Membrane technology holds significant potential for augmenting or partially substituting conventional separation techniques,such as heatdriven distillation,thereby reducing energy consumption.Organic solvent nanofiltr...Membrane technology holds significant potential for augmenting or partially substituting conventional separation techniques,such as heatdriven distillation,thereby reducing energy consumption.Organic solvent nanofiltration represents an advanced membrane separation technology capable of discerning molecules within a molecular weight range of approximately 100-1000 Da in organic solvents,offering low energy requirements and minimal carbon footprints.Molecular separation in non-polar solvent system,such as toluene,n-hexane,and n-heptane,has gained paramount importance due to their extensive use in the pharmaceutical,biochemical,and petrochemical industries.In this review,we presented recent advancements in membrane materials,membrane fabrication techniques and their promising applications for separation in nonpolar solvent system,encompassing hydrocarbon separation,bioactive molecule purification and organic solvent recovery.Furthermore,this review highlighted the challenges and opportunities associated with membrane scale-up strategies and the direct translation of this promising technology into industrial applications.展开更多
A new modified blend ultrafiltration(UF)membrane with good hydrophilicity,high porosity and excellent anti-fouling performance was developed by using carboxylic multi-walled carbon nanotube(CMWCNT)as casting solution ...A new modified blend ultrafiltration(UF)membrane with good hydrophilicity,high porosity and excellent anti-fouling performance was developed by using carboxylic multi-walled carbon nanotube(CMWCNT)as casting solution additive.Furthermore,a composite nanofiltration(NF)membrane with large water flux and good retention rate was fabricated by using the PVDF/CMWCNT blend UF membrane as the substrate,and polyvinyl alcohol(PVA),β-cyclodextrin(β-CD)and polyethylenimine(PEI)as the coating solution.The results show that with the appropriate addition of CMWCNT in the casting solution,the surface roughness,porosity and recovery rate of the PVDF/CMWCNT blend UF membrane is obviously increased.The water flux of blend UF membrane is significantly improved when the CMWCNT content increases from 0 wt%to 0.2 wt%.The water flux of blend UF membrane with 0.2 wt%CMWCNT is 162.7 L/(m^(2)·h),which is 44.3%higher than that of the pure PVDF membrane.Whenβ-CD content is 0.8 wt%,the retention rate of Congo red by PVDF/CMWCNT/β-CD composite NF membrane reaches 98.7%,which is 28.3%higher than that of single PVA/PEI modified membrane.This research will provide a new idea and simple method for developing novel high-performance composite NF membranes.展开更多
Organic solvent nanofiltration(OSN) is an efficient,low-energy and environmentally friendly phase-free separation process.Obviously,the core of OSN lies in the fabrication of solvent-resistant nanofiltration membranes...Organic solvent nanofiltration(OSN) is an efficient,low-energy and environmentally friendly phase-free separation process.Obviously,the core of OSN lies in the fabrication of solvent-resistant nanofiltration membranes.Although membrane materials reported in the literature such as 2D membranes,porous organic cages,etc.have the potential for ultra-high performance,polymeric membranes provide key advantages in mass production and processability.Therefore,this review focuses on polymeric materials for OSN.This review summarizes the recent progress of polymeric materials,including emerging and traditional polymeric membranes.Then,a summary of recent progress about strategies developed for perm-selective nanofilms are presented,followed by a brief overview of commercial membrane technology for OSN.Finally,major challenges of OSN and future research directions are presented.Close interaction between the academic research and practical application would help improve greener and more sustainable manufacturing processes.展开更多
Polydopamine(PDA)and metal-organic skeleton HKUST-1 were co-deposited on the base membrane of hexamethylenediamine(HDA)-crosslinked polyetherimide(PEI)ultrafiltration membrane as the interlayer,and high-throughput org...Polydopamine(PDA)and metal-organic skeleton HKUST-1 were co-deposited on the base membrane of hexamethylenediamine(HDA)-crosslinked polyetherimide(PEI)ultrafiltration membrane as the interlayer,and high-throughput organic solvent nanofiltration membrane(OSN)was prepared by interfacial polymerization and solvent activation reaction.The polyamide(PA)layer surface roughness from 28.4 nm in PA/PEI to 78.3 nm in PA/PDA-HKUST-10.6/PEI membrane,reduced the thickness of the separation layer from 79 to 14 nm,and significantly improved the hydrophilic,thermal and mechanical properties.The flux of the PA/PDA-HKUST-10.6/PEI membrane in a 0.1 g/L Congo Red(CR)ethanol solution at 0.6 MPa test pressure reached 21.8 L/(m^(2)·hr)and the rejection of CR was 92.8%.Solvent adsorption test,N,N-dimethylformamide(DMF)immersion experiment,and long-term operation test in ethanol showed that the membranes had high solvent tolerance.The solvent flux test demonstrated that,under the test pressure of 0.6 MPa,the flux of different solvents ranked as follows:methanol(56.9 L/(m^(2)·hr))>DMF(39.6 L/(m^(2)·hr))>ethanol(31.2 L/(m^(2)·hr))>IPA(4.5 L/(m^(2)·hr))>N-hexane(1.9 L/(m^(2)·hr)).The ability of the membranes to retain dyes in IPA/water dyes solution was also evaluated.The flux of the membrane was 30.4 L/(m^(2)·hr)and the rejection of CR was 91.6%when the IPA concentration reached 50%.This OSN membrane-making strategy is economical,environment-friendly and efficient,and has a great application prospect in organic solvent separation systems.展开更多
The Mg2+/Li+/Cl solutions were filtrated with a commercially available DK nanofiltration membrane to investigate the possibility to enrich the lithium component.The investigation was significant as such an approach mi...The Mg2+/Li+/Cl solutions were filtrated with a commercially available DK nanofiltration membrane to investigate the possibility to enrich the lithium component.The investigation was significant as such an approach might be a competing substitute for the present lithium purification industry and the environmental protection purpose.The Donnan steric pore model(DSPM) was implemented for the prediction.The separation of Mg2+/Li+was mainly affected by the working pressure(or the permeation flux) and a limiting separation factor was found around 0.31.The effective membrane charge density was evaluated and its dependence on the permeation flux as well as the ion pattern was discussed.For predicting an actual separation of electrolytes,the experimental investigation seems necessary for the reliability and efficiency.展开更多
