Photodegradation of chloramphenicol in micro-polluted water using a circulatory thin-layer inclined plate reactor

This study describes the photodegradation of chloramphenicol (CAP) in micro-polluted water with a thin-layer inclined plate reactor. Under simulated sunlight irradiation, the effect of reaction parameters including solution pH, initial CAP concentration, and co-existed humic acid (HA) or chloride was evaluated. The photodegradation of CAP was independent of initial pH in the range of 6.0–9.0, but sharply decreased by 25.5% with the increase of initial CAP concentration from 0.4 to 1.0 mg/L. The presence of HA exhibited a significant inhibitory effect, while Cl − promoted the photoreaction. In this study, CAP was degraded through both direct and indirect photolysis, in which 1 O 2 was the main reactive species responsible for the indirect route. Its steady-state concentration in the micro-polluted water was determined to be 1.40 × 10 −13  mol/L. Transformation intermediates were identified to propose the degradation pathway of CAP, which substantially met the density functional theory (DFT) calculation results. Moreover, four other pharmaceuticals including tetracycline , doxycycline, oxytetracycline , and minocycline were also successfully photodegraded during 5 h irradiation. Therefore, the designed circulatory thin-layer inclined plate reactor is suggested to be effectively applied to the decontamination of organic micro-polluted water.