npj Clean Water最新文献

Surface patterning is a promising anti-fouling strategy, yet its integration with conductive polymers remains underexplored. This study investigates electrically conductive, surface-patterned membranes with integrated porous feed spacers using polyaniline (PANI) as a conductive additive in polyethersulfone (PES) membranes. Among tested concentrations (0.25–2.00 wt.%), 1.00 wt.% PANI membrane (PN1) showed the best performance, with electrical conductivity of ≈130.5 ± 2.87 mS·m⁻¹ and pure water flux of 107.2 ± 15.5 L·m⁻²·h⁻¹ which is around five times that of pristine PES membrane. Under a 4 V electric field, PN1 exhibited lower flux decline (60.6%) and higher flux recovery (FRR 90.1 ± 2.15%). Surface-patterned PN1 membrane (PN1_Patterned) further enhanced performance, achieving a flux of 168.2 ± 20.7 L·m⁻²·h⁻¹ and reduced fouling (51.6% flux decline) compared to surface-patterned PES membrane (66.7%). PN1_Patterned membrane also showed higher FRR (95.4 ± 1.68%) and stable natural organic matter (NOM) rejection ( > 92.9 ± 1.65%). These results highlight the synergistic benefits of combining conductivity with surface patterning, offering a potential approach for improved membrane performance.

Membrane technology is crucial for water treatment as it effectively separates and rejects pollutants. However, its industrial application is often limited by membrane scaling and fouling issues, which degrade membrane performance and affect the efficiency and longevity of membrane systems. Our previous study demonstrated that a 3D-printed carbon nanotube (CNT) spacer improved membrane performance by increasing the membrane flux and controlling scaling in membrane distillation. Here, we present a detailed mechanism by which a CNT spacer mitigates membrane scaling by inducing cooling crystallisation. The CNT spacer delayed crystallisation and reduced crystal adhesion on both the membrane and spacer surfaces. Additionally, the presence of the CNT spacer resulted in the formation of larger crystals that are less likely to adhere to surfaces. The nanoscale roughness and nanochannels created by the exposed CNT in the spacer appeared to strengthen hydrogen bonding within the solution, further delaying crystallisation and reducing crystal adhesion. These findings were corroborated by comparing the experimental observations with theoretical predictions derived from our mechanistic model, providing a comprehensive understanding of the scaling mitigation process. Our approach addresses several limitations of membrane technology, enhancing performance and reducing scaling and fouling risks, paving the way for broader application in water treatment.

High levels of nitrates and nitrites not only threaten aquatic ecosystems and drinking water safety but also impair the biodegradation efficiency of industrial wastewater. In this study, micro-nano-MoS₂-1013 (0.04 g/L) enhanced denitrification by 56.9% and 29.6% in steel pickling and meat processing wastewaters, respectively, and improved chemical oxygen demand (COD) removal by 136.7% in refinery cooling wastewater under continuous-flow conditions using a 3.5 L upflow anaerobic sludge blanket (UASB) reactor. The catalytic effect of micro-nano-MoS₂ on denitrification was achieved by stimulating an increase in the abundance of denitrification genes and the transcript levels of narL (93.82 times), narG (16.34 times), and nirK (12.27 times) within the bacterial cells, which led to an increase in the expression levels of denitrifying enzymes. These findings have significant implications for the design and optimization of biodegradation processes and bio-denitrification systems, particularly for the treatment of high-concentration nitrate wastewater.

Membrane distillation (MD) faces critical challenges at the industrial scale, including poor permeate flux and membrane fouling. To address these issues and efficiently treat highly saline water, this study presents a nature-inspired approach to fabricating a robust multilayer Janus membrane using a gecko-inspired adhesion mechanism. The proposed membrane was fabricated using a layer-by-layer co-deposition method, combining a surface-roughened PVDF flat-sheet membrane prepared via phase inversion with an electrosprayed hydrophobic PVDF-HFP interfacial layer modified with CuO nanoparticles and an electrospun hydrophilic PEI fiber bottom layer. The hydrophobic top layer exhibited a water contact angle of 131.5°, followed by a superhydrophobic interfacial layer and the bottom/support layer with a contact angle of 41.4°, enabling superior directional wettability. The Janus membrane achieved an impressive water gap membrane distillation (WGMD) flux of 37.16 kg m⁻² h⁻¹ with a high salt rejection rate of 99.99% over 24 h. Furthermore, the membrane demonstrated long-term stability and excellent resistance to fouling and delamination in harsh saline environments, maintaining performance over 60 h of continuous MD operation. This work highlights the potential of bio-inspired engineering in developing efficient and durable membranes, offering a promising pathway for advancing MD technology for industrial-scale desalination.

The current study evaluated the innovative application of membrane distillation crystallization (MDCr) for dual treatment and resource recovery from acid mine drainage (AMD), a persistent environmental crisis in South African. This AMD was characterized by exorbitant concentrations of Ca²⁺ (2622 mg·L⁻¹), Fe²⁺ (1421 mg·L⁻¹), SO₄²⁻(9790 mg·L⁻¹) and Cl⁻ (1113 mg·L⁻¹). The current study evaluated the performance of hollow fibre polypropylene membrane in processing both acidic (pH 3.58) and neutralized (pH 6.47) feedwaters. The permeate was 3.3 kg·m⁻²·h⁻¹, 2.2 kg·m⁻²·h⁻¹ and 1.3 kg·m⁻²·h⁻¹ at 70, 60 and 50 °C respectively, which remained relatively stable at high recovery factors ( >80%). Acidic AMD promoted formation of large metal-rich ettringite and halite crystals while neutralized AMD produced small and dense ettringite, hexahydrite and jarosite crystals. This study highlighted the dual functionality of MDCr in water treatment and mineral resource recovery, offering a sustainable solution to address the AMD pollution crisis in South Africa.