Nanofiltration membranes are the core elements for nanofiltration process. The chemical structures and physical properties of nanofiltration membranes determine water permeability, solute selectivity, mechanical/therm...Nanofiltration membranes are the core elements for nanofiltration process. The chemical structures and physical properties of nanofiltration membranes determine water permeability, solute selectivity, mechanical/thermal stability, and antifouling properties, which greatly influence the separation efficiency and operation cost in nanofiltration applications. In recent years, a great progress has been made in the development of high performance nanofiltration membranes based on nanomaterials. Considering the increasing interest in this field, this paper reviews the recent studies on the nanofiltration membranes comprising various nanomaterials, including the metal and metal oxide nanoparticles, carbon-based nanomaterials, metal–organic frameworks(MOFs), water channel proteins, and organic micro/nanoparticles. Finally, a perspective is given on the further exploitation of advanced nanomaterials and novel strategy for fabricating nano-based nanofiltration membranes. Moreover,the development of precision instruments and simulation techniques is necessary for the characterization of membrane microstructure and investigation of the separation and antifouling mechanism of nanofiltration membranes prepared with nanomaterials.展开更多
The performance of different nanofiltration （NF） and reverse osmosis （RO） membranes was studied in treating the toxic metal effluent from metallurgical industry. The characteristics and filtration behavior of the ...The performance of different nanofiltration （NF） and reverse osmosis （RO） membranes was studied in treating the toxic metal effluent from metallurgical industry. The characteristics and filtration behavior of the processes including the wastewater flux, salt rejection and ion rejection versus operating pressure were evaluated. Then the wastewater flux of RO membrane was compared with theoretical calculation using mass transfer models, and good consistency was observed. It was found that a high rejection rate more than 95% of metal ions and a low Chemical Oxygen Demand （COD） value of 10 mg·L^-1 in permeate could be achieved using the RO composite membrane, while the NF rejection of the salt could be up to 78.9% and the COD value in the permeate was 35 mg·L^-1. The results showed that the product water by both NF and RO desalination satisfied the State Reutilization Qualification, but NF would be more suitable for large-scale industrial practice, which offered significantly higher permeate flux at low operating pressure.展开更多
Inspired by the self-polymerization and strong adhesion characteristics of dopamine in aqueous conditions, a novel hydrophilic nanofiltration （NF） membrane was fabricated by simply dipping polysulfone （PSf） ultraf...Inspired by the self-polymerization and strong adhesion characteristics of dopamine in aqueous conditions, a novel hydrophilic nanofiltration （NF） membrane was fabricated by simply dipping polysulfone （PSf） ultrafiltration （UF） substrate in dopamine solution. The changes in surface chemical composition and morphology of membranes were determined by Fourier transform infrared spectroscopy （FTIR-ATR）, X-ray photoelectron spectroscopy （XPS）, scanning electron microscopy （SEM） and atomic force microscopy （AFM）. The experimental results indicated that the self-polymerized dopamine formed an ultrathin and defect-free barrier layer on the PSf UF membrane. The surface hydrophilicity of membranes was evaluated through water contact angle measurements. It was found that membrane hydrophilicity was significantly improved after coating a polydopamine （pDA） layer, especially after double coating. The dyes filtration experiments showed that the double-coated membranes were able to reject completely the dyes of brilliant blue, congo red and methyl orange with a pure water flux of 83.7 L/（mE.h） under 0.6 MPa. The zeta potential determination revealed the positively-charged characteristics of PSf/pDA composite membrane in NF process. The salt rejection of the membranes was characterized by 0.01 mmol/L of salts filtration experiment. It was demonstrated that the salts rejections followed the sequence： NaC1 〈 NaaSO4 〈 MgSO4 〈 MgC12 〈 CaCl2, and the rejection to CaC12 reached 68.7%. Moreover, the composite NF membranes showed a good stability in water-phase filtration process.展开更多
Separation of organic mixture is an inevitable process in most modern industrial processes. In the quest for a more sustainable and efficient separation, solvent-resistant nanofiltration(SRNF) has emerged as a promisi...Separation of organic mixture is an inevitable process in most modern industrial processes. In the quest for a more sustainable and efficient separation, solvent-resistant nanofiltration(SRNF) has emerged as a promising answer. This is because SRNF is a membrane-based process which offers the key advantages of high efficacy and low energy intensity separation. In particular, polymer-based membranes can offer compelling opportunities for SRNF with unprecedented cost-effectiveness. As a result, intensive research efforts have been devoted into developing novel polymer-based membranes with solvent-resistant capacities as well as exploring potential applications in different types of industries. In this review, we aim to give an overview of the recent progress in the development of the state-of-the-art polymer-based membranes for SRNF in the first section. Emerging nanomaterials for mixed matrix and thin film nanocomposite membranes are also covered in this section. This is followed by a discussion on the current status of membrane engineering and SRNF membrane commercialization. In the third section, we highlight recent efforts in adopting SRNF for relevant industrial applications such as food, bio-refinery, petrochemical, fine chemical and pharmaceutical industries followed by separations of enantiomers in stereochemistry, homogeneous catalysis and ionic liquids. Finally, we offer a perspective and provide deeper insights to help shape future research direction in this very important field of SRNF.展开更多
A low operating pressure nanofiltration membrane is prepared by interfacial polymerization between m-phenylenediamine （MPDA） and trimesoyl chloride （TMC） using PVC hollow fiber membrane as supporting. A series of ...A low operating pressure nanofiltration membrane is prepared by interfacial polymerization between m-phenylenediamine （MPDA） and trimesoyl chloride （TMC） using PVC hollow fiber membrane as supporting. A series of PVC nanofiltration membranes with different molecular weight cutoff （MWCO） can be obtained by controlling preparation conditions. Chemical and morphological characterization of the membrane surface was carried out by FTIR-ATR and SEM. MWCO was characterized by filtration experiments. The preparation conditions were investigated in detail. At the optimized conditions （40 min air-dried time, aqueous phase containing 0.5% MPDA, 0.05% SDS and 0.6% acid absorbent, oil phase containing 0.3% TMC, and 1 min reaction time）, under 0.3 MPa, water flux of the gained nanofiltration membrane reaches 17.8 L/m2-h, and the rejection rates of methyl orange and MgSO4 are more than 90% and 60%, respectively.展开更多
