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Ultrathin, molecular sieving membranes composed of microporous materials offer great potential to realize high permeances and selectivities in separation applications, but strategies for their production have remained a challenge. Here we show a route for the scalable production of nanometre-thick metal–organic framework (MOF) molecular sieving membranes, specifically via gel–vapour deposition, which combines sol–gel coating with vapour deposition for solvent-/modification-free and precursor-/time-saving synthesis. The uniform MOF membranes thus prepared have controllable thicknesses, down to ~17 nm, and show one to three orders of magnitude higher gas permeances than those of conventional membranes, up to 215.4 × 10 −7  mol m −2  s −1  Pa −1 for H 2 , and H 2 /C 3 H 8 , CO 2 /C 3 H 8 and C 3 H 6 /C 3 H 8 selectivities of as high as 3,400, 1,030 and 70, respectively. We further demonstrate the in situ scale-up processing of a MOF membrane module (30 polymeric hollow fibres with membrane area of 340 cm 2 ) without deterioration in selectivity. MOF-based membranes have shown great promise in separation applications, but producing thin membranes that allow for high fluxes remains challenging. Here, the authors use a gel–vapour deposition strategy to fabricate composite membranes with less than 20 nm thicknesses and high gas permeances and selectivities.

The development of water-stable metal-organic frameworks is a critical issue for their photocatalysis applications in water treatment. A phenyl-ethyl side chain with low surface energy was grafted into NH 2 -MIL-101(Fe) through a post-synthetic modification (PSM) method. As a result, a novel MIL-101(Fe)-1-(4-(ethyl)phenyl)urea (named MIL-101(Fe)-EPU) was synthesized. Basic morphology, crystal structure, and chemical bond features of MIL-101(Fe)-EPU were retained after PSM. Nitrogen X-ray photoelectron spectroscopy analysis confirmed the successful introduction of the phenyl-ethyl side chain, and this transformation increased its hydrophobicity and water stability. Contact angles of MIL-101(Fe)-EPU to water raised from 59.6 to 140.4°. And its structure maintained intact after 72 h water exposure, indicating higher stability than parent NH 2 -MIL-101(Fe). In the photocatalysis reaction with visible light and oxidant donor (H 2 O 2 ), MIL-101(Fe)-EPU demonstrated a degradation efficiency of tetrabromobisphenol A with a reaction rate at 0.0313 min −1 . The predominant reaction mechanism was OH·oxidation. The acid condition was beneficial for this photocatalysis reaction and high stability was observed. Besides, photocatalysis efficiency, crystal structure, and chemical structures were all retained in different actual water mediums, suggesting high adaptability of MIL-101(Fe)-EPU. In general, hydrophobic group grafting using a PSM method endows MIL-101(Fe)-EPU the potentiality as photocatalyst for organic contaminant elimination from water.

Chlorination disinfection in water treatments may be highly destructive to microplastics (MPs). Herein, low- and high-dose (concentration–time values at 75 and 9,600 mg min L−1, respectively) chlorination processes were used to simulate short-term chlorination in drinking water treatment plants and long-term residual chlorine reaction in drinking water supply systems, respectively. Both chlorination processes induced modifications to polyethylene (PE), polyethylene terephthalate (PET), polystyrene (PS), and polyvinyl chloride (PVC) MPs, varying in polymer types and sizes. Oxidized and chlorinated bonds were detected, and destructed surfaces with increased specific surface area and reduced hydrophobicity were observed. As a result, the sorption capacity of all MPs was weakened, e.g., low-dose chlorination (pH 7) depressed the sorption of ciprofloxacin by 6.5 μm PE (Kf from 0.140 to 0.128 L g−1). The sinking behavior of PET, PS, and PVC MPs was enhanced, e.g., the sinking ratio of 200 μm PET increased by ∼30% after low-dose chlorination (pH 7). By contrast, PE tended to float after high-dose chlorination. Furthermore, chlorination of MPs generated various products, which were the degraded fragments from the MP skeleton. In general, chlorination disinfection reduces the potential of MPs as transport vectors of organic contaminants.

