Original Research Article
Year: 2016 | Month: January-March | Volume: 1 | Issue: 01 | Pages: 22-27
Batch Adsorption for Iron and Chromium Removal by Low Cost
Adsorbents: Studies on Affecting Parameters
Sunil J.
Kulkarni, Lalit Bhole, Mandar Rampure
Datta Meghe
College of Engineering, Airoli, Navi Mumbai, Maharashtra, India.
Corresponding Author: Sunil J. Kulkarni
ABSTRACT
Heavy metal removal from
wastewater can be carried out by various chemical, physical and biological
methods. The presence of heavy metal can affect man and environment adversely.
The heavy metal treatment by using adsorption can be carried out by using low
cost adsorbents. In the present research, the bagasse and groundnut shells are
used as low cost starting materials for adsorbent preparation. Batch studies
are carried out for studying removal of iron and chromium from synthetic
wastewater for bagasse adsorbent (BA) and groundnut shell adsorbent (GSA). It
was observed that optimum adsorbent dosage of 2.5 g/100 ml and 1.5 g/100 ml
were sufficient for adsorption of almost 90% of the initial metal concentration
for iron and chromium respectively. The amount of the metal removed at optimum
pH increased with increase in adsorbent dosage. The optimum pH for the removal
of chromium (VI) and iron (III) was in the range of 2 to 4 for both, BA and
GSA.
Key words: Heavy
metals, adsorbate, adsorbent, contact time, concentration.
Removal
of heavy metal from wastewater can be carried out by methods such as
electrodialysis, ion exchange, membrane separation, biological treatments and
chemical treatments. The presence of iron in natural water may be attributed to
the dissolution of rocks and minerals, acid mine drainage, landfill leachate
sewage or engineering industries. The presence of iron concentration above 0.1
mg/l can damage the gills of fish. Ferrous sulphate is unstable and
precipitates as insoluble ferric hydroxide, which settles out as rust coloured
silt. Such water often tastes unpalatable even at low concentration (0.3 mg/l)
and stains laundry and plumbing fixtures.
Breathing,
eating or drinking and through skin contact with chromium of chromium
compounds are routs through which chromium enters our body. It can cause
allergic reactions, such as skin rash.[1,2]
Inhaling Chromium (VI) can cause nose irritations and nosebleeds. The main
route of chromium uptake is food chain, as chromium (III) occurs naturally in
many vegetables, fruits, meats, yeasts and grains. In the current research low
cost adsorbent materials are used for adsorbent preparation. Removal of heavy
metals by adsorption is widely investigated research. Removal of heavy metals
by adsorption was carried out by various investigators by using various
biological, physical and chemical treatment methods.[3-5]
Membrane
separation is also tried for metal ion removal from water. Adsorption is one of
the widely investigated methods for heavy metal removal.[6-12]
Iron
and Chromium removal has been investigated by various investigators. Banerjee
et.al. investigated removal of Cr(VI) and Hg(II) from aqueous solutions using
fly ash and impregnated fly ash.[13]
Biosorption of heavy metals by sphaerotilus natans
was carried out by Esposito et.al.[14]
Biosorption
of Chromium (VI) from aqueous solutions by green algae spirogyra species was
studied by Gupta et.al.[15]
Removal of toxic metal ions from metal finishing wastewater by solvent
extraction was investigated by McDonald et.al.[16]
In present
investigation, the batch experiments are carried out to study effect of
parameters such as pH, contact time, and adsorbent dose on heavy metal removal.
Preparation
of Adsorbents: Agricultural waste was solar dried & crushed in
hammer mill. The crushed powder was screened and undersize having average
particle size of 0.3mm to 1.2mm was taken for further treatment. Impregnation
of sugarcane Bagasse and ground nut shells powder with strong acid was carried
out. This impregnated powder was then carbonized in the furnace at various
temperatures from 300o to 500oC. The washed product was
then filtered out and dried at 120o C. The carbonized powder was
then washed with hot water at a rate of 20ml/gm of powder to remove the traces
of strong acid. Fig 1 shows physical appearance and nature of raw materials.