The feasibility of employing nanofiltration for the removal of chromium（VI） from wastewater was investigated. Poly （m-phenylene isophthalamide） （PMIA） was used to fabricate asymmetric nanofiltration membrane thr...The feasibility of employing nanofiltration for the removal of chromium（VI） from wastewater was investigated. Poly （m-phenylene isophthalamide） （PMIA） was used to fabricate asymmetric nanofiltration membrane through the phase-inversion technique. Scanning electron microscopy （SEM） and atomic force microscopy （AFM） were used to characterize the obtained membrane, and the both confirmed a much smoother surface which could reduce membrane fouling. The PMIA membrane showed different rejections to electrolytes in a sequence of Na2SO4 〉 MgSO4 〉 NaC1 〉 MgC12, which was similar to the sequence of the negatively charged nanofiltration membranes. Separation experiments on chromium（VI） solution were conducted at various operating conditions, such as feed concentration, applied pressure and pH. It is concluded that chromium（VI） could be effectively removed from chromiumcontaining wastewater by the PMIA nanofiltration membranes while maintaining their pollution resistance under alkaline condition.展开更多
The UF membrane with molecular weight cutoff （MWCO） ranging from 2 to 100 kDa and XAD-8 resin were employed to identify the characteristic of molecular weight （MW） distribution of wastewater effluent organic matt...The UF membrane with molecular weight cutoff （MWCO） ranging from 2 to 100 kDa and XAD-8 resin were employed to identify the characteristic of molecular weight （MW） distribution of wastewater effluent organic matter （EfOM） in terms of TOC and UV254, as well as the amounts of the hydrophilic/hydrophobic organic fractions in different MW ranges. Then, the nanofiltration （NF） membrane fouling experiments were carded out using the above fractionated water to investigate the effect of MW distribution and hydrophihc/hydrophobic characteristics of EfOM on the membrane flux decline using the fractionated water samples. The experimental results have shown that 45.61% of the total organics belongs to the low MW one, among which the percentage of the hydrophilic organics with low MW （less than 2 kDa） was up to 28.07%, while that of the hydrophobic organics was 17.54%. In particular, the hydrophilic fraction was found to be the most abundant fraction in the effluents. MW distribution has a significant effect on the membrane fouling. When the MW was less than 30 kDa, the lower the MW, the larger was the specific flux decline, while in the case of MW higher than 30 kDa, the higher the MW, the larger was the specific flux decline, and the decline degree of low MW organics was larger than the high MW one. With the same MW distribution range, specific flux decline of the hydrophilic organic was considerably slower than that of the hydrophobic organic, which indicated that the hydrophobic organic fractions dominantly contribute to the flux decline.展开更多
Haloacetic acids, disinfection byproducts （DBPs） formed during drinking water chlorination process are carcinogens. The efficacy of nanofiltration （NF） was examined for the removal of five regulated haloacetic aci...Haloacetic acids, disinfection byproducts （DBPs） formed during drinking water chlorination process are carcinogens. The efficacy of nanofiltration （NF） was examined for the removal of five regulated haloacetic acids （HAAs）： chloro-, dichloro-, and trichioro-acetic acid （CAA, DCAA, and TCAA）; bromo-, and dibromo-acetic acid （BAA, and DBAA） in synthetic water. NF with the dense negatively charged membrane （ES 10）, is the most efficient in removing HAAs than the loose negatively charged membrane （NTR 7410） and neutral surface membrane （NTR 729HF）, due to the greater electrostatic repulsion （Donan exclusion） and sieve effect. Excellent HAAs removal efficiency of 90%-100% could be obtained even at a low pressure of 1×10^5 Pa with ES 10. Changes in cross-flow velocity did not effect the performance of membranes with a small pore size such as ES 10 and NTR 729HF. The increase in HAAs concentration exhibited the adverse effect on the performance of three membranes by strengthening the concentration polarization, which was the driving force for the diffusion of HAA anions across the membrane.展开更多
Thin film composite(TFC) membranes represent a highly promising platform for efficient nanofiltration(NF)processes. However, the improvement in permeance is impeded by the substrates with low permeances. Herein,highly...Thin film composite(TFC) membranes represent a highly promising platform for efficient nanofiltration(NF)processes. However, the improvement in permeance is impeded by the substrates with low permeances. Herein,highly permeable gradient phenolic membranes with tight selectivity are used as substrates to prepare TFC membranes with high permeances by the layer-by-layer assembly method. The negatively charged phenolic substrates are alternately assembled with polycation polyethylenimine(PEI) and polyanion poly(acrylic acid)(PAA)as a result of electrostatic interactions, forming thin and compact PEI/PAA layers tightly attached to the substrate surface. Benefiting from the high permeances and tight surface pores of the gradient nanoporous structures of the substrates, the produced PEI/PAA membranes exhibit a permeance up to 506 L? m-2?h-1?MPa-1, which is ~2–10 times higher than that of other membranes with similar rejections. The PEI/PAA membranes are capable of retaining N 96.1% of negatively charged dyes following the mechanism of electrostatic repulsion. We demonstrate that the membranes can also separate positively and neutrally charged dyes from water via other mechanisms.This work opens a new avenue for the design and preparation of high-flux NF membranes, which is also applicable to enhance the permeance of other TFC membranes.展开更多
Lanthanides are widely used in various commercial applications, which results in public exposure to them, and it is a matter of concern. Many methods were used to remove lanthanides from wastewaters generated from the...Lanthanides are widely used in various commercial applications, which results in public exposure to them, and it is a matter of concern. Many methods were used to remove lanthanides from wastewaters generated from their commercial use. In the present work, nanofiltration membrane process was used to remove the cerium and neodymium from their respective feed solutions. The feed and permeates were analyzed for solute concentration by inductively coupled plasma-atomic emission spectroscopy. Irreversible thermodynamics Spiegler-Kedem model, in combination with the film theory, was used to estimate the membrane transport parameters, viz., reflection coefficient of membrane and solute permeability, and mass transfer coefficient to study their dependence on feed solute concentration.展开更多
