Crosslinking treatments for a commercially available aromatic polyamide reverse osmosis membrane were carried out to improve its chlorine resistance.The crosslinking agents including 1,6-hexanediol diglycidyl ether,ad...Crosslinking treatments for a commercially available aromatic polyamide reverse osmosis membrane were carried out to improve its chlorine resistance.The crosslinking agents including 1,6-hexanediol diglycidyl ether,adipoyl dichloride and hexamethylene diisocyanate ester with long flexible aliphatic chains and high reactivity with N-H groups were used in the experiments.Attenuated total reflective Fourier transform infrared spectra verified the successful preparation of highly crosslinked membranes by crosslinking treatments.It was suggested that the crosslinking agents were connected to membrane surface through the reactions with amine and amide Ⅱ groups,which is confirmed by surface charge measurements.Based on contact angle measurements,crosslinking treatments decreased membrane hydrophilicity by introducing methylene groups to membrane surface.With increasing amount of crosslinking agent molecules connected to membrane surface,the hydrolysis of unconnected functional groups of crosslinking agent produced polar groups and increased membrane hydrophilicity.The highly crosslinked membranes showed higher salt rejections and lower water fluxes as compared with the raw membrane.Since the active sites(N-H groups) vulnerable to free chlorine on membrane surface were eliminated by crosslinking treatments,the chlorine resistances of the highly crosslinked membranes were significantly improved by slighter changes in both water fluxes and salt rejections after chlorination.展开更多
Nanoscale thin-film composite(TFC)polyamide membranes are highly desirable for desalination owing to their excellent separation performance.It is a permanent pursuit to further improve the water flux of membrane witho...Nanoscale thin-film composite(TFC)polyamide membranes are highly desirable for desalination owing to their excellent separation performance.It is a permanent pursuit to further improve the water flux of membrane without deteriorating the salt rejection.Herein,we fabricated a high-performance polyamide membrane with nanoscale structures through introducing multifunctional crown ether interlayer on the porous substrate impregnated with m-phenylenediamine.The crown ether interlayer can reduce the diffusion of amine monomers to reaction interface influenced by its interaction with m-phenylenediamine and the spatial shielding effect,leading to a controlled interfacial polymerization(IP)reaction.Besides,crown ether with intrinsic cavity is also favorable to adjust the IP process and the microstructure of polyamide layer.Since the outer surface of the nanocavity is lipophilic,crown ether has good solvency with the organic phase,thus attracting more trimesoyl chloride molecules to the interlayer and promoting the IP reaction in the confined space.As a result,a nanoscale polyamide membrane with an ultrathin selective layer of around 50 nm is obtained.The optimal TFC polyamide membrane at crown ether concentration of 0.25 wt.%exhibits a water flux of 61.2 L·m^(−2)·h^(−1),which is 364%of the pristine TFC membrane,while maintaining a rejection of above 97%to NaCl.The development of the tailor-made nanoscale polyamide membrane via constructing multifunctional crown ether interlayer provides a straightforward route to fabricate competitive membranes for highly efficient desalination.展开更多
Membrane processes are used in the food and nutrient industry in terms of their proper performance and selective separation.Using the membranes in fruit juice concentrating operations improves its quality via shelf-li...Membrane processes are used in the food and nutrient industry in terms of their proper performance and selective separation.Using the membranes in fruit juice concentrating operations improves its quality via shelf-life increases.The advantage of reverse osmosis(RO)and membrane technology over other methods is its nonchemical reaction to fruit juice which increases the concentration of fruit juice.The membranes were made of three layers of non-woven polyester layer for the mechanical strength of the membrane,polyester sulfone polymer with polyamide consisting of polymerization of M-Phenylenediamine(MPD)and benzene tricarbonyl chloride.Trimethyl chloride(TMC)was used to modify the properties of the membrane in the second layer using silica nanoparticles.The feed was sugar-free pomegranate juice added by SUNICH Company with an initial Brix value of 14.9%and an input feed of 6.6%to the RO system.The DESIGN-EXPERT method for the design of experiments(DOE)by considering three parameters of weight percentage of polyester sulfone polymer(12,16,and 20%),silica nanoparticles(0,0.1,and 0.2 wt%),and operating pressure were used(20,25,and 30 times).Under optimal conditions,46.15%of the concentrated pomegranate juice were obtained by experiment and the amount of brix increased from 33.24%to 47.21%.Scanning electron microscope(SEM),Fourier-transform infrared spectroscopy(FTIR),and contact angle tests for membranes were used.In the analysis of contact angle by examining the degree of hydrophilicity and contact angle of water droplets,it was found that the presence of silica nanoparticles and polyamide layer caused more hydrophilicity of membranes.It can be concluded that the pressure parameter,together with the presence of nanoparticles and polymer percentages,contribute to the most successful procedure of concentrating pomegranate juice.展开更多
