversal and
membrane filtration [12,13, 14] but all these methods can remove only arsenate form. Arsenite has to be oxidized to
arsenate for effective removal. To circumvent this problem, an adsorbent compound (Sfca) was prepared in the
laboratory and laboratory trials were conducted. In this study performance data of Sfca for arsenic removal has been
presented.
2. METHODOLOGY
The performance of Sfca for arsenate and arsenite removal was evaluated in batch mode. All the chemicals used in the
experiments were of reagent grade. Stock solutions containing 1000 mg/L of arsenic (V) and arsenic (III) were
prepared from sodium arsenate and sodium arsenite respectively. Test solutions of various concentrations in the range
of 800-1200 ppb of arsenate and arsenite were prepared by dilution of the stock solutions with distilled water. All the
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Volume 03, Issue 09, September 2014
ISSN 2319 - 4847
experiments were conducted in triplicates. Parameters for arsenic uptake were optimized. The effect of different
parameters such as pH, contact time, adsorbent dose, initial arsenic concentration and agitator speed on arsenic
adsorption was studied in order to optimize the conditions for maximum adsorption.
3. RESULTS
The metal removal efficiency 97 % of arsenate and 93.4 % of arsenite removal was achieved at an adsorbent dose of 2.0
g/L. An increase in arsenic removal was observed with increasing adsorbent dose because at higher doses, large surface
area and greater number of adsorption sites get available. The pH, adsorbent dose, initial arsenic concentration and
time of contact were found as the major factors affecting the adsorption capacity of the adsorbent. The results indicated
that the laboratory made iron-silica adsorbent is highly selective for arsenic, cost-effective, easy to operate, produces
very small amount of residue and imparts no color to the treated water because the silica imparts greater strength to the
adsorbent and it does not dissociate in water.
I) The effect of contact time on adsorption of Arsenic:
Time of contact between the adsorbent and adsorbate phases is a very important factor affecting the extent of
adsorption. It is very important to determine the time required to just reach the maximum adsorption or equilibrium
because continuing the process beyond that becomes redundant and affects the economics of the sorption process
adversely. Effect of time on adsorption of arsenate and arsenite has been illustrated in figs. 1 to 2. It has been observed
that the arsenic removal goes on increasing with time untill the equilibrium was reached (5 hrs.), after that there was
not much increase in adsorption rate
100
95
90
85
l
a
v
80
o
m
e
r
75
)
V
(
70
S
A
65
%
0.5 mg/l
0.75 mg/l
1.5 mg/l
1 mg/l
60
55
Time (min.)
Fig. 1: Effect of contact time on arsenate removal
by Sfca at various initial arsenic concentrations (Adsorbent dose= 2 g/l, pH = 7.0, Shaker speed)
100
95
90
85
l
a
v
80
o
m
0.5 mg/l
0.75 mg/l
1.5 mg/l
1 mg/l
re
75
)
(V
70
S
A
65
%
60
55
Time (min.)
Fig. 2: Effect of contact time on arsenite removal
by Sfca at various initial arsenic concentrations (Adsorbent dose= 2 g/l, pH = 7.0, Shaker speed )
It has been observed that the adsorption of arsenic presented a typical sigmoidal curve which can be devided into two
phases. The first phase was represented by rapid sorption, followed by second phase of slow adsorption. The rapid
phase occurred during the initial 1 hour and the adsorption of arsenate and arsenite by Sfca was 95.84 and 92.87
respectively after 6 hours of contact time. This trend is consistent with the earlier reports in literature on sorption of
arsenic by Hering et al, 1997 [15]. This trend can be attributed to the initial abundant availability of active sites for the
binding of both arsenate and arsenite and high driving force which results in rapid adsorption, but as the sorption
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Volume 03, Issue 09, September 2014
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progresses with gradual occupancy of active sites, the sorption becomes slow as represented by second phase. It has
also been observed that beyond 5 hours, there was no increase in uptake of arsenate and arsenite. A number of studies
available in literature are in line with the findings of present study [16].