In this study, graphene quantum dots/titanium dioxide (GQDs/TiO₂) fiber membranes with engineered oxygen vacancies were fabricated using a combination of electrospinning and solvothermal techniques. Oxygen vacancies, as key active sites, enabled spin polarization during the photocatalytic reaction, and the material’s spin polarization was verified by X-ray Absorption Spectroscopy (XAS) and Density Functional Theory (DFT). For the first time, the effects of high magnetic fields (1000–5000 mT) on photocatalytic performance were systematically explored. The findings reveal that the magnetic field markedly enhances spin polarization, facilitating synergistic interactions between oxygen vacancies and photogenerated electrons while significantly suppressing carrier recombination. Under these conditions, the GQDs/TiO₂ fiber membranes achieved a remarkable 52.44% increase in the degradation rate of methylene blue compared to zero-field conditions. Additionally, the study introduces the concept of magnetic field-induced progressive energy level modulation, wherein defect state energy levels undergo gradual adjustment before stabilization under magnetic influence. This work provides critical insights into radical generation mechanisms driven by the interplay between magnetic fields and oxygen vacancies, offering a novel pathway for designing advanced photocatalysts with broad applications in water pollution treatment and sustainable energy solutions.

Solving three-dimensional (3D) multi-physics forward and inverse problems is indispensable for fundamental understanding and optimal design of membrane-based desalination systems. Unfortunately, it is computationally expensive when applying traditional numerical methods. Herein, a modified Fourier neural operator (FNO)-based method is proposed to efficiently solve complex 3D multi-physics problems. The intelligent solver solves the 3D forward problems in seconds, which is approximately 10⁵-10⁶ times faster than traditional finite-element based method with a comparable solution quality. The average prediction accuracy is more than 96%. Moreover, the proposed FNO-based method is mesh-independent and has zero-shot super-resolution ability. It can be used to provide a fast solution for the optimal design of membrane module to mitigate concentration polarization and membrane fouling for next-generation ultrapermeable membrane system.

To overcome the short retention time in small-scale wastewater treatment plants, it is necessary to develop processes with fast reaction rates. The microwave-Fenton-like reaction (MW-Fenton-like reaction), which combines external energy and catalysts, provides a solution with rapid reaction rate and high degradation efficiency. In this reaction, catalysts significantly influence decomposition efficiency. Developing magnetic catalysts can simplify the separation process. In this study, the superiority of copper-based metal oxides for the MW-Fenton-like reaction was confirmed through comparative experiments of various metal oxides. Based on these findings, highly active CuFe₂O₄/Cu particles were developed. The synthesized particles, with rough-surfaced solid-sphere morphology, exhibited ferromagnetic properties and were completely separated using a laboratory-scale magnet. CuFe₂O₄/Cu also showed high degradation over a wide pH range and achieved the highest degradation rate at pH 7. Furthermore, comparison of 4-nitrophenol (4-NP) degradation using MW and conventional heating demonstrated MW was superior in reaction rate, efficiency, and reusability.

Utilizing ligand-mediated homogeneous catalysis to enhance oxidant-driven pollutant removal efficiency presents significant research value while posing substantial challenges. This study utilized ethylenediaminetetraacetic acid (EDTA) to alter the coordination environment of ferrate(VI), thereby steering electron transfer and the phenoxylation pathways to enhance the pollutant removal, which is realized by the complexation-mediated regulation for kinetics and thermodynamics. For example, the introduction of EDTA increased the rate constant of ferrate(VI) oxidizing phenol by four times (from 50.79 M⁻¹ s⁻¹ to 208 M⁻¹ s⁻¹) and the stoichiometric ratio (∆[phenol]/∆[K₂FeO₄]) from 0.17:1 to 0.22:1. Theoretical calculation and experimental characterization proved that the in-situ formed metastable Fe(VI)-EDTA complex facilitates the electron transfer from Fe(VI) to benzene ring and the phenoxylation pathways. Consequently, the related polymerization products were produced in greater quantities (about 5 times) and with broader diversity than Fe(VI) alone. In the application to real water, the introduction of EDTA reduced more than half of ferrate(VI)’s dosage previously required for completely removing phenol. This study presents a novel strategy for optimizing ferrate(VI) oxidizing pollutants in water treatment, which presents notable environmental benefits by minimizing ferrate(VI) consumption and enhancing pollutant removal efficiency.

This study developed a gravity-driven membrane bioreactor (GD-MBR) to reduce energy consumption in wastewater treatment. The system maintained a stable flux of 6 L/m²/h when treating high-organic wastewater loads (TOC: 270 mg/L, SS: 7,000 mg/L), surpassing conventional GDMs (2–4 L/m²/h). Quorum quenching (QQ) extended stable flux duration and increased cumulative permeate volume by 26%, treating 130 L and 73 L over 65 and 35 days, respectively, compared to 105 L and 50 L in the non-QQ system. QQ reduced biofilm extracellular polymeric substances (polysaccharides by 30% and proteins by 20%) and significantly lowered N-acylhomoserine lactone concentrations (e.g., C8-HSL: 0.02 ± 0.01 pM vs. 0.34 ± 0.03 pM after 106 days). Next-generation sequencing showed increased microbial network complexity (edges: 32 vs. 27) and downregulation of biofilm- and quorum-sensing-related genes (HigA-1, Fis, LuxR family). These results highlight the potential of QQ-enhanced GD-MBRs for energy-efficient treatment of high-organic wastewater loads.