E-peroxone process is an emerging electrochemical oxidation process , based on ozone and the in-situ cathodic generation of H 2 O 2 , but the stability of cathode is one of the key restraining factors. In this study, we designed a multilayer gas diffusion electrode (GDE) decorated with a commercial hydrophobic membrane for the degradation of pyridine. It was found that a proper control of membrane pore sizes and hot-pressing temperature can significantly promote the GDE stability. Subsequently, key operational parameters of the constructed E-peroxone system were investigated, including the ozone concentration, current density, pH value, electrolyte type and initial concentration of pyridine. The degradation pathways were proposed according to six identified transformation products. The toxicity variation along the degradation progress was evaluated with microbial respiration tests and Toxicity Estimation Software Tool (T.E.S.T.) calculation and an efficient detoxification capacity of E-peroxone was observed. This research provides a theoretical basis and technical support for the development of highly efficient and stable E-peroxone system for the elimination of toxic organic contaminants.
Given the limitations of unequal H 2 O 2 and O 3 distribution in the E-peroxone (EP) process, a novel dual-wavelength UV enhanced E-peroxone process (VUV/UVC/EP) with high performance for removing emerging contaminants was established. In this paper, carbamazepine (CBZ) removal rates by different oxidation processes were investigated, calculating the kinetic effects of the VUV/UVC/EP processes in various operating parameters, and the degradation mechanisms and pathways of CBZ were comprehensively discussed. Compared with conventional EP, ultraviolet (UVC, wavelength 254 nm), UVC/EP, and dual-wavelength ultraviolet (VUV/UVC, wavelength 185 and 254 nm) processes, the VUV/UVC/EP process exhibits an excellent ability for degradation of carbamazepine (CBZ), the synergy coefficient between VUV/UVC and EP process is 1.44 (>1). In particular, the VUV/UVC/EP process exhibits exceptional degradation performance even at 50 mg L −1 CBZ. It also demonstrates high adaptability to varying pH, humic acid concentration, and different inorganic anions (SO 4 2− , Cl − , NO 3 − , PO 4 3− and CO 3 2− ). In addition, ·OH, 1 O 2 , and·O 2 − were identified to exist in the VUV/UVC/EP process. The dominant reactive species ·OH content was increased by decomposing the excess dissolved O 3 to accelerate CBZ degradation. CBZ was broken down into a series of intermediates, NO 2 − , NO 3 − , and other inorganic compounds through ring reduction and oxidation reactions under the attack of reactive oxygen species (ROS) generated in the VUV/UVC/EP process. It also can remove more than 50% of TOC in 30 min and decrease biological toxicity. An electrical energy-per-order (EEO) value of 3.37 kW h m −3 indicated that the VUV/UVC/EP process is economically feasible. This comprehensive examination provides valuable insights into the CBZ removal in reclaimed water, contributing to the advancement of environmental water resources.
The cathode is the key component in the electro-peroxone process (E-Peroxone), which is popularly constructed with carbon materials. This study developed an innovative method to fabricate a cathode with waste-tire carbon (WTC) whose performance was evaluated for the degradation of tinidazole (TNZ), an antibiotic frequently detected in water. It was found that the addition of WTC in the cathode can significantly promote the yield of H 2 O 2 and the current efficiency: around 2.7 times that of commercial carbon black at the same loading. The critical influencing factors were studied, including the current density, ozone concentration, initial pH value, chlorine ions and initial TNZ concentration. The scavenger tests demonstrated the possible involvement of •OH and . Some transformation products of TNZ were identified with UPLC-MS and the degradation pathway was proposed accordingly. These results demonstrated the potential of WTC for developing E-Peroxone cathodes. The cathode with WTC generated more H 2 O 2 than a commercial carbon black cathode. Reaction conditions including current density, O 3 dose, pH values, initial TNZ concentration and electrolyte were studied. The main reactive oxygen species were probably •OH and . Transformation products were identified and a degradation pathway was proposed.
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