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• Dedusting of real hot producer gas from gasification of biomass. • Guidelines for the development of hot gas filters and their bullet-proofing. • Technical and process solutions for stable dedusting hot producer gases. • Methods for determining operational windows for hot gas filters. • Comparison and evaluation of several pulse-jet cleaning designs. The paper aims to summarize the technical and process development of hot gas filtration technology that was tested and optimized under the conditions of producer gases generated through the gasification of wood chips in a fixed-bed 60kWth GazEla reactor. The paper describes the results of testing two generations of hot gas filters, four types of filtration elements, as well as a range of auxiliary subunits (i.a. methods for secure fixing and sealing of the filters). Additionally, an in-depth analysis was performed on the efficiency of pulse-jet cleaning, which through a statistical study indicated change-effect relationships between the main pulse-jet parameters. Based on this learning curve, the paper presents a set of guidelines that can be used for the development of robust hot gas filters, as well as for resolving their unstable operation. [ABSTRACT FROM AUTHOR]

[Display omitted] • Pre-oxidation of K 2 S 2 O 8 with CuO/FeSO 4 catalytic is effective in removing humic acid. • Pre-oxidation is effective on ceramic membrane fouling control. • CuO enhances the generation of active free radicals facilitated by FeSO 4. Recently, persulfate oxidation technology has been widely utilized for the degradation of natural organic matter (NOM) in water treatment. This study proposed novel enhanced ceramic membrane filtration system by persulfate (PS) pre-oxidation with CuO and FeSO 4 catalytic, which can achieve the high NOM remove performance and low membrane fouling. Firstly, the removal efficiency and mechanism of humic acid (HA) using the CuO/FeSO 4 /K 2 S 2 O 8 advanced oxidation system under various operating conditions were investigated. The results indicate that optimal conditions (FeSO 4 at 0.016 g/L, CuO at 0.048 g/L, and K 2 S 2 O 8 at 0.6 g/L) result in substantial removal effects of total organic carbon (TOC, approximately 80 %) and excitation-emission matrix (EEM) spectra by CuO/FeSO 4 /K 2 S 2 O 8. Subsequently, with the cycling operation conditions, enhanced ceramic membrane filtration with CuO/FeSO 4 /K 2 S 2 O 8 pre-oxidation demonstrates effective removal of HA (approximately 85 %) and significant reduction of membrane fouling (around 60 %), as confirmed by EEM and TOC analysis. Furthermore, during continuous operation, CuO/FeSO 4 /K 2 S 2 O 8 pre-oxidation proves to be effective in removing surface water contaminants (approximately 65 %) and mitigating membrane fouling (around 50 %). Finally, through the measurement of Fe2+, Cu2+, and Cu+ concentrations, as well as Field-Emission Scanning Electron Microscopy (FESEM), X-ray Diffraction (XRD), and X-ray Photoelectron Spectroscopy (XPS) characterization of CuO, it becomes evident that CuO exhibits synergistic effects with FeSO 4 by adsorbing Fe2+ from the solution and reducing Cu2+ to Cu+. This process generates SO 4 •−, ·OH, and ·O 2 −radicals within the CuO/FeSO 4 /K 2 S 2 O 8 oxidation system. The proposed ceramic membrane filtration system in this study shows great potential in the drinking water treatment for NOM removal. [ABSTRACT FROM AUTHOR]

• Role of turbulence in wastewater treatment by shear-enhanced membrane pilots. • Power-law scaling of flux with shear rate and three turbulence measures. • Kolmogorov scale was found to be the best regressor (R2 > 0.96). • Results of previous studies on five different shear-enhanced pilots were used. • CFD simulation was employed to determine the hydrodynamic variables. Recovery of nutrients and minerals from wastewater by membrane filtration holds promise for sustainable water processing. While dealing with such processes that often result in substantial filtrate throughput decline due to membrane fouling, Dynamic Shear Enhanced Membrane Filtration Pilots (DSEMFPs) have proven to be an ideal contender. These devices generate feed flow-independent shear that triggers solute back-transport away from the membrane. Subsequent flux enhancement is a congruous merit. Power-law correlation between the flux and average shear rate has been so extensively used in several studies so that it became the ubiquitous scaling relation for DSEMFPs. However, in this article, we have demonstrated a novel and more expansive scaling between flux and a set of prototypical turbulent measures (i.e., turbulent kinetic energy, kinetic energy dissipation rate, and Kolmogorov scale), relative to shear rate, ranging over five different DSEMFPs. Flux data were collected from previous studies, whereas hydrodynamic variables were evaluated computationally. All turbulent measures exhibited better correlation compared to shear rate with the Kolmogorov scale being the best regressor (R2 > 0.96). The study demonstrates that turbulence has an equivalent, if not superior, role in upscaling flux in DSEMFPs against the conventional idea of shear generation being primary. [ABSTRACT FROM AUTHOR]

[Display omitted] • MOF-based MMMs were formed by in-situ growing the copper-ZIFs for textile wastewater treatment. • Outstanding performances of dye rejection with salt permeation were reached. • MMMs exhibited excellent water permeability and long-term stability. • MMMs have good anti-fouling ability, antibacterial properties and operation stability. Metal-organic frameworks (MOFs) based mixed-matrix membranes (MMMs) exhibited an excellent promise for separating dye molecules and salt ions due to their permeability and selectability. However, controlling interfacial compatibility between the polymer and MOFs remained challenging, and MOF-based MMMs were poorly processable. Herein, the dual-bath coagulation method was developed to form the polyvinylidene fluoride (PVDF) and polyvinylpyrrolidone (PVP) polymer precursor layer, which provided a skeleton support structure. Inspired by the capillary effect, the nanosheet copper-ZIFs were in situ grown in the skeleton support structure, forming capillary microporous channels. The formation of capillary microporous channels endowed the MOF-based MMMs with high permeability of water molecules. Interestingly, the MOF@PVDF/PVP membrane exhibited excellent water permeance (ca. 635.7 L·m−2·h−1·bar) and selectivity for dye/salt separation (dye removal approaching 100 %, salt removal < 10 %). Even for the cationic small-molecule dyes, the MMMs showed an outstanding rejection (e.g., 96.3 % for malachite green and 96.7 % for methylene blue). The water permeance of the MOF@PVDF/PVP membrane was much higher than that of most membranes with similar rejection rates for dyes. Besides, the antifouling and antibacterial properties confirm that the MMMs could maintain long-term stability in practical dyeing wastewater treatment. This study provides an efficient approach to preparing MOF-based MMMs with capillary and skeleton support structures, which exhibited superior performance and outstanding stability for water purification. [ABSTRACT FROM AUTHOR]

Highly hydrophilic carbon nitride nanoparticle-conditioned IP process to improve the separation performance. [Display omitted] • Homogeneously hydrophilic W-CN nanomodifier ensures the interfacial polymerization of ultrathin PA layer. • The water flux of PA-W-CN is twice to that of PA and three times to that of commercial NF270. • W-CN contributes to the well antifouling performance of TFN membrane. Nanomaterial modification provides an effective way to enhance the separation performance of nanofiltration membranes, but the limited hydrophilicity of conventional nanostructures causes their poor solubility in solvents, affecting the quality of polyamide membranes for performance enhancement. Herein, we explored quasi-water soluble carbon nitride as a homogeneous modifier to improve the nanofiltration performance of polyamide membranes. With sufficient hydroxyl, amino, and cyano groups, the introduced quasi-water soluble carbon nitride significantly enhanced the surface hydrophilicity of the support membrane, resulting in the formation of an ultrathin functional layer for high-efficiency desalination. The high permeation flux of 108.64 L m-2h−1 (4 bar) was even twice and three times higher than those of the pristine polyamide membrane and commercial nanofiltration membranes, with a high Na 2 SO 4 barrier rate of 98.84 % and a Cl-/SO 4 2- selectivity of 76. This work provides an effective way to precisely regulate the structure of nanofiltration membranes for high-performance water purification. [ABSTRACT FROM AUTHOR]

• A sandwich structured composite membrane with synergistic removal of TC by photocatalysis and adsorption was prepared. • The combination of photocatalysis and membrane filtration significantly reduces membrane fouling. • The maximum stress borne of the membrane were improved by 10.58% using polyester-cotton fabric as the supporting layer. • The removal percentage of TC by the composite membrane can reach 87.10% after four cycles. Environmental pollution has become increasingly serious, especially the abuse of tetracycline (TC) antibiotics, which has brought serious problems to human life. Therefore, the residual TC in the environment has become an urgent problem to be solved. To improve the efficiency of TC wastewater purification and solve the problem of powder material recovery during photocatalysis, a sandwich layer photocatalytic composite membrane with catalytic/adsorption synergistic effect was prepared in this study. The first layer of the composite membrane is composed of a polyether sulfone (PES) membrane loaded with UiO-66-NH 2 /Bi 2.15 WO 6 (UN/BWO) photocatalyst (named as UN/BWO@PES), the middle layer is a support layer composed of polyester/cotton fabric, and the lower layer is composed of a calcium alginate/diatomite (CA@DE) membrane with adsorption for TC. Under dark conditions, the rejection percentage of TC by sandwich composite membrane (M4.5 D 0.02-3) can reach 50.81%, while under light conditions, the removal efficiency of TC by M4.5 D 0.02-3 can reach 93.94%. Even after four cycles, the removal percentage of TC by M4.5 D 0.02-3 can still reach 87.10%. Therefore, the visible light responsive photocatalytic composite membrane developed in this study has dual advantages of photocatalysis and membrane adsorption filtration, and has enormous application potential in wastewater treatment, which can minimize membrane pollution and improve the reusability of photocatalysts. [ABSTRACT FROM AUTHOR]

