Nanofiltration(NF)membranes with outstanding performance are highly demanded for more efficient desalination and wastewater treatment.However,improving water permeance while maintaining high solute rejection by using ...Nanofiltration(NF)membranes with outstanding performance are highly demanded for more efficient desalination and wastewater treatment.However,improving water permeance while maintaining high solute rejection by using the current membrane fabrication techniques remains a challenge.Herein,polyamide(PA)NF membrane with archbridge structure is successfully prepared via interfacial polymerization(IP)on a composite support membrane of saltreinforced hydrophilic bacterial cellulose nanofibers(BCNs)nanofilm/polytetrafluoroethylene(BCNs/PTFE).The strong hydration of BCNs promotes Marangoni convection along water/organic solvent interface during the IP process,which creates extra area for interfacial reaction and produces a thin PA active layer with arch-bridge structures.These arch-bridge structures endow the resulting PA active layer with substantial larger active area for water permeation.Consequently,the PA NF membrane exhibits exceptional desalination performance with a permeance up to 42.5 L m^-2h^-1bar^-1 and a rejection of Na2SO4as high as 99.1%,yielding an overall desalination performance better than almost all of the state-of-the-art NF membranes reported so far in terms of perm-selectivity.展开更多
Layered double hydroxides(LDHs)are a class of two-dimensional(2D)clay compounds that consist of positively charged host layers and exchangeable interlayer anions.The stability of their assemblies in aqueous environmen...Layered double hydroxides(LDHs)are a class of two-dimensional(2D)clay compounds that consist of positively charged host layers and exchangeable interlayer anions.The stability of their assemblies in aqueous environment is a challenge due to the extremely high hydrophilicity,which limits their use in membrane-based technologies.Here,we propose a graphene oxide(GO)armour protection strategy to substantially improve the stability of LDH membranes in aqueous solution.The sandwich structured GO/LDH/GO membranes(GLGMs)possess a negative-positive-negative charge heterojunction in the vertical direction that effectively blocks the transport of both cations and anions,i.e.,NaCl,but allows the permeation of water molecules.Following this mechanism,the GLGMs are used for desalination in a forward osmosis mode.A high rejection rate of over 95.2% for NaCl and water flux of over 2.1 Lm^(-2)h^(-1) are achieved with simulated seawater.展开更多
基金supported by the National Natural Science Funds for Distinguished Young Scholar(51625306)the Key Project of the National Natural Science Foundation of China(21433012)+2 种基金the National Natural Science Foundation of China(51603229,21406258)the State Key Laboratory of Separation Membranes and Membrane Processes(Tianjin Polytechnic University,No.M1-201801)Funding support from the CAS Pioneer Hundred Talents Program。
文摘Nanofiltration(NF)membranes with outstanding performance are highly demanded for more efficient desalination and wastewater treatment.However,improving water permeance while maintaining high solute rejection by using the current membrane fabrication techniques remains a challenge.Herein,polyamide(PA)NF membrane with archbridge structure is successfully prepared via interfacial polymerization(IP)on a composite support membrane of saltreinforced hydrophilic bacterial cellulose nanofibers(BCNs)nanofilm/polytetrafluoroethylene(BCNs/PTFE).The strong hydration of BCNs promotes Marangoni convection along water/organic solvent interface during the IP process,which creates extra area for interfacial reaction and produces a thin PA active layer with arch-bridge structures.These arch-bridge structures endow the resulting PA active layer with substantial larger active area for water permeation.Consequently,the PA NF membrane exhibits exceptional desalination performance with a permeance up to 42.5 L m^-2h^-1bar^-1 and a rejection of Na2SO4as high as 99.1%,yielding an overall desalination performance better than almost all of the state-of-the-art NF membranes reported so far in terms of perm-selectivity.
基金financially supported by the National Natural Science Foundation of China(21975268)China Postdoctoral Science Foundation(2019M660413)。
文摘Layered double hydroxides(LDHs)are a class of two-dimensional(2D)clay compounds that consist of positively charged host layers and exchangeable interlayer anions.The stability of their assemblies in aqueous environment is a challenge due to the extremely high hydrophilicity,which limits their use in membrane-based technologies.Here,we propose a graphene oxide(GO)armour protection strategy to substantially improve the stability of LDH membranes in aqueous solution.The sandwich structured GO/LDH/GO membranes(GLGMs)possess a negative-positive-negative charge heterojunction in the vertical direction that effectively blocks the transport of both cations and anions,i.e.,NaCl,but allows the permeation of water molecules.Following this mechanism,the GLGMs are used for desalination in a forward osmosis mode.A high rejection rate of over 95.2% for NaCl and water flux of over 2.1 Lm^(-2)h^(-1) are achieved with simulated seawater.
