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Nanofiltration (NF) is considered a competitive technique for acidic stream treatments. However, poorly reactive acid-resistant monomers normally cause thick and uneven separation layers with ultra-low permeability. Herein, catalyst-anchored secondary polymerization is employed after the interfacial polymerization (IP) reaction between trimesoyl chloride (TMC) and 3-aminobenzenesulfonamide (ABSA) to fabricate an extremely acid-resistant NF membrane. Acylation catalysts in ethanol are grafted on the nascent layer by reacting with residual acyl chloride groups to enhance the monomer reactivity, while the ethanol-induced nascent layer structure regulation greatly improves the surface uniformity. Benefiting from the improved self-inhibition effect and optimized phase integrity of the modified IP process, the resulting acid-resistant membrane has unprecedented water permeance (up to 31.4 Lm−2h−1bar−1), desirable Na 2 SO 4 rejection (92.8%), high dye/H+ selectivity and impressive acid stability (20 wt% of H 2 SO 4 for 50 days), outperforming almost all advanced acid-resistant NF membranes. Our work provides a versatile approach for the synthesis of high-performance specialty membranes. [Display omitted] • An acid-resistant NF membrane is fabricated by a catalyst-anchored secondary polymerization. • Anchored catalysts catalyze the secondary polymerization of low-reactive monomers. • Ethanol-induced swelling rearrangement greatly improves the phase interface uniformity. • The NF membrane has unprecedented water permeance up to 31.4 Lm−2h−1bar−1. • The membrane exhibits excellent acid-resistance in 20 wt% H 2 SO 4 for 50 days. [ABSTRACT FROM AUTHOR]

Recovery of volatile organic compounds (VOCs) from industrial wastewaters is important for the prevention of environmental pollution. This study investigated pervaporative recovery of VOCs by vinyltriethoxysilane (VTES)-grafted-silicalite-1/PDMS mixed matrix membrane (MMM) from the methanol-containing binary, ternary and quaternary wastewater solutions. The separation of methanol/water binary mixtures was first conducted. The influence of feed concentration and temperature on the membrane performance, such as permeation fluxes and VOC/water separation factor, was investigated. It was observed that with the increase of VOC concentration in the feed, the total permeation flux increased and the selectivity changed slightly first, then decreased. At a feed methanol concentration of 10.51 wt% at 65 °C, the maximum PSI of 5346 g/m 2 h with a separation factor of over 10 were obtained with the VTES-g-silicalite-1/PDMS MMM, which makes it among the best in the literature and is very competitive for methanol recovery from aqueous solutions. The apparent activation energies of water and VOC during the pervaporation process was calculated based on Arrhenius equation. Then the mixed matrix membrane was applied to ternary and quaternary wastewater model solutions. Compared with binary methanol/water mixture, the addition of ethanol and/or acetone led to a decrease of the total flux, methanol flux, and methanol/water separation factor, but increased the total VOCs flux and the permeate VOCs concentration. Separation factors of individual VOC towards water follow the order of acetone > ethanol > methanol, which is consistent with those in binary aqueous mixtures. [ABSTRACT FROM AUTHOR]

[Display omitted] • NF membranes with particular charge spatial distribution are defined as mix-charged membranes. • Mix-charged NF membrane has higher separation selectivity and better antifouling ability. • Characterization methods with higher resolution and more quantitative index are required. • Polarizing charge distribution by process regulation during interfacial polymerization is promising. • New architectures of mix-charged layer can be designed based on biological ion channel structure. Steric and charge exclusions are mainly responsible for the separation selectivity of nanofiltration (NF) membranes, thereinto membrane charge spatial distribution plays an important role in filtration behavior of charged solutes, yet doesn't get enough attention. In this review, we suggest that NF membranes with particular charge spatial distribution can be called mix-charged membranes. First, the roles of Donnan effect on NF separation selectivity as well as antifouling ability for mix-charged membranes are discussed from practical application point of view. Second, the effect of horizontal/longitudinal charge distribution on the NF performance and corresponding six characterization methods are critically reviewed from the perspective of fundamental research. Third, three fabrication technologies for mix-charged NF membranes including interfacial polymerization (five strategies), sequential coating and self-assemble are summarized, focusing on the strategies to regulate charge proportion and polarize charge distribution. We find that there are still many unclear issues in the separation mechanisms of mix-charged NF membranes, such as micro-electric filed, electrostatic neutralization and ion dehydration, and deeper understanding on the structure-performance relationship and more precise control the charge spatial distribution need a quantitative index of charge distribution and higher-resolution characterization methods. This review not only intends to emphasize the importance of charge spatial distribution of NF membranes, but also offers guidance for designing and developing advanced mix-charged membranes for specialty separations. [ABSTRACT FROM AUTHOR]

Organophilic pervaporation (OPV) has been considered as one of the most promising separation processes for the recovery of biofuels from fermentation broths, however, in addition to preferred target product – liquid biofuels, the yeast cells and fermentation nutrients could affect the recovery efficiency of biofuels from broths by pervaporation. In this paper, the influence of the yeast cells and the fermentation nutrient components such as the sources of carbon, nitrogen and salts on the separation performance of the vinyltriethoxysilane (VTES)-grafted- (VTES- g -) silicalite-1/PDMS/PAN thin-film composite membrane was conducted systematically. The results revealed that glucose, xylose, protein, and salts cannot permeate through the membrane. Glucose concentration in the fermentation broth should be kept at a lower level (less than 20 g/L) to eliminate its deleterious influence on ethanol flux and membrane selectivity. Xylose and corn steep liquor (CSL) have little effect on the pervaporation performance of the composite membrane. The addition of NaCl improved the membrane selectivity and ethanol flux but slightly lowered down total permeation flux. Adding dry yeast cells to the ethanol solution can enhance the turbulence in the feed mixtures, resulting an increase of the membrane flux and selectivity. The pervaporation performance of fermentation broths was also studied. The results showed that the nutrients and the deposition of yeast cells on the membrane surface didn’t deteriorate the pervaporation performance, indicating excellent fouling resistance of the novel VTES- g -silicalite-1/PDMS/PAN composite membrane in operation with fermentation broths. The continuous ethanol fermentation can be directly connected to the in-situ pervaporative recovery system without requiring prior removal of yeast cells. [ABSTRACT FROM AUTHOR]

The electron signals in the cell can be rapidly and accurately transmitted by the spatially confined and adjacently distributed enzyme pairs anchored in the cytomembrane. As inspiration, by leverage of tannic acid‐3‐aminopropyltriethoxysilane‐Fe (TA‐APTES‐Fe) ternary coating, for the first time, a mesoporous biosensing membrane is developed by orderly assembly and targeted confinement of Prussian blue (PB) and glucose oxidase (GOx) with neighborhood nanostructure in the 3D mesoporous carbon nanotubes (CNTs) membrane electrode. The mesoporous biosensing membrane extends the triple‐phase boundary from conventional 2D contact to 3D contact, promotes the transfer rates of the cascade reactants, enhances the proximity of PB, GOx, and the electrode, and achieves in–situ removal of interferents, thereby elevating the utilization of PB, enhancing the cascade reaction efficiency, increasing the availability of the electroactive hydrogen peroxide (H2O2), and improving its stability. It exhibits superior sensitivity (31.2 µA mM−1) and long‐term stability in continuous glucose monitoring with a negligible response drift for up to 8 h. In addition, the multienzyme mimic functions of PB are employed to imitate the "loosening‐degradation" membrane cleaning process via bubble scrubbing and Fenton oxidation, thereby fully regenerating the fouled biosensing membrane. This work provides a novel design strategy for biosensors toward efficient, reliable, and stable sensing. [ABSTRACT FROM AUTHOR]

[Display omitted] • An acid-stable dually charged membrane is obtained by two-layer reverse interfacial polymerization. • Poly(amide-sulfonamide) and polyurea are introduced to enhance the acid resistance and retention ability. • Environmentally friendly additives improve the dually charged structures of separation layer. • Salt-induced permeability enhancement effect of the polyurea separation layer is clarified. • The dually charged nanofiltration membrane has desirable long-term stability in heavy metal removal. Acid-resistant nanofiltration (NF) membrane with precise ionic separation performance and high permeability is imperative for acidic wastewater reuse. However, the trade-off between ions rejection and water permeability is especially serious for acid resistant NF membrane because of the uneven separation layer structure. Herein, we dissect the two-layer reverse interfacial polymerization (r-IP) process for the preparation of high-performance acid-resistant membrane by investigating monomer reactions and phase interface properties. Mixed organic monomers of 1,4-phenylene diisocyanate and trimesoyl chloride are used to react with the negatively charged aqueous monomer 3-aminobenzenesulfonamide to fabricate interlayer with high negative charge density, and then performs a secondary r-IP reaction with another positively charged aqueous monomer polyethyleneimine to construct a positively charged top layer. By changing the monomer compositions and concentrations, the relationship between monomer reaction and membrane performance is elucidated. Importantly, when aqueous additives of ethanol and glycerol are used to regulate the monomer diffusion coefficient, the membrane surface properties and permselectivity can be improved. Compared to the blank, the prepared membrane shows a 200% water permeability enhancement (2.6 Lm-2h-1bar−1) and desirable rejections of both Na 2 SO 4 (97.7%) and MgCl 2 (93.0%). Moreover, the smooth and hydrophilic surface endows the membrane with excellent anti-fouling performance at acidic pH. Benefiting from the robust structure of poly(amide-sulfonamide) and polyurea in the backbone, the membrane shows impressive acid resistance in 10 wt% H 2 SO 4 and long-term stability in heavy metal removal. This work opens new pathways to prepare acid stable NF membrane with desirable permselectivity. [ABSTRACT FROM AUTHOR]