• A reverse filtration mode of catalytic membrane was proposed. • Reverse filtration can highly improve the flux and separation performance. • Algae body can firstly reject by the base membrane and keep integrity during reverse filtration. • The water quality was improved during the reverse filtration mode. During catalytic membrane filtration, algal cells and macromolecules in environmental aqueous conditions load on the surface of the catalytic material, leading to progressive deactivation of the catalytic membrane. Here, we synthesized catalytic membranes with outstanding water flux by anchoring catalyst (δ-MnO 2 and sulfur-doped g-C 3 N 4) on homoporous base membranes and immobilizing them by PIP-TMC interfacial polymerization. And the reverse filtration was used to pre-remove the hard-to-degrade foulings such as algal cells to enhance the degradation performance and antifouling performance of the catalyst membrane. The presence of reverse pre-filtration endowed the catalytic membrane to obtain 1.5 times higher water flux than normal filtration, reducing the contact of foulings with the catalyst and improving the catalytic efficiency and stability. Therefore, the operating conditions of the catalytic layer were optimized to obtain higher degradation rates and maintain long-term catalytic activity compared to normal filtration. Also, in the treatment of algae-laden water, reverse filtration allowed algal cells to be separated due to pore size sieving and catalytic material space, avoiding cell fragmentation and release of extracellular polymers caused by activated generated reactive oxygen species. In the catalytic removal of the refractory pollutants (APAP and SMX), the SK25 membrane was able to remove 100 % of the performance with degradation rates up to 0.36 mol·L−1·s−1. This study proposes a novel strategy for catalytic membrane filtration and promotes the application of catalytic membrane filtration technology in practical environmental problems. [ABSTRACT FROM AUTHOR]

[Display omitted] • Green and biodegradable xylitol was chosen as a new monomer for LNF membranes. • XL-1.5/TMC achieved a CR/Na 2 SO 4 selectivity of 259 and ultrahigh permeance of 97.7 L m−2h−1 bar−1. • XL/TMC membrane performances could be tailored by controlling the XL concentrations. • The XL/TMC membrane exhibited satisfactory antifouling performance and stability. • Novel LNF membranes for efficient resource recovery from dye wastewater were tailored. Polyester (PE) membranes with outstanding permeance and efficient dye desalination performance have become ideal for resource recovery from dye wastewater. However, further improving the performance of PE membranes remains challenging. Herein, a novel high-performance PE loose nanofiltration (LNF) membrane was fabricated via interfacial polymerization, in which nontoxic, rich in hydroxyl, large size, inexpensive, low reactivity, and biodegradable xylitol (XL) was utilized to fabricate PE films. The newly formed XL-based membrane had a hydrophilic, negatively charged, smooth, loose, and thin selective layer. The membrane was optimized by controlling the XL concentrations in the aqueous phase (0.5–2.5 wt%). The optimized membrane (XL-1.5/TMC) exhibited unprecedented water permeance (97.6 L m−2h−1 bar−1) and satisfactory dye desalination performance (Congo red/Na 2 SO 4 selectivity of 259). In addition, the XL-1.5/TMC membrane showed outstanding antifouling performance and stability, which showed great potential for the large-scale application of XL-based membranes. Therefore, this new strategy for the fabrication of PE LNF membranes featuring superior performance using XL was proposed to facilitate resource recovery from dye wastewater. [ABSTRACT FROM AUTHOR]

[Display omitted] • The removal of 2-MIB by NF mainly depends on size exclusion. • NOM in raw water facilitates the removal of 2-MIB by NF. • The interactions of NOM and 2-MIB are hydrogen bond and hydrophobic effect. • In the binding of NOM to 2-MIB, protein-like substances play a major role. • NF270 is capable of virtually eliminating NOM from the water. The presence of natural organic matter (NOM) in surface water and its significance for removing pollutants during nanofiltration (NF) are overlooked since most previous studies were conducted in synthetic water rather than real water. In this paper, using raw water collected from Lake Tai (the third largest lake in China), we investigate the removal of 2-methylisoborneol (2-MIB, one of the most concerned off-flavor compounds in raw water) by NF and analyze the binding behaviors between 2-MIB and NOM, which affect their corresponding migration and removal behaviors of 2-MIB during NF. The results show that the removal of 2-MIB in real raw water is 12.2 ∼ 22.0 % higher than that in pure water (PW). Additionally, we evaluate the increment of the removal of 2-MIB under different backgrounds, which follow the order NOM (17.2 %∼22.0 %) > bovine serum albumin (BSA 16.0 %∼19.1 %) > intracellular organic matter (IOM) of M. aeruginosa (8.3 %∼9.4 %) > sodium carboxymethyl cellulose (CMC 3.9 %∼6.5 %) > humic acid (HA 0.28 %∼0.31 %). These findings demonstrate that the protein-like components in raw water play a major role in binding to 2-MIB, while humic-like components exhibit a weak association with 2-MIB. Overall, the conclusion and findings in this study provide a new perspective on the NOM effect on micropollutant removal during water treatment. [ABSTRACT FROM AUTHOR]

[Display omitted] • Prediction of permeability based on zeolite diameter and porosity. • Experiments verified the accuracy of the calculation model. • Two new structural forms are proposed. • Optimized the parameters of the new structure. Silver zeolite filters have potential applications in nuclear power plant filtration and emission systems due to their high-efficiency adsorption properties for radioactive methyl iodide. The adsorption performance of the filter is closely related to the flow distribution characteristics. To analyze the flow distribution characteristics of the filter element, we established a reasonable numerical calculation model and verified the model through experiments. Then based on the model, the advantages and disadvantages of different filter unit structures are analyzed. We proposed two new structural forms of filters and evaluated the performance of the filters based on the pressure distribution and flow increment curve, considering the difficulty of processing and space utilization. Comparative analysis and characteristic research have been carried out under different sizes, from the cylindrical filter to the round table filter and, finally, to the square filter. Our results show that round table and square filters have significantly improved flow distribution compared to traditional cylindrical filters. However, the structure of the round table filter is irregular, and the space utilization rate is low. Finally, through optimization design, the square filter with channel spacing L of 250 mm has the best performance. Our research results have a certain guiding significance for the design of the silver zeolite filter prototype. [ABSTRACT FROM AUTHOR]

[Display omitted] • Water permeability of SiO 2 -ZrO 2 membranes was significantly enhanced through the addition of glucose. • Water permeability increased and reached a stable value after treatment at 90 °C for 10 h. • SiO 2 -ZrO 2 membranes were hydrothermally stable in hot water as long as for 100 h. SiO 2 -ZrO 2 nanofiltration membranes were prepared by adding glucose into SiO 2 -ZrO 2 sols, followed by coating on cylindrical alumina porous support and firing at 550 °C. The average pore sizes of the SiO 2 -ZrO 2 membranes by adding glucose in the SiO 2 -ZrO 2 sols were larger than without adding glucose in sols. Water permeabilities of SiO 2 -ZrO 2 membranes, prepared from 1.0 wt% SiO 2 -ZrO 2 sols with and without the addition of 0.5 wt% glucose, were 4.2 × 10−12 m3/ (m2 s Pa) and 2.0 × 10−12 m3/ (m2 s Pa), respectively, while both of SiO 2 -ZrO 2 membranes with and without addition of glucose showed approximately the same molecular weight cut-off (MWCO) of 300 g/mol. After membrane treatment in water at 90 °C, the water permeability of 1 wt% SiO 2 -ZrO 2 membranes increased dramatically, while the MWCO of membranes remained the same as that before the treatment. The water permeability of membranes with and without addition of 0.5 wt% glucose increased from 4.2 × 10−12 to 9.1 × 10−12 m3/ (m2 s Pa) for MWCO of 320 g/mol and from 2.0 × 10−12 to 4.9 × 10−12 m3/ (m2 s Pa) for MWCO of 300 g/mol, respectively. An increase in the water permeability of SiO 2 -ZrO 2 membranes after treatment in water at 90 °C can be explained by increasing in the hydrophilic surface and inner membrane pore and the dissolution of silica into hot water. SiO 2 -ZrO 2 membranes with doping glucose achieved enhancement in the water permeability and hydrothermal stability. [ABSTRACT FROM AUTHOR]

[Display omitted] • An anti-quorum sensing (anti-QS) coating layer was fabricated on a mixed cellulose ester (MCE) membrane via electrospinning (ES). • The modified membrane exhibited superior anti-biofouling behavior. • The modified anti-QS membrane showed improved filtration efficiency. The formation of biofilm on the surface of water filtration membranes results in decreased flux through the filter and output of contaminated water despite filtration. The reduction in clean water output due to biofilm diminishes filtration efficiencies and feasibility of filtration in regions where alternatives do not exist. In this work, we sought to lower biofouling concerns through examination of anti-quorum sensing (anti-QS) molecules in P. aeruginosa (PAO1). QS plays a critical initial role in biofilm formation. Therefore, we hypothesized that disruption of this communication mechanism at the filtration surface would result in lower biofilm growth and higher water outputs. An electrospun filter coating was developed to prevent biofilm formation on the surface of filtration membranes. The filter coating was deposited by electrospinning (ES) fibers that contained a polymer blend made up of one hydrophobic (polycaprolactone, PCL) and one hydrophilic (polyethylene glycol, PEG) polymer to provide controlled release of anti-quorum sensing molecules (Urolithin A) to prevent biofilm formation for an extended filtration test. Results showed that a 3:1 PCL to PEG polymer blend coating containing Urolithin A (200 µg/mL) provided significant physical disruption as well as molecular interruption of biofilm formation as compared to the pristine membrane (83.48 % reduction). While fibers exhibited smooth morphologies prior to nanofiltration tests, the fibers became porous after 4 hr tests in areas where PEG had dissolved and released Urolithin A. The controlled release of anti-QS molecules by electrospun fibers provided a significantly improved anti-biofilm methodology, improving biovolume reduction by 26.05 % and increasing flux by 52.78 % as compared to similar technologies reported. In addition to these findings, this work demonstrated Urolithin A disruption of PAO1 motility on agar (65.29 % reduction @ 100 µg/mL) and reduction in biofilm thickness (84.15 % reduction @ 200 µg/mL) by dissolution from electrospun fibers in liquid culture. [ABSTRACT FROM AUTHOR]

