Inhibitory effect of thioacetamide on CdS dissolution during photocatalytic oxidation of 2,4-dichlorophenol

CdS dissolution and 2,4-dichlorophenol oxidation have been studied in the presence of thioacetamide during the photocatalytic reaction. It is interesting to find that both the organic oxidation and the degree of inhibition of CdS dissolution increase with increasing pH. In low pH range, the protonation of CdS surface is the major reason for CdS dissolution. Thioacetamide can inhibit the CdS dissolution to a certain degree only at the beganing of the first 8 hours. At high pH range, the formation of Cd(0H)2 determines the extent of CdS dissolution. The inhibition effect of thioacetamide on CdS has been minimized. The two proposed mechanisms have been confirmed by quantitative analysis of base consumption during the processes. The optimal light intensity is 700 watts and temperature was found to be not an important factor in CdS dissolution