Chunrong Wang

Conventional two-dimensional (2D) electrocatalytic ozonation faces challenges such as low mass transfer efficiency, limited hydroxyl radical (•OH) yield, and insufficient pollutant degradation rates. To address these limitations, this study developed a novel three-dimensional electrocatalytic ozonation system using a 316 stainless-steel skeleton as the cathode. By systematically comparing the ozone decay kinetics, •OH yield, imidacloprid degradation efficiency, and ozone mass transfer characteristics among the 3D electrocatalytic ozonation system, 2D electrocatalytic ozonation system, and conventional ozonation system, combined with electrode interface reaction analysis and structural simulation, the core mechanism by which the 3D structure enhances the electrocatalytic ozonation reaction was revealed. The results showed that the 3D electrocatalytic ozonation technology primarily promotes ozone decay and •OH generation through a reaction pathway dominated by the reduction of ozone at the cathode, while simultaneously enhancing pollutant removal efficiency. The pseudo-first-order kinetic constant for ozone decay in the 3D system reached 1.0 min⁻¹, which was five times that of the 2D system (0.2 min⁻¹). The •OH yield increased to 38%, significantly higher than that of the 2D system (15%) and conventional ozonation (10%). The complete degradation of imidacloprid was achieved within 5 min, and the degradation rate (2.14 min⁻¹) was 10 times that of the 2D system. The high specific surface area (75 cm²/g, 30–90 times that of the 2D flat electrode) and 70% porosity of the 3D framework overcame the mass transfer limitation of the 2D structure, exhibiting excellent reaction activity. The ozone mass transfer amount was approximately 1.5 times that of the 2D electrode and 2 times that of conventional ozonation. This study provides theoretical support and technical basis for the engineering application of 3D electrocatalytic ozonation technology in the field of micro-pollutant control.

The effluent of distilled and extracted Lurgi coal gasification wastewater has been found to have low biodegradability and high toxicity, which inhibits further biodegradation. However, ozonation enhances the biodegradability and reduces the toxicity of this effluent, enabling further biological treatment and increased removal of organic materials. In this study, the dissolved organic matters in Lurgi coal gasification wastewater were isolated into six classes by resin adsorbents, after which TOC, UV₂₅₄, UV-Vis, and 3D EEM were employed to quantitatively and qualitatively analyze organic materials in each part of the fractionated samples. The HoA and HiN fraction accounted for large amounts of the Lurgi coal gasification wastewater, and their TOC values were about 380.21 mg·L⁻¹ and 646.84 mg·L⁻¹, respectively. After ozonation, the TOC removal rates of HoA and HiN reached 42.85% and 67.13%, respectively. The UV₂₅₄ of HoA was basically stable before and after ozonation, while that of HiN increased continuously because a portion of the humic macromolecular organic materials in HoA was oxidized to HiN. Additionally, UV-Vis analysis revealed that the larger molecular organics of HoA were oxidized during ozonation, resulting in high biodegradability. Finally, the 3D EEM spectra indicated that the macromolecular organics were oxidized to smaller molecules with the degradation of soluble microbial by-products.

A novel quinoline-degrading strain, named K4, was isolated from activated sludge of a coking wastewater treatment plant and identified as Brevundimonas sp. on the basis of its 16s rDNA gene sequence analysis. Its optimum temperature and pH for quinoline degradation were 30 °C and pH 9.0, respectively, and during the biodegradation process, at 100 mg/L initial quinoline concentration, an inoculation amount of 8% (OD600 of 0.23) was the optimal strain concentration. In addition, the kinetics of free K4 strains for quinoline degradation showed that it followed a zero-order equation. Furthermore, compared with free K4 strains, immobilized K4 strains’ potential for quinoline degradation was investigated by adding both of them into SBR reactors for actual coking wastewater treatment on operation over 15 days. The results showed that bioaugmentation by both free and immobilized K4 strains enhanced quinoline removal efficiency, and especially, the latter could reach its stable removal after a shorter accommodation period, with 94.8% of mean quinoline removal efficiency.