Photocatalytic degradation of chlorophenols under direct solar radiation in the presence of ZnO catalyst

The photocatalytic degradation of chlorophenols was evaluated under direct solar radiation using commercial ZnO catalyst. Effects of several parameters such as a catalyst loading, pH of solution and initial concentration on the degradation process have been investigated. The photocatalytic degradation efficiency of chlorophenols at the optimum value of the parameters was compared under similar experimental conditions. The results of efficiency and mineralization showed the degradation of 2-chlorophenol and 2,4-dichlorophenol compound with the first order kinetic rate and the rate constant decreases as the initial concentration of the chlorophenols increase. However, the rate constant was strongly affected by type of chlorophenols compound present either 2-chlorophenol or 2,4-dichlorophenol. The highest removal of chlorophenols was obtained after 120 min and the final intermediate compounds of chlorophenols degradation are lower molecular weight compound consisting of acetic acid which was analyzed through the HPLC.