In the face of human society's great requirements for health industry,and the much stricter safety and quality standards in the biomedical industry,the demand for advanced membrane separation technologies continue...In the face of human society's great requirements for health industry,and the much stricter safety and quality standards in the biomedical industry,the demand for advanced membrane separation technologies continues to rapidly grow in the world.Nanofiltration(NF)and reverse osmosis(RO)as the highefficient,low energy consumption,and environmental friendly membrane separation techniques,show great promise in the application of biomedical separation field.The chemical compositions,microstructures and surface properties of NF/RO membranes determine the separation accuracy,efficiency and operation cost in their applications.Accordingly,recent studies have focused on tuning the structures and tailoring the performance of NF/RO membranes via the design and synthesis of various advanced membrane materials,and exploring universal and convenient membrane preparation strategies,with the objective of promoting the better and faster development of NF/RO membrane separation technology in the biomedical separation field.This paper reviews the recent studies on the NF/RO membranes constructed with various materials,including the polymeric materials,different dimensional inorganic/organic nanomaterials,porous polymeric materials and metal coordination polymers,etc.Moreover,the influence of membrane chemical compositions,interior microstructures,and surface characteristics on the separation performance of NF/RO membranes,are comprehensively discussed.Subsequently,the applications of NF/RO membranes in biomedical separation field are systematically reported.Finally,the perspective for future challenges of NF/RO membrane separation techniques in this field is discussed.展开更多
In this study,a quantitative performance of three commercial polyamide nanofiltration(NF) membranes(i.e.,NF,NF90,and NF270) for phosphorus removal under different feed conditions was investigated.The experiments were ...In this study,a quantitative performance of three commercial polyamide nanofiltration(NF) membranes(i.e.,NF,NF90,and NF270) for phosphorus removal under different feed conditions was investigated.The experiments were conducted at different feed phosphorus concentrations(2.5,5,10,and 15 mg·L^-1) and elevated pHs(pH 1.5,5,10,and 13.5) at a constant feed pressure of 1 MPa using a dead-end filtration cell.Membrane rejection against total phosphorus generally increased with increasing phosphorus concentration regardless of membrane type.In contrast,the permeate flux for all the membranes only decreased slightly with increasing phosphorus concentration.The results also showed that the phosphorus rejections improved while water flux remained almost unchanged with increasing feed solution pH.When the three membranes were exposed to strong pHs(pH 1.5 and 13.5) for a longer duration(up to 6 weeks)it was found that the rejection capability and water flux of the membranes remained very similar throughout the duration,except for NF membrane with marginal decrement in phosphorus rejection.Adsorption study also revealed that more phosphorus was adsorbed onto the membrane structure at alkaline conditions(pH 10 and 13.5) compared to the same membranes tested at lower pHs(pH 1.5 and 5).In eonelusion,NF270 membrane outperformed Nf and NF90 membranes owing to its desirable performance of water flux and phosphorus rejection particularly under strong alkali solution.The NF270 membrane achieved 14.0 L·m^-2·h^-1 and 96.5% rejection against 10 mg·L^-1 phosphorus solution with a pH value of 13.5 at the applied pressure of 1 MPa.展开更多
Landfill leachate treated with combined process of ＂pretreatment ＋biological treatment ＋advanced treatment （NF）＂ to produce nanofiltration concentrate, which bio-chemical ratio （B/C） is less than 0.1 and CODer...Landfill leachate treated with combined process of ＂pretreatment ＋biological treatment ＋advanced treatment （NF）＂ to produce nanofiltration concentrate, which bio-chemical ratio （B/C） is less than 0.1 and CODer concentration is 2 000-2 500 mg/L, high salt content. Which cannot be discharged under existing environ- mental standards. According to analysis based on electrochemical advanced oxidation mechanism, a two-step electrochemical tech- nique was recommended. In the first step, a pulse electrochemical technique was adopted. With Fe as consumption electrode and current density of 10 mA/cm2, the pollutants were removed by means of Fenton reaction, electroflotation and electrocoagulation. In the second step, a double function electrode was used to per- form electrocatalytic oxidation by means of titanium metallic oxi- dates. In the condition that current density being 12.5 mA/cm2, the pollutants were further removed by oxidation and electrolytic deposition. Result shows that the removing rate of CODer, NH3-N and CI were 70%-85%, 90% and 25%, respectively; average value of B/C ratio increased from 0.09 to 0.38 and conductivity reduced by 10%.展开更多
A pilot-scale study of advanced drinking water treatment was carried out in test site, and a combination of ozonation, granular activated carbon (GAC) and nanofiltration was employed as the experimental process. By op...A pilot-scale study of advanced drinking water treatment was carried out in test site, and a combination of ozonation, granular activated carbon (GAC) and nanofiltration was employed as the experimental process. By optimizing the operational parameters of ozonation and GAC, a large quantity of micro-pollutants in drinking water was removed, which made the post-positioned nanofiltration operate more reliably. It was evident that nanofiltration shows good performance for removing residual organic matter, meantime partial minerals can also be retained by nanofiltration. Therefore the quality of drinking water can be further improved. In addition, NF membrane fouling and scaling can be solved by concentrate recycling, anti-scalant dosing and chemical rinsing effectively. By GAC adsorption for the residue chlorine and ozone self-decomposition, their oxidation on NF membrane material can be eliminated completely.展开更多
N, O-carboxymethyl chitosan （NOCC） composite nanofiltration （NF） membranes were prepared by coating and cross-linking. The fermentation effluent from a wine factory was treated with the resulting NOCC/polysulfone ...N, O-carboxymethyl chitosan （NOCC） composite nanofiltration （NF） membranes were prepared by coating and cross-linking. The fermentation effluent from a wine factory was treated with the resulting NOCC/polysulfone （PSF） composite NF membranes. The permeate flux and the removal efficiencies of the resulting NF membranes for the color, chemical oxygen demand （CODcr）, total organic carbon （TOC）, and conductivity of the fermentation effluent were investigated in relation to the driving pressure, the feed flow, and the operation time. The permeate flux and the removal efficiencies were found to increase with the increase of the driving pressure or the feed flow. At 0.40 MPa and ambient temperature the removal efficiencies were 95.5%, 70.7%, 72.6%, and 31.6% for color, CODcr, TOC, and conductivity, respectively. The membrane was found to be stable over a 10-h ooeration for the fermentation effluent treatment.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.2230081973)Shanghai Pilot Program for Basic Research(22TQ1400100-4).
