International Journal of Natural and Applied Sciences, 5(1): 7-12, 2009
www.tapasinstitute.org/journals/ijonas

Tapas Institute of Scientific Research and Development, 2009
DIFFUSION MECHANISM AND THE KINETICS OF BIOSORPTION OF
TEXTILE DYE BY H3PO4 AND ZnCl2 IMPREGNATED POUTRY WASTE
SORBENT
A. U. Itodo1, F. W. Abdulrahman2, L. G. Hassan2, S. A. Maigandi3 and U. O. Happiness4
Department of Applied Chemistry, Kebbi State University of Science and Technology, Aliero,
Nigeria
2
Department of Pure and Applied Chemistry, Usmanu Danfodiyo University, Sokoto, Nigeria
3
Faculty of Agriculture, Usmanu Danfodiyo University, Sokoto, Nigeria
4
Department of Chemistry, Benue State University, Makurdi, Nigeria
Corresponding author: A. U. Itodo; E-mail: itodoson2002@yahoo.com
1
ABSTRACT
Chemical modification of adsorbent efficacy was performed on poultry waste impregnated with
H3PO4 and ZnCl2. The thermo-chemical activation process was carried out at different dwell time.
Two simplified kinetic models, including the intra particle diffusion model were selected to follow
the adsorption process. Sorption of industrial dye effluent on poultry wastes could best be
described by the second order kinetics (with R2>0.985 and 0.999, a close agreement between the
qe experimented and qe calculated with justifiable SSE (%) range of 1.33 to 5.60). Diffusion process
does not follow the intra particle diffusion process (C > 0), implying that more than one process
affected the adsorption.
Keywords: Poultry wastes, kinetics, intra particle diffusion, textile, dye adsorption
INTRODUCTION
One of the major menaces of textile waste water is the colored effluent arising from the coloring
agent called dye. Color is the first contaminant to be recognized in water and has to be removed
from waste water before discharging it into water bodies. Residual dyes are the major contributors
to color in waste water generated from textile and dye manufacturing industries. According to Garg
et al. (2004), color impedes high penetration, retards photosynthetic activities, inhibits the growth
of biota and also has the tendency to chelate metal ions resulting in micro toxicity to aquatic life
along the food chain. Malik et al. (2006) added that the contamination of drinking water by dyes
at a concentration as low as 1.0 mg/l could impact significant color, making it unfit for human
consumption. The dye effluent has unaesthetic impact on the receiving water bodies, causes eye
burns to human and animals (Hameed et al., 2006).
The used of activated carbon in the removal of dyes is preferred over other adsorption methods in
that most of the used dyes are stable to biodegradation and oxidizing agents (Garg et al., 2004).
The activated carbon adsorption method is best for organic compound, but commercially available
biosorbents are not affordable for frequent use since their precursors (lignite, coal, coconut shells,
wood and peat) are not inexpensive and readily available. The disposal of commercial agricultural
wastes is currently a major economic and ecological issue, and their conversion into adsorbent,
such as activated carbon, is a possible outlet or remedy. Ioannidou and Zabaniotou (2005),
reviewed most of the agricultural residues used as activated carbon precursors.
The idea of using poultry waste to generate adsorbent is linked to different reasons but mainly due
to the synergistic effect of the blends from different cellulose and lignocellulose materials, which
make up the feed and the trace of poultry droppings, which gave the adsorbent an identity linked
to animal sources. Although there are studies in literature relating to the preparation and
characterization of biosorbents from poultry waste, there is no information on its use in textile dye
uptake, catalysis, kinetics and mode of diffusion.
In this present study, poultry waste obtained from a commercial farm has been chosen as
precursor to study the influence of contact time on % dye removal, the effect of chemical catalysis,
the kinetics and mode of diffusion.
MATERIALS AND METHODS
Poultry waste preparation: Poultry waste randomly collected from different section of the
Labana farms, Aliero, Kebbi State, Nigeria was gently and properly washed to remove any mud,
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Itodo et al.: Diffusion mechanism and the kinetics of biosorption of textile dye
debris, droppings etc, dried and ground to particle size, which was filtered through a <2 mm
aperture Endecott sieve.
The sample was directly activated in a conventional electric furnace by a one stage process.
Impregnation was done by adding 3 cm3 of 1M activating agent (ZnCl2 and H3PO4) to 3 g of the
pretreated precursor. Mixture was allowed to stand for 24 hours followed by a 5 and 10 minutes
separate activation at 800oC. The activated products was treated with 1:1 HCl for removal of
impregnated chemicals followed by hot water washing to remove chloride and acidity (Malik et al.,
2006). The final rinsing with distilled water was done before sun-drying and oven drying the
sample at 110oC overnight. Samples were labeled and stored for use at room temperature.