• NF membrane fouling by alginate is studied at low-to-moderate temperatures (5-15 °C) • Warmer water results in more fouling, due to higher permeance, and strong foulant adhesion. • AFM revealed weaker foulant-membrane repulsive forces with rising temperature. We investigated the effect of solution temperature on organic fouling and cleaning of polypiperazine nanofiltration (NF) membranes. Fouling experiments were conducted in the temperature range 5 °C ≤ T ≤ 15 °C, characteristic of surface waters in northern latitudes, such as Scottish lochs. Results of laboratory-scale fouling experiments using alginate, a polysaccharide constituent of extracellular polymeric substances, showed a moderate increase in flux loss at 15 °C (41 %) compared to 5 °C (36 %). Analysis of the fouling experiments using a series-resistance model showed that the greater extent of fouling with rising temperature stems from a monotonic increase in water permeance with T. Interfacial property characterisation provided further insight into the effect of temperature on fouling determinants such as membrane hydrophobicity, nanoscale roughness, surface charge, and surface forces. No T- dependence of surface roughness was found. Similarly, we found that water contact angle is invariant within the temperature range investigated, suggesting that the observed fouling behaviour is not due to modulation of hydrophobic interactions. Conversely, colloidal-probe force spectroscopy (CPFS) measurements showed that adhesion forces become stronger with rising temperature. Further analysis showed that repulsive forces – which oppose colloidal particle deposition – become weaker with rising temperature, consistent with fouling trends. Determination of the membrane zeta potential showed that surface charge is invariant over the range of temperatures investigated, suggesting that repulsive forces have a non-electrostatic (likely steric) origin. Additionally, we assessed the effect of temperature on physical and chemical cleaning efficiency, comparing cleaning at the same temperature as the fouling experiments (5 °C ≤ T ≤ 15 °C) with cleaning at 30 °C. We observed that physical cleaning, consisting of water circulation over the fouled membrane surface, is insufficient to remove the foulant layers. On the other hand, chemical cleaning is able to restore 95 % of the original membrane permeance at 10 °C, but only 74 % at 5 °C. [ABSTRACT FROM AUTHOR]

[Display omitted] • BIEX resin pre-treatment performance for subsequent GDCM process was investigated. • BIEX removed 74 % DOC, followed by 27 % removal by M3 (50 wt% kaolin + 50 wt% alumina) • M3 showed the highest flux (5.7 LMH) and decreased turbidity from 2.20 to 0.09 NTU. • BIEX pretreatment improved DOC, turbidity and flux compared to GDCM only process. • Biofilm physical characteristics were lower in BIEX + GDCM than GDCM only process. In this study, the performance of a biological ion exchange (BIEX) resin and gravity-driven ceramic membrane (GDCM) filtration hybrid process in terms of membrane permeate quality, flux, and membrane biofilm characteristics during river water treatment for drinking water was investigated. The hybrid process results were compared with those of the GDCM process without the BIEX pre-treatment. Three types of previously synthesized microfiltration membranes were used: M1 (100 wt% kaolin), M2 (75 wt% kaolin + 25 wt% alumina), M3 (50 wt% kaolin + 50 wt% alumina), and M4 (commercial ceramic microfiltration membrane). In terms of permeate quality, the BIEX column removed approximately 74 % of the dissolved organic carbon (DOC) compared with the influent water, followed by 27 % DOC removal using M3 compared with the BIEX column effluent on day 65 (6,240 BV), which was mainly due to the removal of humic and fulvic acids. BIEX removed turbidity of the influent water from 2.20 NTU to 0.77 NTU, which was further decreased to 0.09 NTU by membranes. The maximum stabilized flux of the membranes was approximately 5.7 LMH, which was almost doubled compared to GDCM without pre-treatment. The membrane biofilm showed lower thickness and roughness in the hybrid process than that in GDCM without pre-treatment. Higher extracellular polymeric substance (EPS) concentration and biological activity were observed for M3, the membrane with the highest stabilized flux and highest DOC removal efficiency. The results indicate that the hybrid BIEX + GDCM is a robust, high-performance, and easy-to-use process that can increase the flux and permeate quality of GDCM systems. [ABSTRACT FROM AUTHOR]

[Display omitted] • MXene nanosheets at 1.0 mg/cm2 were ideal for ceramic membrane coating. • Membrane pore size and surface charge decreased after MXene nanosheet coating. • The MXene membrane improved dissolved silica, DMSO, and IPA removal efficiency. • Fluoride was almost completely removed by the developed MXene ceramic NF membrane. • The MXene nanosheets increased separation performance compared to other membranes. Ceramic membranes, known for their exceptional chemical stability, have found practical applications in the treatment of semiconductor wastewater. In this study, we have developed an innovative ceramic nanofiltration membrane featuring a nanochannel network created by two-dimensional (2D) nanomaterials, enabling high-performance separation and permeation. This accomplishment is realized through precise control of the size and thickness of MXene nanomaterials, which can be tailored using various coating conditions. The repeated stacking of MXene nanosheets onto the ceramic membrane substrate resulted in the formation of additional nanochannels and surface chemistry modifications, leading to significant enhancements in pollutant removal. These MXene-coated ceramic nanofiltration (NF) membranes significantly improved the removal efficiency of representative organic contaminants in semiconductor wastewater when compared to the pristine ceramic membrane. It enhanced the removal efficiencies by 4.2 times for dissolved silica, 3.7 times for dimethyl sulfoxide (DMSO), and 2.5 times for isopropyl alcohol (IPA). Furthermore, the MXene ceramic NF membrane exhibited exceptional fluoride removal capability, achieving approximately 99.1% removal, in addition to organic solvents. These findings not only help meet regulatory standards for wastewater discharge but also provide valuable insights into the transport behaviors of contaminants and their separation mechanisms. This innovative approach brings us one step closer to efficient and sustainable solutions for semiconductor wastewater treatment. [ABSTRACT FROM AUTHOR]

[Display omitted] • One-step in-situ immobilization of lipase on a ceramic membrane was successful. • Optimized immobilization conditions resulted in a more hydrophilic membrane. • Optimized immobilization conditions resulted in better membrane hydrolytic activity. • The modified membrane showed strong fouling resistance and self-cleaning capacity. • The membrane was successfully regenerated by calcination or in-situ chemical cleaning. Enzyme immobilization on inorganic membranes is typically a difficult, time-consuming, multi-step process carried out ex-situ (outside the filtration system). To enable process scaling, an in-situ immobilization technique is essential. Therefore, an in-situ method to immobilize the lipase Eversa Transform 2.0 (ET2) on a ceramic membrane was developed using polydopamine as a bonding agent. The in-situ immobilization was successful, and optimum dopamine hydrochloride and ET2 concentrations (0.3 mg·mL−1 and 4 mg·mL−1, respectively) resulted in an enzyme loading of 10 g·m−2 that increased the membrane water affinity and hydrolytic activity towards soybean oil (38 mmol·min−1·m−2). The enzymatic membrane demonstrated great self-cleaning capability (pure water permeance recovery of 97 % after cleaning with deionized water at 40 °C for 6 h) and strong fouling resistance (pure water permeance decline limited to 43 % following oil emulsion filtration). To reuse the membrane after it lost its hydrolytic activity, calcination or in-situ chemical cleaning were tested. There were no morphological or chemical alterations on the membrane surface after five cycles of modification-regeneration. When compared to ex-situ immobilization techniques, in-situ enzyme immobilization and chemical regeneration can save costs, improve the sustainability of the process, and ease scale-up. [ABSTRACT FROM AUTHOR]

[Display omitted] • Chitosan membranes were fabricated via wet precipitation with an alkaline dope. • Coagulating conditions were regulated to optimize the filtration performance for UF. • Optimization was achieved using ethanol as the coagulant at a subzero temperature. • Role of forming a hierarchical substructure was highlighted in the optimization. • OCT-based characterization was implemented to understand the structural formation. A key to the sustainable development of membrane technology is the green fabrication of biopolymer membranes, whose filtration performance is comparable to that made from petroleum-based polymers. In this study, chitosan membranes were fabricated via wet precipitation of the alkaline dope; both the composition and temperature of the coagulation bath were regulated to optimize the filtration performance for ultrafiltration. It is revealed by comparing the morphological characterization with the filtration-performance evaluation that the use of pure ethanol as the coagulant at a subzero temperature would be in favor of the formation of a laminated substructure, which can enhance the water permeance not at the cost of decreasing the rejection of micron-sized particles and macromolecules. Optical coherence tomography (OCT) was employed to in-situ characterize the film formation in an effort to understand how the variation in coagulating conditions could change the geometrical and topological characteristics of the resulting membrane. The OCT-based characterization highlights the key role of the Liesegang phenomenon in forming the hierarchical substructures, while resolving the synergistic effects emanating from the ethanol-induced film shrinkage and the structural preservation in the subzero environment. [ABSTRACT FROM AUTHOR]

• A rapid & eco-friendly surface mineralization approach was applied on NF membrane. • BaSO 4 -mineralized membrane showed excellent flux & rejection.. • The mineralized membrane also displayed better antifouling ability with higher FRR. • The rejection of mineralized membrane was very stable for multiple filtration cycles. In this study, an environmentally friendly and rapid surface modification method known as surface mineralization was adopted to alter the polyamide (PA) layer of commercial NF270 thin film composite (TFC) membrane, aiming to improve its characteristics for enhanced desalination process. An alternate soaking process was applied on the membrane surface by using barium chloride solution and sodium sulfate solution at varying concentrations (0.01 M, 0.05 M and 0.1 M). The reaction of these two salts can form a layer of barium sulfate (BaSO 4) minerals atop the PA layer via an ionic interaction. Our result revealed that the best-performing membrane could be developed using salt solutions at 0.05 M with its water contact angle descended to 33.5° compared to the pristine membrane of 46.4°. Furthermore, the surface roughness of the BaSO 4 -mineralized membrane was reported to be higher than the pristine membrane. The increase in surface roughness together with improved surface hydrophilicity yielded the BaSO 4 -mineralized membrane to exhibit 12% higher water flux than the pristine membrane. Nonetheless, the difference in Na 2 SO 4 rejection before and after surface mineralization was not found to be statistically significant owing to the high Na 2 SO 4 rejection of the control membrane. The BaSO 4 -mineralized membrane also achieved excellent performance in filtering solutions containing sodium alginate and showed very stable salt rejection for multiple cycle of combined chemical cleaning and water filtration process. These results highlighted the potential of the surface mineralization process in overcoming the trade-off effect between water flux and selectivity of TFC membrane. [ABSTRACT FROM AUTHOR]

