Ionic partition equilibrium in charged membrane immersed in solution of single electrolyte with monovalence or multi-valence is systematically investigated and several expressions are established for determination of ...Ionic partition equilibrium in charged membrane immersed in solution of single electrolyte with monovalence or multi-valence is systematically investigated and several expressions are established for determination of partition coefficients. On this basis, the effects of the ratio of membrane charge density to bulk electrolyte solution concentration, the charge sign and valence of electrolyte ions and the type of membrane on the partition equilibrium were analyzed and simulated within chosen parameters. It is revealed that ion partition is not related solely with the respective concentrations but also definitely with the concentration ratio of fixed group to bulk solution in addition to the charge sign and the valence. For a counterion, the partition coefficient increases with this ratio and the valence; while for a coion, the partition coefficient decreases with this ratio and the valence. The theoretical calculations were compared with the experimental data and a good agreement was observed.展开更多
A novel matrix of macropore cellulose membrane was prepared by chemical graft, and immobilized the cationic charged groups as affinity ligands. The prepared membrane Fan be used for the removal of endotoxin from human...A novel matrix of macropore cellulose membrane was prepared by chemical graft, and immobilized the cationic charged groups as affinity ligands. The prepared membrane Fan be used for the removal of endotoxin from human serum albumin (HSA) solutions. With a cartridge of 20 sheets affinity membrane of 47 mm diameter, the endotoxin level in HSA solution can be reduced ro 0.027 eu/mL. Recovery of HSA was over 95%.展开更多
Ionic partition equilibrium on a charged membrane immersed in a mixed electrolyte solution was systematically investigated and several models were established for the determination of partition coefficients. On the ba...Ionic partition equilibrium on a charged membrane immersed in a mixed electrolyte solution was systematically investigated and several models were established for the determination of partition coefficients. On the basis of theoretical models, the effects of the concentration ratio λ of the fixed group(charged density) to reference electrolyte, the concentration ratio η between the two electrolytes existing in the solution and the valence of the electrolyte ions on the partition equilibrium in a positively charged membrane were analyzed and simulated within the chosen parameters in detail. The obtainable results can also be applicable to a sytem of mixed electrolytes contacting with a negatively charged membrane. The theoretical calculations were confirmed with the experimental data of model mixed electrolytes, NaCl+HCl and CaCl 2+NaCl partitioned in the system of self made negatively charged membrane sulphonated poly(phenylene oxide)(SPPO) with different charge densities.展开更多
A novel composite charged mosaic membrane(CCMM) was prepared via interfacial polymerization(IP) of polyamine[poly(epichlorohydrin amine) ]and trimesoyl chloride(TMC) on the polyethersulfone(PES) support. Fourier trans...A novel composite charged mosaic membrane(CCMM) was prepared via interfacial polymerization(IP) of polyamine[poly(epichlorohydrin amine) ]and trimesoyl chloride(TMC) on the polyethersulfone(PES) support. Fourier transform infrared spectroscopy(FT-IR) ,environmental scanning electron microscopy(ESEM) ,atomic force microscopy(AFM) and water contact angle analysis were applied to characterize the resulted CCMM.The FT-IR spectrum indicates that TMC reacts sufficiently with polyamine.ESEM and AFM pictures show that the IP process produces a dense selective layer on the support membrane.The water contact angle of the CCMM is smaller than that of the substrate membrane because of the cross-linked hydrophilic polyamine network.Several factors affecting the IP reaction and the performance of the CCMM,such as monomer concentration,reaction time,pH value of aqueous phase solution and post-treatment,were studied.The pure water flux of the optimized CCMM is 14.73 L·m -2 ·h -1 ·MPa -1 at the operating pressure of 0.4 MPa.The values of separation factorαfor NaCl/PEG1000/water and MgCl2/PEG1000/water are 11.89 and 9.96,respectively.These results demonstrate that CCMM is promising for the separation of low-molecular-weight organics from their salt aqueous solutions.展开更多