文摘Membrane technology holds significant potential for augmenting or partially substituting conventional separation techniques,such as heatdriven distillation,thereby reducing energy consumption.Organic solvent nanofiltration represents an advanced membrane separation technology capable of discerning molecules within a molecular weight range of approximately 100-1000 Da in organic solvents,offering low energy requirements and minimal carbon footprints.Molecular separation in non-polar solvent system,such as toluene,n-hexane,and n-heptane,has gained paramount importance due to their extensive use in the pharmaceutical,biochemical,and petrochemical industries.In this review,we presented recent advancements in membrane materials,membrane fabrication techniques and their promising applications for separation in nonpolar solvent system,encompassing hydrocarbon separation,bioactive molecule purification and organic solvent recovery.Furthermore,this review highlighted the challenges and opportunities associated with membrane scale-up strategies and the direct translation of this promising technology into industrial applications.
基金Funded by the National Natural Science Foundation of China(No.52278453)Basic Scientific Research Project of Colleges and Universities of Liaoning Provincial Department of Education(Nos.LJ212410153013,LJKQZ2021060)。
文摘A new modified blend ultrafiltration(UF)membrane with good hydrophilicity,high porosity and excellent anti-fouling performance was developed by using carboxylic multi-walled carbon nanotube(CMWCNT)as casting solution additive.Furthermore,a composite nanofiltration(NF)membrane with large water flux and good retention rate was fabricated by using the PVDF/CMWCNT blend UF membrane as the substrate,and polyvinyl alcohol(PVA),β-cyclodextrin(β-CD)and polyethylenimine(PEI)as the coating solution.The results show that with the appropriate addition of CMWCNT in the casting solution,the surface roughness,porosity and recovery rate of the PVDF/CMWCNT blend UF membrane is obviously increased.The water flux of blend UF membrane is significantly improved when the CMWCNT content increases from 0 wt%to 0.2 wt%.The water flux of blend UF membrane with 0.2 wt%CMWCNT is 162.7 L/(m^(2)·h),which is 44.3%higher than that of the pure PVDF membrane.Whenβ-CD content is 0.8 wt%,the retention rate of Congo red by PVDF/CMWCNT/β-CD composite NF membrane reaches 98.7%,which is 28.3%higher than that of single PVA/PEI modified membrane.This research will provide a new idea and simple method for developing novel high-performance composite NF membranes.
基金Knowledge Innovation Program of Wuhan-Basic Research(2022010801010321)Wuhan Limo Technology Limited Company(2022420111000256)。
文摘Organic solvent nanofiltration(OSN) is an efficient,low-energy and environmentally friendly phase-free separation process.Obviously,the core of OSN lies in the fabrication of solvent-resistant nanofiltration membranes.Although membrane materials reported in the literature such as 2D membranes,porous organic cages,etc.have the potential for ultra-high performance,polymeric membranes provide key advantages in mass production and processability.Therefore,this review focuses on polymeric materials for OSN.This review summarizes the recent progress of polymeric materials,including emerging and traditional polymeric membranes.Then,a summary of recent progress about strategies developed for perm-selective nanofilms are presented,followed by a brief overview of commercial membrane technology for OSN.Finally,major challenges of OSN and future research directions are presented.Close interaction between the academic research and practical application would help improve greener and more sustainable manufacturing processes.
基金supported by the National Natural Science Foundation of China(No.41662004)the 2022 Jiangxi University Student Innovation and Entrepreneurship Training Program(No.S202210407027)+1 种基金the Jiangxi Graduate Innovation Fund(No.YC2021-S557)the Opening Project of Henan Province Key Laboratory of Water Pollution Control and Rehabilitation Technology(No.CJSP2022002)。
文摘Polydopamine(PDA)and metal-organic skeleton HKUST-1 were co-deposited on the base membrane of hexamethylenediamine(HDA)-crosslinked polyetherimide(PEI)ultrafiltration membrane as the interlayer,and high-throughput organic solvent nanofiltration membrane(OSN)was prepared by interfacial polymerization and solvent activation reaction.The polyamide(PA)layer surface roughness from 28.4 nm in PA/PEI to 78.3 nm in PA/PDA-HKUST-10.6/PEI membrane,reduced the thickness of the separation layer from 79 to 14 nm,and significantly improved the hydrophilic,thermal and mechanical properties.The flux of the PA/PDA-HKUST-10.6/PEI membrane in a 0.1 g/L Congo Red(CR)ethanol solution at 0.6 MPa test pressure reached 21.8 L/(m^(2)·hr)and the rejection of CR was 92.8%.Solvent adsorption test,N,N-dimethylformamide(DMF)immersion experiment,and long-term operation test in ethanol showed that the membranes had high solvent tolerance.The solvent flux test demonstrated that,under the test pressure of 0.6 MPa,the flux of different solvents ranked as follows:methanol(56.9 L/(m^(2)·hr))>DMF(39.6 L/(m^(2)·hr))>ethanol(31.2 L/(m^(2)·hr))>IPA(4.5 L/(m^(2)·hr))>N-hexane(1.9 L/(m^(2)·hr)).The ability of the membranes to retain dyes in IPA/water dyes solution was also evaluated.The flux of the membrane was 30.4 L/(m^(2)·hr)and the rejection of CR was 91.6%when the IPA concentration reached 50%.This OSN membrane-making strategy is economical,environment-friendly and efficient,and has a great application prospect in organic solvent separation systems.
基金Supported by the National Natural Science Foundation of China （20576052） the Joint Innovation Fund of Jiangsu Province （BY2009107）
文摘The Mg2+/Li+/Cl solutions were filtrated with a commercially available DK nanofiltration membrane to investigate the possibility to enrich the lithium component.The investigation was significant as such an approach might be a competing substitute for the present lithium purification industry and the environmental protection purpose.The Donnan steric pore model(DSPM) was implemented for the prediction.The separation of Mg2+/Li+was mainly affected by the working pressure(or the permeation flux) and a limiting separation factor was found around 0.31.The effective membrane charge density was evaluated and its dependence on the permeation flux as well as the ion pattern was discussed.For predicting an actual separation of electrolytes,the experimental investigation seems necessary for the reliability and efficiency.
