npj Clean Water最新文献

Polyamide is the most commonly used selective layer in nanofiltration membranes at an industrial scale. However, polyamide membranes lack flexibility, as their performance in terms of rejection and flux becomes fixed once the membrane is formed. Although several studies have explored during- and post-fabrication modifications of polyamide membranes, these approaches result in irreversible changes to membrane properties. Herein, we developed an electrically conductive polyamide membrane with dynamically tunable salt rejection performance by applying external positive or negative potentials. The observed changes in membrane performance were reversible, indicating that the chemical and structural integrity of the membrane is maintained. Furthermore, unlike findings from previous studies, the salt rejection performance of this membrane remains uncompromised even at voltages that induce electrochemical reactions. These results highlight the potential of this membrane for adaptive filtration systems and applications requiring electrochemical reactions without sacrificing separation efficiency.

As an integral component of the global nitrogen cycle, nitrate are readily transferred from urban sewage discharge, agricultural activities, and atmospheric sedimentation to surface water. This paper introduces an innovative framework that combines multi-source remote sensing technology with stable nitrate nitrogen (δ¹⁵N-NO₃⁻) and oxygen (δ¹⁸O-NO₃⁻) isotopes mixing model, to identify nitrate sources quantitatively in surface water for the first time (R² range from 0.50 to 0.99, RMSE range from 0.05‰ to 2.31‰, MAE range from 0.03‰ to 1.35‰). By reconstructing the historical nitrate isotopes from 2006 to 2023, we found that manure and sewage were the main contributing sources, followed by soil nitrogen, fertilizer and atmospheric deposition (contribution ratio of 3.5:2.5:2.5:1.5), wastewater discharge and fertilizer application in Xijiang river had a significant impact on this. This framework fills a gap in the research pertaining to remote sensing technology’s identification of surface nitrate sources, facilitating straightforward and user-friendly forecasting of nitrate source spatio-temporal sequences.

While self-cycled Fenton (SC-Fenton) systems represent an innovative advancement in water purification technologies, their practical implementation remains constrained by inefficient in situ H₂O₂ generation. To address this limitation, we developed a mechano-driven contact-electro-catalysis (CEC) platform employing fluorinated ethylene propylene (FEP) as a triboelectric catalyst. Under ultrasound irradiation, this system achieves an exceptional H₂O₂ generation rate of 7.67 mmol·g_cat^–1·h^–1, outperforming conventional piezo-catalysis systems. Mechanistic studies reveal that a built interfacial electric field generated on the FEP surface effectively reduces the free energy for the indirect 2e^– water oxidation pathway. This unique characteristic promotes the generation of interfacial hydroxyl radical (^*OH) and enhances its subsequent recombination into H₂O₂. The strategic integration of Fe^III as a catalytic initiator with the CEC system enables the establishment of SC-Fenton reaction (Fe^III/FEP/CEC). Notably, the contact-electrification electrons accumulated on the FEP interface drive efficient Fe^III/Fe^II redox cycling, achieving a remarkable degradation rate for sulfadiazine at 0.125 min^–1. This enhanced catalytic performance stems from Fe^III-mediated amplification of dissociative hydroxyl radical (^•OH) generation. This study provides fundamental insights into the underlying mechanisms of CEC-mediated Fe^III-initiated SC-Fenton reaction, offering new possibilities for sustainable water purification processes.

Per- and polyfluoroalkyl substances (PFAS) are a class of synthetic chemicals that are highly resistant to degradation because of the strong C-F bond and their unique physico-chemical properties. Several techniques, both destructive and non-destructive, have been explored for removing PFAS from contaminated water. However, the most desirable techniques, ideally capable of effective separation and complete PFAS destruction and mineralization, have not progressed beyond bench-scale testing. This paper provides an overview of the existing treatment techniques demonstrated at laboratory, pilot, and industrial scales, and their associated treatment mechanisms. Insufficient data on pilot-scale and full-scale applications for PFAS remediation has limited the optimization and advancement of these systems at a large scale. Most research related to PFAS-remediation is based on laboratory-scale studies under ideal conditions that do not represent the complexity of PFAS-contaminated media. Factors such as inhibition by competing background compounds and secondary water or air pollution limit the application of some PFAS removal techniques at full-scale. Additionally, high energy intensity, cost, and inappropriate reactor design restrict the scalability of some proposed innovations. Here, we propose integrated systems and treatment trains as potential approaches to effectively remove and destroy PFAS from contaminated waters. This review also offers and contextualizes implementation barriers and scalable approaches for PFAS treatment.