Abstract: Nanofiltration (NF), as a powerful tool for separation of small molecules and salts, has attracted growing attention in many applications such as wastewater treatment, water purification, desalination, food processing and bio-separation. It is well known that pH and salt conditions have significant influence on NF performance. In order to manipulate NF process and optimize its efficiency, it is very important to get insights into the effects of pH and salt on nanofiltration. This paper aims at reviewing the reports on NF performance at different pH and salt conditions, focusing on the mechanisms behind various phenomena induced by pH and salt. The effects of pH and salt on NF are mainly reflected in the variations of membrane flux/permeability, solute rejection and fouling behavior, which also depend on both solute type and solution composition. In order to explain these effects, the changes of membrane properties are evaluated by physical, chemical and mathematical characterization methods. Eight mechanisms for pH and salt effects are summarized and several practical advices for NF operation are provided. Besides, some interesting opinions such as dominant-ions, co-ions competition, salting-out induced pore swelling, charge-induced concentration polarization (CP) are reviewed to elucidate some confusing phenomena reported previously. This review intends to not only offer a clear illustration on this special issue but also to provide a guide to optimize NF separation and maintenance. [Copyright &y& Elsevier]

Abstract: Nanofiltration (NF) has been widely used for treatment of industrial effluents, but very few work concerns NF process in concentrated saline solution, especially for NF-desalination aiming at permeation of monovalent salts and retention of organic solutes. In this study, NF270 membrane was chosen to treat model solutions and three industrial effluents with highly concentrated salt (crude iron dextran solution, iminodiacetic acid mother liquor, and raw soy sauce), showing that with increase of salt concentration, the retention of all the solutes decreased while concentration polarization was increased. In the presence of charged organic solutes, inorganic salt retention would decline, even negative retention of monovalent salt was found. Increasing pH would induce membrane swelling in saline solution, which might be caused by the higher local salt concentration around the membrane polymers at higher pH. As NF-desalination of industrial effluents with highly concentrated salt was scaled up from laboratory to pilot-plant, the dead-end stirred filtration at constant flux could provide some important information for pilot-plant tests, such as membrane selection, optimum operating parameters and mechanism analysis, but it was necessary to re-optimize operating mode and method for crossflow filtration at constant pressure, in order to control the concentration polarization at high salt concentration. [Copyright &y& Elsevier]

Abstract: During desalination of feed with highly concentrated salt by nanofiltration (NF), predictive modeling was difficult due to the effect of salt on retention of organic solutes. Consequently, a better understanding of salt effect on membrane and organic solutes was required. In this study, four well-known commercially available NF polymeric membranes, NF270, NF-, Desal-5 DL and Nanomax50, were analyzed by a model based on an extended Nernst–Planck equation, using highly concentrated glucose and sodium chloride (NaCl) solutions. The results showed that with increasing salt concentration, the solute-to-pore size ratio (λ i) decreased while the ratio of effective membrane thickness to porosity (Δx/ɛ) increased, indicating that the effect of salt may include decreasing solutes size, increasing membrane pore size, and increasing effective membrane thickness. Moreover, such salt effect appeared to be independent of membrane and solute types, and the correction model could well predict the retention of charged solutes at high salt concentration because electrostatic repulsion effect between charged solutes and membranes was completely screened by the salt ions. Meanwhile, several hypotheses such as membrane swelling, hydration layer thinning and particle collision were provided to explain the change of model parameters by highly concentrated salt. [Copyright &y& Elsevier]

Abstract: Using a methodology based on the combination of recently developed parameter scanning ultrafiltration with carrier phase ultrafiltration (CPUF), this article examines the separation of lysozyme directly from natural chicken egg white (CEW) solutions with 30kDa membranes. The suitability of two membranes, i.e. Biomax 30kDa polyethersulfone and Ultracel Amicon YM 30kDa regenerated cellulose membranes were rapidly assessed and the physicochemical conditions likely to be optimal were identified by parameter scanning ultrafiltration. Under suitable conditions, with the Biomax 30kDa membrane, lysozyme transmission from the CEW solution could be more than 80% and the lysozyme purity obtained in permeate was greater than 94% after one stage ultrafiltration process. [Copyright &y& Elsevier]

The effects of pH and ionic strength (salt concentration) on transmission of single protein human serum albumin (HSA) and human immunoglobulins (HIgG) through a 100 kDa molecular weight cut-off (MWCO) polyethersulfone membrane have been studied using a pulsed sample injection technique. Experimental results obtained clearly demonstrate the effectiveness of changing solution pH and ionic strength optimisation for selective transmission of HSA or HIgG. These also demonstrate the usefulness of pulsed injection experimental technique for the optimization of ultrafiltration processes. A pulse input carrier phase ultrafiltration (CPUF) was employed to fractionate a binary protein mixture of HSA and HIgG at low NaCl concentration, showing that it is feasible to separate the binary protein at optimised conditions. [Copyright &y& Elsevier]

The development of high-performance nanofiltration (NF) membranes with extreme chemical stability is urgently needed for the recovery of spent lithium. In this study, a series of polyurea membranes with high lithium recovery efficiency and pH stability were fabricated by zone-regulated interfacial polymerization (IP). The reaction inhibitor Cu2+ in the bulk aqueous phase reduces IP intensity by reversibly binding to the amino groups of polyethyleneimine monomers through chelate bonds. Meanwhile, surfactant promote the uniform diffusion of macromolecular aqueous monomers at the phase interface. The milder polymerization reaction and the more stable phase interface endow the polyurea membrane (NF 10k PEI-SDS-Cu 2+) with higher water permeance (2.1 L m−2 h−1 bar−1), desirable MgCl 2 rejection (94.7 %), and excellent fabrication repeatability. Moreover, the membrane demonstrates stable separation selectivity for Co2+/Li+ and SO 4 2−/Li+ under conditions of 0.05 mol L−1 H 2 SO 4 and 2 mol L−1 LiOH, respectively. Our study provides a facile method for constructing NF membranes with extreme pH stability and confirms the feasibility of membrane-based lithium recovery. [Display omitted] • The diffusion behavior of aqueous monomers is zone-regulated by adding Cu2+ and SDS. • PEI monomer chelated by Cu2+ reduces its diffusion in bulk phase and the intensity of IP reaction. • SDS improves distribution and diffusion of macromolecular monomers at the phase interface. • Milder IP reaction endows the membrane with better fabrication repeatability, especially for larger PEI. • The PU NF membrane is used for purification of Li + at extreme pH in spent lithium-ion battery recycling. [ABSTRACT FROM AUTHOR]

To study the stability control scheme of chemical grouting agent for ionic rare earth mine slope. The improved chemical grouting agent comprised lime, sodium silicate, silica micro powder, calcium lignosulfonate and other water solvents. The differences between the enhanced chemical grouting agent and the traditional chemical grouting agent were observed by using indicators such as slope displacement and soil nail tension. The improved chemical grouting agent showed a positive stability effect in both simulation and field experiments. The improved chemical grouting agent is more suitable for the slope stability control scenario of an ionic rare earth mine. [ABSTRACT FROM AUTHOR]

