A novel UV based advanced oxidation process with electrochemical co-generation of chlorine and H2O2 for carbamazepine abatement: Better performance, lower energy consumption and less DBPs formation

To promote the performance of traditional UV/chlorine and UV/H 2 O 2 processes, the novel UV based advanced oxidation process with electrochemical co-generation of chlorine and H 2 O 2 (UV/E-Cl&H 2 O 2 ) was for the first time used for degradation of carbamazepine (CBZ), a refractory antiepileptic drug with resistance to photodegradation and microbial degradation . Compared with UV/E-Cl and UV/E-H 2 O 2 processes, the apparent first-order rate constant of CBZ degradation by UV/E-Cl&H 2 O 2 process increased by 3.87 and 5.84 times respectively with a lower energy consumption (1.12 kWh/m 3 -log). Meanwhile, the disinfection by-products (DBPs) formation by the novel process was 21.4% less than that by UV/E-Cl process. Under the optimal condition of initial pH 7, applied current 600 mA and 15 mM NaCl, the UV/E-Cl&H 2 O 2 process could almost completely eliminate CBZ within 4 min and obtain 57.8% TOC removal in 1 h. The mechanism of UV/E-Cl&H 2 O 2 was investigated through processes comparison, quenching experiments, EPR analysis and determination of OH concentration. The generated radicals (i.e., OH and reactive chlorine species), especially OH, played a major role in CBZ removal. Besides, the possible degradation pathways of CBZ were proposed and the stability of UV/E-Cl&H 2 O 2 process for CBZ removal was certified based on ten consecutive runs. The degradation of typical pollutants (sulfamethazine, rhodamine B, methylene blue , atrazine and phenol) and treatments in three kinds of real wastewater confirmed the wide application feasibility of the novel process. In summary, this study provides a novel efficient and energy-saving process for removing organic pollutants with promising perspectives..