Organic and inorganic phosphonates often co-exist in municipal sewage, and it is a challenge to remove them simultaneously. Nanoparticle Fe₃O₄ (Fe₃O₄ NPs) has attracted significant attention due to its high adsorption activity, low cost, environmental friendliness, and magnetic separation. Herein, the adsorption performance and mechanism of hydroxyethylidene diphosphonic acid (HEDP) and orthophosphate (PO₄³⁻) onto Fe₃O₄ NPs were systematically investigated. When the dosages were 0.4 g/L, the removal efficiencies of HEDP and PO₄³⁻ reached 96.3% and 95.1%, respectively. pH had no significant impact on the adsorption, whereas the presence of HCO₃⁻/CO₃²⁻ markedly suppressed the removal of HEDP and PO₄³⁻. The adsorption of HEDP and PO₄³⁻ onto Fe₃O₄ NPs conformed to the pseudo-second-order kinetics and Langmuir isotherm models in single and binary P systems. HEDP consistently inhibited the removal of PO₄³⁻ in the binary P system. The adsorption mechanisms were primarily driven by the combined effect of electrostatic attraction, hydrogen bonding, and coordination complexation. DFT molecular simulation showed higher adsorption energy between HEDP and Fe₃O₄ NPs, and the simulation outcomes were in excellent agreement with the experimental data. Although the adsorption of HEDP and PO₄³⁻ was competitive, total phosphorus in the effluent of municipal sewage could still meet the discharge standard.

This study introduces a hydrogenated FeCo-MOF derivative catalyst (HC-FeCo@C₃₅₀) to activate peracetic acid (PAA) for efficient degradation dye wastewater. Rhodamine B (RhB) as a model pollutant, the HC-FeCo@C₃₅₀/PAA achieved a 99.33% removal efficiency within 20 min, with a rate constant 18 times higher than the non-hydrogenated system. Liquid chromatography-mass spectrometry (LC-MS) and the toxicity evaluation software (T.E.S.T.) confirmed reduced intermediate toxicity. Quenching experiments, electron paramagnetic resonance (EPR) tests, and density functional theory (DFT) calculation show that HC-FeCo@C₃₅₀ can effectively activate PAA to produce ¹O₂, CH₃C(O)O•, and CH₃C(O)OO•. The magnetically recoverable catalyst maintained over 80% efficiency after 4 cycles. In actual dye wastewater treatment, the RE of chemical oxygen demand (COD), ammonia nitrogen (NH₃-N), total nitrogen (TN), total phosphorus (TP) could reach approximately 53.57%, 53.23%, 29.25%, 19.2%, respectively, with reduced toxicity validated by mungbean germination experiment. This technology offers a promising approach for refractory dye wastewater treatment and reuse.

The Yangtze River Delta (YRD) region, a pivotal economic hub in China, relies on water, energy, food, ecology, land, for its prosperity development. Therefore, evaluating their coupling and coordination aids the YRD’s sustainable development. This study integrated ecology and land into the water-energy-food system to form a water-energy-food-ecology-land system (WEFEFS), and the entropy weight model, comprehensive evaluation index model and coupling coordination degree models were used to assess the WEFELS in the YRD (2005-2022), and identified key influencing factors through an obstacle model. The results demonstrate that the comprehensive evaluation index of WEFELS in the YRD rose slowly, with the food system contributing the most (22.15%) and the water system contributed the least (18.25%). The degree of coupling coordination (DCC) of WEFELS in the YRD improved from 0.561 to 0.653, exhibiting spatiotemporal heterogeneity, with Anhui Province leading spatially. The main obstacle factors were Per land GDP and Energy self-sufficiency rate.