[Display omitted] • Continuous carbon membranes were prepared via simple mechanical rubbing of pencil graphite. • Carbon membranes prepared from 2B pencil graphite showed the highest dye rejection rates. • The spent membranes could be recycled by erasing, enabling complete recycling and reuse of substrates. Although having shown great promise in gas separation, reverse osmosis, and nanofiltration, preparation of carbon membranes, which commonly involves elaborate high-temperature pyrolysis or exfoliation-reassembly, still suffers from complicated fabrication procedure and/or high production cost. In this study, we pioneered the preparation of continuous asymmetric carbon membrane through facile mechanical rubbing of a pencil graphite. Among them, 2B-type pencil with 64 wt% graphite exhibited superior nanofiltration performance (Congo Red rejection rate of 99.4% and water flux of 21.91 L·m−2·h−1·bar−1). Long-time operation confirmed its excellent stability. Of particular note, the spent membrane could be facilely recovered by erasing, resulting in not only zero pollutant discharge but also full recovery and reutilization of the substrate. The above protocol is anticipated to pave an avenue for facile and sustainable production of versatile carbon membranes with superior separation performances. [ABSTRACT FROM AUTHOR]

[Display omitted] • pH-responsive BNNS-based nanofiltration membrane was developed by introducing PAA. • Size sieving played a crucial role in nanofiltration for dyes separation. • BNNS/PAA membrane displayed the exceptional separation and cycle stability. Two-dimensional lamellar nanofiltration membranes have great application potential for water purification. Here, in order to achieve tunable water permeance and efficient dye separation, we reported a pH-responsive boron nitride nanosheets (BNNS)-based nanofiltration membrane by introducing polyacrylic acid (PAA). The strong hydrophilicity and electronegativity of PAA endow BNNS/PAA membrane with a fast water flux of 228 L·m−2·h−1 and a high methylene blue (MLB) rejection of 98%, increased by 235% and 4% compared to the neat BNNS membrane, respectively. Owing to the size sieving effect, the BNNS/PAA membrane possesses the better selectivity for the different types of dyes and dye/salt mixture from the potential pollutants in the water. Meanwhile, it exhibits diverse and tunable nanofiltration performances at different pH, implying excellent pH-responsive ability of BNNS/PAA membrane. In addition, the BNNS/PAA membranes also display the exceptional separation and long-term stability at different environments. This work provides a novel and simple strategy for designing the BNNS-based nanofiltration membrane with the pH-responsive ability, the tunable water permeance and selectively. [ABSTRACT FROM AUTHOR]

[Display omitted] • Hydrophilicity in PE membrane matrix via in-situ growth of poly(m -phenylenediamine) (PMPD) • PA skin layer with Turing structure as regulated by PMPD on PE for significant increase of the water flux. • Over 10-day nanofiltration with water permeance (17.7 LMH bar−1) and Na 2 SO 4 rejection (99.3%) • Outstanding selectivity of 115 for NaCl/Na 2 SO 4 and 339.8 for Cl-/SO 4 2- without reducing the water flux. • Ultra-high selectivity of 990 for CR/NaCl and 1039 for MB/NaCl with enhanced water flux. Membrane-based nanofiltration is a crucial technique for treating dyestuff-salts wastewater, owing to its excellent selectivity towards mono/multivalent ions and organic matter. In this study, a facile and highly practical method was employed to enhance the hydrophilicity of the PE matrix through in-situ growth of poly(m -phenylenediamine) on the PE fibrils via the chemical oxidative polymerization of MPD. The inclusion of the poly(m -phenylenediamine) on PE enables the formation of homogenous and defect-free PA layer showing a unique honeycomb-like Turing morphology with characteristic crater-belt structure. Furthermore, the pendant amine groups from the poly(m -phenylenediamine) chain promotes the formation of a PA layer with a smaller effective mean pore size and a sharper pore size distribution, resulting from the formation of an extra polyamide network (reaction of PMPD with TMC) within the PA layer. The as-prepared PE-based NF membrane exhibits a high pure water permeance of 17.7 LMH bar−1, exceptional Na 2 SO 4 rejection of 99.3%, and a long-term stability for cross-flow filtration for over 10 days. The PE-based NF membrane exhibits the water flux 2.2 times higher than that of the commercially available DK and DL membranes while maintaining a high salt rejection. Additionally, the PE-based NF membrane demonstrates exceptional selectivity, with a value of 115 for the separation of NaCl/Na 2 SO 4 and 339.8 for Cl-/SO 4 2- in a binary salt mixture. Furthermore, the PE-based NF membrane shows ultra-high selectivity values of 990 for CR/NaCl and 1039 for MB/NaCl in the treatment of dye/salt mixtures, respectively, which are significantly higher than those of the DK and DL membranes. The findings of this study highlight the potential of the in-situ growth of poly(m -phenylenediamine) on PE fibrils as a simple and cost-effective method for the modulation of hydrophilicity to enhance the NF membrane performance. [ABSTRACT FROM AUTHOR]

• Integration of a green biorefinery with ethanol fermentation was evaluated. • 90% of the green juice crude protein was recovered in the protein concentrate. • Nanofiltration raised the sugar composition in the brown juice from 2.4 to 13.6 %. • Purification of ethanol from concentrated brown juice used up to 45% less energy. • DWC was the best choice to purify ethanol among the tested extractive distillations. The objective of this study is to propose the integration of a green protein biorefinery with ethanol production and to highlight the potential of nanofiltration membrane technologies and extractive distillation in the separation and purification of valuable substances. Depending on the product and its purity, the nanofiltration membrane can help in decreasing energy expenditure and greenhouse gas emissions while extractive distillation overcomes the water–ethanol azeotrope formation. The aim is to enhance the sustainability of biorefinery processes by integrating new separation techniques and adopting process intensification. The concentration of the residual brown juice using nanofiltration reduced its water content and favored the sugar conversion into ethanol while concomitantly decreasing the formation of byproducts. It has been shown that these configurations (with the presence of nanofiltration and intensified) have lower energy consumption compared to the proposed classical sequence. The results of the simulations indicate that better results are obtained with the extractive distillation using a dividing-wall column, achieving around a 50 % reduction in energy consumption and a 58 % reduction in CO 2 emissions. [ABSTRACT FROM AUTHOR]

[Display omitted] • Streaming zeta potentials and EDL theory were utilized to study ion adsorption on membrane surfaces. • Divalent ions could occupy membrane surfaces much more facilely than monovalent ions. • The adsorption of ions is Langmuir-type and more likely to result from the Coulomb force. • Little difference was observed between Ca2+ and Mg2+, or between –COOH and –SO 3 H. • The obtained mechanisms of ion adsorption help to explain the counter-ion competition effect. The net charge on nanofiltration (NF) membrane surface, which differs from the inherent fixed charges due to the adsorption of ions from the feed water, has a great effect on the rejection selectivity of the membrane. In this study, by taking advantage of the electric double layer theory, streaming zeta potentials of the membrane varying with solution composition and concentration were utilized to investigate the characteristics and mechanisms of ion adsorption on the typical negatively charged NF membrane surface, which were then utilized to interpret the (selective) rejection behaviors for different solutes. Results showed that the cation adsorption all followed the Langmuir isotherm, indicative of monolayer adsorption mechanism. Both Langmuir adsorption fitting results and Gibbs free energy calculation showed that the cation adsorption is primarily of Coulomb force origin, rather than the chemical complexation. In addition, Ca2+ and Mg2+ could occupy the membrane surface much more facilely than Na+, with the adsorption of divalent cations reaching near saturation at relatively low concentrations in the magnitude of 1 mmol L−1. Contrary to the original presumption, no remarkable difference was observed between the adsorptions of Ca2+ and Mg2+, as was also the case between -COOH and -SO 3 H, the two common types of acidic functional groups on membrane surface for cation adsorption. These mechanisms of ion adsorption, when incorporated with the existing NF theory, could well interpret the seemingly "strange" rejection behaviors including the counter-ion competition effect. This study evidenced that zeta potential measurements could act as a useful approach for the study of ion adsorption on NF membrane surface and selective rejection mechanisms of NF membranes as well. [ABSTRACT FROM AUTHOR]

• The mesh with eco-friendly iron coating was prepared by one-step liquid phase reduction route. • The coated mesh has good superoleophobicity under pure and corrosive water. • The mesh can separate hot corrosive water from oils. • The mesh has good recyclability in oil/corrosive water separation. Although many underwater superoleophobic surfaces for separating immiscible oil/water mixtures have been constructed, the fabrication process of most of surfaces is non-green, complex, and time-consuming. Herein, a novel underwater superoleophobic stainless steel mesh (SSM) with eco-friendly coating was successfully prepared by simple and rapid one-step liquid phase chemical reduction route. The reduction treatment produces the iron (Fe) coating with micro/nano-structure, resulting in the underwater superoleophobicity, with oil contact angle as high as 152°. Such special wettability makes the surface to be readily wetted by water phase while repelling immiscible oil phase simultaneously. For this, the effective separation (separation efficiency: >96.2%) of oil/room temperature water and oil/hot (90 °C) water mixtures can be achieved by the decorated mesh. Specially, oil/hot corrosive water mixed liquid can be efficiently separated, and the mesh still maintains good separation efficiency (>94.6%) even after 30 cycles of separation. This research work provides a green, facile, and cost-effective strategy to construct the coating for oil/water filtration on metal mesh. It is expected that the as-fabricated mesh can be used as the filtration material for oily wastewater purification and oil spill treatment. [ABSTRACT FROM AUTHOR]

• The fate of micronutrients and heavy metals upon digestate processing was studied. • Vibrating membrane filtration (VSEP) was used for treatment of liquid fractions. • Production of dischargeable water was possible using VSEP and a lagoon. • Concentrates from VSEP show potential for reuse as a green fertilizer. • Heavy metals may be extracted/recovered from thick fractions of digestate. This study aims to evaluate the full-scale performance of vibrating membrane filtration (VSEP) technology in resource recovery from the liquid fraction of digestates, while reducing macronutrient concentrations down to dischargeable water. Although increasing attention is paid to mass flow assessment of macronutrients, to date little is known about the fate of micronutrients and heavy metals upon digestate processing. In this research, process streams were characterized and mass balances for micronutrients and heavy metals were performed throughout a complete digestate processing train. The VSEP system operated with reversed osmosis membranes and followed by a lagoon was capable of producing dischargeable water according to Flemish regulatory standards. Concentrates produced by one VSEP filtration of the liquid fraction of digestate and dried thick fractions resulting from solid-liquid separation were rich in macro- and micronutrients, while heavy metal concentrations did not exceed regulatory standards. Hence, these products showed high potential for reuse in agriculture. [ABSTRACT FROM AUTHOR]