• Adding Fe3+ to GO membrane can amplify signals of the membrane transverse defects. • Thicker TA-APTES coating is targeted on the large transverse defects of GO membrane. • TA-APTES coating improves both membrane pore size distribution and antifouling ability. • GO membrane with targeted coating has a high and stable rejection of micropollutants. • Such GO membrane is stable under high pressure and cross-flow mode for a long-term. Removal of organic micropollutants (OMPs) in the wastewater treatment is greatly important due to their adverse effects on human health and ecosystem. In this work, we provide a new perspective to prepare graphene oxide (GO) nanofiltration (NF) membrane with narrow pore size distribution for robust removal of OMPs. Ferric ions (Fe3+) mediated GO nanosheets are firstly used to prepare GO membrane, then the membrane surface is modified by a targeted coating layer consisting of tannic acid-aminopropyltriethoxysilane (TA-APTES) via their strong affinity to Fe3+, where the larger membrane defects with more Fe3+ would be patched by thicker TA-APTES. Such "speckled" TA-APTES coating can simultaneously enhance antifouling ability and regulate nanochannels of the GO membrane. The resulted GO membrane shows high and steady rejections on various OMPs, even in the long-term operation, cross-flow filtration or under high-pressure. This work proposes an innovative idea for constructing hydrophilic surface and narrow pore size distribution of NF membrane. [ABSTRACT FROM AUTHOR]

• Loose NF membrane characterized by having large MWCO (500–2000 Da) and high salt permeation. • Loose NF membrane with specific selectivity can be obtained by tuning membrane charge and pore size. • Loose NF for resource recovery not only gains economic interest but also lessens environmental burden. • Membrane selectivity, antifouling and chemical/thermal resistance are important for resource recovery. • Loose NF membrane based on advanced materials is promising but large-scale fabrication is challenging. Compared to the traditional nanofiltration (NF) membrane with molecular weight cut-off (MWCO) below 500 Da, an emerging loose NF (LNF) membrane with MWCO of 500 ~ 2000 Da has attracted increasing interests due to its higher selectivity and lower operating pressure, which exhibited distinct advantages in resource recovery from biomass and wastewater. This review summarizes the development of the LNF membranes, focusing on their preparations and applications. Regarding the membrane preparation, phase inversion and interfacial polymerization are the two leading and scalable fabrication methods, and other methods including dip coating, mussel-inspired deposition, self-assembly, grafting polymerization, and nanomaterials assembly/growth are also widely studied at a laboratory scale. As for the application of LNF, the fractionation of saccharides, polyphenols, and pigments for bioresource recovery as well as the separation of dyes and salts for "zero discharge" become research hotspots due to the increasing industrial demand. Besides the existing challenges faced by the applications of LNF, many opportunities to advance the field are also pointed out. This review not only provides a comprehensive overview on the development of the LNF membrane but also offers guidance to improve the membrane separation performance, especially for the resource recovery to minimize environmental pollution. [ABSTRACT FROM AUTHOR]

Biofouling is inevitable when reverse osmosis (RO) membrane is applied in water treatment. The adhesion and proliferation of microorganisms on the membrane surface severely degrade the performance of RO membrane, including a sharp decrease in permeate flux, a decline in salt rejection, and a shortened service life. Based on the biofouling mechanism, we designed and prepared a dual-functional RO membrane with excellent antibacterial and anti-adhesion properties by simultaneously grafting ionic liquid and sulfonic acid monomers onto the surface of RO membrane using a simple redox radical polymerization. Compared with the pristine membrane, the water flux of the grafted membrane increased by 13.0 %, and the salt rejection slightly increased. Meanwhile, the grafted membrane possessed good antibacterial activity against E. coli and S. aureus. The bacterial mortality rates increased from 20.3 % and 80.0 % of the pristine membrane to 98.2 % and 96.1 %, respectively. Comparing the changes in membrane flux and rejection before and after bacterial fouling, the grafted membrane had significant advantages over the pristine membrane. The grafted membrane also exhibited excellent antifouling ability towards bovine serum albumin (BSA), humic acid (HA), and sodium alginate (SA). After 10 h of continuous filtration experiment, the flux decline of membrane for HA and BSA solutions was about 7 %, for SA solution about 14 %. And the grafted membrane showed good long-term stability in the application of tap water purification. This study provides an innovative path for preparing RO membrane with excellent anti-biofouling capabilities. [Display omitted] • A dual-functional RO membrane was constructed by redox radical polymerization. • The grafted membrane has higher permeation flux and salt rejection. • The grafted membrane has broad-spectrum antibacterial activity. • The grafted membrane shows lower decay in flux and rejection after bacterial fouling. • The grafted membrane exhibits excellent antifouling ability and long-term stability. [ABSTRACT FROM AUTHOR]

Nanofiltration (NF) with advantages of high efficiency and low‐cost has attracted increasing attentions in bio‐separation. However, the large‐scale application is limited by the inferior molecular selectivity, low chemical stability and serious membrane fouling. Many efforts, thus, have been devoted in NF materials design for specific applications to enhance the separation efficiency of bio‐products and increase membrane life‐time, as well as reduce the operating cost. This review summarized the recent progress of NF applications in bio‐separation, discussed various demands for NF membrane in the bio‐products purification and corresponding material innovations, finally proposed several practical suggestions for future research, which provided directions and guidance toward further product development and process industrialization. [ABSTRACT FROM AUTHOR]

Highlights • Cellulase was successfully immobilized on magnetic UIO-66-NH 2. • pH stability, thermal stability and catalytic efficiency were improved. • Immobilized cellulase retained most of its hydrolysis ability after 5 cycles. • Immobilized cellulase showed better tolerance to formic acid and vanillin. Abstract For the first time, cellulase was successfully immobilized on a magnetic core-shell metal-organic framework (MOF) material, UIO-66-NH 2. The as-prepared immobilized cellulase demonstrated a high protein loading efficiency of 126.2 g/g support and a high enzyme activity recovery of 78.4%. Cellulase immobilized on magnetic UIO-66-NH 2 exhibited a superior performance in terms of pH stability, thermal stability and catalytic efficiency compared to its free form. Notably, immobilized cellulase could be recycled for up to 5 consecutive runs. Furthermore, compared to free cellulase, immobilized cellulase showed better tolerance to formic acid and vanillin, two typical inhibitors found in lignocellulosic prehydrolysates. In the presence of 5 g/L of formic acid and vanillin, immobilized cellulase demonstrated 16.8% and 21.5% higher activity than free enzyme, respectively, and its improvement in hydrolysis yield was 18.7% and 19.6% respectively. This is firstly confirmed that immobilization can alleviate the inhibitory effects of certain pretreatment inhibitors on cellulase. [ABSTRACT FROM AUTHOR]

Aquatic micropollutants seriously affect human health. Biocatalytic membranes with immobilized laccase show a great potential for micropollutants removal. However, highly efficient and stable biocatalytic membranes are still under development. Herein, the separation and support layers of polyacrylonitrile (PAN) ultrafiltration membrane are sequentially modified by polyethyleneimine (PEI), metal–organic frameworks (MOFs), laccase and polydopamine (PDA), termed as “three dimensional (3D) modification”. The PEI polymers inserted in the selective separation layer result in charge reversal, thus immobilizing laccase mainly by electrostatic adsorption. The water-stable MOFs particles adhered on the support layer fibers can enhance the membrane adsorption capacity to laccase and micropollutants (called dual adsorption effect). PEI and MOFs dominate laccase loading and distribution in the membrane, thus greatly affecting micropollutants removals. The LacPAN-MIL-101-L biocatalytic membrane shows high permeability with desirable micropollutants removal, wide pH operating range and good reusability. Theoretically, this “3D modification” strategy can enable all the composite membranes to be biocatalytic membrane prepared by simple reverse filtration and subsequent coating. [ABSTRACT FROM AUTHOR]

A trade-off between operation stability and activity regeneration limits the application of biocatalytic membrane, and when it is applied for micropollutants removal from drinking water under flow-through mode, a high removal efficiency is required. To address these issues, a regenerable nanofiltration (NF) biocatalytic membrane was fabricated by immobilizing laccase on polydopamine/ polyethyleneimine (PDA/PEI)-coated NF membrane via physical adsorption. The effect of base membrane properties, dopamine coating time, PEI molecular weight, loading pH on the biocatalytic membrane performance was investigated in terms of permeability, enzyme loading and activity. It was proved that electrostatic and hydrophobic interactions between laccase and PEI molecules were the main immobilization mechanisms, and 750000 Da PEI molecule was selected to immobilize laccase at pH 5. The bisphenol A (BPA) removal by such biocatalytic membrane under flow-through mode was improved mainly due to its enhanced rejection ability (pore narrowing and surface hydrophilicity enhancement by the PDA/PEI layer). To further increase the BPA removal, the synthetic and natural mediators were introduced to improve the laccase-induced BPA oxidation by accelerating electron transfer, and the BPA removal kept higher than 97% during 7 reuse cycles without detectable loss of mediators. Moreover, traces of BPA in water was enriched on the surface of the biocatalytic membrane by pressure-driven filtration, thus improving BPA biodegradation by the laccase-mediator system. The biocatalytic membrane could be fast regenerated by chemical cleaning and reloading, and during the storage or operation, the leaked enzymes were also able to be recaptured. This work not only proposed a novel concept of regenerable biocatalytic NF membrane, but also offered a sustainable solution to quickly remove micropollutants in drinking water. [ABSTRACT FROM AUTHOR]

