Degradation of Chloramphenicol Using UV-LED Based Advanced Oxidation Processes: Kinetics, Mechanisms, and Enhanced Formation of Disinfection By-Products

As an emerging light source, ultraviolet emitting diodes (UV-LEDs) are adopted to overcome the shortcomings of conventional mercury lamp, such as pollution. The degradation chloramphenicol (CAP) using three UV-LED-based advanced oxidation processes (AOPs)—UV-LED/persulfate (UV-LED/PS), UV-LED/peroxymonosulfate (UV-LED/PMS) and UV-LED/chlorine—was investigated. Results indicate that CAP can be more effectively degraded by hybrid when compared UV irradiation oxidants alone. Degradation AOPs followed pseudo-first-order kinetics. rate constants (kobs) for UV-LED/PS, UV-LED/PMS, UV-LED/chlorine were 0.0522, 0.0437 0.0523 min?1, removal rates 99%, 98.1% 96.3%, respectively. constant increased with increasing oxidant dosage UV-LED/chlorine, whereas overdosing reduced UV-LED/PS UV-LED/PMS. Ultraviolet wavelength influenced efficiency UV-LED based maximum observed at a 280 nm. application enhanced formation DBPs during subsequent chlorination. uUV-LED/PMS produced disinfection by-products than UV-LED/PS. Compared UV-LED, dichloroacetonitrile trichloronitromethane chlorination owing its capacity degrade nitro group in CAP. intermediates dichloroacetamide, 4-nitrobenzoic acid, 4-nitrophenol each UV-LED/chlorine. present study provides further evidence supporting AOPs.