Hollow fiber membranes were fabricated using polyvinylidene fluoride (PVDF) via the thermally induced phase separation method for oil-water separation. By introducing glycerol triacetate (GTA) or propylene carbonate as an extruded solvent, membrane porosity and pore size were controlled, significantly enhancing water permeance. The highest porosity and permeance were achieved with GTA as the co-extruded solvent. To further improve separation performance, a polyvinyl alcohol (PVA) coating was applied, forming a superhydrophilic and superoleophobic membrane composite. The coated membranes exhibited complete water absorption (0° contact angle) while repelling oil, preventing droplet adhesion. Antifouling performance was significantly improved, with flux recovery ratios exceeding 90% compared to 2–26% for uncoated membranes. The best-performing membrane achieved a high oil-in-water emulsion permeance of 3551 LMH/bar and 99.2% soybean oil removal efficiency. These findings demonstrate the potential of superhydrophilic and superoleophobic membranes with controlled porosity for efficient oil-water separation.

Corrosion in buried concrete sewer pipelines remains a critical challenge for infrastructure sustainability, driven by the complex interplay of environmental, material, operational, pipe-related, and physical factors with inherent uncertainty and interdependency, aspects often overlooked previously. This study introduces a novel compounded fuzzy entropy-based approach to systematically prioritize critical corrosion-inducing factors, integrating environmental (H₂S, pH, humidity, temperature, O₂), material (cement content, alkalinity, w/c ratio, porosity, permeability), pipe-related (age, length, diameter, depth, slope), operational (flow velocity, water pressure, hydraulic energy loss, sewage residence time, sewer type), and physical (soil type, corrosivity, moisture, groundwater level, external load) factors. Results identify H₂S (0.2073), pH (0.2055), humidity (0.2031), pipe age (0.2039), length (0.2019), cement content (0.2026), alkalinity (0.2015), water pressure (0.2073), flow velocity (0.2043), soil type (0.2042), and soil corrosivity (0.2025) as the most influential contributors, enabling targeted corrosion mitigation strategies and enhancing infrastructure resilience.

To address the environmental threats posed by dye pollution, it is crucial to develop adsorbents with high selectivity and adsorption capacity for the removal of chemical dye pollutants. In this study, five types of Ni/Fe-MOFs were synthesized via a one-pot solvothermal method by varying the Ni/Fe molar ratio. Their physicochemical structures, surface morphologies, and compositions were characterized through a series of techniques, and their adsorption performances for different dyes were preliminarily investigated. The results demonstrated that the Ni/Fe ratio significantly affects the microstructure and adsorption performance of the MOFs. As the molar ratio of Ni/Fe increased, the structures of the five materials transformed from nanoflowers_(Fe-MOFs) to nanospheres_{(Ni/Fe(3:1)MOFs)}, and eventually to rhombic blocks_(Ni-MOFs). The specific surface area decreased from 281.3 m²/g_(Fe-MOFs) to 67.11 m²/g_{(Ni/Fe(1:1)MOFs)} and further to 0.5369 m²/g_(Ni-MOFs). XPS analysis confirmed the synergistic coordination between Ni and Fe, and FT-IR spectra revealed characteristic peaks for hydroxyl groups on the MOF surface and carboxylate ligands. XRD analysis indicated that materials with higher Ni content were more prone to ligand decomposition, which is consistent with the weight loss observed in the TG-DSC between 230 and 350 °C. The materials exhibited selective adsorption for different dyes. Under optimal conditions, the maximum adsorption capacities for Eosin Y (EY), Neutral Red (NR), and Acid Fuchsin (AF) were 54.92 mg/g_(Fe-MOFs), 636.31 mg/g_(Ni-MOFs), and 79.30 mg/g_{(Ni/Fe(1:1)MOFs)}, respectively. The adsorption kinetics followed a pseudo-second-order model, and the adsorption isotherms conformed to the Langmuir model, while Fe-MOFs and Ni/Fe(1:1) MOFs also exhibited compatibility with the Freundlich model. The adsorption mechanism primarily involved monolayer adsorption as the dominant process, with localized multilayer adsorption, as well as chemisorption, hydrogen bonding, hydroxyl interactions, and electrostatic interactions. These MOFs demonstrated high dye removal efficiency in actual water samples and fruit and vegetable juices, exhibiting excellent reusability and anti-interference capabilities. Importantly, compared with the single system, Fe-MOFs and Ni/Fe(1:1)MOFs exhibit competitive adsorption, and Ni-MOFs exhibit synergistic adsorption in the binary system. This study confirms that by adjusting the Ni/Fe molar ratio, MOFs with high selectivity and adsorption performance for different dyes can be designed, providing new theoretical insights and technical support for environmental remediation and food safety applications.