Biocatalytic membranes are promising to remove micro-pollutants in aqueous environment due to their mild and green operation condition. However, more efforts need to be devoted to improving their removal efficiency and stability. In this study, metal chelating affinity membrane chromatography (MCAMC) was used to construct a biocatalytic membrane by selectively capturing laccase from a crude fermentation broth. Metal ions had a significant effect on the activity of the immobilized laccase and copper ion was the best choice. A pH of 4.5 was selected for laccase adsorption and its loading seemed the same under flow rates from 0.5 to 10 mL min −1 thanks to the inherent convective transport of membrane chromatography. The pH value and salt concentration in the storage buffer had an obvious effect on the stability of the immobilized laccase, and the prepared biocatalytic membrane retained 87% of initial activity after 20 days storage. When applying such membrane to micro-pollutant removal (taking bisphenol A (BPA) as an example), a high BPA removal efficiency (99.3%) could be obtained. The biocatalytic membranes could be operated at a high flux of 50 L m −2 h −1 without recycling the permeate into the feed, and its throughput and BPA removal rate were superior to the most results in the literature. However, BPA removal decline (from 99.6% to 56.6% after five cycles) occurred during the successive water treatment due to the membrane fouling caused by BPA polymerization products. Membrane regeneration could be achieved by simple elution-cleaning-reloading, and the laccase activity and BPA removal were fully recovered. [ABSTRACT FROM AUTHOR]

Candida viswanathii ipe-1 was used to produce α , ω -dodecanedioic acid (DC 12 ), which showed capability to ferment xylose and glucose simultaneously, while arabinose utilization was less efficient. A low concentration of furfural enhanced cell growth, and the addition of 4.0 g/L sodium acetate largely increased DC 12 production. It indicated that detoxification of the wheat straw hydrolysates was not necessary for the biosynthesis of DC 12 . Based on the promising features of our strain, an efficient process was developed to produce DC 12 from co-utilization of wheat straw hydrolysates and n -dodecane. Using this process, 129.7 g/L DC 12 with a corresponding productivity of 1.13 g·L −1 ·h −1 could be produced, which was increased by 40.0% compared with a sole carbon of glucose. The improved DC 12 yield by the co-utilization of wheat straw hydrolysates and n -dodecane using C. viswanathii ipe-1 demonstrates the great potential of using biomass as a feedstock in the production of DC 12 . [ABSTRACT FROM AUTHOR]

Enzyme purification and subsequent immobilization usually require multiple steps and consume plenty of chemicals. Traditional dipping incubation operation is lengthy and the interior of porous carrier is not fully exploited due to the diffusion barrier. To solve these problems, one-step enzyme purification and immobilization was developed based on membrane chromatography concept. A membrane adsorber was prepared by polydopamine coating on a PVDF microfiltration membrane (or on a cheap and disposable cellulose filter paper) and subsequent polyethyleneimine grafting, without any solvent usage. Laccase was selectively immobilized on such membrane adsorber (enzyme activity: 39.9±4.4 U/mL; expressed activity: 19.6±3.0%) by directly capturing it from a crude fermentation broth without pH adjustment under flow-through mode. The immobilized laccase had a high purity of 92.2%, while the membrane permeability decreased due to the adsorption of laccase and impurities (“membrane fouling”). Thanks to the dominant convective transport, the enzyme loading was high and much faster than that by dipping incubation (5 min vs. 80 min). Moreover, enzyme reloading on membrane adsorber was easily realized by reversible desorption-adsorption process. The constructed biocatalytic membrane exhibited a commendable reusability for bisphenol A (BPA) removal only driven by its gravity. [ABSTRACT FROM AUTHOR]

It is critical to detect Fe3+ and Al3+ rapidly and accurately due to their high risk to humans and the ecological environment. In this work, a kind of terbium-based metal–organic framework fluorescent probe (Tb-MOF) is facilely fabricated that displays ultra-high selective detection of Fe3+ and Al3+ over various coexisting ions (i.e. Mn2+, Co2+, K+, Ca2+, Na+, Mg2+, Cd2+, Cu2+, Fe2+, Zn2+, Ni2+, Pb2+ and Cr3+). The obtained Tb-MOF exhibits emission at 547 nm and possesses outstanding thermal, fluorescent and chemical stability. The Tb-MOF shows a ratiometric fluorescence signal for Al3+, and the detection limits for Fe3+ and Al3+ are 0.91 and 6.10 μM, respectively. Moreover, the fluorescence intensities and concentrations of Fe3+ and Al3+ have good linear relationships across wide concentration ranges. Furthermore, the quantifications of Fe3+ and Al3+ are achieved in complex tap and river water samples with good recoveries. This study offers a facile and efficient method of developing a fluorescent probe that possesses the ability to quantify Fe3+ and Al3+ in real environmental water samples. [ABSTRACT FROM AUTHOR]

A near-infrared (NIR) glass–ceramic (GC) photocatalyst was synthesized via in-situ etching fluorine-containing waste introduced upconversion GC with HCl, which possesses stable structure, regenerative and efficient photocatalytic activity under NIR light irradiation. [Display omitted] • A NIR GC photocatalyst is synthesized from fluorine-containing waste via in-situ etching of upconverted glass-ceramics. • The photocatalytic activity of photocatalyst is higher than most photocatalysts (including commercial P25 and BiOCl). • The photocatalyst characteristic by stable structure, regenerative, can be prepared on a large scale, and low cost. • The upconversion emission performance is not weakened with HCl etching. Fluorine-containing waste is one kind of hazardous waste characteristic by hard disposal and utilization, it is an attractive way to prepare for fluoride-based luminescent matrix. In this work, to realize the high value-added utilization of fluorine-containing waste and reduce cost of the raw materials for preparation near-infrared (NIR) glass–ceramic (GC) photocatalyst, the pure fluoride of luminescent matrix was replaced by introducing fluorine-containing waste. The waste contained NIR GC photocatalyst was synthesis by the method of facile in-situ etching of an upconversion GC with HCl, which possesses core–shell structure, where the GC micro-powder including optically active centers lanthanides doped CaF 2 nanocrystals are displayed as the core, and the BiOCl is as the superficial coating. The upconversion emission performance of CaF 2 based luminescent matrix in photocatalyst is not weakened with HCl etching. NIR GC photocatalyst has high methyl orange and enrofloxacin degradation rate of 86 % and 82 % over 180 min after NIR light irradiation, respectively. The UV–Vis–NIR photocatalytic activity was enhanced degradation rate (93 % in 15 min) of enrofloxacin compared with those of commercial P25 and BiOCl. In addition, the photocatalyst had stable photocatalytic activity and it also can be regenerated. The study provided references for high value-added utilization fluorine-containing waste. [ABSTRACT FROM AUTHOR]

Sedimentation of silicalite-1 occurs in the fabrication of thin silicalite-1 filled polydimethylsiloxane (PDMS) hybrid composite membranes if the viscosity of membrane solution is low, which makes this preparation challenging. In this work, a new method that use a platinum catalytic agent to assist the pre-polymerization of PDMS polymer to increase the viscosity of the membrane solution was studied. With this method, supported silicalite-1 filled PDMS hybrid composite membranes were fabricated and applied in the pervaporative separation of a 5 wt% dilute ethanol aqueous solution. The effect of the concentration of platinum catalytic agent on the membrane properties was first investigated using CRM, DSC and extraction experiment. Optimum of viscosity of the composite membrane solution was then conducted and a selective layer of as thin as 5 µm thickness was obtained with a flux of 5.52 kg/m 2 h in combination with a separation factor of 15.5 at 50 °C. After that the separation performances of different thick membranes, interfacial adhesion properties of hybrid membranes, comparisons with other reported results and membrane stability were investigated. Results showed homemade silicalite-1-PDMS hybrid composite membrane offers relatively high separation performance, indicating a potential industrial application for the separation of ethanol from aqueous solutions. [ABSTRACT FROM AUTHOR]