II) The effect of adsorbent dose on Arsenic removal:
It is evident from the Fig. 3 that the adsorbent dose affects the arsenic uptake. Increasing the amount of adsorbent dose
results in higher adsorption of arsenate and arsenite from the solution. Arsenate adsorption by Sfca increased from 52.6
% to 96.86 % with increase in adsorbent dose from 0.1 to 2.5.g/L. Also, arsenite adsorption increased from 38.9 % to
93.15 % with increase in dose from 0.1.to 2.5 g/L. An adsorbent dose of 2.0 g/l has been used for further experiments.
Since uptake capacity is a measure of the amount of arsenate and arsenite bound by unit weight of adsorbent, its
magnitude decreased with increase in adsorbent dose.
120
100
80
l
a
v
o
m
re 60
I)I
(
s
A40
%
A s (III)
A s (V)
20
0
0
500
1000
1500
Adsorbent d ose (mg/l)
2000
2500
Fig. 3: Effect of adsorbent dose on arsenic removal
by Sfca (Initial As concentration = 1000 ppb, pH = 7.0, Shaker speed =100 rpm,
100
98
96
94
l
92a
v
o
m
e
90r
c
i
n
e
88s
r
a
%
86
As (V)
84
As(III)
82
80
0
1
2
3
4
5
6
7
pH
8
9
10
11
12
13
Fig. 4: Effect of pH on arsenic removal
by Sfca (Initial As concentration = 1000 ppb, adsorbent dose = 2.0 g/l, Shaker speed =100
Temperature =350 C) rpm, Temperature =350 C)
III) The effect of pH on Arsenic removal:
The adsorption of arsenic on studied adsorbent was found to be strongly dependent on the initial pH. Experiments were
conducted at different pH values (2 to 11) to find out the optimum pH for maximum adsorption of arsenate and
arsenite. It was observed that the adsorption first increases with pH, reaches to a maximum value and then decreases
with further increase in pH. Because with increase in pH, the portion of positively charged surface sites on the
adsorbent decreases, causing the reduction of adsorption. The adsorption is governed by both the surface charge of
adsorbent and the form of arsenic species in the water. In pH range between 3 to 6, As (V) ion occurs mainly in the
form of H2AsO4 while a divalent anion HAsO4 dominates at higher pH values (between 8 to 10.5). In the intermediate
region, i.e. at pH range between 6 to 8, both species co-exist. It is evident that the studied adsorbent effectively adsorbs
both species of H2AsO4 and HAsO4. Adsorption of arsenate was maximum at pH 7 and for arsenite; it was maximum
at pH 10. The maximum removal of arsenate and arsenite by Sfca was 96.63% and 91.37% respectively (Fig. 4). The
adsorption of arsenic is a function of pH as it exhibits different ionic equilibria at different pH. At lower pH, adsorbent
surface gets protonated and the monovalent and bivalent negatively charged arsenate ions get attracted towards the
adsorbent surface whereas arsenite remains uncharged upto pH 9 so can be removed in pH range 9-11. With further rise
of pH beyond 11, the concentration of OH- ions increases and overall charge on the adsorbent surface becomes negative
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Volume 03, Issue 09, September 2014
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which causes hindrance in the sorption of negatively charged arsenate and arsenite ions, thus results in the decreased
adsorption.
IV) The effect of initial Arsenic concentration on its adsorption:
The initial concentration of arsenic in the solution influenced its equilibrium uptake remarkably. It has been observed
that with increase in initial concentration, the adsorption rate decreased. With increase of initial concentration from 50
ppb to1000 ppb, the arsenate adsorption decreased from 99.92 to 94.56 % and arsenite adsorption rate decreased from
91.36 to 87.4% (Fig. 5). Decrease in adsorption of arsenate and arsenite at high initial concentration can be attributed
to the competition among ions for active surface sites on the adsorbent. The trend is in agreement with the earlier many
reports on adsorption of arsenic. Manju et al, 1998 noted that with increase in initial Arsenic (III) concentration from
50 mg/l to150 mg/l, the removal percentage reduced from 88.6% to 73.9 % [15].
