Zhonglin Chen

Odorous metabolites produced by algae in source water pose severe threats to drinking water safety. Compared with conventional powdered activated carbon (PAC), in situ surface-amplified PAC exhibits superior adsorption capacity and favorable anti-interference performance in simplified aqueous systems containing selected inorganic ions for the removal of 2-methylisoborneol (2-MIB) and geosmin (GSM). This study systematically investigated the influences of PAC dosage, initial contaminant concentration, air exposure duration, inorganic anion and cation concentration, pH, and temperature on the adsorption behavior of 2-MIB and GSM onto surface-amplified PAC. Kinetic analyses reveal that the adsorption process follows the pseudo-second-order kinetic model (R² ≥ 0.98): the rate-limiting step is governed by liquid film diffusion at low concentrations, while intraparticle diffusion dominates adsorption under high-concentration conditions. Satisfactory fitting results of the Freundlich isotherm model (R² > 0.99) indicate heterogeneous energy distribution of surface active sites, demonstrating that heterogeneous adsorption characteristics serves as the main adsorption pathway. The relatively high adsorption energy (E) obtained from the Dubinin–Radushkevich (D-R) model suggests a possible contribution of micropore-related adsorption for both pollutants. Thermodynamic results prove that the adsorption is spontaneous (ΔG < 0) with a possible endothermic tendency (ΔH > 0). Active adsorption sites are distributed across both internal pore channels and external surfaces of PAC. This work provides a solid theoretical basis and experimental data for odor pollution remediation by the structural optimization of PAC.

H ⁺ and ˙O ₂ ⁻ as the dominant reactive species responsible for the degradation of TCs and ARGs and A Z-scheme heterojunction mechanism was proposed for the Bi ₂ WO ₆ /g-C ₃ N ₄ composite to explain the enhanced charge separation.

Catalytic ozonation with metal oxides is of interest for advanced water treatment technology. The amount of active oxygen-containing radicals produced is a primary objective of this process. Fe₂O₃ is a widely used catalyst because of its high performance. In this study, Fe₂O₃/SBA-15 was synthesized and characterized. The results revealed that Fe₂O₃/SBA-15 was a nano-/mesoporous material with high-order hexagonal array structures and exhibited greater catalytic performance than Fe₂O₃ in ozonation processes. To investigate the role of the Fe₂O₃/SBA-15 surface in O₃ decomposition, the kinetic constant was measured, and the interfacial reactions were discussed. Compared with Fe₂O₃, Fe₂O₃/SBA-15 significantly increased the formation of hydroxyl radicals (•OH) and the efficient utilization of O₃ in the catalytic O₃ decomposition process. The SBA-15 support decreased the O₃ self-decomposition rate during catalytic ozonation with Fe₂O₃/SBA-15, which resulted in increased formation of •OH via the reaction between O₃ and Fe₂O₃. From a practical point of view, Fe₂O₃/SBA-15 is an efficient green ozonation catalyst for water treatment.

Hydrothermal carbonation carbon (HTCC) is emerging as a promising material for the adsorption and photodegradation of environmental contaminants. However, the chemical and structural properties of HTCC derived from different lignocellulose biomass have obvious impacts on adsorption and photodegradation. This work employed three different lignocellulose components, including cellulose, hemicellulose, and lignin to synthesize HTCC within a hydrothermal temperature range of 210~290 °C. In comparison to HTCC derived from cellulose and hemicellulose, HTCC derived from lignin (HTCC-L) demonstrated the optimal synergistic adsorption and photodegradation ability for TC degradation, achieving a 63.5% removal efficiency within 120 min. Characterization highlighted the crucial involvement of oxygenated functional groups, especially carboxyl groups, presented on the surface of HTCC-L in TC adsorption. Moreover, the photodegradation of HTCC-L was found to follow a non-radical mechanism, characterized by the charge transformation occurring between the excited unpaired electrons of HTCC-L and TC adsorbed on its surface. This work clarified the differences in HTCC derived from different lignocellulose components on the adsorption and photodegradation of organic pollutants, and provided a novel perspective on the application of HTCC in water treatment.

In this paper, magnetic molecularly imprinted polymers (MMIPs) were fabricated on the surface of Fe₃O₄ by surface molecular imprinting technology, which can selectively adsorb 17β-estradiol (E2). The optimized experiments demonstrated that MMIPs possessed the best adsorption capacity when methanol was used as the solvent and MAA was used as the crosslinking agent, with a molar ratio of E2: MMA: EGDMA as 1:4:50. SEM, FTIR, and XRD were employed to investigate the morphologies of MMIPs and the results demonstrated that the MMIPs that can selectively adsorb E2 were successfully prepared on Fe₃O₄ particles. The adsorption experiments showed that 92.1% of E2 was adsorbed by the MMIPs, which is higher than the magnetic non-molecularly imprinted polymers (MNIPs). The Freundlich isotherm model was more suitable to describe the adsorption process of E2 by MMIPs. Meanwhile, MMIPs had a better recognition ability for E2 and its structural analogs such as estrone and estriol. The MMIPs still had good adsorption performance after methanol regeneration five times. The prepared MMIPs had the advantages of efficient adsorption ability and high reusability, so they can be applied for selective recognition and removal of E2.

Natural organic matter (NOM) has always been considered the main precursor of disinfection by-products (DBPs) during the chlorine disinfection of drinking water. This research focuses on investigating the correlation between the functional group (carboxyl and carbonyl groups) content of NOM and the formation of trichloromethane (TCM) and chloral hydrate (CH). The quantitative determination of carboxyl groups, carbonyl groups, TCM, and CH were conducted during the drinking water treatment processes with different coagulant dosages and with/without pre-oxidation by KMnO₄ or NaClO. The most appropriate coagulant for the removal of conventional components was polyaluminum chloride (PAC), and the dosage was 110 mg/L. Up to 43.7% and 14.5% of the carboxyl and carbonyl groups, respectively, were removed through the coagulation and sedimentation processes, which can be enhanced by increasing PAC dosage. The filtration process further increased the removal rates of these two functional groups to 59.8% and 33.5%, respectively. The formation potential of the TCM and CH decreased as the PAC dosage increased. Pre-oxidation by KMnO₄ (0.8–1.0 mg/L) effectively controlled the formation of DBPs while increasing the carboxyl and carbonyl group content. Pre-oxidation by NaClO decreased the formation of TCM rather than CH, and a suitable amount (0.5–1.0 mg/L) decreased the carboxyl and carbonyl groups. It was found that there was a good linear correlation between carboxyl groups and TCM and CH. The linear fit R² values of the carboxyl groups to TCM and CH were 0.6644 and 0.7957, respectively. The linear fit R² values of the carbonyl groups to TCM and CH were 0.5373 and 0.7595, respectively.