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[Display omitted] • A dual-cathode peroxi-coagulation (PC) process and pilot device was first proposed. • It enhanced the oxidative degradation of pollutants in PC process at neutral pH. • It promoted the Fe(II) recycling cycle and greatly reduced iron sludge production. • The improved PC process could produce •OH and O 2 •- more efficiently. • Improved PC process showed application prospect in decentralized sewage treatment. An improved dual-cathode peroxi-coagulation (PC) process using natural air diffusion electrode (NADE) and HNO 3 modified carbon felt (MCF) was first proposed to improve the removal efficiency of organic pollutants in neutral and alkaline wastewater and reduce the formation of iron sludge. The improved PC process does not require any additional oxidants or catalysts, nor does it need to adjust the pH of the wastewater in advance but can directly treat actual wastewater, achieving a target pollutant (C 12 H 14 N 4 O 2 S, sulfamethazine) removal of 87%-100% within 60 min and TOC removal of 46–76% within 240 min with the corresponding energy consumption below 0.02 kWh gTOC-1. Compared with the conventional PC process, this improved process could produce hydroxyl radical (•OH) and superoxide radical (O 2 •-) more efficiently, which greatly increased the SMT removal rate constant by 3–4 times and oxidative removal proportion of organic pollutants from 42 ∼ 47% to 85 ∼ 90%. Thanks to the Fe(II) regeneration capacity of MCF to promote iron circulation, the yield of •OH was 4.1 times higher while the iron sludge production was less than a quarter when compared with that of conventional PC. The improved PC process illustrated better purification performance and lower energy consumption for actual wastewaters such as pharmaceutical wastewater, surface water and rural decentralized domestic sewage than the conventional PC process. Our work elucidated the mechanism of promoting Fe(II) regeneration through MCF cathode under alkaline conditions to enhance •OH production and O 2 •- oxidation, showing a good environmental application prospect. [ABSTRACT FROM AUTHOR]

• A novel UV/E-Cl&H 2 O 2 process was proposed to degrade pollutants cost-effectively. • UV/E-Cl&H 2 O 2 showed better pollutants and TOC removal performance than UV/E-Cl and UV/E-H 2 O 2. • Radicals, especially OH and Cl, dominated carbamazepine (CBZ) removal by UV/E-Cl&H 2 O 2. • Degradation pathway and mechanism of CBZ by UV/E-Cl&H 2 O 2 process were proposed. • UV/E-Cl&H 2 O 2 system showed great stability and wide application perspective. 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/m3-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.. [ABSTRACT FROM AUTHOR]