Fig 1: Bagasse and groundnut shells
Preparation
of Stock Solution: An aqueous stock solution of Iron(Fe)
(III) ions (1000ml/l) is prepared by dissolving 7.022gm of ferrous ammonium
salt in 500ml of water and 50 ml of 1:1 sulfuric acid was added. The solution
was warmed and oxidized with approximately 0.1% KMnO4 until the
solution remains faint pink. The pH of the solution was adjusted using 0.1N HCl
or NaOH. Fresh dilutions were used for each study. In this solution 1ml=200 µg
Fe.
Chromium
(Cr) stock solution was prepared by dissolving 141.4 mg of K2Cr2O7 in 100 ml of water. Therefore in 1ml of solution concentration is 0.141mg of K2Cr2O7 and 70.5 µg of Cr. Dilute 1ml of Chromium stock solution to 100ml of water.
Therefore concentration of chromium in standard solution was 70 µg/ml. 0.04 gm
of 1, 5 diphenylcarbazide was dissolved in 20 ml Iso-propyl alcohol. 8 ml of
conc. H2SO4 diluted by addition of 72 ml distilled water
was added. Above solutions were mixed. In this solution 1ml = 500µg Cr. Fig.2
and 3 shows stock solution samples.
Batch
Experimentation: The standard stock solutions of iron and chromium
were prepared and adsorbents were segregated on the basis of weight such as
0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4 g/100ml. And pH of chromium solution was
adjusted to 3-4.
Batch
experiment were performed to study the
adsorption parameters like effect of adsorbent dosage, effect of agitation
time, and effect of pH on metal uptake efficiency. The effect of adsorbent
dosage for different dosage ranging as 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4 g/100ml
bagasse and ground nut shells. The agitation time and pH were kept constant. For determination of rate
of sorption by bagasse and groundnut shells, the supernatant was analysed for
residual metal at different time intervals. The pH and the adsorbent
doses were kept constant and the
agitation time was changed. To determine
the effect of pH on the adsorption of metal solution of different
concentration, pH was adjusted to values and effluent was mixed with known
weight of adsorbent and agitated. Dilute HCl or NaOH were used to adjust the pH of the solution.
Bagasse
Adsorbent; For Iron and chromium
removal by bagasse adsorbent, effect of adsorbent dosage was studied
by keeping agitation time constant as 45 minutes and also initial
concentration(C) was kept constant for chromium(Table1,2). The effect of agitation was studied with keeping
adsorbent dose constant as 2.5 g/100ml for bagasse also initial concentration
was kept constant (Table3,4). Effect of pH was studied by keeping agitation
time constant as 70 minutes for iron and 60 minutes for chromium and also
adsorbent dose was kept constant as 2.5 g/100ml for bagasse (Table 5, 6).
Table
1: Iron Removal by Bagasse Adsorbent: Effect Of Adsorbent Dose
Adsorbent
Dose (g)
|
%
Adsorbed
|
C
(ppm)
|
0.5
|
19.10
|
161.8
|
1
|
27.79
|
144.42
|
1.5
|
43.27
|
113.46
|
2
|
56.82
|
86.36
|
2.5
|
89.72
|
20.56
|
3
|
78.21
|
43.58
|
3.5
|
69.74
|
60.52
|
4
|
74.93
|
50.14
|
Table 2: Chromium Removal by Bagasse
Adsorbent: Effect Of Adsorbent Dose
Adsorbent
Dose (g)
|
%
Adsorbed
|
C(ppm)
(ppm)
|
0.5
|
13.19
|
434.05
|
1
|
47.32
|
263.4
|
1.5
|
91.47
|
42.65
|
2
|
86.72
|
66.40
|
2.5
|
68.11
|
159.45
|
3
|
74.21
|
128.95
|
3.5
|
67.37
|
163.15
|
4
|
55.81
|
220.95
|
Table 3: Iron Removal By Bagasse Adsorbent:Effect Of Agitation Time
Agitation
Time (min)
|
%
Adsorbed