10 0
98
96
94
l
a
v9 2
o
m
e
r
90
c
i
n
e
s
r88
A
%
86
84
As
(V)
82
80
0
100
2 00
30 0
40 0
50 0
600
Ini tial Ar senic c onc. (ppb)
700
800
900
100 0
Fig. 5: Effect of initial arsenic concentration on
100
99
l 98
a
v
o
m
e
r
ic
n 97
e
rs
A
%
As( V)
96
As( II I)
95
94
25
50
75
100
125
150
175
200
rpm
Fig.6: Effect of agitaor speed on arsenic removal
arsenic removal by Sfca (Adsorbent dose = 2.0 g/l, by Sfca (Initial Arsenic concentration= 1000 ppb, Shaker speed
=100 rpm, Temperature =350 C) Adsorbent dose = 2.0 g/l, Temperature =350 C)
V) The effect of agitator speed on adsorption of Arsenic:
The effect of agitator speed i.e. turbulence of the sorbent-sorbate system on arsenic adsorption was monitored in the
range of 50-250 rpm, using non-agitated system as control. With increase in agitator speed, the adsorption of arsenic
increased upto the speed of 100 rpm, while increasing the agitator speed beyond 100 rpm caused decrease in adsorption
of arsenic. This is due to te fact that the arsenic ions are bound to the surface of adsorbents with weak forces and at
higher agitation speed due to high turbulence the bond between the adsorbent-adsorbate may break resulting in reduced
adsorption. The maximum adsorption for arsenate was found to be 98.88% and for arsenite it was 95.5% (Fig. 6).
Adsorption equilibrium:
Adsorption from aqueous solutions involves concentration of the solute on the solid surface. As the adsorption process
proceeds, the sorbet solute tends to desorbed into the solution. Equal amounts of solute eventually are being adsorbed
and desorbed simultaneously. Consequently the rates of adsorption and desorption will attain an equilibrium state,
called adsorption equilibrium. At equilibrium, no change can be observed in the concentration of the solute in the solid
surface or in the bulk solution. The position of equilibrium is characteristic of the entire system, the solute, the
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adsorbent, the solvent, temperature, pH and so on. The distribution of solute between the liquid phase (unabsorbed
solute) and the adsorbent surface is a measure of the position of equilibrium. For any design of adsorption system,
equilibrium data that are generally referred to as adsorption isotherms are basic requirement. The presentation of the
amount of solute adsorbed per unit of adsorbent as a function of the equilibrium concentration in bulk solution at
constant temperature is termed as the adsorption isotherm, that is useful is indicating the affinity of an adsorbate for a
particular adsorbent (adsorption capacity of an adsorbent). The adsorption data can be described with several models,
like Langmuir [17] model, Freundlich [18] model, Redlich and Peterson model and BET equation etc. Two most
commonly used model equations have been used in present study:
Langmuir’s equation:
The Langmuirs equation is based on certain assumptions as:
The molecules are adsorbed on definite sites on the surface of the adsorbent. Each site can accommodate only one
molecule i.e. the adsorbate forms a monolayer on the surface of the adsorbent consisting of finite number of identical
sites. The area of each site is a fixed quantity determined solely by geometry of the surface. The adsorption energy is
the same at all sites and the adsorbed molecules cannot migrate across the surface or interact with neighboring
molecules.
Mathematically, it is expressed as:
qe = (qmax b Ce) / (1+ b Ce)
Eq. 1 indiactes that qe approaches qmax asymptotically as Ce approaches infinity. For linearization of the data, it can
be written in the form:
Ce/q = 1/b. qmax + Ce/ qmax
or
1/ qe = 1/ b qmax Ce + 1/ qmax
aids in comparison of performance of different adsorbents, particularly It also in cases where full saturation of the
sorbent is achieved in the experiment. From a linear plot of 1/qe vs. 1/Ce, qmax and b can be determined from the
respective slope and intercept of the graph [19]. The monolayer capacity qmax determined from the Langmuir isotherm
defines the total capacity of adsorbent for a specific adsorbate. Also, it may be used to determine the specific surface
area of the adsorbent by utilizing a solute of known molecular area.