Nanofiltration(NF) technology,with its capacity for nanoscale filtration and controllable selectivity,holds significant promise in diverse applications.However,the current upper bound of permeance and selectivity of N...Nanofiltration(NF) technology,with its capacity for nanoscale filtration and controllable selectivity,holds significant promise in diverse applications.However,the current upper bound of permeance and selectivity of NF membranes is intrinsically constrained by the morphology and structure of the polyamide(PA) selective layer.This issue arises because NF membranes typically exhibit relatively smooth nodular structures,which theoretically impede efficient water transport.In this study,we enhanced the formation of nanobubbles by synergistically regulating with surfactant and low temperatures,resulting in the fabrication of PA NF membranes with a crumpled morphology.We observed that lower temperatures promote enhanced gas solubility in the aqueous phase,facilitating increased nanobubble formation through the foaming effect of surfactant sodium dodecylbenzene sulfonate(SDBS).Consequently,this resulted in the creation of PA NF membranes with more crumpled structures and superior performance,with pure water permeance reaching 36.25 ± 0.42 L m^(-2)h^(-1)bar^(-1),representing an improvement of 14.47 L m^(-2)h^(-1)bar^(-1)compared to the control group.Additionally,it maintains a high Na_(2)SO_(4) rejection rate of97.00 % ± 0.58 %.The PA NF membranes produced by eliminating nanobubbles and free interfaces exhibited a smooth structure,whereas introducing nanobubbles(through Na HCO_(3) addition,N_(2) pressurization,and ultrasonication) resulted in the formation of crumpled membranes.This emphasized that the large amount of nanobubbles generated by SDBS and low temperature in the interfacial process played a critical role in shaping crumpled PA NF membranes and enhancing membrane performance.This approach has the potential to provide valuable insights into customizing the structural design of TFC PA NF membranes,contributing to further advancements in this field.展开更多
The recent emergence of pollutants of concern in the water bodies is becoming a challenge for the water treatment community.In such a scenario,the deployment of the polyamide(PA)nanofiltration(NF)has proved to be a su...The recent emergence of pollutants of concern in the water bodies is becoming a challenge for the water treatment community.In such a scenario,the deployment of the polyamide(PA)nanofiltration(NF)has proved to be a successful solution.Hence,the current study focused on applying a set of PA NF membranes for their potential to treat saline water containing organic pharmaceutical pollutants of emerging concern.The membranes have a varied active layer chemistry owing to the use of a set of aliphatic amines of varying chain lengths during interfacial polymerization(IP).Five membranes,ranging from M1 to M5[M1(2%w/v PIP+0.15%w/v TMC),M2(1.8%w/v PIP and 0.2%w/v EDA+0.15%w/v TMC),M3(1.8%w/v PIP and 0.2%w/v DETA+0.15%w/v TMC),M4(1.8%w/v PIP and 0.2%w/v BAEP+0.15%w/v TMC),and M5(1.8%w/v PIP and 0.2%w/v TEPA+0.15%w/v TMC)],were fabricated,exhibiting varied physical and chemical features,including different surface charges,roughness,and wettability.The M4 membrane was found to be the best-performing membrane for rejecting the majority of pharmaceutical pollutant drugs and having higher permeate flux compared to other membranes.The M4 membrane has an entirely different surface morphology of larger-sized PA globules observed in the scanning electron microscopy(SEM)analysis of the M4 membrane.In addition,the M4 membrane possessed a hydrophilic surface with a water contact angle of 24.5°,resulting in higher clean water permeability compared to other membranes.It was observed that the rejection of the pharmaceutical pollutant drugs was mainly governed by size exclusion,augmented by the Donnan effect,where the positively charged drugs were rejected almost entirely by the membranes.The M4 membrane rejected 66.9%of 4-hydroxyacetanilide,82.0% of sulfamethoxazole,96.9%of caffeine,and>99%of amitriptyline and ranolazine,where amitriptyline and ranolazine have positive charges.The presence of monovalent and divalent salts affected the rejection of the drugs,where the rejection of the drugs increased with increasing concentration of the salts.Moreover,the long-term stability tests revealed that the membranes exhibited stable rejection performance and a stable permeate flux,with only slight variations.The ultrahigh-performance liquid chromatography(UHPLC)analyses confirmed rejection of drugs from the water.This study demonstrated that variations in the chemistry of the PA active layer can yield promising membranes for removing organic pharmaceutical pollutants from saline water bodies,enabling safe reuse of treated water.展开更多