Herein, triphenyltin (TPT) biodegradation efficiency and its transformation pathway have been elucidated. To better understand the molecular mechanism of TPT degradation, the interactions between amino acids, primary structures, and quaternary conformations of effector proteins and TPT were studied. The results verified that TPT recognition and binding depended on amino acid sequences but not on secondary, tertiary or quaternary protein structure. During this process, TPT could change the molecular weight and isoelectric point of effector proteins, induce their methylation or demethylation, and alter their conformation. The effector proteins, alkyl hydroperoxide reductase and acetyl-CoA acetyltransferase, recognizing TPT were crucial to TPT degradation. Electron transfer flavoprotein subunit alpha, phosphoenolpyruvate carboxykinase, aconitate hydratase, branched-chain alpha-keto acid dehydrogenase E1 component, biotin carboxylase and superoxide dismutase were related to energy and carbon metabolism, which was consistent with the results in vivo . The current findings develop a new approach for investigating the interactions between proteins and target compounds.

Colorful spectra are important for the diverse applications of persistent phosphors. A color conversion concept is developed to obtain abundant persistent luminescence color by mining capacities of known persistent phosphors with the most efficient persistent properties. Here, SiO2/Sr2MgSi2O7:Eu,Dy nanoparticles are chosen as a blue persistent luminescence donor nanophosphor, while ultrafine CaAlSiN3:Eu is utilized as a red conversion phosphor to tune the persistent luminescence spectra from blue to red. The red afterglow emission can persist for more than 5 h. The decay of the red afterglow follows nearly the same kinetics as that of the blue one. Continuous color tuning can be successfully obtained by simply changing the mass ratio of the donor/conversion phosphor pair. This color conversion strategy may be significant in indicating numerous persistent/conversion nanocomposites or nanostructures and advance the development of persistent phosphors in diverse fields which need colorful spectral properties.

: Metal–organic frameworks (MOFs) are attractive novel classes of porous materials with diverse potentiality and easily tailored structures. It is desirable to evaluate the performance of MOFs as photocatalysts for organic contaminant removal in aqueous matrixes. In this study, iron-based MIL-101(Fe) was synthesized and a photo-Fenton reaction system (multiple wavelength light + MIL-101(Fe) + H 2 O 2 ) was developed for elimination of tris(2-chloroethyl) phosphate (TCEP). Degradation pattern of TCEP followed an S-shape curve, which included a slow induction period and a rapid radical oxidation process. Transport of reactants into MIL-101(Fe) and the activation of electron transport within Fe–O clusters of MIL-101(Fe) may be the dominant mechanisms in the induction period, while a pseudo-first-order kinetics was observed in the hydroxyl radical oxidation process. Removal efficiencies in these two stages highly depended on the reaction conditions. Irradiation at 420 nm and acid condition were conductive, while high temperature and high [H 2 O 2 ]:[MIL-101(Fe)] mass ratio accelerated the reaction. Before complete mineralization, eleven degradation products were generated, and the dominant degradation pathways included cleavage, hydroxylation, carbonylation, and carboxylation. Under acid condition (pH = 3), only 1% mass loss was observed after 60-min reaction, but the iron leakage was aggravated when pH increased. Furthermore, this MOF-photo-Fenton system demonstrated a robust performance on TCEP degradation in actual wastewater matrixes under acid condition. Generally, the MOF-photo-Fenton system is a potential technology for elimination of organic pollutants in aqueous solution.

Pre-treatment (oxidation) may induce potential modifications to microplastics (MPs), further affecting their behaviors and removal efficiency in drinking water treatment plants. Herein, potassium ferrate(VI) oxidation was tested as a pre-treatment for MPs with four polymer types and three sizes each. Surface oxidation occurred with morphology destruction and oxidized bond generation, which were prosperous under low acid conditions (pH 3). As pH increased, the generation and attachment of nascent state ferric oxides (Fe x O x ) gradually became dominant, making MP-Fe x O x complexes. These Fe x O x were identified as Fe(III) compounds, including Fe 2 O 3 and FeOOH, firmly attaching to the MP surface. Using ciprofloxacin as the targeted organic contaminant, the presence of Fe x O x enhanced MP sorption dramatically, e.g., the kinetic constant K f of ciprofloxacin raised from 0.206 (6.5 μm polystyrene) to 1.062 L g −1 (polystyrene-Fe x O x ) after oxidation at pH 6. The sinking performance of MPs was enhanced, especially for small MPs (< 10 μm), which could be attributed to the increasing density and hydrophilicity. For instance, the sinking ratio of 6.5 μm polystyrene increased by 70% after pH 6 oxidation. In general, ferrate pre-oxidation possesses multiple enhanced removals of MPs and organic contaminants through adsorption and sinking, reducing the potential risk of MPs.