Freundlich Adsorption Isotherm:
The empirical Freundlich equation that is based on adsorption on a heterogeneous surface is expressed as:
qe = x/m = K. Ce 1/n
The above equation was linearized to determine the process parameters as given below:
log (qe) = log (K) + 1/n log (Ce)
K and 1/n can be determined from the linear plot of log (qe) vs. log (Ce). As the Freundlich equation indicates the
adsorptive capacity, qe (or loading factor on the adsorbent) is a function of the equilibrium concentration of the solute.
Therefore, higher capacities are obtained at higher equilibrium concentrations. The Freundlich equation can be used for
calculating the amount of adsorbent required to reduce any initial concentration to a predetermined final concentration.
The above equation can be written as:
log ((C0-Ce)/m) = log (K) + 1/n log (Ce)
where qe = x/m and x = C0 – Ce
Eq. 6 is useful for comparing different adsorbents in removal of different compounds. In view of the values of linear
regression coefficients, it was noted that for both the arsenic-adsorbent systems, the Langmuir isotherm model
exhibited better fit to both arsenate and arsenite than the Freundlich isotherm model, Redlich and Peterson model and
BET euation in the studied concentration and temperature range. The plot of linearized Lagmuir isotherms and various
isotherm constants of arsenate and arsenite adsorption on both arsenic-adsorbent systems obtained at 300C, 400C and
500C are presented below.
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Isotherm study of adsorption of arsenate on Sfca:
The linearized plots of Langmuir isotherm model for adsorption of arsenate and arsenite on Sfca at different
temperatures are presented in Figs. 7 and 8. From slope and intercept of these plots isotherm constants were calculated
and are presented in table 1.
3
3
2.5
2.5
2
2
50 C
/x 1.5
m
1
30 C
/x1.5
m
40 C
1
30 C
50 C
40 C
0.5
0.5
0
0
-50
0
50
100
150
200
250
300
350
400
0
1/Ce
Fig. 7: Linearized plots of Langmuir isotherm
2
4
6
1/ ce
8
10
12
14
Fig. 8: Linearized plots of Langmuir isotherm
for adsorption of arsenate on Sfca at different for adsorption of arsenite on Sfca at different temperatures
Table 1: Isotherm parameters for arsenate adsorption on Sfca
T
Qmax (mg/g)
r2
b(1/mg)
(0C)
Ar
sen
ate
Arsen
ite
Arsen
ate
Arsenit
e
30
6.3
5.9
25.4
2.4
0.99
0.99
40
5.7
4.6
23.6
2.0
0.99
0.99
50
5.1
2.5
22.9
1.9
0.98
0.99
the present study, the experimental data follow the Langmuir isotherm model. From literature review, it has been seen
that adsorption of arsenic by different adsorbents follow one or more of the studied isotherms [20].
The kinetics of adsorption:
Process performance and ultimate cost of a sorption system depends on the effectiveness of the process design and the
efficiency of process operation. Evaluating the efficiency of the process operation requires an understanding of the
kinetics of uptake or the time dependence of the concentration distribution of the solute in both bulk solution and solid
sorbent and identification for rate determining step. Kinetic models have been used to test experimental data to
investigate the adsorption mechanism. The kinetic models most commonly used include the first-order rate equation
and pseudo-second order equations. The first order rate expression of Legergren [21] is based on the solid capacity and
is given by:
dq/dt = K1 ad.. (qe-qt)
After integration and applying boundary conditions, t = 0 to t = t and q = 0 to qe = q, the above equation becomes:
log (qe -qt) = log (qe) – ((K1ad .t)/ 2.303)
A straight line plot of log (qe-qt) vs. ‘t’ suggests the applicability of this model and the value of adsorption rate
constant (K1ad) can be obtained from slope of the plot. Kinetic studies for the adsorption of arsenic were conducted at
different initial concentrations of arsenate and arsenite.
The effect of initial concentration of arsenate and arsenite on kinetic parameters of adsorption:
Effect of initial concentration (C0) of arsenic on kinetic parameters of its adsorption on Sfca was studied by varying the
concentration range from achieved earlier 250 ppb to 1000 ppb at 350 C at
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Volume 03, Issue 09, September 2014
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Table 2: Effect of initial concentration of arsenic on kinetic parameters for its adsorption on Sfca
Initial
Con.
