Search

A double-layer [MIL-88A/graphitic carbon nitride(g-C3N4) + MoS2] nanofiber was prepared by electrospinning technology as a functional layer for fabricating a multifunctional hydrophilicity filter membrane (named as C-P@MIL-P@MoS2) after coating a smooth and dense chitosan (CS) on the nanofiber surface. This C-P@MIL-P@MoS2 membrane exhibted excellent adsorption and oxidation performance for eliminating dyes and Sb(III) in printing and dyeing wastewater. When adding H2O2 and light conditions at the same time, the C-P@MIL-P@MoS2 membrane can completely degrade 50 mg·L−1 of MB within 20 min. Further mechanism research found that the PAN(polyacrylonitrile)@MIL-88A/g-C3N4 catalytic layer and PSF(polysulfone)@MoS2 promoter layer have a good synergistic effect, which can produce more hydroxyl radicals( OH) for effectively degrading MB. The pure water flux can reach 431.2 LMH when the C-P@MIL-P@MoS2 membrane is used as the filter membrane, while [MB + Sb(III)] wastewater flux is significantly influenced by the membrane fouling. The photo-Fenton reaction on [MIL-88A/g-C3N4 + MoS2] layer can efficiently degrade MB by OH to recover the water flux of contaminated membrane and increase the rejection rate. Meanwhile, Sb(III) was oxidized to Sb(V) with low toxicity and adsorbed on MIL-88A/g-C3N4 particles in the C-P@MIL-P@MoS2 membrane for removal. In this study, the MoS2 co-catalyst was introduced into the multifunctional catalytic membrane for the first time, which provide a new idea for the development of high-efficiency self-cleaning filter membranes.

Membrane distillation (MD) holds great potential in the desalination of high concentration brines but need improvement to achieve sustained permeate flux and durable performance in long-term MD operation. In this study, a novel Janus membrane with sandwich structure was fabricated. Detailly, the microporous PVDF membrane was single-side modified with a bio-inspired hydrophilic polydopamine/polyethylenimine (PDA/PEI) coating, then a hydrophobic nanofiber layer was constructed via forcespinning on the other side as an anti-wetting layer. As the PDA/PEI deposition time increases from 0 to 1.5 h, the contact angle of the modified PVDF membrane surface decreases gradually from 124.6° to 31.3° with little change in membrane morphology and pore structures, resulting in an upward trend of permeate flux up to 50.9 LMH at a feed temperature of 70 °C. The rough forcespun nanofiber layer endows the membrane surface with good hydrophobicity, which brings improved LEP (136.4 kPa) and operation durability for the membrane during MD process. Moreover, numerical simulations were conducted to verify and predict the permeate flux variation of MD membranes under different operation conditions, revealing the superiority of the sandwich-structured Janus membrane combined with the experimental results. Finally, the optimized PDA-PVDF-NF membrane was used for the desalination of model inland brine, exhibiting stable MD performance with high permeate flux of 25 LMH, ~100% salt rejection, and excellent water recovery during a continuous operation as long as 96 h.

As antibiotic resistance genes have continued to spread, they have become a new research hotspot in the field of sewage treatment. Herein, the rejection of tetracycline-resistant genes (TRGs) in reclaimed water by forward-osmosis (FO) membranes, were modified by silver nanoparticles (AgNPs) anchored titanium dioxide (TiO2), and investigated. The AgNPs were immobilized in TiO2 with dopamine as a reducing agent and a binder. The composite FO membranes were obtained by interfacial polymerization with the electrospun-polysulfone/TiO2/AgNPs-composite nanofiber membranes. Results show that the thin-film nanocomposite membrane with 0.3 wt% TiO2/AgNPs-loading (TFN0.3) exhibited excellent physicochemical properties and performed prominently in regards to water flux, reverse salt flux, and antimicrobial activity. Moreover, rejection characteristics of five kinds of TRGs (tetA, tetC, tetM, tetO, and tetX) and the integrase gene of class 1 integrons (int1) by the as-prepared FO membranes were also studied. In the sample results, TFN0.3 had a better performance in rejecting TRGs and int1 than others. The rejection of TRGs by TFN0.3 under AL-FS (active layer-facing feed solution) and AL-DS (active layer-facing draw solution) mode were 28.53% and 24.48% higher than those using a pristine thin-film composite membrane, respectively.