The enzymatic membrane reactor (EMR) offers a sustainable approach to biomanufacturing, yet maintaining stable performance over prolonged periods remains a significant challenge due to membrane fouling and enzyme activity decline. To tackle these issues, we innovatively utilized a loose ultrafiltration membrane in a cross-flow EMR that completely retains enzymes while lacking the capability to separate intermediate and target products, thereby preventing the excessive retention of target products by the fouled membrane. By optimizing the dextran/dextranase ratio and substrate residence time, we achieved flexible control over the molecular weight (Mw) of products in the permeate. Our findings indicate that decreased enzyme activity exacerbates concentration polarization, leading to reduced permeate flux and prolonged residence time. This dynamic facilitates a re-matching of the substrate/enzyme ratio with residence time, effectively addressing the instability of the EMR caused by declining enzyme activity. Notably, this study reveals the intrinsic relationships between enzyme activity, permeate flux, and membrane fouling dynamics, alongside their self-regulation mechanisms for product Mw. Leveraging the ability of dextranase to preferentially degrade higher Mw dextran, a continuous feeding mode was employed under optimal conditions, allowing the EMR to sustain steady-state operation for 28 h while consistently producing oligodextran within the target Mw range of 3–6 kDa. Furthermore, the successful application of industrial-grade dextran substrate highlights the scalability and industrial relevance of EMRs for continuous oligodextran production. [Display omitted] • A loose UF membrane is used in EMR to avoid excessive retention of target products caused by fouling. • Product molecular weight is well controlled by optimizing dextran/dextranase ratio and residence time. • Self-regulation effect among enzyme activity, permeate flux, and residence time in the EMR is clarified. • It exhibits unique fouling behavior in a mixed molecular weight dextran and enzymatic reaction system. • Industrial-grade dextran is used in the EMR for the first time and shows similar results as pure dextran. [ABSTRACT FROM AUTHOR]

Achieving uniform dispersion of nanoparticles within the polymer membrane matrix while simultaneously constructing continuous selective permeation channels has always been key to preparing high-performance mixed matrix membranes. In this study, we employ glycerol (Gol) molecules as "bridges" to harness the hydrogen bonding interactions between Gol, TpHz, and poly(vinyl alcohol) (PVA) molecules. This approach facilitates the nanoscale dispersion of TpHz nanoparticles within the PVA membrane, establishing continuous channels that selectively permit the permeation of water molecules. By incorporating just 0.3 wt % of TpHz nanoparticles, the resultant PVA/Gol/TpHz membrane demonstrates a mechanism that favors the selective adsorption, dissolution, and rapid diffusion of water molecules from the feed, thereby reducing the activation energy required for their permeation through the membrane. The prepared PVA/Gol/TpHz membrane with pure water contact angle of only 19.6° has total flux and separation factor of 134 L m−2 h−1 and 705, which were 3.4 and 3.5 times higher than those of the pure PVA membrane, respectively. It broke the "trade-off" effect of traditional PVA membrane. Moreover, the tensile strength and thermal decomposition temperature of the PVA/Gol/TpHz membrane were increased from 130.31 MPa to 120.90 °C to 442.05 MPa and 246.8 °C, respectively. The membrane structure and separation performances remained stable during the 80-h pervaporation test, which suggests potential for industrial applications. [Display omitted] • Glycerol molecules facilitate the stripping and dispersion of TpHz nanosheets. • Hydrogen bond was observed between glycerol molecules and TpHz nanosheets. • TpHz nanosheets were uniformly dispersed in the PVA membrane matrix. • Fast permeation channels for water molecules are constructed in the membrane. • The membrane's FFV and pervaporation performances are significantly enhanced. [ABSTRACT FROM AUTHOR]

[Display omitted] • Lignin was modified with PEI through Mannich reaction. • PEI-lignin removed over 90 % of SDBS from aqueous solution. • PEI-lignin removed exceeding 90 % of SDBS from synthesized/real greywater. • Lignin source exerted little effect on adsorption of SDBS on PEI-lignin. Greywater reuse is a promising solution to alleviate water scarcity, but surfactants in greywater can harm the environment. This study presents a novel lignin-based adsorbent, synthesized by modifying lignin with polyethyleneimine (PEI), to effectively eliminate anionic surfactants from greywater. Batch experiments showed a remarkable removal efficiency exceeding 90 % for sodium dodecyl benzene sulfonate (SDBS) within one hour at a starting concentration of 100 mg/L and an adsorbent loading of 1 g/L. The source of lignin did not significantly impact SDBS removal. Adsorbents based on organosolv lignin and lignosulfonate exhibited similar maximum adsorption capacities for SDBS (626.53 mg/g vs 629.78 mg/g), much higher than that of alkali lignin-based counterparts (520.74 mg/g). Moreover, PEI-lignin demonstrated remarkable reusability over six adsorption–desorption cycles. Notably, treatment of synthetic and real greywater indicated minimal interference from coexisting substances (NO 3 −, SO 4 2−, PO 4 3−, etc.), achieving SDBS removal rates exceeding 90 %. The primary adsorption mechanisms involved hydrogen bonding and hydrophobic interactions, supplemented by the electrostatic interactions and π-π stacking. This study presents a low-cost lignin-based material with exceptional efficiency, regeneration performance, and practical application potential for surfactant removal, while also providing a viable approach for reutilizing discarded lignin. [ABSTRACT FROM AUTHOR]

Choline chloride-lactic acid, a common carboxylic acid-based deep eutectic solvent (DES), was used to pretreat corn stover (CS). Despite significant lignin and xylan removal, enzymatic cellulose conversion remained below 30 %, only slightly higher than untreated CS. Structural characterization confirmed esterification between the CS's hydroxyl groups and lactic acid during pretreatment. A brief 5-min saponification effectively removed these ester groups, leading to a 1.08-, 2.75-, and 2.50-fold increase in 48-h cellulose hydrolysis for 2-, 5-, and 8-h DES-pretreated samples, respectively. Analysis of chemical composition, surface morphology, crystallinity, and degree of polymerization revealed that these factors did not contribute to the enhanced hydrolysis observed in the saponified samples. This study concludes that saponification-induced de-esterification is the key factor driving the significant increase in enzymatic cellulose hydrolysis, highlighting the detrimental impact of esterification occurring during carboxylic acid-based DES pretreatment on subsequent cellulose saccharification. • Choline chloride-lactic acid DES was used for corn stover pretreatment. • FTIR confirmed esterification of biomass during DES pretreatment. • Pretreated biomass showed significantly reduced cellulose saccharification. • Brief saponification substantially increased enzymatic glucose yields. • Esterification is the key factor inhibiting enzymatic hydrolysis efficiency. [ABSTRACT FROM AUTHOR]

[Display omitted] • Room-temperature synthesis of COF materials enriched with anchoring sites. • The spherical COF probe has superior performance of dispersion. • Pore restriction and antenna effect facilitate the selective recognition. • COF-Eu shows excellent performance of recovery and detection for Flumequine. The overuse of quinolone antibiotics has led to a series of health and environmental issues. Herein, we combine the distinct luminescence properties of Eu3+ with the unique structure of covalent organic frameworks (COFs) to develop a precise and sensitive fluorescent probe for detecting Flumequine (Flu) in water. Eu3+ is thoroughly anchored into the channels of COFs as recognition sites, while the synthesized probe material still maintains its intact framework structure. The unique structure of COFs provides excellent support and protection for Eu3+. Therefore, COF-Eu can rapidly bind with Flu which can transfer the absorbed energy to Eu3+ through an "antenna effect", resulting in red fluorescence. Moreover, there is a good linear relationship between Flu concentration in the range of 0–30 µM, with a detection limit of 41 nM. Simultaneously, the material maintains remarkable reproducibility, with its performance remaining almost unchanged after five cycles of use. Remarkably, the probe demonstrates excellent Flu recovery rates in real samples. This study provides a viable approach for the recognition of flumequine in the environment through a customized fluorescence detection method. [ABSTRACT FROM AUTHOR]

Silica scaling is a major challenge in the application of high-pressure reverse osmosis (RO) membranes. In this work, we modified commercially available RO membranes by grafting different sulfonic acid monomers onto their surface using redox polymerization. We systematically studied the effects of various sulfonic acid monomers on membrane performance. Due to the different grafting abilities of sulfonic acid monomers on the membrane, the modified membranes exhibited different physicochemical properties. Simulated silica scaling experiments revealed that the initial permeate flux and sulfonic acid grafting rate of the membrane played crucial roles in its antifouling performance. Molecular dynamics (MD) simulation indicated that the adsorption of silica scale on the membrane was positively correlated with the grafting degree of sulfonic acid monomers. The membrane modified with 3-sulfopropyl potassium methacrylate (SPM) demonstrated a 14 % higher initial flux than the pristine membrane and the highest sulfonic acid grafting rate, resulting in the lowest flux decay rate. Additionally, the SPM modified membrane outperformed the pristine membrane against composite foulants with organic matters and silica. Our research demonstrated that the redox grafting polymerization of sulfonic acid monomers can simultaneously improve the flux and silica scaling resistance of RO membranes without compromising salt rejection. This provides a scalable strategy for preparing RO membranes with enhanced resistance to silica scaling. [Display omitted] • The grafting of sulfonic acid monomers makes the membranes have higher water flux without sacrificing salt rejection. • The enhanced permeability by modification is not conducive to the improvement of the silica scaling resistance. • More sulfonic acid groups on the membrane surface can increase electrostatic repulsion with silicate ions. • The SPM modified membrane exhibited better resistance to silica scaling and combined fouling of silicate and organics. [ABSTRACT FROM AUTHOR]