基金Supported by the National Natural Science Foundation of China （20676095）the Program of Introducing Talents of Discipline to Universities （B06006）
文摘Crosslinking treatments for a commercially available aromatic polyamide reverse osmosis membrane were carried out to improve its chlorine resistance.The crosslinking agents including 1,6-hexanediol diglycidyl ether,adipoyl dichloride and hexamethylene diisocyanate ester with long flexible aliphatic chains and high reactivity with N-H groups were used in the experiments.Attenuated total reflective Fourier transform infrared spectra verified the successful preparation of highly crosslinked membranes by crosslinking treatments.It was suggested that the crosslinking agents were connected to membrane surface through the reactions with amine and amide Ⅱ groups,which is confirmed by surface charge measurements.Based on contact angle measurements,crosslinking treatments decreased membrane hydrophilicity by introducing methylene groups to membrane surface.With increasing amount of crosslinking agent molecules connected to membrane surface,the hydrolysis of unconnected functional groups of crosslinking agent produced polar groups and increased membrane hydrophilicity.The highly crosslinked membranes showed higher salt rejections and lower water fluxes as compared with the raw membrane.Since the active sites(N-H groups) vulnerable to free chlorine on membrane surface were eliminated by crosslinking treatments,the chlorine resistances of the highly crosslinked membranes were significantly improved by slighter changes in both water fluxes and salt rejections after chlorination.
基金the Deanship of Scientific Research at Imam Mohammad Ibn Saud Islamic University(IMSIU)for funding and supporting this work through Research Partnership Program(No.RP-21-09-75)。
文摘Nanoscale thin-film composite(TFC)polyamide membranes are highly desirable for desalination owing to their excellent separation performance.It is a permanent pursuit to further improve the water flux of membrane without deteriorating the salt rejection.Herein,we fabricated a high-performance polyamide membrane with nanoscale structures through introducing multifunctional crown ether interlayer on the porous substrate impregnated with m-phenylenediamine.The crown ether interlayer can reduce the diffusion of amine monomers to reaction interface influenced by its interaction with m-phenylenediamine and the spatial shielding effect,leading to a controlled interfacial polymerization(IP)reaction.Besides,crown ether with intrinsic cavity is also favorable to adjust the IP process and the microstructure of polyamide layer.Since the outer surface of the nanocavity is lipophilic,crown ether has good solvency with the organic phase,thus attracting more trimesoyl chloride molecules to the interlayer and promoting the IP reaction in the confined space.As a result,a nanoscale polyamide membrane with an ultrathin selective layer of around 50 nm is obtained.The optimal TFC polyamide membrane at crown ether concentration of 0.25 wt.%exhibits a water flux of 61.2 L·m^(−2)·h^(−1),which is 364%of the pristine TFC membrane,while maintaining a rejection of above 97%to NaCl.The development of the tailor-made nanoscale polyamide membrane via constructing multifunctional crown ether interlayer provides a straightforward route to fabricate competitive membranes for highly efficient desalination.
文摘Membrane processes are used in the food and nutrient industry in terms of their proper performance and selective separation.Using the membranes in fruit juice concentrating operations improves its quality via shelf-life increases.The advantage of reverse osmosis(RO)and membrane technology over other methods is its nonchemical reaction to fruit juice which increases the concentration of fruit juice.The membranes were made of three layers of non-woven polyester layer for the mechanical strength of the membrane,polyester sulfone polymer with polyamide consisting of polymerization of M-Phenylenediamine(MPD)and benzene tricarbonyl chloride.Trimethyl chloride(TMC)was used to modify the properties of the membrane in the second layer using silica nanoparticles.The feed was sugar-free pomegranate juice added by SUNICH Company with an initial Brix value of 14.9%and an input feed of 6.6%to the RO system.The DESIGN-EXPERT method for the design of experiments(DOE)by considering three parameters of weight percentage of polyester sulfone polymer(12,16,and 20%),silica nanoparticles(0,0.1,and 0.2 wt%),and operating pressure were used(20,25,and 30 times).Under optimal conditions,46.15%of the concentrated pomegranate juice were obtained by experiment and the amount of brix increased from 33.24%to 47.21%.Scanning electron microscope(SEM),Fourier-transform infrared spectroscopy(FTIR),and contact angle tests for membranes were used.In the analysis of contact angle by examining the degree of hydrophilicity and contact angle of water droplets,it was found that the presence of silica nanoparticles and polyamide layer caused more hydrophilicity of membranes.It can be concluded that the pressure parameter,together with the presence of nanoparticles and polymer percentages,contribute to the most successful procedure of concentrating pomegranate juice.