Improving the removal efficiency of microplastics (MPs) in water treatment plants is important to reduce their threats to the environment and human beings. In this study, the removal performance and mechanisms of MPs by pre-treatment-enhanced coagulation-flocculation-sedimentation (CFS) were evaluated. The sinking ratio of MPs was employed to quantify their removal efficiency in CFS, while zeta potentials and floc morphology were analyzed to understand the underlying mechanisms. Two key mechanisms for MP removal were identified: charge neutralization and sweep flocculation. As KMnO4 pre-treatment was conducted, oxidation and MnO2 attachment made the MP surface tend to interact with coagulants to form compact flocs. The removal efficiencies of 200-μm polyethylene terephthalate, polystyrene, and polyvinyl chloride increased 24%, 22%, and 17%, respectively, after KMnO4 pre-treatment was performed. The increases were 38%, 40%, and 41%, respectively, for 6.5-μm ones. Notably, 6.5-μm polythene MPs seemed persistent in floating on the surface. Yet, chlorination pre-treatment contributed slight improvements. The intrinsic features of MPs, including density, size, hydrophobicity, and roughness, affected the basic removal in CFS. KMnO4 oxidation and chlorination changed these features, promoting their interactions with coagulants and removal efficiencies. KMnO4-enhanced CFS can be a potential treatment method for MP removal in water treatment plants.

Benzotriazoles (BTs) attract increasing concerns because of abundant presence in environmental water bodies. In this study, degradation of 1H-benzotriazole (1H-BT) was performed by a customized vacuum ultraviolet (VUV) device emitting 185 + 254 nm (VUV/UV-C) irradiation. Degradation of 1H-BT presented an apparent rate constant reached 8.17 × 10−4 s−1. Degradation mechanisms included 185 + 254 nm photodegradation and radical reaction. The later one may be the predominant one, which presented a k·OH-1H-BT at (7.3 ± 0.8) × 109 M−1 s−1. Effects of anions revealed that VUV interception and radical trapping were the dominant restraining factors. Degradation of 1H-BT can be attributed to VUV induced radical-based oxidation. Radical-induced addition, substitution and fracture generated abundant hydroxylated and open-loop products during 10–45 min. Identification using reactive oxygen species and apoptosis in Escherichia coli was conducted. Variations of these two indicators revealed that the incomplete degradation products presented higher toxicities than 1H-BT, and a further mineralization reduced their toxicities. In the pure water solution with little impurities, VUV can induce efficient degradation of 1H-BT, suggesting its potential for eliminating and detoxifying MPs.

The development of water-stable metal-organic frameworks is a critical issue for their photocatalysis applications in water treatment. A phenyl-ethyl side chain with low surface energy was grafted into NH -MIL-101(Fe) through a post-synthetic modification (PSM) method. As a result, a novel MIL-101(Fe)-1-(4-(ethyl)phenyl)urea (named MIL-101(Fe)-EPU) was synthesized. Basic morphology, crystal structure, and chemical bond features of MIL-101(Fe)-EPU were retained after PSM. Nitrogen X-ray photoelectron spectroscopy analysis confirmed the successful introduction of the phenyl-ethyl side chain, and this transformation increased its hydrophobicity and water stability. Contact angles of MIL-101(Fe)-EPU to water raised from 59.6 to 140.4°. And its structure maintained intact after 72 h water exposure, indicating higher stability than parent NH -MIL-101(Fe). In the photocatalysis reaction with visible light and oxidant donor (H O ), MIL-101(Fe)-EPU demonstrated a degradation efficiency of tetrabromobisphenol A with a reaction rate at 0.0313 min . The predominant reaction mechanism was OH·oxidation. The acid condition was beneficial for this photocatalysis reaction and high stability was observed. Besides, photocatalysis efficiency, crystal structure, and chemical structures were all retained in different actual water mediums, suggesting high adaptability of MIL-101(Fe)-EPU. In general, hydrophobic group grafting using a PSM method endows MIL-101(Fe)-EPU the potentiality as photocatalyst for organic contaminant elimination from water.