Poly (β-L-malic acid) (PMLA) is attracting industrial interest for its potential application in medicine and other industries. In this study, electrolytic stimulation assisted PMLA production was developed. Firstly, it was found that the pentavalent nitrogen source (i.e., NO 3 −) was more suitable for PMLA production. Secondly, a usual single-chamber bioelectric-fermentation system (BES) cannot improve PMLA production, which can only promote cell growth. Then, a new single-chamber BES with an external circulation was developed, where the PMLA metabolism was further intensified. Finally, the integration of NO 3 − addition and electrolytic stimulation mode (c) showed a positive synergy on the PMLA production. Compared to the case without NO 3 − addition and electrolytic stimulation, the PMLA production was increased by 22.9 % using the integrated process. Moreover, compared to the case without the electrolytic stimulation mode (c), it was revealed that the different genes involved in 12 metabolic subsystems using the integrated process, where 31 and 177 genes were up-regulated and down-regulated, respectively. The up-regulated genes were mainly participated in melanin metabolic process, catalase activity, and oxidoreductase activity. Hence, the integration of electrolytic stimulation represents a novel approach to improve PMLA production. • A novel single-chamber BES with an external circulation was developed. • An oxidation state inorganic nitrogen source was more suitable for the PMLA production. • Electrolytic stimulation promotes PMLA production from A. melanogenum ipe-1. • The integration of NO 3 − addition and electrolytic stimulation showed positive synergy. [ABSTRACT FROM AUTHOR]

Interfacial polymerization (IP) remains the leading technique for fabricating thin-film composite (TFC) nanofiltration (NF) membranes. Recent innovations have introduced substantial strategies to fine-tune the IP process, particularly by controlling monomer distribution, diffusion, and chemical reactivity to enhance membrane performance. Among these strategies, the molecular design of monomers emerges as one of the most straightforward, effective, and scalable approaches. However, a comprehensive understanding of how the physicochemical properties of monomers influence the IP process-and, consequently, the structure and performance of the resulting membranes-remains underdeveloped. This review focuses on the key regulatory factors in IP, including bulk diffusion, interfacial diffusion, and monomer reactivity (i.e., crosslinking potential). We explore the mechanisms by which critical molecular characteristics of monomers impact the IP process, affecting the microstructure and performance of TFC membranes. Furthermore, we outline strategies for enhancing membrane permeability, selectivity, antifouling properties, and operational stability through the precise control of the IP process, achieved by the design and optimization of monomer molecular structures. Finally, this review addresses the challenges associated with monomer design in the context of IP-based NF membrane fabrication and offers guidance for advancing monomer design to improve membrane production. This review highlights the effect of bulk and interfacial diffusion and monomer reactivity on the interfacial polymerization process, explores how monomer characteristics shape membrane microstructure, and discusses strategies for enhancing permeability, selectivity, antifouling properties and stability by optimizing monomer design. It also offers guidance for advancing monomer design in the large-scale fabrication of nanofiltration membranes. [Display omitted] • Effect of monomer molecules structure on interfacial polymerization process is thoroughly analyzed. • Effect of monomer key characteristics on TFC membranes microstructure and performance is discussed. • Monomer design optimized for TFC NF membrane separation performance is summarized. • Challenges of monomer design in NF membrane preparation via interfacial polymerization are discussed. • Precise in-situ monitoring, computational modeling, advanced characterization techniques are required. [ABSTRACT FROM AUTHOR]

[Display omitted] • Three shapes of CeO 2 nanoparticles including sphere, rod and flake were used to fabricate the interlayer of TFN membranes. • The rodlike CeO 2 nanoparticles tended to form a homogeneous network-like interlayer due to the large specific surface area and good dispersion. • The morphologies of the PA layer could be changed between nodule and ridge-valley structure with the change of the shape and loading of CeO 2 nanoparticles. • The introduction of interlayer made PA layer coarser, the pore size smaller and the distribution more uniform. • The permeability of TFN membrane was increased due to the "gutter" effect. Constructing an interlayer in the thin-film nanocomposite (TFN) membranes has been proved to be an effective strategy to break the trade-off between permeability and selectivity. The interlayer plays an important role in the formation of polyamide (PA) layer. In this study, cerium oxide (CeO 2) nanoparticles with three shapes, including sphere, rod and flake were used to fabricate the interlayers of TFN membranes. The effects of nanoparticle shape and loading on the morphologies and properties of the interlayers and resultant TFN membranes were systematically investigated. The results showed the morphologies and physicochemical properties of the PA layers could be regulated well by the shape and loading of CeO 2 nanoparticles. The surface morphologies of the TFN membranes exhibited the transformation from nodule structure to ridge-valley structure. At the same time, the introduction of interlayer made PA layer coarser, the pore size smaller and the pore distribution more uniform. Under the same loading conditions, the rodlike CeO 2 nanoparticles tended to form a homogeneous network-like interlayer due to the large specific surface area and good dispersion. The interlayer reduced the transport path of water molecules in the PA layer based on the "gutter" effect, thus improving the permeability of TFN membrane. The water permeability of the TFN membrane with rodlike CeO 2 interlayer could be 124% higher than that of the control, while the rejection of salts did not significantly change. This study deepens our understanding on the role of nanoparticle in regulating the morphologies and properties of interlayer and TFN membrane, and provides an effective method to enhance separation performance of nanofiltration membrane. [ABSTRACT FROM AUTHOR]

[Display omitted] • Mechanical activation can enhance the solubility of LYSO waste. • 98.7% of lutetium was leached out under milder acid leaching conditions. • Recycling costs have been reduced by at least 22% compared to traditional methods. The lutetium has been known to be used in medical imaging materials, but its scarcity in the Earth's crust makes it expensive. In this work, we present a process for efficient lutetium recovery from the lutetium-yttrium oxyorthosilicate crystals (LYSO) waste. The process involves preliminary mechanical activation, followed by rare earth extraction via acid leaching. The key factors for activation and leaching were studied and optimized. The mechanism of mechanical activation promoting rare earth leaching was revealed by employing the characterizations of morphology and crystal structure of LYSO. It was found that the mechanical activation process could destroy the crystal structure of LYSO waste, forming numerous amorphous phases and grain boundaries, which facilitated the breaking of existing bonds and mass transfer of acid. It was also discovered that the formation of silica gel during leaching impedes the leaching of rare earth, and low concentrations of hydrochloric acid, combined with stirring during acid leaching, could reduce the impact of silica gel. Ultimately, following a mechanical activation pretreatment at 300 rpm for 90 min, 98.7 % of lutetium could be leached after 60 min of acid leaching in 3 mol/L hydrochloric acid. This process addresses the problems associated with high energy consumption and excessive usage of acidic and alkaline reagents in conventional recycling techniques. Compared to conventional methods, the mechanical activation-acid leaching method has a minimum economic benefit improvement of 20.8 % in the process of recovery from LYSO waste. It offers an alternative and more energy-efficient and economical recycling route for waste scintillation crystals. [ABSTRACT FROM AUTHOR]

