A Comparison of Central Composite Design and Taguchi Method for Optimizing Fenton Process
Table 4
Interaction of operating parameters for COD removal efficiency.
COD (%)
Effects
Dye (mg/L)
Dye : Fe+2 (wt/wt)
H2O2 : Fe+2 (wt/wt)
pH
COD (%)
Reason
Effect of Dye : Fe+2 ratio (Figure A.4)
100
10–23
15
3
65–72.5 (increased)
At low dye concentrations, increase in Dye : Fe+2 (wt/wt) results in a decrease in Fe+2 concentration and increase in H2O2 addition (H2O2 : Fe+2) which increases the production of HO• radical for dye degradation
35–50
15
3
72–65 (decreased)
Scavenging of HO• radical by H2O2 at low concentrations of Fe+2 and high concentrations of H2O2 [3]
250–300
10–25
15
3
80 (increased)
Optimum amounts of H2O2 and Fe+2 result in the production of HO• radical adequate enough for maximum dye degradation
Effect of H2O2 : Fe+2 ratio (Figure A.5)
100
30
5–10
3
70–72
100–150
30
5
3
73–68 (decreased)
Less availability of HO•
100
30
20–25
3
73–68 (decreased)
Scavenging of HO• radical by excess amount of H2O2
300
30
10–25
3
74–80 (increased)
COD removal efficiency increases from 74% to 80% because of the proportionate amount of HO• radical production
pH
100–300
10–50
5–25
3
80
80% COD removal efficiency because of the availability of Fe+2 and H2O2 in aqueous medium (optimum conditions of other variables)
(Figure A.6)
100–300
10–50
5–25
9
60
Decomposition of H2O2 to H2O and O2 at pH above 4 [3] Deactivation of ferrous catalyst with the formation of ferric hydroxocomplex [35]