• Hybrid system separates removal way between particulate and soluble organic matter. • Particulate organic matter is removed from water by mechanical filtration. • Removal of soluble organic matter consists of transfer from water and biodegradation. • The change of OUR of biofilm clears the behaviour of soluble organic matter. The removal of organic matter is a fundamental process in sewage treatment. Small scale sewage treatment plants, in particular, demand low cost and easy operation and maintenance. It is said that a hybrid water treatment system incorporating more physicochemical than biological processes for the removal of organic matter can be more convenient and incur less cost compared with a conventional activated sludge systems. Therefore, in this study, we propose a hybrid water treatment system equipped with a jet mixed separator (JMS), which is a type of pre-coagulation-sedimentation tank, and an aerobic moving bed biofilter (MBB). We then investigate the behaviour of particulate and soluble organic matter and the oxygen consumption by the biofilm in this hybrid system. The results indicate that the addition of the poly silicate iron coagulant in JMS increases the quantity of removed organic matter by approximately 30% compared with the process without coagulant, and that the majority of the removed organic matter is soluble. That is, the JMS effectively reduced the organic matter that can be eliminated only by biological treatment, and not by mechanical treatment. The residual organic matter of JMS was removed from the liquid phase within an hour, which is the hydraulic retention time (HRT) of MBB, and the removed soluble organic matter was almost perfectly biodegraded in the biofilm within a day. That is, MBB could continuously operate without excess growth of microorganisms as long as the filtering was working properly. Thus, the hybrid system is expected to maximize the performance of MBB. [ABSTRACT FROM AUTHOR]

• Tanzanian brackish water was treated by a photovoltaic powered NF/RO system. • Two configurations of NF/RO modules with the same membrane area were investigated during a fluctuation period. • The overall performance of the 1 × 4″ module was superior to the 3 × 2.5″ module. • The third element of the 3 × 2.5″ module reduced overall performance significantly. • The cumulative permeate fluoride of BW30, BW30LE and NF90 could meet the guideline. Integration of renewable energy and membrane filtration technologies such as nanofiltration (NF) and reverse osmosis (RO) can provide drinking water in places where freshwater is scarce and grid electrical connections are unavailable. This study investigated a directly-connected photovoltaic-powered membrane system under fluctuating solar conditions. Specifically, two configurations of NF/RO membranes with the same membrane area were investigated: a) 1 × 4″ module, which contained one 4″ NF/RO element; and b) 3 × 2.5″ module, which contained three 2.5″ NF/RO elements in series. A high fluoride brackish water ([F−] = 56.2 mg/L, total dissolved solids [TDS] = 4076 mg/L) collected from northern Tanzania was treated by different membranes in the two configurations. Performance indicators such as flux, specific energy consumption, and permeate F− concentration were monitored over a 60-min period of energy fluctuation that are part of a typical solar day. The results showed that the overall performance of the 1 × 4″ module was superior to that of the 3 × 2.5″ module. This is because the performance of a 3 × 2.5″ module degraded significantly from the first element to the third element due to the increased feed concentration and the decreased net driving pressure. Three 1 × 4″ modules (BW30, BW30LE and NF90) and one 3 × 2.5″ module (BW30) were able to meet the drinking water guideline for fluoride. During cloud periods, the transient permeate F− concentration exceeded the guideline value due to insufficient power, however the cumulative permeate F− concentration was always well below the guideline. The photovoltaic-powered membrane system equipped with the above modules provides a promising solution for addressing drinking water problems in remote and rural areas. [ABSTRACT FROM AUTHOR]

Highlights • Iron pretreatment significantly mitigates ceramic membrane fouling. • Ferrate pretreatment achieves the best membrane fouling control performance. • Ferrate greatly improves the water quality of reclaimed water. • Biopolymers with the MW of 20–2000 kDa are mainly removed. • Ferrate has dual functions of chemical oxidation and coagulation. Abstract Coagulation-membrane filtration hybrid process has been widely applied in water treatment to improve water quality and alleviate membrane fouling. Herein, we systematically investigated the comparable effect of ferrate, ferrous and ferric pretreatment on fouling alleviation of ceramic membrane in reclaimed water treatment. Our results showed that the pretreatment of ferric, ferrous and ferrate remarkably alleviated membrane fouling with the fouling alleviation performance following the order: ferrate > ferrous > ferric > control. The t crit (subcritical fouling time) after which the fouling rate (dTMP/dt) became much more severe was remarkably extended from 0 (control) to 432 (ferric), 576 (ferrous) and 888 h (ferrate), respectively. Meanwhile, hydraulically reversible fouling resistance had the greatest contribution (58.3%) to the overall fouling resistance in the control case, however, hydraulically irreversible membrane fouling caused by inorganics (R ir-citrate) became more severe in long-term operation with the contribution of R ir-citrate to the total fouling resistance of 40.7%, 46.3% and 50.3% in the cases with ferric, ferrous and ferrate pretreatment, respectively. Moreover, the redundancy analysis results showed that the alleviated membrane fouling was principally owing to the sharp reduction of organic matters and the significant increase of particle size and particle concentration in influent. Compared with ferric and ferrous, ferrate had the best fouling alleviation performance, which was mainly due to its dual functions of chemical oxidation (including OH, Fe(V) and Fe(IV)) and coagulation (ferric oxyhydroxides). [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • A new strategy to break through permeability-selectivity trade-off was proposed. • A conductive membrane was prepared by electroless Ni plating of PVDF membrane. • The conductive membrane shows improved hydrophilicity and antifouling ability. • The conductive membrane integrating electric field has high selectivity and permeability to dyes. Abstract The permeability-selectivity trade-off remains the major drawback limiting application of membrane technology. This study provided a new strategy to break through this trade-off. A novel conductive membrane prepared by electroless Ni plating of the polyvinylidene fluoride (PVDF) membrane was used for dyeing wastewater treatment by applying an electric field. Series analyses demonstrated success of immobilizing a Ni/NiO layer on the pristine PVDF membrane. The conductive membrane possessed improved hydrophilicity indicated by the water contact angle decrease from 75.5° to 45.0°. Moreover, the conductive PVDF membrane integrating electric field voltage of 20 V simultaneously possessed high selectivity (97.93% rejection) and extremely high permeability (202.51 ± 9.63 L m−2 h−1 at 0.1 MPa) for filtration of Congo red (CR) solution, significantly breaking through the permeability-selectivity trade-off. The filtration performance was quite stable even after 6 filtration cycles, indicating the feasibility of the conductive membrane for long-term treatment of CR wastewater. In addition, the conductive membrane showed high antifouling ability to methylene blue (MB), rhodamine B (RB), CR and microorganisms. The conductive membranes, together with the new strategy, offered in-depth insights into membrane fabrication. [ABSTRACT FROM AUTHOR]

• A pilot-scale NF system was investigated for conventionally treated surface water. • Effective TOC removal was obtained to reduce taste and odor problem. • Loose NF was found more effective for end user health and preventing pipeline corrosion. • Tight NF was found more economic. • Cost analysis was done for upgrading the conventional water treatment plant. Natural organic matter (NOM) is responsible for a variety of problems in water, including taste, odor, and color. If NOM is present in treated water, it can also promote microbial growth in water distribution systems. Another problem related with NOM is that it combines with chemicals such as chlorine in water resulting in the formation of disinfection by-products (DBPs). With the DBP regulations becoming more stringent, several advanced treatment methods started to be applied to enhance NOM removal. Pilot-scale advanced treatment tests employing tight nanofiltration (T-NF) membrane with high ion rejection capacity and loose nanofiltration (L-NF) membrane with low ion rejection capacity were conducted in this study in order to remove total organic carbon (TOC) having an average concentration of 2 mg/L at the sand filter effluent of a full-scale drinking water treatment plant and to avoid DBP production. The cost of incorporating membrane processes into the treatment process scheme was also determined during the study, in addition to the experimental studies. At constant 6 bar, the average fluxes for the T-NF and L-NF were determined to be 12.7 and 7.6 L /m2 h, respectively. L-NF had a TOC removal efficiency of 96.0%, which is quite similar to the removal efficiency achieved by T-NF (96.3%). Heavy metals, anions, and cations removal efficiency in T-NF membranes were greater than in L-NF, as expected. The removal efficiencies of Cl-, and Fe on T-NF membrane were determined to be 90.3 ± 2.2% and 69.6 ± 5.6, respectively, which are much greater than those achieved in L-NF membrane The total cost of 400,000 m3/d L-NF membrane system upgrade is calculated as 28,901,262 $/y including capital and operation and maintenance (O&M) costs, while in T-NF is calculated as 28,074,282 $/y. The total cost of NF upgrading is estimated to be around 0.191–0.198 $/m3, which is nearly 50% of the cost of the conventional treatment plant. When upgrading a conventional treatment system with this type of membrane system, additional expenses are typically incurred, resulting in a higher total cost; however, the resultant water quality is significantly improved. [ABSTRACT FROM AUTHOR]

[Display omitted] • Successful removal of undissolved substances from polystyrene-packaging waste. • Removal of up to 100 % of pigments can be achieved with dissolution recycling. • PS-PB particles from HIPS and carbon black cause membrane fouling. • Centrifugation successfully removes insoluble rubber particles from PS-based waste. • Applying centrifugation as first step allows further cleaning by filtration. Polystyrene (PS) is a versatile polymer typically used in applications such as yogurt cups, packaging trays, disk cases and toys. To increase recycling rates of PS, dissolution recycling is being investigated, which involves the liquefication of the polymer in a suitable solvent, allowing deep cleaning of the polymer from impurities. Quite specific to PS is that polystyrene waste contains both general-purpose polystyrene and high-impact polystyrene (HIPS), which is composed of free PS and polystyrene-grafted polybutadiene particles. In this work the potential of filtration and centrifugation is analyzed with the aim of cleaning the polymer from both, insoluble PB-PS particles and pigments (TiO 2 , Cr/Sb/Ti oxide and carbon black). The dead-end lab scale filtration were performed at room temperature and at pressures between 1.5 and 30 bar. The pigments were successfully removed, yet, filtration of HIPS solutions results in low fluxes due to extreme membrane fouling caused by the PB-PS particles, which was confirmed by the application of pore-blockage filtration models. Alternatively, centrifugation at 14,052 G-force has shown to be a promising alternative to separate the particles from HIPS, resulting in 100% turbidity reduction. Equally, the separation of pigments was successful, highlighting that TiO 2 and Cr/Sb/Ti oxide have shorter sedimentation times compared to carbon black. Finally, the two separation processes are tested on a PS rigid packaging waste sample coming from a sorting line and the results show that centrifugation allows a high turbidity reduction and that a two-step separation process starting with centrifugation for PB-PS particles removal can facilitate further downstream cleaning. [ABSTRACT FROM AUTHOR]