To develop a depth filter based on the electrostatic adsorption principle, positively charged microporous ceramic membrane was prepared from a diatomaceous earth ceramic membrane.The internal surface of the highly por...To develop a depth filter based on the electrostatic adsorption principle, positively charged microporous ceramic membrane was prepared from a diatomaceous earth ceramic membrane.The internal surface of the highly porous ceramic membrane was coated with uniformly distributed electropositive nano-Y2O3 coating. The dye removal performance was evaluated through pressurized filtration tests using Titan Yellow aqueous solution. It showed that positively charged microporous ceramic membrane exhibited a flow rate of 421 L/（m^2·hr） under the trans-membrane pressure of 0.03 bar. Moreover it could effectively remove Titan Yellow with feed concentration of 10 mg/L between pH 3 to 8. The removal rate increased with the enhancement of the surface charge properties with a maximum rejection of 99.6%. This study provides a new and feasible method of removing organic dyes in wastewater. It is convinced that there will be a broad market for the application of charged ceramic membrane in the field of dye removal or recovery from industry wastewater.展开更多
A selfmade positively charged nanofiltration （NF） membrane was used to treat textile dye effluent to generate water for reuse, and the factors affecting nanofiltration process such as operating pressure, feed flow a...A selfmade positively charged nanofiltration （NF） membrane was used to treat textile dye effluent to generate water for reuse, and the factors affecting nanofiltration process such as operating pressure, feed flow and membrane cleaning were investigated. With an applied pressure of 1.0 MPa and a feed flow of 40 L/h, this NF membrane has a removal of 93.3% for CODor and a reduction of approximately 51.0% in TDS, salinity and conductivity achieving the chroma removal of 100%. The permeate obtained through this membrane is suitable for recycling. Moreover, the membrane could be reused after being cleaned with 1% NaOH solution.展开更多
Membrane potentials across hybrid charged mosaic membrane in organic solutions were measured. Equilibrium swelling degree （SD） and fixed charge density in both organic solutions and water were also determined. Ethyl...Membrane potentials across hybrid charged mosaic membrane in organic solutions were measured. Equilibrium swelling degree （SD） and fixed charge density in both organic solutions and water were also determined. Ethylene glycol, ethanol, n-propanol and glycerol were used as organic solutes; meanwhile 0.001mol-dm^-3 aqueous KCl solution was utilized as a strong electrolyte to measure the electrical difference. Equilibrium swelling degree indicated that it could be affected by the density of organic solutes; while it enhanced with the increasing density of these solutes. The measurement of fixed charge density showed that the membrane had the maximal absolute value in water among these solvents whether for cationic or anionic groups; the difference of dielectric constant between the water and the organic solutes might be responsible for these change trends. It was confirmed that membrane potentials increased with both the increasing concentration of the organic solutions and the elevated pH values. These results demonstrated that the characteristics of the hybrid charged mosaic membrane could be highly impacted by the properties of the organic solutes. A theoretical modal for charged membranes in ternary ion systems of weak electrolyte can be used to explain the above-mentioned phenomena.展开更多
Positively charged composite nanofiltration （NF） membranes were prepared through interfacial polymerization of poly[2-（N,N-dimethyl amino）ethyl methacrylate]（PDMAEMA） on porous polysulfone （PSF） substrate memb...Positively charged composite nanofiltration （NF） membranes were prepared through interfacial polymerization of poly[2-（N,N-dimethyl amino）ethyl methacrylate]（PDMAEMA） on porous polysulfone （PSF） substrate membranes. The effects of pH on swelling ratio （SR） of the pure crosslinked PDMAEMA membrane and on separation performances of the composite NF membrane were investigated. The results show that the quaternized amino groups produced through interfacial polymerization technique are soluble in both phases, which accelerate the crosslinking reaction as self-catalysts. The swelling/contracting behavior of the pure crosslinked PDMAEMA exhibited a well reversible pH sensitive property. Importantly, the rejection and flux of the composite NF membrane show pH-sensitive behavior in NF process. Furthermore, with the help of a relatively novel method to measure membrane conduction, the true zeta potentials calculated on the basis of the streaming potential measurements proved the pH-sensitive behavior of the NF membrane.展开更多