基金Supported by the National Natural Science Foundation of China(21306163)the National Basic Research Program of China(2015CB655303)
文摘Nanofiltration membranes are the core elements for nanofiltration process. The chemical structures and physical properties of nanofiltration membranes determine water permeability, solute selectivity, mechanical/thermal stability, and antifouling properties, which greatly influence the separation efficiency and operation cost in nanofiltration applications. In recent years, a great progress has been made in the development of high performance nanofiltration membranes based on nanomaterials. Considering the increasing interest in this field, this paper reviews the recent studies on the nanofiltration membranes comprising various nanomaterials, including the metal and metal oxide nanoparticles, carbon-based nanomaterials, metal–organic frameworks(MOFs), water channel proteins, and organic micro/nanoparticles. Finally, a perspective is given on the further exploitation of advanced nanomaterials and novel strategy for fabricating nano-based nanofiltration membranes. Moreover,the development of precision instruments and simulation techniques is necessary for the characterization of membrane microstructure and investigation of the separation and antifouling mechanism of nanofiltration membranes prepared with nanomaterials.
基金Supported by the National Natural Science Foundation of China （20476096, 20776133）, Zhejiang Provincial Bureau of Science ＆ Technology （2005C33040） and Bureau of Education （Key Discipline of Environmental Engineering 56310503014）.
文摘The performance of different nanofiltration （NF） and reverse osmosis （RO） membranes was studied in treating the toxic metal effluent from metallurgical industry. The characteristics and filtration behavior of the processes including the wastewater flux, salt rejection and ion rejection versus operating pressure were evaluated. Then the wastewater flux of RO membrane was compared with theoretical calculation using mass transfer models, and good consistency was observed. It was found that a high rejection rate more than 95% of metal ions and a low Chemical Oxygen Demand （COD） value of 10 mg·L^-1 in permeate could be achieved using the RO composite membrane, while the NF rejection of the salt could be up to 78.9% and the COD value in the permeate was 35 mg·L^-1. The results showed that the product water by both NF and RO desalination satisfied the State Reutilization Qualification, but NF would be more suitable for large-scale industrial practice, which offered significantly higher permeate flux at low operating pressure.
基金financially supported by the National Natural Science Foundation of China(No.50803054)Zhejiang Provincial Nature Science Foundation of China(No.Y4100204)
文摘Inspired by the self-polymerization and strong adhesion characteristics of dopamine in aqueous conditions, a novel hydrophilic nanofiltration （NF） membrane was fabricated by simply dipping polysulfone （PSf） ultrafiltration （UF） substrate in dopamine solution. The changes in surface chemical composition and morphology of membranes were determined by Fourier transform infrared spectroscopy （FTIR-ATR）, X-ray photoelectron spectroscopy （XPS）, scanning electron microscopy （SEM） and atomic force microscopy （AFM）. The experimental results indicated that the self-polymerized dopamine formed an ultrathin and defect-free barrier layer on the PSf UF membrane. The surface hydrophilicity of membranes was evaluated through water contact angle measurements. It was found that membrane hydrophilicity was significantly improved after coating a polydopamine （pDA） layer, especially after double coating. The dyes filtration experiments showed that the double-coated membranes were able to reject completely the dyes of brilliant blue, congo red and methyl orange with a pure water flux of 83.7 L/（mE.h） under 0.6 MPa. The zeta potential determination revealed the positively-charged characteristics of PSf/pDA composite membrane in NF process. The salt rejection of the membranes was characterized by 0.01 mmol/L of salts filtration experiment. It was demonstrated that the salts rejections followed the sequence： NaC1 〈 NaaSO4 〈 MgSO4 〈 MgC12 〈 CaCl2, and the rejection to CaC12 reached 68.7%. Moreover, the composite NF membranes showed a good stability in water-phase filtration process.
基金funding support from the Singapore Economic Development Board to Singapore Membrane Technology Center
文摘Separation of organic mixture is an inevitable process in most modern industrial processes. In the quest for a more sustainable and efficient separation, solvent-resistant nanofiltration(SRNF) has emerged as a promising answer. This is because SRNF is a membrane-based process which offers the key advantages of high efficacy and low energy intensity separation. In particular, polymer-based membranes can offer compelling opportunities for SRNF with unprecedented cost-effectiveness. As a result, intensive research efforts have been devoted into developing novel polymer-based membranes with solvent-resistant capacities as well as exploring potential applications in different types of industries. In this review, we aim to give an overview of the recent progress in the development of the state-of-the-art polymer-based membranes for SRNF in the first section. Emerging nanomaterials for mixed matrix and thin film nanocomposite membranes are also covered in this section. This is followed by a discussion on the current status of membrane engineering and SRNF membrane commercialization. In the third section, we highlight recent efforts in adopting SRNF for relevant industrial applications such as food, bio-refinery, petrochemical, fine chemical and pharmaceutical industries followed by separations of enantiomers in stereochemistry, homogeneous catalysis and ionic liquids. Finally, we offer a perspective and provide deeper insights to help shape future research direction in this very important field of SRNF.
基金financially supported by the National Natural Science Foundation of China(No.20974094)National 973 Program(No.2009CB623402)Postdoctoral Science Foundation funded project of Zhejiang Province,China(Bsh1202045)
文摘A low operating pressure nanofiltration membrane is prepared by interfacial polymerization between m-phenylenediamine （MPDA） and trimesoyl chloride （TMC） using PVC hollow fiber membrane as supporting. A series of PVC nanofiltration membranes with different molecular weight cutoff （MWCO） can be obtained by controlling preparation conditions. Chemical and morphological characterization of the membrane surface was carried out by FTIR-ATR and SEM. MWCO was characterized by filtration experiments. The preparation conditions were investigated in detail. At the optimized conditions （40 min air-dried time, aqueous phase containing 0.5% MPDA, 0.05% SDS and 0.6% acid absorbent, oil phase containing 0.3% TMC, and 1 min reaction time）, under 0.3 MPa, water flux of the gained nanofiltration membrane reaches 17.8 L/m2-h, and the rejection rates of methyl orange and MgSO4 are more than 90% and 60%, respectively.