Dye waste water: Industrial dyeing waste water was procured from effluent reservoir of Chellco
textile Ltd, Kaduna, Nigeria. The samples were collected and stored in plastics containers without
further purification. However, a stock of 1000 mg/l was prepared from the concentrate obtained
after mild and prolonged evaporation.
Discontinuous (Batch) experiment: Equilibration of sorbent and adsorbate dye was attained at
90 minutes contact time. 0.1g of the prepared active waste was interacted with 10 cm3 of 1000
mg/l dye solution in several 50 cm3 Erlenmeyer flask and allowed to stand for 15, 30, 45, 60, 75
and 90 minutes. At any attained time, mixture was filtered through a Watmann filter paper number
42 and absorbance of filtrate was carried out, using a Jenway 6100 spectrophotometer.
Batch kinetic studies: The procedures of kinetic experiment, adopted from Hameed et al.
(2006), were basically identical to those of equilibrium test. The aqueous sample were analyzed at
preset time interval (between 15, 30,… , and 90 minutes). The amount of adsorption at time, t, is
given as qt (mg/g) (Abdulrahman et al., 2009) and presented as equation 1
qt = (Co –Ct)V/m -(1)
Co and Ct are the liquid phase concentration of dye at initial and any time, t respectively, Co and Ce
are also called the residual dye concentration (mg/l) before and after the treatment at 630 nm by
the spectrophotometer. The effect of the interaction time, t (minutes) on dye uptake was also
studied.
RESULTS AND DISCUSSION
Figure 1 showed that the percentage dye removal increased only slightly with contact time. This
increase is not pronounced for the time range used in this research. 86.432% dye was removed at
15 minute as against the 97.236% removal by pw/acid/5 at 90 minutes.
Pw/z/5 presented the least amount of dye uptake (61.055 - 85.425). This could be linked to steric
hindrance imposed by the activating agent when the sample is activated at low temperature.
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Itodo et al.: Diffusion mechanism and the kinetics of biosorption of textile dye
Investigation of the controlling mechanism of adsorption was done by fitting the equilibrium data
into the first and second order kinetic models. The rate constant of adsorption obtained for the
pseudo first order kinetic was given by the Langergren and Svenska relationship as equation (2).
log (qe-qt) = log qe – (K1/2.303)t
(2)
Where qe and qt are the amount of dye adsorbed (mg/g) at equilibrium and time t (min)
respectively. K1 is the rate constant of adsorption (min-1). Values of k1 were calculated from the
plot of log (qe - qt) versus t, similar to the one presented as figure II.
The experimental qe value (14.555 – 25.409) on table 1, did not agree in closeness with the
calculated qe values (85.422 - 97.236). This implies that adsorption of dye unto the biosorbent does
not conform to the first order kinetics model. The shape of the graph and parameters falls within
the range of those obtained from the adsorption of methylene blue onto Bamboo based activated
carbon by Hameed et al. (2009).
Table 1: First order kinetic parameters for the adsorption of dye onto H 3PO4 and ZnCl2
activated poultry waste biosorbent.
Biosorbent
Relationship =(Y
=)
K1
(min-1)
qeCal
(mg/g)
qe exp(mg/g)
R2
%SSE
Pw/acid/5/t
Pw/acid/5/t
Pw/z/5/t
Pw/z/15/t
- 0.017x + 1.399 0.039
25.061
97.236
0.799
29.465
- 0.002x + 1.163 0.005
14.555
96.734
0.543
33.549
-0.010x + 1.342 0.023
21.978
85.427
0.706
25.90
- 0.012x
+ 0.028
25.409
96.482
0.991
29.015
1.405
Pw/acid/5 – poultry waste, treated with, H3PO4activated for 5 minute dwell time. pw/z/15 –
poultry waste, treated with ZnCl2, activated for 15 minute dwell time.
The pseudo second order kinetics models (Selhan et al., 2007) is expressed as equation 3.
t/qt = 1/h + (1/qe) t -(3)
h= K2q2. where q2 is the maximum adsorption capacity (mg/g) for the pseudo second order
adsorption kinetics, K2 is the equilibrium rate constant (g mg-1min-1). Values of K2 and q2 were
calculated from the plot of t/qt against t similar to the one on figure III. This forms the bases of
data summarized on table 2.
When values of the correlation coefficient of pseudo first and second order kinetic model were
compared, the R2 values for the pseudo second order kinetics model were higher (R2 > 0.98 0.999) than those of the first order kinetics (R 2> 0.5-0.991). This indicates that the kinetics
modeling of dye uptake by poultry waste active biosorbent is well followed by pseudo second order
rate. A good justification of this fact was made by comparing the proximity or agreement of q e
calculated and qe experimental for both models. The wide range observed for the first order
9
Itodo et al.: Diffusion mechanism and the kinetics of biosorption of textile dye
kinetics support the fact that adsorption followed the second order kinetics model where close
range data was estimated (Hameed, 2009).This is unlike the proximity of both q e values on table 2.