基金the National Natural Science Foundation of China (Nos.52430001,52470091,52200108) for the financial support。
文摘Nanofiltration(NF) technology,with its capacity for nanoscale filtration and controllable selectivity,holds significant promise in diverse applications.However,the current upper bound of permeance and selectivity of NF membranes is intrinsically constrained by the morphology and structure of the polyamide(PA) selective layer.This issue arises because NF membranes typically exhibit relatively smooth nodular structures,which theoretically impede efficient water transport.In this study,we enhanced the formation of nanobubbles by synergistically regulating with surfactant and low temperatures,resulting in the fabrication of PA NF membranes with a crumpled morphology.We observed that lower temperatures promote enhanced gas solubility in the aqueous phase,facilitating increased nanobubble formation through the foaming effect of surfactant sodium dodecylbenzene sulfonate(SDBS).Consequently,this resulted in the creation of PA NF membranes with more crumpled structures and superior performance,with pure water permeance reaching 36.25 ± 0.42 L m^(-2)h^(-1)bar^(-1),representing an improvement of 14.47 L m^(-2)h^(-1)bar^(-1)compared to the control group.Additionally,it maintains a high Na_(2)SO_(4) rejection rate of97.00 % ± 0.58 %.The PA NF membranes produced by eliminating nanobubbles and free interfaces exhibited a smooth structure,whereas introducing nanobubbles(through Na HCO_(3) addition,N_(2) pressurization,and ultrasonication) resulted in the formation of crumpled membranes.This emphasized that the large amount of nanobubbles generated by SDBS and low temperature in the interfacial process played a critical role in shaping crumpled PA NF membranes and enhancing membrane performance.This approach has the potential to provide valuable insights into customizing the structural design of TFC PA NF membranes,contributing to further advancements in this field.
文摘The recent emergence of pollutants of concern in the water bodies is becoming a challenge for the water treatment community.In such a scenario,the deployment of the polyamide(PA)nanofiltration(NF)has proved to be a successful solution.Hence,the current study focused on applying a set of PA NF membranes for their potential to treat saline water containing organic pharmaceutical pollutants of emerging concern.The membranes have a varied active layer chemistry owing to the use of a set of aliphatic amines of varying chain lengths during interfacial polymerization(IP).Five membranes,ranging from M1 to M5[M1(2%w/v PIP+0.15%w/v TMC),M2(1.8%w/v PIP and 0.2%w/v EDA+0.15%w/v TMC),M3(1.8%w/v PIP and 0.2%w/v DETA+0.15%w/v TMC),M4(1.8%w/v PIP and 0.2%w/v BAEP+0.15%w/v TMC),and M5(1.8%w/v PIP and 0.2%w/v TEPA+0.15%w/v TMC)],were fabricated,exhibiting varied physical and chemical features,including different surface charges,roughness,and wettability.The M4 membrane was found to be the best-performing membrane for rejecting the majority of pharmaceutical pollutant drugs and having higher permeate flux compared to other membranes.The M4 membrane has an entirely different surface morphology of larger-sized PA globules observed in the scanning electron microscopy(SEM)analysis of the M4 membrane.In addition,the M4 membrane possessed a hydrophilic surface with a water contact angle of 24.5°,resulting in higher clean water permeability compared to other membranes.It was observed that the rejection of the pharmaceutical pollutant drugs was mainly governed by size exclusion,augmented by the Donnan effect,where the positively charged drugs were rejected almost entirely by the membranes.The M4 membrane rejected 66.9%of 4-hydroxyacetanilide,82.0% of sulfamethoxazole,96.9%of caffeine,and>99%of amitriptyline and ranolazine,where amitriptyline and ranolazine have positive charges.The presence of monovalent and divalent salts affected the rejection of the drugs,where the rejection of the drugs increased with increasing concentration of the salts.Moreover,the long-term stability tests revealed that the membranes exhibited stable rejection performance and a stable permeate flux,with only slight variations.The ultrahigh-performance liquid chromatography(UHPLC)analyses confirmed rejection of drugs from the water.This study demonstrated that variations in the chemistry of the PA active layer can yield promising membranes for removing organic pharmaceutical pollutants from saline water bodies,enabling safe reuse of treated water.