Precise and selective separation of target solutes from complex mixtures remains a critical yet challenging goal in industrial separation processes.Conventional membranes typically excel at separating either cations o...Precise and selective separation of target solutes from complex mixtures remains a critical yet challenging goal in industrial separation processes.Conventional membranes typically excel at separating either cations or anions but struggle to differentiate both simultaneously.In this study,we develop covalent organic framework(COF)membranes with vertically asymmetric charge distributions,fabricated via interfacial polymerization followed by nanosheet casting.These membranes exhibit pronounced ionic current rectification.Under single-salt conditions,the optimal membrane achieves exceptional selectivity values of H^(+)/Mg^(2+)=702 and NO_(3)^(-)/PO_(4)^(3-)=201.Remarkably,selectivity improves further in multicomponent systems.In an eightcomponent acid/salt mixture,the membrane demonstrates separation ratios of NO_(3)^(-)/PO_(4)^(3-)=380,NO_(3)^(-)/SO_(4)^(2-)=234,NO_(3)^(-)/Cl^(-)=11,H^(+)/Li^(+)=698,H^(+)/Na^(+)=1120,H^(+)/K^(+)=525,and H^(+)/Mg^(2+)=17182,maintaining stability for a continuous run for at least 216 h.This work introduces a robust membrane design strategy for highly selective solute separation from complex mixtures,offering valuable advancements for sustainable chemical recovery technologies.展开更多
A series of amphiphilic copolymers containing poly（vinyl chloride-r-acrylic acid） （P（VC-r-AA）） was synthesized and used to prepare membranes via a non-solvent induced phase separation method. The prepared membra...A series of amphiphilic copolymers containing poly（vinyl chloride-r-acrylic acid） （P（VC-r-AA）） was synthesized and used to prepare membranes via a non-solvent induced phase separation method. The prepared membranes were characterized by scanning electron microscopy, X-ray photoelectron spectroscopy, and water contact angle and zeta potential measurements. The copolymer P（VC-r-AA） chains did not dissolved in a coagulation bath, indicating that the AA segments were completely retained within the membrane. Enriching degree of AA segments in surface layer was 2 for copolymer membrane. In addition, the introduction of AA segments made the membrane electronegative and hydrophilic so that the membrane was sensitive to the solution pH. The fouling resistance, adsorption of Cu（II）, Cr（III） and Ce（IV） ions and the desorption properties of the membranes were also determined. The copolymer membranes exhibited good antifouling performance with a fouling reversibility of 92%. The membranes also had good adsorption capacities for Cu（II）, Cr（III） and Ce（IV） ions. The optimal pH for Cu（II） adsorption was 6 and the copolymer membrane has potential applications for low concentration Cu（II） removal.展开更多
基金Supported by the National Natural Science Foundation of China (No. 29976040), the Natural Science Foundation of Anhui Province(No. 99045431) and the Foundation of Environments and Resources of USTC (2000).
文摘Ionic partition equilibrium in charged membrane immersed in solution of single electrolyte with monovalence or multi-valence is systematically investigated and several expressions are established for determination of partition coefficients. On this basis, the effects of the ratio of membrane charge density to bulk electrolyte solution concentration, the charge sign and valence of electrolyte ions and the type of membrane on the partition equilibrium were analyzed and simulated within chosen parameters. It is revealed that ion partition is not related solely with the respective concentrations but also definitely with the concentration ratio of fixed group to bulk solution in addition to the charge sign and the valence. For a counterion, the partition coefficient increases with this ratio and the valence; while for a coion, the partition coefficient decreases with this ratio and the valence. The theoretical calculations were compared with the experimental data and a good agreement was observed.
文摘A novel matrix of macropore cellulose membrane was prepared by chemical graft, and immobilized the cationic charged groups as affinity ligands. The prepared membrane Fan be used for the removal of endotoxin from human serum albumin (HSA) solutions. With a cartridge of 20 sheets affinity membrane of 47 mm diameter, the endotoxin level in HSA solution can be reduced ro 0.027 eu/mL. Recovery of HSA was over 95%.
基金Supported by the National Natural Science Foundation of China(No.2 0 10 6 0 15 and2 9976 0 4 0 ) Natural Science Foun-dation of Anhui Province(No.990 4 5 4 31) and Key Foundation of Educational Comm ittee of Anhui Province(No.2 0 0 0 jl2 5 5 zd)
文摘Ionic partition equilibrium on a charged membrane immersed in a mixed electrolyte solution was systematically investigated and several models were established for the determination of partition coefficients. On the basis of theoretical models, the effects of the concentration ratio λ of the fixed group(charged density) to reference electrolyte, the concentration ratio η between the two electrolytes existing in the solution and the valence of the electrolyte ions on the partition equilibrium in a positively charged membrane were analyzed and simulated within the chosen parameters in detail. The obtainable results can also be applicable to a sytem of mixed electrolytes contacting with a negatively charged membrane. The theoretical calculations were confirmed with the experimental data of model mixed electrolytes, NaCl+HCl and CaCl 2+NaCl partitioned in the system of self made negatively charged membrane sulphonated poly(phenylene oxide)(SPPO) with different charge densities.