Arsenate
Arsenite
k1
r2
0.990
0.007
0.955
0.007
0.992
0.007
0.991
.007
0.990
0.010
0.990
k1
r
250
0.007
500
1000
2
(ppb)
adsorption became faster and equilibrium was (Fig.9). Data was analyzed for pseudo-first order rate model and rate
constant was calculated as described above. Analysis of data showed that all the arsenic-sorbent model systems tested,
followed pseudo-first order kinetic model for all the studied concentrations. The change in initial concentration of
arsenic influenced the kinetic parameters of the sorption process. With an increase in initial concentration of arsenic,
value for pseudo-first order rate constant k1 increased. The linearised plots for pseudo-first order rate kinetics are
presented in Fig. 10 for Arsenate. From the slope of these plots, the rate constant k1 was calculated (Table 2).
- 0.6
0.85
- 0.8
0.75
-1
0.65
500 ppb
) 0.55
/g
g
(m
0.45
m
/
x
750 ppb
1000 ppb
0.35
1500 ppb
0.25
1000
ppb
500 ppb
- 1.2
)t
q
e
- 1.4
q
(
g
lo
- 1.6
- 1.8
-2
0.15
- 2.2
0
50
100
150
200
250
Time (mins.)
300
350
400
Fig. 9: Effect of initial concentration of arsenic
0
50
10 0
150
Tim e ( min.)
200
2 50
300
Fig. 10: The linearized pseudo-first order plot for
on Sfca adsorption of arsenate on Sfca on its adsorption
4. CONCLUSIONS
The study carried out indicated that the adsorbent is highly selective for arsenic, cost-effective, easy to operate,
produces non-leachable residue and no skilled personnel is required for operation and maintenance. The adsorbent
material is to be replaced after exhaustion. The adsorbent dose required depends upon the feed water quality. It can
remove both Arsenate and Arsenite forms of Arsenic without any pre treatment. Thus, this adsorbent may be the
preferred option for Arsenic removal from groundwater in rural areas.
5. ACKNOWLEDGEMENT
I would like to express our sincere thanks to Prof.Dr.Hussein Manie Ahmed AL Wadai Dean College of Engineering,
King Khalid University,Abha City and Dr. Ibrahim Falqi, Vice Dean for providing us encouraging environment for the
research.
REFERENCES
[1] Chakrabarty, A.K. and K.C. Saha, ‘Arsenical Dermatosis from Tubewell water in West Bengal,’ Ind. J. Med.
Research, 85 (1987) 326.
[2] Bellack, E., ‘ Arsenic Removal from Potablr Water,’ J. AWWA, 63, 7 (1971) 454.
[3] Shen, Y.S., ‘ Study of Arsenic Removal from Drinking Water,’ J. AWWA, 65, 8 (1973) 543.
[4] Pontius, F.W., K. G. Brown and C.J. Chen, ‘ Health Implications of Arsenic in Drinking Water,’ J. AWWA, 86,
(1994) 52-63.
Volume 3, Issue 9, September 2014
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International Journal of Application or Innovation in Engineering & Management (IJAIEM)
Web Site: www.ijaiem.org Email: editor@ijaiem.org
Volume 03, Issue 09, September 2014
ISSN 2319 - 4847
[5] Pontius, F.W., ‘Uncertainties Drive Arsenic Rule Delay,’ J. AWWA, 87, 4 (1995) 12.
[6] WHO (World Health Organization), ‘Guidelines for Drinking Water Quality (Vol. II): Health Criteria and
Supporting Information,’ World Health Organization, Geneva, Switzerland (1984).
[7] Ferguson, J. F. and M. Anderson, ‘Chemical form of arsenic in water supplies and their removal.’ In Chemistry of
Water Supply, Treatment and Distribution (Edited by A.J. Rubin), Ann Arbor Science, Ann Arbor, MI. (1974)
137-158.
[8] Chen, H.W; M.M. Frey; D. Clifford; L.S. McNeill and M. Edwards, ‘Arsenic treatment considerations,’ J. IWWA,
91, 3 (1999) 74-84.
