Environmental Engineering Reference
In-Depth Information
Table 1 Column C1: Zn, Cu and Pb concentrations in the desorption experiment
Zn (mg/L)
Cu (mg/L)
Pb (mg/L)
Layer
pH2
pH6
pH2
pH6
pH2
pH6
C1-1
0.86
0.40
0.52
0.21
0.252
0.064
C1-2
0.65
0.49
0.58
0.36
0.199
0.087
C1-3
0.65
0.58
0.54
0.45
0.192
0.111
C1-4
0.68
0.63
0.64
0.62
0.199
0.184
C1-5
0.73
0.64
0.76
0.69
0.249
0.191
C1-6
0.61
0.60
1.28
1.26
0.287
0.291
Table 2 Column C2: Zn, Cu and Pb concentrations in the desorption experiment
Zn (mg/L)
Cu (mg/L)
Pb (mg/L)
Layer
pH2
pH6
pH2
pH6
pH2
pH6
C2-1
1.15
0.62
0.39
0.091
0.327
0.063
C2-2
4.49
0.59
0.23
0.006
0.128
0.004
C2-3
4.47
0.59
0.32
0.008
0.189
0.004
C2-4
4.87
0.64
1.19
0.036
0.703
0.021
C2-5
5.87
0.69
5.06
0.051
1.37
0.058
C2-6
2.00
0.70
3.38
0.23
0.876
0.078
Table 3 Column C3: Zn, Cu and Pb concentrations in the desorption experiment
Zn (mg/L)
Cu (mg/L)
Pb (mg/L)
Layer
pH2
pH6
pH2
pH6
pH2
pH6
C3-1
0.86
0.40
0.52
0.21
0.252
0.064
C3-2
0.65
0.49
0.58
0.36
0.1999
0.087
C3-3
0.65
0.58
0.54
0.45
0.192
0.111
C3-4
0.68
0.63
0.64
0.62
0.1999
0.184
C3-5
0.73
0.64
0.76
0.69
0.249
0.191
C3-6
0.61
0.60
1.28
1.26
0.287
0.291
Retention efficiencies and desorption results obtained can be used for estimating
the fraction of heavy metals that can be desorbed. Hereafter, the values obtained for
Zn, Cu and Pb, in the three columns and at the different layers are compared and
discussed.
Column C1
The desorption results obtained for column C1 with a sand filter bed demonstrated
small variations of the results from pH2 and pH6. Zn values have small differences
through the different layers, while the results obtained for Cu and Pb denote higher
values at the bottom layer, but increasing as the layer depth decreases. These results
suggest that although heavy metals are retained in the sand layers, a very high
 
Search WWH ::




Custom Search