基金Supported by the National High Technology Research and Development Program of China（2008AA06Z330） the National Natural Science Foundation of China（20676125） the Technician Service Enterprise Action Program（2009GJD00048）
文摘A novel composite charged mosaic membrane(CCMM) was prepared via interfacial polymerization(IP) of polyamine[poly(epichlorohydrin amine) ]and trimesoyl chloride(TMC) on the polyethersulfone(PES) support. Fourier transform infrared spectroscopy(FT-IR) ,environmental scanning electron microscopy(ESEM) ,atomic force microscopy(AFM) and water contact angle analysis were applied to characterize the resulted CCMM.The FT-IR spectrum indicates that TMC reacts sufficiently with polyamine.ESEM and AFM pictures show that the IP process produces a dense selective layer on the support membrane.The water contact angle of the CCMM is smaller than that of the substrate membrane because of the cross-linked hydrophilic polyamine network.Several factors affecting the IP reaction and the performance of the CCMM,such as monomer concentration,reaction time,pH value of aqueous phase solution and post-treatment,were studied.The pure water flux of the optimized CCMM is 14.73 L·m -2 ·h -1 ·MPa -1 at the operating pressure of 0.4 MPa.The values of separation factorαfor NaCl/PEG1000/water and MgCl2/PEG1000/water are 11.89 and 9.96,respectively.These results demonstrate that CCMM is promising for the separation of low-molecular-weight organics from their salt aqueous solutions.
基金supported by the National Natural Science Foundation of China (No. 51202292)
文摘To develop a depth filter based on the electrostatic adsorption principle, positively charged microporous ceramic membrane was prepared from a diatomaceous earth ceramic membrane.The internal surface of the highly porous ceramic membrane was coated with uniformly distributed electropositive nano-Y2O3 coating. The dye removal performance was evaluated through pressurized filtration tests using Titan Yellow aqueous solution. It showed that positively charged microporous ceramic membrane exhibited a flow rate of 421 L/（m^2·hr） under the trans-membrane pressure of 0.03 bar. Moreover it could effectively remove Titan Yellow with feed concentration of 10 mg/L between pH 3 to 8. The removal rate increased with the enhancement of the surface charge properties with a maximum rejection of 99.6%. This study provides a new and feasible method of removing organic dyes in wastewater. It is convinced that there will be a broad market for the application of charged ceramic membrane in the field of dye removal or recovery from industry wastewater.
基金Funded by the Major State Basic Research Development Program of China (973 Program)( No.2003CB615706)
文摘A selfmade positively charged nanofiltration （NF） membrane was used to treat textile dye effluent to generate water for reuse, and the factors affecting nanofiltration process such as operating pressure, feed flow and membrane cleaning were investigated. With an applied pressure of 1.0 MPa and a feed flow of 40 L/h, this NF membrane has a removal of 93.3% for CODor and a reduction of approximately 51.0% in TDS, salinity and conductivity achieving the chroma removal of 100%. The permeate obtained through this membrane is suitable for recycling. Moreover, the membrane could be reused after being cleaned with 1% NaOH solution.
基金Supported by the National Natural Science Foundation of China （No.20576130） and the National Basic Research Program of China （973 program, No.2003CB615700）, and the Innovation Fund for the Graduate Students of USTC （No. KD2005022）.
文摘Membrane potentials across hybrid charged mosaic membrane in organic solutions were measured. Equilibrium swelling degree （SD） and fixed charge density in both organic solutions and water were also determined. Ethylene glycol, ethanol, n-propanol and glycerol were used as organic solutes; meanwhile 0.001mol-dm^-3 aqueous KCl solution was utilized as a strong electrolyte to measure the electrical difference. Equilibrium swelling degree indicated that it could be affected by the density of organic solutes; while it enhanced with the increasing density of these solutes. The measurement of fixed charge density showed that the membrane had the maximal absolute value in water among these solvents whether for cationic or anionic groups; the difference of dielectric constant between the water and the organic solutes might be responsible for these change trends. It was confirmed that membrane potentials increased with both the increasing concentration of the organic solutions and the elevated pH values. These results demonstrated that the characteristics of the hybrid charged mosaic membrane could be highly impacted by the properties of the organic solutes. A theoretical modal for charged membranes in ternary ion systems of weak electrolyte can be used to explain the above-mentioned phenomena.
