Degradation of triclosan in the presence of p-aminobenzoic acid under simulated sunlight irradiation

This study aimed to investigate the degradation of triclosan (TCS) in the presence of p -aminobenzoic acid (PABA) under simulated sunlight irradiation ( λ  ≥ 290 nm). The effect of PABA concentration, pH, dissolved organic matter (DOM), and DOM-hydrolytic Fe(III) species complexes on the photodegradation of TCS in the presence of PABA (TCS -PABA ) was also studied. The photolysis of TCS -PABA obeyed pseudo-first-order kinetics well, and the degradation of TCS -PABA enhanced with increasing solution pH (from 3.0 to 11.0). The presence of PABA inhibited the degradation of TCS -PABA , and the weakest inhibitory effect was observed while the concentration of PABA was 5 mg L −1 . The addition of DOM (Suwannee River fulvic acid standard I [SRFA], Suwannee River HA standard II [SRHA], and Suwannee River natural organic matter [SRNOM]) showed different inhibition effects on TCS -PABA degradation. However, higher Fe(III) concentration at the DOM concentration of 5 mg L −1 could favor the formation of DOM-hydrolytic Fe(III) species complexes, further accelerating the degradation of TCS -PABA . In comparison with deionized water (DI water), TCS -PABA could be better photodegraded in river water nearby the effluent of a wastewater treatment plant. This study provides useful information for understanding the natural behavior of TCS in the presence of other organic contaminants.