• The effect of BFA on filtration performance of NF270 was significant. • BFA increased water flux and reduced salt rejection and HAA rejection. • Carboxyl-based components reduced surface charge and increased pore size and hydrophilicity. • Amine-based components weakened the influence of carboxyl-based components. Considering the co-presence of body fluids and haloacetic acids (HAAs) in swimming pool waters (SPWs), as well as the potential for interaction among these substances and membranes, we have conducted a systematic investigation into the impact of body fluid analogue (BFA) on membrane performance. The minor impact of BFA on the rejection behavior of NF90 was attributed to its dominant effect of size exclusion. However, for NF270, 30 mg/L BFA increased water flux by 5%, decreased NaCl rejection from 59% to 47%, and decreased HAA rejection from 88% to 75%. The carboxyl-based components in BFA, including citric acid (CA) and hippuric acid (HA), were mainly responsible for the varied performance. Carboxyl-based components reduced the negative charge on membrane surfaces, increased the effective pore size and hydrophilicity, resulting in an increase for water flux and a decrease for NaCl and HAA rejection. The amine-based components (other BFA components with CA, HA, and salt excluded) did not directly influence the membrane performance, but their effect became remarkable under the coexistence of carboxyl-based components. The amine-based components neutralized the effect of the carboxyl-based components by forming hydrogen bonds. The practical application of membrane technology for water purification can be better predicted by the underlying mechanism for resolving the interaction among polyamide membranes, organic substances, and trace contaminants. [ABSTRACT FROM AUTHOR]

[Display omitted] • Pretreament media and nanofiltration exhibit complementary performance in PFAS removal. • Zero valent iron plays a critical role as a key ingredient in ZIFGEM for PFAS removal. • ZIPGEM removes dissolved organic carbon for membrane to prevent membrane fouling. Short-chain per- and polyfluoroalkyl substances (PFAS) have higher mobility than long-chain PFAS. This study investigated the application potential of two specialty adsorbents as pretreatment media for nanofiltration (NF) to enhance the removal of both short- and long-chain PFAS from water matrices. In this hybrid process, two specialty adsorbents, known as green sorption media (GSM), were prepared using recycled and natural materials for cost-effective, scalable, and sustainable water pretreatment. These two GSM are named the clay-perlite and sand (CPS) sorption media and zero-valent iron and perlite-based green environmental media (ZIPGEM). Such pretreatment led to significant removal of long-chain PFAS (up to 100 %) in addition to natural organic matter (NOM) and Ca2+ from the source water (canal water); however, for the short-chain PFAS (Perfluorobutanoic acid and Perfluorobutanesulfonic acid), the removal rate only rose to approximately 25 %. Such a contrasting removal rate is attributable to the source water concentration of PFAS and the hydrophobic and electrostatic interactions of the compounds within the treatment media. Yet the CPS–NF and ZIPGEM–NF hybrid processes exhibited significantly higher removal of perfluorooctanesulfonic acid (long-chain PFAS; approximately 16 % higher) when compared to the control (i.e., NF only). Because the pretreatment media removed higher percentages of long-chain PFAS, NOM, and Ca2+ from the water, the performance of the subsequent NF declined due to less calcium bridging involving NOM and PFAS and less micelle/complex formation by the compounds in bulk water. However, the integration of GSM with NF significantly improved (up to approximately 25 % higher) PFAS removal efficiency via the hybrid functionality. This signifies the membrane plays a complementary role in enhancing the overall removal efficiency of PFAS. In addition to contributing to PFAS removal from the source water, GSM pretreatment can help reduce NF membrane fouling/scaling by removing NOM and cations. [ABSTRACT FROM AUTHOR]

[Display omitted] • V 2 O 5 -WO 3 /TiO 2 nanocones was successfully loaded on the pore surface of SiC membrane. • VWTi/SiC membrane shows good performance of NH 3 -SCR denitration and dust filtration. • Nanocones structure inhibits the crack of VWTi catalyst layer on the pore surface. • Nanocones structure avoids the fall of catalyst layer during pulse-jet cleaning. In this work, TiO 2 nanocones grown on SiC membrane was used as the support of V 2 O 5 -WO 3 species to prepare V 2 O 5 -WO 3 /TiO 2 @SiC (VWTi(C-X)@SiC) catalytic membrane for dust filtration and NH 3 -SCR denitration. On account of the large specific surface area, abundant surface acid sites and prominent redox property, the optimized VWTi(C-550)@SiC catalytic membrane shows >90% NO removal efficiency at the temperature of 280–360 °C, which are much higher than VWTi(P-550)/SiC catalytic membrane (TiO 2 nanoparticles prepared by traditional vacuum coating titanium sol method was used as the support of V 2 O 5 -WO 3 species, NO conversion <80% at whole tested temperature). Additionally, VWTi(C-550)@SiC displays superior stability during the SO 2 + H 2 O resistance and 300 h long-term test at 300 °C, and exhibits an excellent dust filtration performance (2.5 μm SiO 2 particles interception rate exceeded 99.99%) under all test conditions. More importantly, the structure of nanocones decrease the influence of tensile stresses due to the different thermal expansion coefficients of TiO 2 and SiC membranes, which significantly suppress the fall of VWTi catalyst layer from the surface of SiC during pulse-jet cleaning. Among above results, it can be concluded that the optimized VWTi(C-550)@SiC catalytic membrane shows a prosperous application prospect for the simultaneously dust filtration and NH 3 -SCR denitration of medium–high temperature flue gas. [ABSTRACT FROM AUTHOR]

[Display omitted] • Sulfuryl chloride (SC) was used for NF membrane surface modification and mechanism study. • SC behaved alike small and reactive diacyl chlorides in tuning pore size and surface charge. • SC was incorporated with a low percentage but endowed the membrane with substantial effects. • SC could elevate the crosslinking degree of the top segment of nascent membrane. • The effect of secondary amidation on membrane after heat curing would be restricted. Surface modification via secondary interfacial polymerization (IP) is a promising technology for the enhancement of nanofiltration (NF) membrane performance such as rejection selectivity. In this study, sulfuryl chloride (SC), containing sulfur element, was employed to introduce sulfonic groups into the active layer of membranes, with a main purpose of investigating the secondary IP mechanisms as well as the variation of membrane structural and physicochemical properties. Moreover, the SC-modified membranes would be endowed with favorable performance. Results showed that SC in a hexane environment behaved similarly with small and reactive diacyl dichloride in enhancing membrane surface negative charge density and contracting membrane pores. Membrane surface characterization showed that the sulfur element had a low concentration with an S/N ratio less than 0.04. This indicated that, on the one hand, the residual amine groups in the nascent active layer for secondary IP were quite limited, and on the other hand, the improvement of membrane performance was remarkably affected by the introduced sulfonyl groups. Consequently, SC in the hexane environment could further enhance the crosslinking degree of the active layer. In addition, SC modification could increase the membrane surface hydrophilicity and narrow the pore size distribution. The SC-modified membranes would be suitable for advanced treatment of drinking water. An optimized membrane with SC modification had a molecular weight cutoff of ∼350 Da and a surface zeta potential of ∼−55.8 mV, and could effectively reject five negatively charged per- and polyfluoroalkyl substances (with molecular weight ranging from 214 to 414 Da) by over 80% while with a low rejection of MgCl 2 below 30%.. [ABSTRACT FROM AUTHOR]

[Display omitted] • A flexible, robust melamine foam composite was designed for TC removal via adsorption filtration. • Interfacial TA and BSA architecture onto MF based on simple coordination-driven assembly. • The modified MF displays excellent dynamic adsorption performance for tetracycline (TC) removal. • MF exhibited >95% removal of TC from milk and wastewater within 60 min, at flowrate 100 mL.h−1. Effective capture of antibiotic residues from different fluidic sources is still a challenge in dealing with existence of the chemicals in nature, especially with presence of other pollutants and suspended solids in the systems. Here, we report preparation of a novel macroporous metal − polyphenol/melamine foam (MF) composite (FTBS@MF) as a filtration matrix. The FTBS@MF matrix has rapid and effective adsorption to tetracycline (TC) in aqueous systems and could provide 99% TC removal efficiency from wastewater with a maximum capacity (650 mg·g−1) within 30 min. The TC adsorption on FTBS@MF are basically via multiple types of chemical interactions between TC and the functionalized MF surfaces, these mechanisms were confirmed by confocal imaging, XPS and fluorescence spectra. The FTBS@MF could reach 100% removal of TC at a flow rate 60 mL·h−1 with a dynamic adsorption capacity 600 mg·L−1. Furthermore, the FTBS@MF showed proper thermal and chemical stability and reusability of up to 20 cycles of reuses, and the recycling process was environmentally friendly. In addition, the FTBS@MF showed >95% removal efficiency of TC from real milk and dairy manure wastewater through a dynamic adsorption system. The macroporous framework matrix with rapid and efficient removal of antibiotics from milk and wastewater present great potential for practical applications of removing other emerging pollutants from various fluidic streams. [ABSTRACT FROM AUTHOR]

Biotech 1812 spiral-wound elements manufactured by GE Powe&Water have been characterized, operating in NF with aqueous solutions containing 50 g/dm 3 dextrose at 50 °C and pH = 4. Operative conditions were selected in order to get experimental results of flux and observed rejections highly dependent on feed flow rate, so that a confident mass transfer correlation in the feed side has been obtained. The mass transfer correlation accounts of the feed spacer geometrical characteristics included in the description of the hydraulic diameter. It matches in a surprising manner with the well-known correlation derived from heat and mass transfer analogies in turbulent flow regime, it is in a good agreement with a recently published correlation derived from OSN in 1812 modules, whereas it is heavily in contrast with the widely used Shock and Miquel equation. In addition, the elaboration of the experimental data according to the velocity variation method does not lead to confident results. The correlation here presented can be extended to the simulation of industrial modules operating at feed flow conditions corresponding to Reynolds number in the range from 100 to 700, since it is rather independent of the way in which it was calculated. A critical discussion is also presented about the differences between the values of membrane permeability and of the module permeability and about the role of the “module length to membrane width” ratio in data elaboration. A sensitivity analysis concludes the work, in which authors discuss how the results of module characterization depend on the quality of the mass transfer correlation in the feed side and give some recommendations for a proper elaboration of experimental results. [ABSTRACT FROM AUTHOR]