基金supported by the High Technology Research and Development Program (863) of China(No. 2007AA06Z339)the National Key Technologies R&D Program of China (No. 2006BAD01B02-02,2006BAJ08B00)
文摘The feasibility of employing nanofiltration for the removal of chromium（VI） from wastewater was investigated. Poly （m-phenylene isophthalamide） （PMIA） was used to fabricate asymmetric nanofiltration membrane through the phase-inversion technique. Scanning electron microscopy （SEM） and atomic force microscopy （AFM） were used to characterize the obtained membrane, and the both confirmed a much smoother surface which could reduce membrane fouling. The PMIA membrane showed different rejections to electrolytes in a sequence of Na2SO4 〉 MgSO4 〉 NaC1 〉 MgC12, which was similar to the sequence of the negatively charged nanofiltration membranes. Separation experiments on chromium（VI） solution were conducted at various operating conditions, such as feed concentration, applied pressure and pH. It is concluded that chromium（VI） could be effectively removed from chromiumcontaining wastewater by the PMIA nanofiltration membranes while maintaining their pollution resistance under alkaline condition.
基金supported by the National Natural Science Foundation of China (No. 50578131)the National Basic Research Program (973) of China (No. 2008CB417211)the Fund of Shann'xi Educational Committee (No. 05JK243).
文摘The UF membrane with molecular weight cutoff （MWCO） ranging from 2 to 100 kDa and XAD-8 resin were employed to identify the characteristic of molecular weight （MW） distribution of wastewater effluent organic matter （EfOM） in terms of TOC and UV254, as well as the amounts of the hydrophilic/hydrophobic organic fractions in different MW ranges. Then, the nanofiltration （NF） membrane fouling experiments were carded out using the above fractionated water to investigate the effect of MW distribution and hydrophihc/hydrophobic characteristics of EfOM on the membrane flux decline using the fractionated water samples. The experimental results have shown that 45.61% of the total organics belongs to the low MW one, among which the percentage of the hydrophilic organics with low MW （less than 2 kDa） was up to 28.07%, while that of the hydrophobic organics was 17.54%. In particular, the hydrophilic fraction was found to be the most abundant fraction in the effluents. MW distribution has a significant effect on the membrane fouling. When the MW was less than 30 kDa, the lower the MW, the larger was the specific flux decline, while in the case of MW higher than 30 kDa, the higher the MW, the larger was the specific flux decline, and the decline degree of low MW organics was larger than the high MW one. With the same MW distribution range, specific flux decline of the hydrophilic organic was considerably slower than that of the hydrophobic organic, which indicated that the hydrophobic organic fractions dominantly contribute to the flux decline.
基金supported by the National Center of Excellence for Environmental and Hazardous Waste Man- agement (NC-EHWM).
文摘Haloacetic acids, disinfection byproducts （DBPs） formed during drinking water chlorination process are carcinogens. The efficacy of nanofiltration （NF） was examined for the removal of five regulated haloacetic acids （HAAs）： chloro-, dichloro-, and trichioro-acetic acid （CAA, DCAA, and TCAA）; bromo-, and dibromo-acetic acid （BAA, and DBAA） in synthetic water. NF with the dense negatively charged membrane （ES 10）, is the most efficient in removing HAAs than the loose negatively charged membrane （NTR 7410） and neutral surface membrane （NTR 729HF）, due to the greater electrostatic repulsion （Donan exclusion） and sieve effect. Excellent HAAs removal efficiency of 90%-100% could be obtained even at a low pressure of 1×10^5 Pa with ES 10. Changes in cross-flow velocity did not effect the performance of membranes with a small pore size such as ES 10 and NTR 729HF. The increase in HAAs concentration exhibited the adverse effect on the performance of three membranes by strengthening the concentration polarization, which was the driving force for the diffusion of HAA anions across the membrane.
基金Supported by the National Basic Research Program of China(2015CB655301)the Natural Science Foundation of China(21825803)+2 种基金and the Natural Science Foundation of Jiangsu Province(BK20150063)the Program of Excellent Innovation Teams of Jiangsu Higher Education Institutionsthe Project of Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD).
文摘Thin film composite(TFC) membranes represent a highly promising platform for efficient nanofiltration(NF)processes. However, the improvement in permeance is impeded by the substrates with low permeances. Herein,highly permeable gradient phenolic membranes with tight selectivity are used as substrates to prepare TFC membranes with high permeances by the layer-by-layer assembly method. The negatively charged phenolic substrates are alternately assembled with polycation polyethylenimine(PEI) and polyanion poly(acrylic acid)(PAA)as a result of electrostatic interactions, forming thin and compact PEI/PAA layers tightly attached to the substrate surface. Benefiting from the high permeances and tight surface pores of the gradient nanoporous structures of the substrates, the produced PEI/PAA membranes exhibit a permeance up to 506 L? m-2?h-1?MPa-1, which is ~2–10 times higher than that of other membranes with similar rejections. The PEI/PAA membranes are capable of retaining N 96.1% of negatively charged dyes following the mechanism of electrostatic repulsion. We demonstrate that the membranes can also separate positively and neutrally charged dyes from water via other mechanisms.This work opens a new avenue for the design and preparation of high-flux NF membranes, which is also applicable to enhance the permeance of other TFC membranes.
文摘Lanthanides are widely used in various commercial applications, which results in public exposure to them, and it is a matter of concern. Many methods were used to remove lanthanides from wastewaters generated from their commercial use. In the present work, nanofiltration membrane process was used to remove the cerium and neodymium from their respective feed solutions. The feed and permeates were analyzed for solute concentration by inductively coupled plasma-atomic emission spectroscopy. Irreversible thermodynamics Spiegler-Kedem model, in combination with the film theory, was used to estimate the membrane transport parameters, viz., reflection coefficient of membrane and solute permeability, and mass transfer coefficient to study their dependence on feed solute concentration.