|
C(ppm)
(ppm)
|
10
|
17.12
|
165.76
|
20
|
25.43
|
149.14
|
30
|
47.83
|
104.14
|
40
|
56.40
|
87.2
|
50
|
69.81
|
60.38
|
60
|
81.31
|
37.80
|
70
|
88.42
|
23.16
|
80
|
88.24
|
23.52
|
90
|
88.67
|
22.56
|
Table 4: Chromium Removal By Bagasse
Adsorbent: Effect Of Agitation Time
Agitation
Time (min)
|
%
Adsorbed
|
C(ppm)
(ppm)
|
10
|
13.42
|
432.9
|
20
|
22.87
|
385.65
|
30
|
46.12
|
269.4
|
40
|
66.17
|
169.15
|
50
|
84.32
|
78.4
|
60
|
84.57
|
77.15
|
70
|
84.82
|
75.90
|
80
|
84.94
|
75.30
|
90
|
84.99
|
75.50
|
Table 5: Iron removal by bagasse
adsorbent: effect of pH
pH
|
%
Adsorbed
|
C
(ppm)
|
1
|
79.43
|
41.14
|
2
|
91.47
|
17.06
|
3
|
68.21
|
63.38
|
4
|
56.83
|
86.34
|
5
|
81.11
|
37.78
|
6
|
84.29
|
31.42
|
Table 6: Chromium removal by bagasse
adsorbent : effect of pH
pH
|
%
Adsorbed
|
C(ppm)
(ppm)
|
1
|
66.27
|
168.65
|
2
|
71.43
|
142.85
|
3
|
87.21
|
63.95
|
4
|
79.83
|
100.85
|
5
|
56.21
|
218.95
|
6
|
62.11
|
189.45
|
Groundnut Shell
Adsorbent:
Effect of adsorbent dosage was studied by keeping agitation time constant as 45
minutes and constant initial concentration iron and chromium (Table 7, 8). The
effect of agitation was studied with keeping adsorbent dose constant as 1.5
g/100ml for groundnut shell also initial concentration is kept constant as
200ppm/1ml for iron and 500ppm/1ml for chromium (Table 9, 10).Also effect of pH
was studied on metal uptake as indicated in table 11 and 12.
Table
7: Removal of Iron by groundnut shell adsorbent: Effect of adsorbent dosage
Adsorbent
Dose (g)
|
%
Adsorbed
|
C(ppm)
|
0.5
|
9.21
|
181.58
|
1
|
21.43
|
157.14
|
1.5
|
43.47
|
113.06
|
2
|
55.08
|
89.84
|
2.5
|
88.67
|
22.66
|
3
|
91.27
|
17.46
|
3.5
|
83.61
|
32.78
|
4
|
71.81
|
56.38
|
Table
8 Removal of Chromium by Groundnut Shell Adsorbent: Effect of Adsorbent Dosage
Adsorbent
Dose (g)
|
%
Adsorbed
|
C(ppm)
|
0.5
|
19.72
|
401.41
|
1
|
29.48
|
252.60
|
1.5
|
57.83
|
210.85
|
2
|
72.43
|
137.82
|
2.5
|
87.21
|
63.95
|
3
|
76.87
|
115.63
|
3.5
|
63.21
|
183.95
|
4
|
80.82
|
95.90
|
Table
9: Removal of Iron by Groundnut shell adsorbent: Effect of agitation time
Agitation
Time (min)
|
%
Adsorbed
|
C(ppm)
(ppm)
|
10
|
11.34
|
177.32
|
20
|
27.41
|
145.18
|
30
|
39.66
|
120.68
|
40
|
57.83
|
84.34
|
50
|
81.77
|
36.46
|
60
|
85.32
|
29.36
|
70
|
84.92
|
30.16
|
80
|
85.11
|
29.78
|
90
|
85.81
|
28.38
|
Table 10: Removal of Chromium by Groundnut
shell adsorbent: Effect of agitation time
Agitation
Time (min)
|
%
Adsorbed
|
C
(ppm)
|
10
|
10.11
|
449.45
|
20
|
22.73
|
386.35
|
30
|
35.53
|
322.35
|
40
|
43.21
|
283.95
|
50
|
56.81
|
215.75
|
60
|
65.43
|
172.85
|
70
|
86.83
|
65.85
|
80
|
86.91
|
65.45
|
90
|
86.98
|
65.10
|
Table 11: Removal Of Iron By Groundnut
Shell Adsorbent: pH Effect
pH
|
%
Adsorbed
|
C(ppm)
|
1
|
61.83
|
76.34
|
2
|
73.06
|
53.88
|
3
|
79.12
|
41.76
|
4
|
88.72
|
22.56
|
5
|
64.82
|
70.36
|
6
|
57.77
|
84.46
|
Table
12: Removal of Chromium by groundnut shell: pH effect
pH
|
% Adsorbed
|
C(ppm)
|
1
|
67.42
|
162.9
|
2
|
81.23
|
93.85
|
3
|
92.44
|
37.8
|
4
|
87.63
|
61.85
|
5
|
70.12
|
149.4
|
6
|
59.87
|
200.65
|
Effect
of adsorbent dosage was studied. From the results it was observed that
adsorption efficiency or metal uptake varies with the adsorbent dosages. The optimum
metal uptake was noted for particular adsorbent dosage such as for bagasse
adsorbent maximum removal of iron and chromium was obtained for 2.5 g/100ml and
1.5 g/100ml respectively.
