Effect of UV Input on Degradation of 4-Chlorophenol by Peroxy Acetic Acid

Abstract

In this present work, photochemical degradation of 4-chlorophenol (4-CP) using ultraviolet irradiation (UV) of 125, 250 and 400 W with peroxy acetic acid (PAA) was studied in a batch reactor. It was observed that degradation efficiency increases with increasing UV input and followed the order 400 > 250 > 125 W. Degradation rate and efficiency of degradation were influenced by pH, PAA and 4-CP concentration. An excess amount of PAA acted as a free-radical scavenger. The order of reaction by differential analysis was fractional order. Overall and initial reaction rate constants were evaluated by integral method. The overall reaction rate was more likely to be second order. However, the initial reaction rate was followed first-order rate constant. Reaction efficiency was decreased with increasing initial 4-CP concentrations. More than 95 % mineralization of 4-CP was observed by UV/PAA process. Chloride ion and COD were decreased gradually with increasing UV input. Samples were analyzed by HPLC and UV spectrophotometer for residual concentrations. GC-MS was used for degraded product identification.