Forward osmosis (FO) is a promising key strategy for energy efficient water purification. Different draw solutions, that create an osmotic gradient, and water selective FO membranes exist that allow for a significant concentration of waste streams while water is being filtered and absorbed into the draw solution. Such technologies are often limited by the solute rejection and water flux characteristics of the membrane used. A new approach is the utilization of aquaporin-based membranes (ABMs). These biomimetic membranes make use of the high water permeability and selectivity of aquaporin proteins, which are embedded into the active layer of the membrane. In this study, a 0.6 m 2 hollow fiber ABM module was tested for its rejection of three different trace organic contaminants: the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D), the plastic component bisphenol A (BPA) and the preservative methyl paraben. Over 95% of methyl paraben was rejected by the membrane while for 2,4-D and BPA rejection rates of over 99% were attained. However, it could also be observed that BPA and methyl paraben adsorbed on the aquaporin membrane and were flushed out again during subsequent experiments. This phenomenon may have to be addressed in future studies by developing specific cleaning protocols for ABMs. [ABSTRACT FROM AUTHOR]

[Display omitted] • Optimization of VERW pretreatment via EC and PEC was investigated. • Organics in VERW was effectively removed via EC followed by PEC. • Membrane fouling of DCMD was significantly alleviated by PEC. • The volume of VERW was remarkably reduced and the high-quality distillate was obtained. Vinyl ester resin production wastewater (VERW) contains high concentrations of organics particularly, methacrylic acid and bisphenol A, which are hazardous chemicals and harmful to the aquatic environment. Therefore, there is an urgent need to properly treat the effluent before discharge into the aquatic system. In this work, direct contact membrane distillation (DCMD) was explored as an advanced treatment of the VERW pre-treated by a continuous flow electrocoagulation (EC) and peroxi-electrocoagulation (PEC) processes. Optimization of EC and PEC processes were investigated and the DCMD performance was evaluated. Results showed that the optimal value of current density and polyacrylamide (PAM) dosage was 15 mA/cm2 and 1 mg/L, respectively in the EC process. For the PEC process, the optimal addition of hydrogen peroxide (H 2 O 2) dosage was four times of the chemical oxygen demand (COD) concentration of EC effluent. The COD of VERW was effectively removed via EC followed by PEC (EC-PEC), resulting in the significant alleviation of membrane fouling during DCMD filtration of VERW. The initial flux of DCMD filtration of VERW pre-treated via EC-PEC improved by 35%, compared that only pre-treated by EC. Moreover, the concentration factor (CF) of the DCMD system reached up to 8.1 and the conductivity of distillate was less than 33.2 μS/cm. Hence, the EC and membrane distillation hybrid process paves a new way for the effective treatment of waste steam from resin production. [ABSTRACT FROM AUTHOR]

[Display omitted] • Biochar microspheres and spherical biochar colloidal probes were prepared. • Spherical biochar had superior properties to irregular biochar. • Dosing biochar can efficiently mitigate protein (BSA) fouling. • Biochar's influence on membrane fouling was predicted using force measurements. To better unravel biochar's interface behavior and mitigation mechanism on membrane fouling, spherical biochar colloidal probes were prepared by adhering microspheres to the free end of the probe cantilever. The prepared colloidal probes were used to measure the interaction forces between the membrane and foulant/biochar and between the foulant and foulant/biochar by atomic force microscopy (AFM). The study investigated the differences in physicochemical properties of biochars and their mitigating effects on membrane fouling caused by bovine serum albumin (BSA). Results indicated that dosing biochar strengthened the electrostatic repulsion between BSA and membranes, thereby, mitigating the adhesion or deposition of BSA on the membrane surface. Additionally, spherical biochar (SBC) and hydrochar (HC) exhibited better membrane fouling mitigation than conventional biochar (CBC) due to better physicochemical properties, adsorption capacity, and a more porous fouling layer structure composed of microparticles. Importantly, the stronger adhesion force of SBC-PVDF (0.90 mN/m) than BSA-PVDF (0.50 mN/m) alleviated membrane fouling in the initial stage of the filtration, and the adhesion force of SBC-BSA (0.049 mN/m) alleviated membrane fouling in the later stage, resulting in higher water flux. The interaction force between mature SBC and BSA was comparable to that between BSA and BSA (0.14 mN/m) and stronger than that between original SBC and BSA (0.049 mN/m), implying further membrane fouling mitigation. [ABSTRACT FROM AUTHOR]

• CTS enhanced the interaction force, enhancing the membrane mechanical strength. • The loose membrane structure makes it have ultra-high flux. • The fixed layer spacing makes the membrane have super high retention efficiency. • The stable structure makes membrane have a long service life and high reusability. Nanofiltration membranes made of MXene, a two-dimensional (2D) material, hold great promise for water purification. However, the commercialization of these membranes is hindered by their well-known swelling problem, which reduces their size-sieving performance and service life. To overcome these challenges, this study presents a novel approach by combining positively charged chitosan (CTS) and negatively charged MXene to form CTS-MXene/polyacrylonitrile (PAN) membranes. The use of CTS in the preparation process leads to enhanced mechanical strength and extended service life due to the strong interaction forces between CTS and MXene. The CTS-MXene/PAN membranes have a fixed layer spacing of 14.33 Å, contributing to ultra-high separation efficiency with over 99% rejection of Congo Red (CR) and ultra-high flux of 715.3 L m-2h−1 at 0.4 MPa. Moreover, the membranes exhibit remarkable filtration efficiency for bovine serum albumin under a pressure of 0.5 MPa. The membranes also demonstrate excellent reusability, making them a cost-effective option for water purification. This study not only provides a simple and reproducible strategy for preparing MXene-based membranes but also offers potential for the industrialization of these membranes. The development of CTS-MXene/PAN membranes as a promising approach for nanofiltration membrane development could pave the way for future applications in water purification and other separation processes. [ABSTRACT FROM AUTHOR]

[Display omitted] • EVOH nanofibrous scaffold with high conformality to fabric support was prepared. • PA nanofiltration membrane with periodical diagonal microprotrusion was engineered. • NF membrane shows 31.7 L m−2 h−1 bar−1 permeance, rejection of 97.5% to Na 2 SO 4. • Flux recovery rate is larger than 96% indicating the high antifouling performance. • Periodical diagonal microprotrusions show eddy self-cleaning function in filtration. Tuning the surface structure and roughness of selective layer is effective but a challenge to enhance the permeance and antifouling performance of nanofiltration membrane without sacrificing selectivity. In this work, we developed a novel method to engineer an aromatic polyamides (PA) selective layer atop nanofibrous scaffold with periodical diagonal microprotrusion, which inherits from the morphology of twill fabric. The hydrophilic nanofiber layer presents a compact feature (pore size: 100–300 nm) and high conformality towards the fabric support with twill morphology beneficial to the IP process. The generated PA nanofiltration membrane presented a hierarchical surface structure involving periodical diagonal microprotrusion (around 85 μm cell distance) and ridge-valley structure (∼100 nm). The resultant membrane exhibited not only a high permeance of 31.7 L m−2 h−1 bar−1 and a rejection rate of 97.5% to Na 2 SO 4 solution, but also ameliorated antifouling performance with a high flux recovery rate larger than 96.5% in five filtration-washing tests. This is attributed to the synergistic effects between highly porous nanofiber scaffold and the eddy self-cleaning function derived from periodical diagonal microprotrusion of the fabric supported by the numerical simulation study. This work presents the superiority in designing high permeable membranes with excellent antifouling performance for advanced nanofiltration application. [ABSTRACT FROM AUTHOR]

[Display omitted] • Urea/HCl cleaning reduced the NF270 contact angle (from 36.3° to 21.2°) without changing the zeta potential. • Urea/HCl cleaning restored the pore size and permeability of NF270 better than NaOH/HCl. • Urea/HCl cleaning restored 90% of TrOCs rejection in NF270, with albendazole rejection recovering beyond the pristine membrane. • Urea/HCl cleaning did not significantly affect the permeability and separation performance of NF90. Nanofiltration (NF) is an effective method for removing trace organic compounds (TrOCs) from drinking and reused water. However, chemical cleaning of NF membranes may impact their properties, leading to a decrease in TrOCs rejection. To better understand the mechanisms behind changes in membrane rejection after chemical cleaning, we investigated the changes in surface properties and TrOCs rejection of two commercial membranes (NF270 and NF90) after urea/ hydrochloric acid (HCl) cleaning, and compared them to conventional sodium hydroxide (NaOH)/HCl cleaning. The findings indicated that urea cleaning increased the membrane pore size and hydrophilicity while marginally affecting membrane crosslinking and zeta potential. Possibly due to the thicker and denser active layer of NF90, neither urea-based nor NaOH-based cleaning had a significant impact on its TrOCs rejection and permeability. In contrast, NF270 was more susceptible to chemical cleaning, and urea-based cleaning had less impact on its TrOCs rejection than NaOH-based cleaning. Although urea cleaning increased the pore size of the NF270 membrane, its pore size recovered well after HCl cleaning, resulting in good recovery of the rejection of hydrophilic neutral TrOCs. Moreover, urea cleaning had limited effects on the electrical properties of the NF270 and might enhance the hydrophilicity of the membrane, resulting in full recovery of the rejection of hydrophobic and negatively charged TrOCs after urea/HCl cleaning. [ABSTRACT FROM AUTHOR]