Table 2: Second order kinetic parameters for the adsorption of dye unto H3PO4 and ZnCl2
activated poultry waste biosorbent.
Biosorbent
Relationship,(Y =)
K2 (gmg1
min-1)
qe
cal
(mg/g)
qe
exp
(mg/g)
R2
%SSE/%
Pw/A/5/
Pw/A/15
Pw/z/5
Pw/z/15
0.009X + 0.037
0.010X + 0.047
0.011X + 0.066
0.01X + 0.047
0.002
0.002
0.002
0.002
111.11
100.00
90.91
100
97.23
96.734
85.427
96.482
0.998
0.985
0.997
0.999
5.66
1.33
2.24
1.44
The second order rate constants were approximately the same (0.002) for all the samples. This
could be responsible for situations where there are no considerable differences between the % dye
removals along the series.
The validity of the models was determined using two statistical tools, the sum of error square (SSE
%) and the normalized standard deviation (∆q %), which were represented as equation 4 (Hameed
et al., 2006) and equation 5 (Inbaraj et al., 2006) respectively.
SSE (%) =
√ ∑( qe,exp – qe, cal ) 2 / N
(4)
∆q % (%) = 100× √ ∑ ( (qe,exp – qe, cal)/qe exp ) 2 / N-1
--(5)
Where N is the number of data points. Irrespective of the good R 2 values for all models, the best fit
model is characterized by high R2, low % SSE values, least % ∆q % and close agreement between
the calculated and experimental qe values. The second order kinetic model carries the entire
characteristics. In comparison, the values of first order: (second order) kinetics include, 0.54-0.99
:( 0.985-0.999) for R2,25.90 - 33.55: (1.33 - 5.60) for % SSE and 47.34 %: (7.28 %) for ∆q %.
There is also very close proximity or agreement between the qe cal and qe exp value for the second
order kinetics models. It therefore follows that the experimental kinetic data of chemically treated
poultry waste biosorbent is best described by the pseudo second order kinetics than it does by the
first order model.
The intra -particle model (Hameed, 2009; Selhan et al., 2008) can be written as equation 6.
qt = Kp t1/2 + C
(6)
Where C is the intercept and Kp is the intra-particle diffusion rate constant (mgg-1min-1). This
model, argued that the plot of the uptake, q t, versus the square root of time, t ½ is linear, and if
transport process is characterized by intra particles diffusion then the line must through the origin.
At such, the intra particle diffusion will be the rate controlling step (Selhan et al., 2008). This
however was not observed in this research.
Table 3 also revealed that the R2 values of intra particle model are least compared to the 2nd order
kinetic model (R2 similar to the study involving methylene blue adsorption using H2SO4 treated
biomass and using activated carbon prepared from Euphorbia rigida by Selhan et al. (2008) and
Gercel et al. (2007) respectively.
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Itodo et al.: Diffusion mechanism and the kinetics of biosorption of textile dye
Usually, adsorption in a particular sorbent may be due to physical adsorption, complexation with
functional groups, ionic exchange, surface sites (Monika et al., 2009). The model of transportation
could either occur via intra particle diffusion on direct single or multi layer coverage.
Table 3: Intra particle diffusion model experimental data for the adsorption of dye unto H 3PO4
and ZnCl2 activated poultry waste biosorbent.
Biosorbent
Relationship,(Y =)
KP (mg/g)
C
R2
Pw/acid/5/t
Pw/acid/15/t
Pw/z/5/t
Pw/z/15/t
2.869X
1.857X
3.532X
2.128X
2,869
1.857
3.532
2.128
69.43
73.95
53.10
77.28
0.980
0.580
0.746
0.901
+
+
+
+
69.43
73.95
53.10
77.28
CONCLUSION
The present investigation shows that chemically modified poultry waste based biosorbent is an effective
absorbent for removal of dye (% Re range of over 80%) from textile effluent. The results also revealed that
the type of activating agents, to some extent affected the adsorption capacity and proved more favorable
for ZnCl2 carbon. Similarly, sorbent generated at high activation dwell time proved to be of a better
quality and the kinetic modeling of dye uptake followed the pseudo second order kinetics with R 2
values as high as 0.999, % SSE of 1.32 - 5.60% and close qe exp/qe calculated values range.
Adsorption process was not described by intra particle diffusion (C > 0) and the graph did not pass
through the origin). It therefore follows that second order kinetics best described the adsorption of
dye unto ZnCl2 and H3PO4 biosorbent.
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Itodo et al.: Diffusion mechanism and the kinetics of biosorption of textile dye
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