基金financially supported by the Provincial Key Research and Development Program of Zhejiang Province(2021C01173)the National Natural Science Foundation of China(21975221 and 21776252)。
文摘In the face of human society's great requirements for health industry,and the much stricter safety and quality standards in the biomedical industry,the demand for advanced membrane separation technologies continues to rapidly grow in the world.Nanofiltration(NF)and reverse osmosis(RO)as the highefficient,low energy consumption,and environmental friendly membrane separation techniques,show great promise in the application of biomedical separation field.The chemical compositions,microstructures and surface properties of NF/RO membranes determine the separation accuracy,efficiency and operation cost in their applications.Accordingly,recent studies have focused on tuning the structures and tailoring the performance of NF/RO membranes via the design and synthesis of various advanced membrane materials,and exploring universal and convenient membrane preparation strategies,with the objective of promoting the better and faster development of NF/RO membrane separation technology in the biomedical separation field.This paper reviews the recent studies on the NF/RO membranes constructed with various materials,including the polymeric materials,different dimensional inorganic/organic nanomaterials,porous polymeric materials and metal coordination polymers,etc.Moreover,the influence of membrane chemical compositions,interior microstructures,and surface characteristics on the separation performance of NF/RO membranes,are comprehensively discussed.Subsequently,the applications of NF/RO membranes in biomedical separation field are systematically reported.Finally,the perspective for future challenges of NF/RO membrane separation techniques in this field is discussed.
基金Supported by the Ministry of Education(MoE)Malaysia to Universiti Teknologi Malaysia(UTM)under the grant of Higher Institution Centre of Excellence(HICoE)(R.J090301.7846.4J175)Universiti Tunku Abdul Rahman(UTAR)under the research publication scheme(6251/K02)
文摘In this study,a quantitative performance of three commercial polyamide nanofiltration(NF) membranes(i.e.,NF,NF90,and NF270) for phosphorus removal under different feed conditions was investigated.The experiments were conducted at different feed phosphorus concentrations(2.5,5,10,and 15 mg·L^-1) and elevated pHs(pH 1.5,5,10,and 13.5) at a constant feed pressure of 1 MPa using a dead-end filtration cell.Membrane rejection against total phosphorus generally increased with increasing phosphorus concentration regardless of membrane type.In contrast,the permeate flux for all the membranes only decreased slightly with increasing phosphorus concentration.The results also showed that the phosphorus rejections improved while water flux remained almost unchanged with increasing feed solution pH.When the three membranes were exposed to strong pHs(pH 1.5 and 13.5) for a longer duration(up to 6 weeks)it was found that the rejection capability and water flux of the membranes remained very similar throughout the duration,except for NF membrane with marginal decrement in phosphorus rejection.Adsorption study also revealed that more phosphorus was adsorbed onto the membrane structure at alkaline conditions(pH 10 and 13.5) compared to the same membranes tested at lower pHs(pH 1.5 and 5).In eonelusion,NF270 membrane outperformed Nf and NF90 membranes owing to its desirable performance of water flux and phosphorus rejection particularly under strong alkali solution.The NF270 membrane achieved 14.0 L·m^-2·h^-1 and 96.5% rejection against 10 mg·L^-1 phosphorus solution with a pH value of 13.5 at the applied pressure of 1 MPa.
文摘Landfill leachate treated with combined process of ＂pretreatment ＋biological treatment ＋advanced treatment （NF）＂ to produce nanofiltration concentrate, which bio-chemical ratio （B/C） is less than 0.1 and CODer concentration is 2 000-2 500 mg/L, high salt content. Which cannot be discharged under existing environ- mental standards. According to analysis based on electrochemical advanced oxidation mechanism, a two-step electrochemical tech- nique was recommended. In the first step, a pulse electrochemical technique was adopted. With Fe as consumption electrode and current density of 10 mA/cm2, the pollutants were removed by means of Fenton reaction, electroflotation and electrocoagulation. In the second step, a double function electrode was used to per- form electrocatalytic oxidation by means of titanium metallic oxi- dates. In the condition that current density being 12.5 mA/cm2, the pollutants were further removed by oxidation and electrolytic deposition. Result shows that the removing rate of CODer, NH3-N and CI were 70%-85%, 90% and 25%, respectively; average value of B/C ratio increased from 0.09 to 0.38 and conductivity reduced by 10%.
基金This work is supported by Fok Ying Tung Education Foundation (No. 94004),Shanghai Natural Science Foundation(No.04ZR 14010)and Laboratory of Water Quality Science & Water Environment Recovery Engineering of Beijing.
文摘A pilot-scale study of advanced drinking water treatment was carried out in test site, and a combination of ozonation, granular activated carbon (GAC) and nanofiltration was employed as the experimental process. By optimizing the operational parameters of ozonation and GAC, a large quantity of micro-pollutants in drinking water was removed, which made the post-positioned nanofiltration operate more reliably. It was evident that nanofiltration shows good performance for removing residual organic matter, meantime partial minerals can also be retained by nanofiltration. Therefore the quality of drinking water can be further improved. In addition, NF membrane fouling and scaling can be solved by concentrate recycling, anti-scalant dosing and chemical rinsing effectively. By GAC adsorption for the residue chlorine and ozone self-decomposition, their oxidation on NF membrane material can be eliminated completely.
基金the Special Funds for Major State Basic Research Program of China(2003CB615706)
文摘N, O-carboxymethyl chitosan （NOCC） composite nanofiltration （NF） membranes were prepared by coating and cross-linking. The fermentation effluent from a wine factory was treated with the resulting NOCC/polysulfone （PSF） composite NF membranes. The permeate flux and the removal efficiencies of the resulting NF membranes for the color, chemical oxygen demand （CODcr）, total organic carbon （TOC）, and conductivity of the fermentation effluent were investigated in relation to the driving pressure, the feed flow, and the operation time. The permeate flux and the removal efficiencies were found to increase with the increase of the driving pressure or the feed flow. At 0.40 MPa and ambient temperature the removal efficiencies were 95.5%, 70.7%, 72.6%, and 31.6% for color, CODcr, TOC, and conductivity, respectively. The membrane was found to be stable over a 10-h ooeration for the fermentation effluent treatment.