[Display omitted] • Inorganic membranes are investigated for uranium rejection from fresh and salt waters. • Conditions for an efficient separation of uranium are determined. • Performance of the rejection declines with the presence of CaCl 2 or MgCl 2. • Experimental and theoretical investigations are proposed to explain uranium rejection. Ultra/nano filtration (UF/NF) is widely explored for ion separation in aqueous solution, which can be effective, by the electric and steric effect. The uranium extraction from unconventional resources such as seawaters constitutes an important secondary source of uranium for nuclear fuel production. Commercial inorganic UF/NF membranes of different molecular weight cut-off (MWCO) have been investigated for separation of uranium from other salts in natural or synthetic seawaters and freshwaters. Various physical–chemical parameters, such as pH value, temperature, pressure, salt concentration, solution composition, are studied for their influence on different metal (U, Ca, Mg, Na, etc.) rejections. Speciation diagrams implemented with PHREEQC software have helped to understand the rejection mechanism. The pH value and salt concentration are two key parameters determining rejection since the high salinity shields the electric rejection. Experimental conditions for an efficient separation of U to Na was determined to concentrate the uranium. Filtration experiments with natural or synthetic seawaters and freshwaters show that the presence of CaCl 2 or MgCl 2 hinders the reject of every specie including U(VI). Three hypotheses based on the filtration experiments and theoretical simulations have been proposed to explain this phenomenon. This study examines the membrane electric effect to reject solution species and demonstrate the potential for uranium concentration by UF/NF. [ABSTRACT FROM AUTHOR]

[Display omitted] • Nitrogen-doped carbon nanotubes modified ultrafiltration membrane coupled with PMS activation. • Efficient degradation and transformation of EDTMP could be realized rapidly. • The coupled system demonstrated remarkable anti-fouling and water purification capability. • The surface-bound SO 4 •−/•OH was proposed to be the major reactive species. The nitrogen-doping carbon nanotube modified polyethersulfone membrane (NCNT@PES) was prepared by vacuum-assisted filtration. The catalytic activity and anti-fouling capacity of NCNT@PES/peroxymonosulfate (PMS) system were both systematically investigated. Selecting ethylenediamine tetra(methylene phosphonic acid) (EDTMP) as a target phosphonate, the NCNT@PES/PMS system degraded almost 100% of EDTMP, and about 60% of the total phosphorus (TP) in EDTMP could be transformed into orthophosphate (PO 4 3−) within 1 min. Scavenger experiments and electron paramagnetic resonance (EPR) technique verified that the surface-bound radicals were mainly contributed the degradation and transformation of EDTMP in the NCNT@PES/PMS system. The presence of HCO 3 −, SO 4 2− and NOM weakened the catalytic reactions, nevertheless, the NCNT@PES/PMS system still showed considerable effectiveness on the transformation of EDTMP in real sewage effluent. Moreover, the anti-fouling experiment proved that NCNT@PES/PMS system were superior on the removal of fluorescent components in the real sewage effluent, and their removal rates for the dissolved organic matter (DOC) and UV absorbance at 254 nm (UV 254) were also improved. During the filtration cycles, the NCNT@PES/PMS system mitigated the membrane fouling significantly, which had been verified by the slower decline of normalized flux, less ultrapure water flux loss rates and higher ultrapure water flux recovery rates. This study provided a novel but simple way for effective EDTMP decontamination, at the same time, confirmed the potential of NCNT@PES membrane coupled with PMS activation on anti-fouling and water purification ability. [ABSTRACT FROM AUTHOR]

[Display omitted] • The effects of bitumen on the filtration of aqueous clay suspensions were studied. • Bulk bitumen did not have significant detrimental effect on the filtration. • Emulsified bitumen facilitated filtration possibly by mopping the ultrafine particles. • The effect of adsorbed bitumen depended on the bitumen content on the mineral surface. • Thin bitumen coating facilitated filtration; thick bitumen coating impeded filtration. Typical mine tailings can be dewatered by filter press to filter cakes containing >=85 wt% solids that are ready for reclamation, but Alberta oil sands tailings could only reach about 60 wt% solids using the same technology, even when the dominant particle sizes are similar. In this work, the effects of residual bitumen, one of the distinguishing features of oil sands tailings, were investigated. The residual bitumen in the oil sands tailings exists in the forms of bulk bitumen, emulsified bitumen, and adsorbed bitumen. The roles of the three forms of bitumen were investigated in the filtration of primarily a model mineral kaolinite mineral slurry supplemented by rutile, quartz and montmorillonite slurries. Generally, bulk bitumen was found not to affect filtration significantly, emulsified bitumen facilitated filtration possibly by mopping the ultrafine particles, while bitumen adsorbed on mineral surfaces had more complex effects: a thin bitumen coating improved filtration because of the induced surface hydrophobicity, while a thick bitumen coating impeded filtration due to its mobile and deformable nature. The poor filterability of oil sands tailings may be partly caused by the mobile and deformable bitumen coating on the sands/clay mineral surfaces. This study elucidated the effects of a third deformable organic phase on the filtration of an aqueous mineral slurry, providing insights for solid–liquid separation in the presence of a mobile third phase. [ABSTRACT FROM AUTHOR]

[Display omitted] • The link between microbial community, biofilm structure and flux was explored. • The presence of PAC reduced the abundance of metazoans, especially Nematoda. • The lower stable flux with PAC was due to increased EPS and decreased metazoans. • The presence of PAC promoted the nitrification within the biofilm. • The PAC/GDM system exhibited an excellent and long-lasting removal of organics. Gravity-driven membrane (GDM) filtration, an appealing approach for decentralized drinking water treatment, tolerates the development of membrane biofilms for the benefit of low energy consumption and stable flux. In this study, the effect of introducing powdered activated carbon (PAC) on the biofilm generated during long-term GDM filtration was investigated. The results indicated that the addition of PAC significantly enhanced the removal of dissolved organic compounds (DOC) (31 %), whereas only 15.7 % removal was achieved in the control GDM system without PAC. The improved permeate quality was attributed to the combined effects of adsorption and biodegradation of organic compounds by PAC. However, the presence of PAC reduced the permeability of the GDM system by 39 % compared to the control one, which was related to the synergetic effect of the increased extracellular polymeric substances (EPS) content and the decreased metazoan amounts (especially Nematoda) in the biofilm. A large number of substrates adsorbed by PAC facilitated the growth of bacteria and hence intensified the secretion of EPS. Meanwhile, the deposition of PAC on the membrane surface limited the movement space of metazoans, leading to a denser and flatter biofilm basal structure. Furthermore, fewer metazoans meant less predation on bacteria, which also contributed to bacterial reproduction. In addition, an enhanced removal efficiency of ammonia nitrogen was observed in the PAC/GDM system, corresponding to a much higher abundance of Nitrospira in bacterial community. This study links microbial community to hydraulic resistance of biofilm and has practical implications for the application of GDM processes. [ABSTRACT FROM AUTHOR]

[Display omitted] • The fouling of different proteins on ceramic membrane is systematically compared. • Environmental proteins prefer to aggregate and interact with membrane surface. • Unsaturated groups facilitate intermolecular interaction and proteins aggregation. • Tested proteins show light membrane fouling at the early stage of microfiltration. Membrane-based filtration is widely applied for water and wastewater treatment, while membrane fouling caused by contaminants such as proteins is an inevitable problem. Protein-containing mixtures or intact model proteins (e.g., bovine serum albumin, BSA) have been conventionally adopted and recognized as important membrane foulants. However, due to the complex composition of the protein-containing mixture or the inappropriate concentrations of model substances adopted, the real contribution of protein-like fractions toward ceramic membrane fouling remains unknown yet. In this work, the fouling behaviors of BSA and tryptones, representing the intact protein and the mixture of peptides, respectively, in a ceramic membrane microfiltration system were investigated. Both of them exhibited a negligible flux decrease and membrane fouling. For comparison, the fouling behaviors of the environmental protein-like substances (EP) extracted from different sludge sources were also examined. In addition, the experimental and simulation results demonstrate that all the EP samples were easier to aggregate and be adsorbed on the membrane surface than the two model proteins because the environmental protein-like substances had more unsaturated groups. However, those properties were insufficient to cause rapid membrane pore blockage or biocake formation compared with the previous studies. Both the model and actual protein fractions led to light membrane fouling, implying that proteins were not mainly responsible for membrane fouling at the early stage of ceramic membrane microfiltration. [ABSTRACT FROM AUTHOR]

• Micro-patterned PES membranes exhibit underwater superoleophobic of 150 ± 2°. • Micro-patterned membranes have water permeance of 8036 L·h−1·m−2·bar−1. • Membranes show excellent oil-in-water emulsion separation efficiency. • Developed membranes demonstrate flux recovery ratio (FRR) of 99 % over three subsequent cycles. • Comprehensive separation mechanisms for oil removal are introduced and discussed. Developing polymeric membranes for oily wastewater treatment has attracted great interest over the last few years. However, the low permeance and poor fouling resistance are considered the most challenging issues. Introducing topographic patterns on the membrane surface to increase active area and surface roughness is one practical strategy for reducing membrane fouling. Here, isotropic polyethersulfone (PES) membranes with line patterns and continuous sponge-like porous structure were prepared using phase separation micro-molding processes. Various techniques were used to characterize the morphologies and physicochemical properties of the as-prepared membranes. The surface wettability of the membranes was evaluated by measuring contact angle of a water drop in air and of industrial crude oil under water. The as-prepared membranes separation and antifouling performance were assessed using water permeance, oil rejection, and flux recovery ratio after emulsion filtration. The results showed that the patterned PES membrane has superior hydrophilic and antifouling capabilities, with a lower static water contact angle (CA) of 32° as compared to a flat PES membrane (CA = 39°). Furthermore, the patterned membrane had pure water permeance (PWP) of 8036 ± 65 L·h−1·m−2·bar−1, which was ∼ 68 % greater than that of the flat PES membrane. This is mainly attributable to the discernible increase in the membrane pore size distribution and the enhancement in membrane surface hydrophilicity due to the increase in surface roughness as a result of micro-patterning. The patterned membranes showed superior separation efficiency (>99.0 %) and permeance (7031 ± 65 L·h−1·m−2·bar−1) for the oil-in-water emulsion of 0.1 g·L−1. At a higher concentration of crude oil-in-water emulsion (50 g·L−1), the patterned PES membranes achieved promising permeance of 90 L/h.m2.bar and 99.9 % rejection. Furthermore, the flux recovery ratio of the patterned membrane exceeded 91 % after three consecutive cycles of dead-end filtration and backwashing with water, demonstrating the benefit of using micro-patterned membranes for treating high concentration and industrial oil-in-water emulsions. [ABSTRACT FROM AUTHOR]