Transcript Kinetic Studies of Adsorption of Copper Ion from Aqueous

Kinetic Studies of Adsorption of Copper Ion from Aqueous Solution by
Palm Kernel Fibre
Ming-Huang Wang1#, Pei-Yu Lin1, Wen-Ta Chiu2,3 and Yuh-Shan Ho4*
1School of Public Health, Taipei Medical University
2Graduate Institute of Injury Prevention and Control, Taipei Medical University
3Department of Neurosurgery, Taipei Medical University - Wan-Fang Hospital
4Bibliometric Centre, Taipei Medical University - Wan-Fang Hospital
Introduction
The removal of copper ions from water using agricultural waste products has gain popularity in recent times. Some agricultural waste products that have been
successfully applied as adsorbent for copper ions from aqueous solution includes seed of Capsicum annum, carrot residues, banana pith, soybean hulls,
cottonseed hulls, rice straw, sugarcane bagasse, apple wastes, groundnut shells, grape stalks, wheat shell, tea waste, sunflower stalk, and tree fern. In this study,
the dynamic behavior of copper ion adsorption onto palm kernel fibre was studied with the effect of initial copper concentration and temperature. A comparison
was made of the linear least-squares method and non-linear method of the widely used pseudo-second-order kinetic model to the experimental adsorption of
copper onto fibre. A trial-and-error procedure was used for the non-linear method using the solver add-in with Microsoft’s spreadsheet, Microsoft Excel.
Methods
Table 1. Pseudo-second-order kinetic model linear forms
A range of reaction temperatures (299, 309, 319, 329, and 339K) were used and
the flasks were agitated for 60 min. All contact investigations were performed in a
1 dm3 flask. A 1.0 g sample of palm kernel fibre was added to 100 ml volume of
copper ion solution set at pH 5.01 and agitated at 200 rpm for all the experiments.
The experiments were carried out at initial copper ion concentration 250 mg/dm3
for all the studies.
Results
50
100
qe (mg/g)
4.451
7.005
k (g/mg min)
0.4079 0.1063 0.04746 0.02601 0.01633
h (mg/g min)
8.080
1.000
5.215
1.000
150
9.125
3.952
1.000
200
11.19
3.255
1.000
250
1  1 1 1
 

qt  kq e2  t qe
 1  qt

Type 3 qt  qe  
 kq e  t
1.000
309 K
319 K
329 K
339 K
qe (mg/g)
14.75
16.42
18.11
20.12
qt (mg/g)
k (g/mg min) 0.01633 0.02286 0.03059 0.03926 0.05213
h (mg/g min) 2.791
4.974
8.253
12.88
21.10
r2
1.000
1.000
1.000
1.000
1.000
10
8
6
2
0.5
0
0
0.5
1
1.5
2
2.5
3
0
3.5
qt/t (mg/g min)
0.25
C0 = 50 mg/dm3
C0 = 100 mg/dm3
C0 = 150 mg/dm3
C0 = 200 mg/dm3
C0 = 250 mg/dm3
Type 2
0.2
0.05
40
60
80
t (min)
Figure 1. Type-1 pseudo-second-order linear
equations obtained by using the linear method for the
adsorption of copper onto palm kernel fibre at various
initial copper concentrations
10
12
14
Palm kernel fibre has been shown to have
a fairly high capacity for the removal of
copper ions from solution.

It was also revealed that the copper
ions/palm kernel fibre interaction is
endothermic with an activation energy
higher than 22 kJ/mol.

The adsorption equilibrium capacity, the
adsorption rate constant, and the initial
adsorption rate are function of the initial
copper concentration, and the reaction
temperature.

Both linear and non-linear method could be
a way to obtain the kinetic parameters
when fitting experimental data and kinetic
model are in a high correlation.
0
20
8

0.3
0.1
0
6
Conclusions
0.15
0
4
Figure 2. Type-4 pseudo-second-order
linear equations obtained by using the
linear method for the adsorption of copper
onto palm kernel fibre at various initial
copper concentrations
0.35
2
2
qt (mg/g)
0.4
4
1.5
1
0.5
6
2
4
0.45
8
C0 = 50 mg/dm3
C0 = 100 mg/dm3
C0 = 150 mg/dm3
C0 = 200 mg/dm3
C0 = 250 mg/dm3
Type 4
2.5
Figure 1. Type-3 pseudo-second-order linear
equations obtained by using the linear method for
the adsorption of copper onto palm kernel fibre at
various initial copper concentrations
1/qt (g/mg)
t/qt (min g/mg)
12
qe = intercept
k = -1/(interceptslope)
h = -intercept/slope
qe = -intercept/slope
k = slope2/intercept
h = intercept
3
0
16
C0 = 50 mg/dm3
C0 = 100 mg/dm3
C0 = 150 mg/dm3
C0 = 200 mg/dm3
C0 = 250 mg/dm3
Type 1
qt vs. qt/t
3.5
C0 = 50 mg/dm3
C0 = 100 mg/dm3
C0 = 150 mg/dm3
C0 = 200 mg/dm3
C0 = 250 mg/dm3
Type 3
12
Parameters 299 K
Parameters
qe = 1/slope
t/qt vs. t
k = slope2/intercept
h = 1/intercept
qe = 1/intercept
1/qt vs. 1/t k = intercept2/slope
h = 1/slope
qt/t vs. qt
14
2.791
10
13.07
qt
 kq e2  kq e qt
t
Type 4
13.07
Table 3. Pseudo-second-order rate parameters obtained
using the non-linear methods at different temperatures
14
Plot
qt/t (mg/g min)
Parameters
r
Linear form
t
1
1
 2 t
Type 1
qt kqe qe
Type 2
Table 2. Pseudo-second-order rate parameters obtained using the nonlinear methods at different initial copper concentrations
2
Type
0
0.2
0.4
0.6
0.8
1
1.2
1/t (1/min)
Figure 2. Type-2 pseudo-second-order linear
equations obtained by using the linear method for the
adsorption of copper onto palm kernel fibre at various
initial copper concentrations