[Display omitted] • The hard acid Ce(Ⅳ) and hard base H 3 BTB are used to synthesize stable Ce 6 BTB. • Ce 6 BTB is first incorporated into PIM-1 to fabricate MMMs for CO 2 separations. • PIM-1 shows excellent compatibility with ultrathin Ce 6 BTB nanosheets. • CO 2 permeability and CO 2 /N 2 selectivity are improved with the addition of Ce 6 BTB. • PIM/Ce 6 BTB-2 exhibits excellent anti-pressure properties and long-term stability. Two-dimensional (2D) metal–organic framework nanosheets (MONs) materials exhibit significant potential in achieving high CO 2 separation performance. This study presents a demonstration of the rapid synthesis of Ce 6 BTB nanosheets at a low temperature of 80 °C and atmosphere pressure of approximately 1 atm. The resulting Ce 6 BTB nanosheets possess notable characteristics, such as high aspect ratios and 1D diamond shaped channels, which facilitate the fast rapid transport of CO 2 molecules. The Ce 6 BTB was firstly blended into PIM-1 with different loadings to form PIM/Ce 6 BTB mixed matrix membranes (MMMs). The incorporation of well-dispersed Ce 6 BTB fillers enhances the efficiency of CO 2 transport by inter-flake nano-channels and intra-flake pores. Moreover, the increased crystallinity, dense chain spacing, and hydrogen bonding contribute to enhanced sieving ability, resulting in high gas selectivity. Consequently, the MMMs containing 2 wt% Ce 6 BTB demonstrate high CO 2 permeability of 5930 Barrer and CO 2 /N 2 selectivity of 23.2, which is far surpasses 2008 upper bound from Robeson and approaches the refined 2019 upper bound from MeKenow. Furthermore, the PIM/Ce 6 BTB-2 MMMs present relatively good anti-pressure properties and long-term operation stability, which is advantageous in terms of industrial applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • Surface segregation of D–amino acid modified HNTs in PAN membrane matrix was studied. • D–Aa@HNTs' distribution in membranes were regulated by D–Aas' methyl group. • Permeance and BSA rejection of the MMM were greatly improved by the D–Leu@HNTs. • D–Leu@HNTs/PAN membrane showed excellent anti-biochemical fouling property. • Corporation of D–Aa@HNTs in MMM has a synergistic effect on wastewater filtration. Membrane fouling has always been one of the key problems to be solved in the liquid–liquid separation process of biomacromolecules, proteins, bacteria, etc. Here, halloysite nanotubes (HNTs) surface-modified with D-Amino acid (D-Aa) is synthesized in one step and introduced into the polyacrylonitrile (PAN) ultrafiltration membrane matrix to obtain a PAN mixed matrix membrane (MMM). D-Aas with three different R groups are selected to modify the HNTs. The results show that the carboxyl and amino groups of the D-Aa molecules interact with the surface of HNTs through hydrogen bonds, while the R groups are oriented towards the outside of the tube, thereby becoming the main factor affecting the surface chemical structure of the HNTs. Therefore, due to the low polarity of isobutyl and the good affinity with PAN and DMAc molecules, D-leucine-modified halloysite nanotubes (D-Leu@HNTs) can be evenly dispersed in the PAN membrane matrix and segregate to the membrane top-surface and pore wall during the non-solvent induced phase separation (NIPS) process with the solvent exchange between water and DMAc, thereby significantly improving the pore structure and hydrophilicity of the polyacrylonitrile membrane, and ultimately giving the PAN/D-Leu membrane ultra-high pure water permeability (PWP) of 1334 L·m−2·h−1·bar−1, rejection of 100 %, and excellent anti-biochemical fouling performances. The prepared PAN/D-Leu membrane maintains stable and efficient filtration performances in the 300-hour cross-flow experiment, and the membrane after testing still has excellent anti-biofilm fouling performance, showing a promising industrial application prospect. [ABSTRACT FROM AUTHOR]

Abstract: High and stable permeate flux can be obtained with shear-enhanced nanofiltration (NF) in model dairy wastewater treatment. In order to sustain such flux in long-term operation, critical fouling conditions should be studied and an optimum flux needs to be selected. Based on resistance-in-series and particle deposition models, a threshold flux was proposed to make a distinction between low and high fouling rates. At and below threshold flux, adsorption and reversible fouling are almost stable, and the fouling rate is low and nearly constant, irrespective of permeate flux; while above it, flux declines markedly with increasing flux mainly due to incremental reversible fouling. Flux remained quite stable with slight fouling (<5%) in 6h operation at threshold flux, up to 6.1×10−5 ms−1 at shear rate of 1.81×105 s−1 for diluted milk. Flux anomaly occurred in operations above threshold flux and fouling was more important (permeability loss>20% for undiluted milk). This threshold flux is determined by pressure stepping experiments as the point above which flux ceases to increase linearly with transmembrane pressure (TMP). Each flux step only needs to last a few minutes to ensure reversible fouling stabilization at high shear rate. In shear-enhanced filtration, these threshold fluxes are, of course, larger than critical ones, and more compatible with industrial expectations. It is concluded that the separation performance of membranes should be evaluated at or below threshold flux to eliminate the effect of fouling, and the effect of feed characteristic on membrane fouling should be investigated above threshold flux, while operating at threshold flux is recommended for industrial long-term operation. [Copyright &y& Elsevier]

Abstract: High pressures can be employed in shear-enhanced nanofiltration (NF) process in order to obtain large permeate flux, and under this extreme hydraulic condition, membrane fouling behavior may be different and need to be investigated. In this study, a rotating disk laboratory module capable of very high shear rates and pressure was used to treat model dairy wastewater with a NF270 membrane. The presence of lipids had a negligible effect on flux profile and permeate quality, although it slightly increased adsorption fouling. Higher shear rates decreased concentration polarization and produced higher permeate fluxes with lower permeability loss. After the flux remained stable for several hours, adsorption fouling and subsequent cake layer formation occurred. The surface adsorption of small foulants such as lactose and calcium ions caused a slow flux decline, and in the absence of chemical cleaning, it induced cake fouling and severe flux decline. Inorganic ions such as calcium and phosphate engaged with milk proteins in micelles or aggregates, and thus inorganic scaling was negligible and alkaline cleaning could remove most surface fouling. We concluded that, with suitable chemical cleaning, a high and stable flux could be obtained for a long time in dairy wastewater treatment by NF under shear-enhanced extreme hydraulic conditions. [Copyright &y& Elsevier]

Abstract: Treatment of wastewater containing a cleaning-in-place detergent was investigated by using a rotating disk module equipped with a nanofiltration (NF) membrane. At a rotational speed of 2000rpm, a pH 7.2 and 25°C, the permeate flux reached a plateau at 350Lm−2 h−1 above 35bar while rejection of conductivity and COD were respectively 93 and 97%. When a pretreatment by ultrafiltration (UF) was carried out before the NF, the NF flux increased linearly with TMP to reach 450Lm−2 h−1 at 40bar while COD of NF permeate was a little lower than without pretreatment. Both permeate flux and conductivity rejection increased with increasing pH. High membrane shear rates prevented flux decline with time, as surfactant molecules were dragged away from membrane surface, preventing surfactant aggregates formation. The disk rotational speed necessary for flux stability increased with TMP from 1000rpm at 10bar to 2000rpm at 30bar. Increasing feed pH had a similar effect by enhancing electrostatic repulsion between surfactant molecules and membrane. Raising the temperature to 45°C increased the permeate flux to over 500Lm−2 h−1 at 30bar and 2000rpm. This work confirms the high performance of high shear dynamic filtration in detergent wastewater treatment by NF system both in terms of permeate flux and ion and COD rejections due to reduction in concentration polarization, so that a UF pretreatment was not necessary. [Copyright &y& Elsevier]

Abstract: Dairy wastewater can be concentrated by membrane technology to produce reusable water, and the retentate with high concentration could be reutilized as feed supplement for animals or substrate for biohydrogen production. Treatment of a model dairy wastewater (diluted skim milk) by nanofiltration (NF) with a rotating disk membrane (RDM) module was investigated using a NF membrane NF270 (Dow-Filmtec). Compared with the Desal-5 DK (Ge-Osmonics) membrane studied previously, the NF270 membrane gave much higher permeate flux, but same rejection. At a high enough shear rate for reducing concentration polarization, permeate flux and solutes rejection increased while specific energy per m3 of permeate decreased when transmembrane pressure (TMP) rose from 10 to 40bar. Because the RDM module could produce very high shear rates, concentration of dairy wastewater by NF could be operated under extreme hydraulic conditions that combined extreme TMP with high shear rate. Process efficiency and permeate quality were improved by operating under these condition, while membrane fouling was a little higher than when operating below critical flux. A real dairy wastewater was also treated by NF270 under same hydraulic conditions, and results were very similar to those of model solution. Membrane fouling was decreased by raising pH above 9. Irreversible fouling was almost removed using a commercial cleaning agent at high shear rate in a short time. The RDM module appeared to be a suitable technology to treat dairy waste without any biological and chemical treatments. Permeate qualities were suitable for reuse or discharge in river. These results from laboratory-scale tests can be very useful in the analysis of membrane process under extreme hydraulic conditions and can serve as valuable guide for process design in industrial application. [Copyright &y& Elsevier]