The
effect of agitation time was studied with keeping adsorbent dose constant as
2.5 g/100ml for bagasse also 1.5 g/100ml for groundnut shell and initial
concentration was kept constant It was observed that adsorption goes on
increasing till equilibrium time is achieved, and then onwards no significant
rise in adsorption is observed. Also effect of pH was studied by keeping other
parameters constant. Acidic conditions favoured adsorption. The availability of
adsorbent sites, availability of adsorbate, interference of H+ and
OH- ions and difficulty in reaching the active sites may be reasons
for the effect of these parameters on adsorption.
Effect of pH was studied by keeping
agitation time constant as 70 minutes for iron and 60 minutes for chromium and
also keeping adsorbent dose constant as 2.5 g/100ml for bagasse and 1.5 g/100ml
for groundnut shell. The analysis has been carried out and it was observed
that, for iron maximum metal recovery was obtained at pH value 2 and
for chromium the maximum recovery was obtained at pH value 2.5-3.
The
present investigation shows that the agricultural by-products like sugarcane
bagasse and groundnut shells can be used as effective raw materials for
adsorbent preparation for the treatment of wastewaters containing metals like
chromium (VI) and iron (III). Effect of parameters such as agitation time,
adsorbent dosage and pH on the removal of metals was examined.
The
uptake of metals increased with increase in the agitation time till the
equilibrium was reached. The percentage of metal removed increased with
increase in adsorbent dosage due to increased adsorption surface area. For all
the adsorbents studied adsorbent dosage of 1.5 g – 2.5 g/100 ml were sufficient
for adsorption of almost 90% of the initial metal concentration. The optimum pH
for the removal of chromium (VI) and iron (III) was in the range of 2 to 4 for
both, BA and GSA.
4.
Sunil J. Kulkarni, Dr. Jayant p. Kaware,
Fixed Bed Removal of Heavy Metal- a Review, International Journal of Research
(IJR), 2014, 1(6), 861-870.
7.
Kulkarni S.J, Goswami A.K, Applications
And Advancements In Treatment Of Waste Water By Membrane Technology- A Review,
International Journal Of Engineering Sciences and Research Technology, 2014,
3(9),446-450.
8.
Kulkarni S.J, Kaware J.P, Adsorption For
Cadmium Removal From Effluent- A Review, International Journal of Science,
Engineering and Technology Research 2013, 2(10), 1840-1844.
9.
Yuh-Shan Hoa, Augustine E. Ofomaja,
Kinetic Studies of Copper Ion Adsorption on Palm Kernel Fibre, Journal of
Hazardous Materials, 2006, B137, 1796–1802.
10.
Kulkarni S.J, Dhokpande S.R, Kaware J.P,
A Review On Isotherms And Kinetics Of Heavy Metal Removal, International
Journal of Ethics in Engineering & Management Education, 2014, 1(2), 1-4.
11.
Sunil J Kulkarni, Dr Jayant P Kaware. Removal of Cadmium
from Wastewater by Groundnut Shell Adsorbent-Batch and Column Studies,
International Journal of Chemical Engineering Research, 2014, 6(1), 27-37.
How to
cite this article: Kulkarni SJ, Bhole L, Rampure M.
Batch adsorption for iron and chromium removal by low cost adsorbents: studies
on affecting parameters.
International Journal of Science & Healthcare Research. 2016; 1(1):22-27.
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