基金Funded by the National Natural Science Foundation of China (No.50673077)National Basic Research Program of China (No.2006CB708602)
文摘Positively charged composite nanofiltration （NF） membranes were prepared through interfacial polymerization of poly[2-（N,N-dimethyl amino）ethyl methacrylate]（PDMAEMA） on porous polysulfone （PSF） substrate membranes. The effects of pH on swelling ratio （SR） of the pure crosslinked PDMAEMA membrane and on separation performances of the composite NF membrane were investigated. The results show that the quaternized amino groups produced through interfacial polymerization technique are soluble in both phases, which accelerate the crosslinking reaction as self-catalysts. The swelling/contracting behavior of the pure crosslinked PDMAEMA exhibited a well reversible pH sensitive property. Importantly, the rejection and flux of the composite NF membrane show pH-sensitive behavior in NF process. Furthermore, with the help of a relatively novel method to measure membrane conduction, the true zeta potentials calculated on the basis of the streaming potential measurements proved the pH-sensitive behavior of the NF membrane.
基金supported by the National Key Research and Development Program of China(2024YFB3815700)the National Natural Science Foundation of China(22421004)the National Natural Science Foundation of Zhejiang Province(LR23B060001)。
文摘Precise and selective separation of target solutes from complex mixtures remains a critical yet challenging goal in industrial separation processes.Conventional membranes typically excel at separating either cations or anions but struggle to differentiate both simultaneously.In this study,we develop covalent organic framework(COF)membranes with vertically asymmetric charge distributions,fabricated via interfacial polymerization followed by nanosheet casting.These membranes exhibit pronounced ionic current rectification.Under single-salt conditions,the optimal membrane achieves exceptional selectivity values of H^(+)/Mg^(2+)=702 and NO_(3)^(-)/PO_(4)^(3-)=201.Remarkably,selectivity improves further in multicomponent systems.In an eightcomponent acid/salt mixture,the membrane demonstrates separation ratios of NO_(3)^(-)/PO_(4)^(3-)=380,NO_(3)^(-)/SO_(4)^(2-)=234,NO_(3)^(-)/Cl^(-)=11,H^(+)/Li^(+)=698,H^(+)/Na^(+)=1120,H^(+)/K^(+)=525,and H^(+)/Mg^(2+)=17182,maintaining stability for a continuous run for at least 216 h.This work introduces a robust membrane design strategy for highly selective solute separation from complex mixtures,offering valuable advancements for sustainable chemical recovery technologies.
基金This research was supported by the National High Technology Research and Development Program of China （Granted No. 2012AA03A602 ） , the National Basic Research Program of China （Granted No. 2009CB623402） and the National Natural Science Foundation of China （Grant No. 20974094）.
文摘A series of amphiphilic copolymers containing poly（vinyl chloride-r-acrylic acid） （P（VC-r-AA）） was synthesized and used to prepare membranes via a non-solvent induced phase separation method. The prepared membranes were characterized by scanning electron microscopy, X-ray photoelectron spectroscopy, and water contact angle and zeta potential measurements. The copolymer P（VC-r-AA） chains did not dissolved in a coagulation bath, indicating that the AA segments were completely retained within the membrane. Enriching degree of AA segments in surface layer was 2 for copolymer membrane. In addition, the introduction of AA segments made the membrane electronegative and hydrophilic so that the membrane was sensitive to the solution pH. The fouling resistance, adsorption of Cu（II）, Cr（III） and Ce（IV） ions and the desorption properties of the membranes were also determined. The copolymer membranes exhibited good antifouling performance with a fouling reversibility of 92%. The membranes also had good adsorption capacities for Cu（II）, Cr（III） and Ce（IV） ions. The optimal pH for Cu（II） adsorption was 6 and the copolymer membrane has potential applications for low concentration Cu（II） removal.
