Yue Yuan

Chloride (Cl ^‒ ) exerts complex and condition-dependent effects in heterogeneous catalytic ozonation (HCO), yet current mechanistic interpretations remain fragmented and often lack direct evidence. This Perspective rethinks Cl ^‒ effects across ozone availability, interfacial accessibility, and oxidation pathway regulation, while considering complexities under realistic saline conditions. A roadmap integrating comprehensive performance assessment, subprocess-specific validation, and application-oriented evaluation is proposed to enable more reliable interpretation of Cl ^‒ effects.

Carbon membranes have emerged as a promising class of inorganic membranes for desalination due to their tunable pore structures, superior chemical and thermal stability, and molecular-sieving properties. In pursuit of sustainability, recent research has shifted focus towards replacing petrochemical-based precursors with renewable natural polymers. This review provides a comprehensive examination of the fundamentals, developments, and prospects of carbon membranes derived from natural polymer precursors—such as cellulose, chitosan, lignin, starch, and sugars—specifically for pervaporation desalination. It begins by summarizing the fundamentals of membrane separation and the mechanisms of carbon membrane formation, emphasizing the critical relationships between precursor structure, carbonization conditions, and the resulting membrane performance. The core of the review is dedicated to a detailed analysis of various natural polymer precursors, discussing their unique chemistries, carbonization behaviors, and the characteristics of the derived carbon membranes. Particular attention is given to their application in pervaporation desalination, where they demonstrate competitive water flux and high salt rejection (>99%) under moderate operating conditions, highlighting their potential for treating hypersaline brines. Finally, the challenges of large-scale fabrication, structural durability, and data-driven optimization are discussed, along with future directions toward scalable and sustainable membrane technologies.

To promote sustainable wastewater treatment, this study developed an eco-friendly and low-cost ozone catalyst using natural zeolite for the advanced treatment of petrochemical wastewater. The Ca-Cu/zeolite catalyst (0.75 mol/kg Ca and 0.25 mol/kg Cu) demonstrated high efficiency in catalytic ozonation, achieving 55.52% TOC removal under optimized conditions (ozone dosage: 108.0 mg/(L·h), catalyst dosage: 406.0 g/L, reaction time: 90 min). Compared to ozonation alone, the catalyst enhanced oxidation rates by 10 times, promoting ozone decomposition into reactive oxygen species (e.g., OH and ¹O₂) while improving gas–liquid–solid mass transfer for efficient pollutant mineralization. Remarkably, the natural zeolite-based catalyst exhibited superior sustainability: compared to conventional alumina-based catalysts, its production cost (4000–4500 CNY/ton) is 44–53% lower, while its carbon footprint (533.7 kg CO₂/ton) is reduced by 45.4%. This work presents a sustainable, low-carbon, and economically viable catalytic ozonation solution, contributing to the development of green and cost-effective industrial wastewater treatment technologies.

Global municipal solid waste (~2B tons/year) affects sustainability, as landfill and incineration face persistent leachate contamination, demanding effective management to advance water recycling and circular economies. Accelerated investigation of hybrid biocatalytic ozonation systems is imperative to enhance contaminant removal efficiency for stringent discharge compliance. This study investigates the catalytic ozonation effects of γ-Al₂O₃-based catalysts loaded with different metals (Cu, Mn, Zn, Y, Ce, Fe, Mg) on the biochemical effluent of landfill leachate. The catalysts were synthesized via a mixed method and subsequently characterized using scanning electron microscopy (SEM) and X-ray diffraction (XRD). Pseudo-second-order kinetics revealed active metal loading’s impact on adsorption capacity, with Cu/γ-Al₂O₃ and Mg/γ-Al₂O₃ achieving the highest Q_e (0.85). To elucidate differential degradation performance among the catalysts, the ozone/oxygen gas mixture was introduced at a controlled flow rate. Experimental results demonstrate that the Cu/γ-Al₂O₃ catalyst, exhibiting optimal comprehensive degradation performance, achieved COD and TOC removal efficiencies of 84.5% and 70.9%, respectively. UV–vis absorbance ratios revealed the following catalytic disparities: Mg/γ-Al₂O₃ achieved the highest aromatic compound removal efficiency; Ce/γ-Al₂O₃ excelled in macromolecular organics degradation. EEM-PARAFAC analysis revealed differential fluorophore removal: Cu/γ-Al₂O₃ exhibited broad efficacy across all five components, while Mg/γ-Al₂O₃ demonstrated optimal removal of C2 and C4, but showed limited efficacy toward C5. These findings provide important insights into selecting catalysts in practical engineering applications for landfill leachate treatment. This study aims to elucidate catalyst formulation-dependent degradation disparities, guiding water quality-specific catalyst selection to ultimately enhance catalytic ozonation efficiency.

Ecological floating beds, with their compact footprint and mobility, offer a promising solution for sustainable surface water remediation in rural areas. However, low removal efficiency and instability still limit its application. In this study, iron–carbon-based fillers were integrated into ecological floating beds to investigate their impact and mechanisms in removing pollutants, including carbon, nitrogen, phosphorus, and heavy metals. Results indicate that all five fillers (activated carbon, iron–carbon fillers, sponge iron, activated carbon + iron–carbon fillers, and activated carbon + sponge iron) can completely remove orthophosphate, and the sponge iron filler system can completely remove nitrate. Then, fillers were applied to ecological floating beds, and the iron–carbon microelectrolysis (activated carbon + sponge iron filler)-enhanced ecological floating bed showed superior removal efficiency for pollutants. It achieved 95% removal of NH₄⁺-N, 85% removal of NO₃⁻-N, 75% removal of total phosphorus, 90% removal of chemical oxygen demand, and 90% removal of heavy metals. Typical nitrifying bacteria Nitrospira, denitrifying bacteria Denitratisoma, and a variety of bacterial genera with denitrification functions (e.g., Rhodobacter, Dechloromonas, Sediminibacterium, and Novosphingobium) coexisted in the system, ensuring efficient and robust nitrogen removal performance. These findings will provide support for the sustainable treatment of surface water in rural areas.

The Yellow River basin serves as an important economic belt and industrial base in China, featuring numerous industrial parks. However, alongside its economic significance, the basin struggles with significant water environmental challenges. This study analyzed the operational status, influent water quality, and energy consumption of 63 centralized wastewater treatment plants (WWTPs) from 54 major industrial parks in the Yellow River basin. The scale of these WWTPs was primarily within the range of 1 × 10⁴~5 × 10⁴ m³/d, with an average hydraulic loading rate of 53.8%. Aerobic treatment processes are predominant. The influent concentrations of chemical oxygen demand (COD), biochemical oxygen demand (BOD), ammonia nitrogen (NH₃-N), total nitrogen (TN), and total phosphorus (TP) in the WWTPs exhibited a right-skewed distribution. The BOD/COD ratio of the WWTPs fluctuated between 0.1 and 1.6, and 75% of the WWTPs showed a COD/TN ratio lower than eight. The average BOD₅/TN was 2.7, and the probability of influent BOD₅/TP > 20 was 84.6%. A significant linear correlation exists between the influent BOD and COD concentrations, while moderate linear relationships are also observed among NH₃-N, TN and TP, emphasizing the importance of maintaining appropriate nitrogen and phosphorus levels for efficient pollutant removal. The average electricity consumption of WWTPs in the Yellow River basin in 2023 was 1.1 kWh/m³. It is important to upgrade these WWTPs and reduce their energy consumption. Further strengthening the construction of industrial wastewater collection and treatment facilities based on regional characteristics is recommended to promote the high-quality development of industrial wastewater treatment in the Yellow River basin.