Transcript A two-stage batch adsorption optimised design for Basic

A Two-Stage Batch Adsorption Optimised Design for Basic Blue 69
Dye Removal to Minimum Contact Time
Yu-Ting Feng1#, Pei-Yu Lin1, Ming-Huang Wang1, I-Hsin Lin1 and Yuh-Shan Ho2*
1School of Public Health, Taipei Medical University
2Bibliometric Centre, Taipei Medical University - Wan-Fang Hospital
Introduction
In some cases, a single-stage batch adsorber cannot achieve the high levels of dye removal specified but which can be readily achieved
using an optimized two-stage batch adsorber design.
The cost and performance of product/equipment/system or the mode of application are always to control the process efficiency. This study
investigates the adsorption of Basic Blue 69 onto wood and develops a two-stage batch adsorber design model. A design analysis method
was developed to predict the percentage of Basic Blue 69 removal at various times of contact for a fixed mass of wood. The model
minimizes the total contact time to achieve a fixed percentage of phenol removal using a fixed mass of wood.
Materials and Methods
A 0.1 g sample of wood (500±710 m) was added to each 50 ml
volume of BB69 dye solution. The initial concentrations of BB69 dye
solution tested were 50, 100 and 200 mg/dm3. Samples were
withdrawn at suitable time intervals, filtered through a filter paper and
then analysed with UV.
Figure 1. Pseudo-second order sorption kinetics of BB69
onto wood at various initial concentrations
80
60
Mass balance equation
Pseudo-second-order kinetic model
t
t
1
1

 t
qt kqe2 qe
1
t

kqe2 qe
50
40
30
100 St n kqn2
Rn 


LC0 n1 1  kqn t
n1
n
qe  1.69C
1.24
0
k  0.371C
0.685
0

10
0
0


100Cn 1  Cn  100S 0.371C01.24 1.69C00.685 t

C0
LC0 1  0.371C01.24 1.69C00.685 t
 



50
100
150
Time (min)
200
250
300
2



Table 1. Parameters for effect of initial concentration on the
BB69/wood system
2
100St n 0.371C01.24 1.69C00.685
R



n
LC0 n 1 1  0.371C01.24 1.69C00.685 t
n 1
n


Figure 3. Minimum contact time for various percentage BB69 removal
in a two-stage process
600
C0
mg/dm3
qe
mg/g
k
g/mg min
h
mg/g min
r2
50
24.1
0.00309
1.80
1.000
100
41.3
0.00114
1.94
0.997
200
62.2
0.000558
2.16
0.995
Figure 2: Comparison of 90% BB69 removal time of each
stage in two-stage BB69/wood process
500
350
Stage 1
300
400
Stage 2
250
300
200
90% Removal
92% Removal
94% Removal
96% Removal
100
0
0
2
Conclusions
4
6
8
10
12 14 16 18 20 22 24
Adsorption system number
Time (min)
Time (min)
100 mg/dm3
2nd order model
20
Skqn2t
Cn  Cn1 
L1  kqn t 
Rn 
LC0  Cn1   S qn  q0 
qt (mg/g)
Batch Adsorber Design
qt 
50 mg/dm3
200 mg/dm3
70
90% Removal
200
150
100
50
0
0
2
4
6
8 10 12 14 16 18 20 22 24
Adsorption system number
 The design model presented is based on a pseudo-second-order kinetic model, and this has been used for minimizing the reaction time
used in a two-stage contact system that operating cost would be reduced.
 The model has been optimized with respect to contact in order to minimize total contact time to achieve a fixed percentage of BB69 dye
removal using a fixed mass of wood.