[9] Chakravarty, S., V. Dureja, G. Bhattacharyya, S. Maity and S. Bhattacharjee, ‘Removal of Arsenic from
Groundwater using low cost Ferruginous Manganese Ore,’ Water Research, 36 (2002) 625-632.
[10] Emett, T.M. and G. H. Khoe, “ Photochemical Oxidation of Arsenic by Oxygen and Iron in acidic Solutions,”
Water Research, 35, 3 (2001) 649-656.
[11] Myoung, J.K, ‘Oxidation of Arsenite in Groundwater using Ozone and Oxygen,’ The Science of total
Environment, 247 (2000).
[12] Sorg, T.J. and G.S. Logsdon, ‘Treatment technology to meet the interim primary drinking water regulations for
inorganics: part 2,’ J. AWWA, 70, 7 (1978) 379-393.
[13] Hering, J.G., P.Y. Chen, J.A. Wilkie, M. Elimelech and S. Liang, ‘Arsenic removal by ferric chloride,’ J. AWWA,
88, 4 (1996) 155-167.
[14] McNeill, L.S. and M. Edwards, ‘Arsenic removal during precipitative softening,’ Jour. Envir. Engrg., 123, (1997)
453-460.
[15] Hering, J.G.; P. Chen; J.A. Wilke and M. Elimelech, ‘Arsenic Removal from Drinking Water during
Coagulation,’ J. Environ. Energy, 123, 8 (1997) 800-806.
[16] Ramaswami, A.; S. Tawashsupa and M. Tsleyen, ‘Batch Mixed Iron treatment of high arsenic water’, Water
Research, 35, 18 (2001) 4474 – 4479.
[17] Langmuir, I., ‘The adsorption of gases on plane surfaces of glass, mica and platinum,’ J. Am. Chem. Soc., 40
(1918) 1361-1368.
[18] Freundlich, H., ‘Uber die adsorption in losungen (Adsorption in solution),’ Z. Phys. Chem., 57 (1906) 384-470.
[19] Holan, Z.R. and Volesky, B., ‘Biosorption of lead and nickel by biomass of marine algae,’ Biotech. Bioengg., 43
(1994) 819-825.
[20] Vaishya, R.C. and I.C. Agarwal, ‘Adsorption of As (III) on Ganga Sand,’ Indian J. of Environ. Protection, 13
(1993) 2.
[21] Lagergren, S., ‘About the theory of so called adsorption of soluble substances,’ in K. Sven. Vetenskapsakad
Handl., 24 (1898) 1-39.
AUTHOR
Dr Ram Karan Singh is presently Professor in the Civil Engineering Department, King Khalid
University in the Kingdom of Saudi Arabia. He has over 22 years of teaching, research, administrative,
and consultancy experience in top institutions/universities in India (14 years) and abroad (8 years). He
held various administrative positions such as Dean of Research and Development, Head of the
department and Head of the Research, Development and Industrial Liaison in various universities during the tenure of
his work. He is a member of various national and international academic, research and administrative committees.
Awarded by JSPS (Japan Society for the Promotion of Science) Post-Doctoral Fellowship, Japanese Govt. (letter no.
JSPS/FF1/185; ID No. P 02413) for a period of 2 years from 2002-2004 to carry out “Diffuse pollution modeling of
water environment of Japanese low land watersheds”, in Japan at Department of Hydraulics Engineering, NIRE,
Tsukuba Science City, Japan 305-8609, JAPAN. Also recipient of several National and International awards for
research work in the area of his interest and academic excellence awards. He has over 100 research papers in reputed
peer reviewed Journals and conference proceedings and two books. He has visited all major continents on research,
teaching and collaborative assignments some important one are Keimyung University, South Korea (December 2011),
University of Michigan, Ann Arbor, U.S.A.(May,2011); Michigan Technological University, Houghton ,U.S.A.(May,2011); NIRE,
Tsukuba Science City, Japan(July,2002-July,2004); Dublin University, Ireland (September 2003).
Volume 3, Issue 9, September 2014
Page 306