Abstract: To improve the affinity between silicalite-1 and polydimethylsiloxane (PDMS), the silicalite-1 particles were modified by a silane coupling agent vinyltriethoxysilane (VTES) and incorporated into polydimethylsiloxane (PDMS) matrix for the preparation of silicalite-1/PDMS hybrid membranes. The modified silicalite-1 particles were examined by XRD, FT-IR and TGA, and the results showed that the silane coupling agent was bonded to the surface of silicalite-1 particles through chemical bonds and the modification did not influence the framework of silicalite-1 crystals. VTES could enhance the interaction of silicalite-1 particles with PDMS through chemical bonds and hence suppressed the formation of microvoids at polymer–silicalite-1 interface, as a result, the thermal stability of the hybrid membrane could be improved. The effect of silicalite-1 loading on the pervaporation performances of the hybrid membranes with dilute ethanol solutions was investigated. As compared with the unmodified hybrid membranes, the VTES modified silicalite-1/PDMS hybrid membranes effectively improved the pervaporation selectivity at different silicalite-1 loadings. With increasing silicalite-1 loading, membrane selectivity increased for both unmodified and VTES modified silicalite-1/PDMS hybrid membranes, and a selectivity of 32 was obtained when VETS modified silicalite-1 loadings was 67%. It was also found that with increasing silicalite-1 loading, the total flux of both unmodified and VTES modified silicalite-1/PDMS hybrid membranes decreased while the ethanol flux of both hybrid membranes increased. With increasing the feed ethanol concentration at a given temperature, the total flux, ethanol flux, and ethanol concentration in permeate increased almost proportionally, while water flux decreased and the separation factor decreased slightly. An increase in temperature increased the permeation fluxes of both ethanol and water, while the separation factor was more or less constant at a given ethanol concentration. [Copyright &y& Elsevier]

Abstract: Pretreating wheat straw (WS) with combined use of varied sulfuric acid concentration (0–3%, w/v) and Tween 20 concentration (0–1%) was investigated in an attempt to enhance the hydrolysis and fermentability of pretreated WS. Enzymatic hydrolysis yield of glucan and xylan and ethanol production by simultaneous saccharification and fermentation (SSF) of water-insoluble solids (WIS) were significantly affected by the amount of Tween 20 added during acid pretreatment. Any further addition of Tween 20 in either hydrolysis stage or fermentation stage only led to small increase in glucan conversion and ethanol production. Determination of adsorption of cellulases during hydrolysis showed that Tween 20-assisted acid treated straw solution contained more free cellulases than individual acid treated straw solution, indicating that modification of lignin surface by Tween 20 added during pretreatment likely occurred. In addition, the effects of pretreatment conditions on overall recovery of glucose and xylose after pretreatment and enzymatic hydrolysis were also investigated. [Copyright &y& Elsevier]

Sugarcane bagasse was pretreated with lewis acid-mediated glycerol, results showed that 98.47% glucan recovery, 95.31% xylan removal and 49.69% delignification were achieved by pretreatment using 80 wt% aqueous glycerol combined with 1.0 wt% AlCl 3 at 150 °C for 1 h. Reutilization experiments of acidified glycerol showed that its pretreatment efficiency was relatively well maintained during four consecutive cycles. Enzymatic in situ saccharification of pretreated bagasse led to about 50% glucose yield at 16 wt% glycerol concentration. After pretreatment, the lignin distributed in pretreatment hydrolysate and pretreated solid residue (referred to as organosolv lignin (OL) and cellulolytic enzyme lignin (CEL), respectively) demonstrated contrasting effect on enzymatic hydrolysis with OL slightly increasing while CEL decreasing cellulose conversion, which could be explained by their differences in hydrophobicity and surface charge. Further analysis of the structure and molecular weights of two lignin samples indicated their great potential for valorization into value-added products. • Lignin and xylan were significantly removed with nearly complete glucan recovery. • Recycled acidified glycerol maintained good pretreatment efficacy. • High-concentration glycerol in one-pot process strongly inhibit cellulase. • Organosov lignin slightly increased cellulose hydrolysis. • Cellulolytic enzyme lignin decreased cellulose hydrolysis. [ABSTRACT FROM AUTHOR]

[Display omitted] • ● Simultaneous extraction and stripping of light rare earth elements were conducted. • ● Hollow fiber supported liquid membrane system with P507 as extractant effectively fractionate La3+ and Nd3+. • ● No saponification was required by hollow fiber supported liquid membrane system for LREEs fractionation. • ● Hollow fiber supported liquid membrane system had the superior selectivity for Nd3+. Rare earth elements (REEs) are commonly categorized into light (LREEs), medium (MREEs), and heavy (HREEs) groups. Separation between LREEs and MREEs or MREEs is relatively straightforward. However, isolating LREEs themselves is particularly challenging because of their similar ionic radii and identical charges. Traditional separation processes are hindered by drawbacks including low recovery rates for dilute REEs, poor selectivity, complex protocols, and environmental pollution. Consequently, developing a cleaner and more efficient method for LREEs separation is imperative. In this study, we employed a single-module hollow fiber supported liquid membrane (HFSLM) system with 2-ethylhexyl phosphoric acid mono-2-ethylhexyl ester (P507) as an extractant to concurrently extract and strip La3+ and Nd3+ from the mixed LREEs containing solutions. We also investigated the impact of flow rate, stripping solution acidity, feed solution pH, P507 concentration, Nd3+ concentration of feed solution, and the volume ratio between the feed and stripping solutions influence the extraction and stripping of LREEs, as well as the molar fractions of La3+ and Nd3+ in the solutions. Under optimal condition, the molar fraction of La3+ was 99.0% in the feed solution, whereas the molar fraction of Nd3+ reached 91.6% in the stripping solution. Furthermore, the experimental results demonstrated a consistent preference of P507-HFSLM system for extracting Nd3+ over La3+, and the underlying mechanism was thoroughly investigated. In summary, this study offers comprehensive insights and technical approaches for selective separation and purification of LREEs. [ABSTRACT FROM AUTHOR]

[Display omitted] • Endo-hydrolytic activity of free dextranase is transformed to exo -hydrolytic after covalent immobilization. • Noncovalent immobilization of dextranase maintains its endo -hydrolysis behavior. • Matching target products generation and separation efficiency can control product molecular weight and mitigate fouling. • A desirable enzyme membrane reactor requires highly active enzyme, strong internal mass transfer and high permselective membrane. • Immobilization is not necessary in enzyme membrane reactor if enzyme has good shear resistance and acceptable stability. Enzyme membrane reactor (EMR) provides an effective strategy for controlling molecular weight (Mw) of oligodextrans. However, the synergistic effect between dextran hydrolysis and product separation as well as continuous operation stability remains still unclear. We observed that covalently immobilized dextranase exhibited more obvious exo -hydrolysis behavior compared to free enzymes probably due to enzyme conformational alterations. Using non-covalently immobilized enzyme, suitable ultrafiltration membrane, optimal substrate/enzyme ratio and matched permeate flux, the yield of the target product reached 62.8%. However, the non-covalently immobilized dextranase exhibited reduced hydrolytic activity and more obvious membrane fouling (caused by high-Mw dextran). When free dextranase with high activity was used together with suitable permeate flux and high shear rate, the yield increased to 72.0%. The obtained EMR maintained stable for 8 h with slight fouling formation because enzymatic hydrolysis and membrane separation were well matched. The polydispersity index of the target product reached 1.3 (analytical grade) following diafiltration purification. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel approach was proposed to separate Mg and RE ions in ion-adsorption type RE ore leaching liquor by combining RE ions complexation and UF processes. • Using Gly as the complexing agent, the process could increase RE ion concentration from 101 to 3940 mg/L and enhance RE/Mg separation factor from nearly 0 to 36.4. • The novel strategy significantly improved the RE precipitation process, resulting in an 8% increase in RE recovery and a 2.8-fold enhancement in RE purity. • This study will introduce innovative ideas and methods for efficiently recovering RE from leaching liquor by the novel approach. Taking advantage of the environmentally-friendly properties of a magnesium salt leaching agent, magnesium oxide (MgO) was used as a precipitant to enrich rare earth (RE) from leaching liquor in the magnesium salt system. This approach not only tackles the issue of ammonia–nitrogen pollution but also enables efficient magnesium recycling. However, due to the high concentration of magnesium ions and the low concentration of RE ions in the leaching solution, the precipitation kinetics of RE concentrates are sluggish, leading to low RE purity in the resulting precipitated product. In this work, we proposed a novel strategy that combines complexation-ultrafiltration (UF) pre-concentration with subsequent MgO precipitation to enhance the hydrolysis of MgO, promoting the precipitation of RE. We further improved the RE enrichment efficiency by optimizing membrane type, complexing agent selection, concentration levels, precipitation temperature, and MgO dosage. Under the conditions of concentrating the leaching solution using optimal UF membrane and employing glyphosate as the complexing agent, the RE ions concentration increased from 101 to 3940 mg/L, and we successfully separated magnesium ions with a separation factor of 36.4. A comparison between direct MgO precipitation and the pre-concentration approach revealed an 80 % reduction in precipitation time and an 80 % decrease in MgO usage with pre-concentration. Furthermore, this combined process led to an 8 % increase in RE recovery and a 2.8-fold enhancement in RE purity, and similar results were obtained when using actual mine leaching solutions. Additionally, the glyphosate present in the UF permeate and the precipitated mother liquor can be efficiently reclaimed through resin adsorption. This proposed process holds significant potential for engineering applications aimed at enriching RE. [ABSTRACT FROM AUTHOR]