For solving the dilemma of the short exothermic life-span of WO_(3)based metastable interstitial composites(MICs)with extensive application prospect,this paper has firstly designed the promising antiwetting Al/WO_(3)M...For solving the dilemma of the short exothermic life-span of WO_(3)based metastable interstitial composites(MICs)with extensive application prospect,this paper has firstly designed the promising antiwetting Al/WO_(3)MICs via electrophoresis assembly of nano-Al and WO_(3)particles fabricated by hydrothermal synthesis method,followed by the subsequent fluorination treatment.A combination of X ray diffraction(XRD),field emission scanning electron microscope(FESEM),energy dispersive X-ray spectroscopy(EDX),and Fourier transform infrared spectroscopy(FT-IR)techniques were utilized in order to characterize the crystal structure,microstructure,and elemental composition distribution of target films after different natural exposure tests.The product with uniform distribution and high purity possesses a high contact angle of~170°and a minute sliding angle of~1°,and displays the outstanding anti-wetting property using droplets with different surface tensions.It also shows great moisture stability in high relative-humidity circumstances after one year of the natural exposure experiment.Notably,the heat output of a fresh sample can reach up to 2.3 kJ/g and retain 96%after the whole exposure test,showing outstanding thermo-stability for at least one year.This work further proposed the mechanism of antiwetting Al/WO_(3)MICs considering the variation tendency of their DSC curve,providing a valuable theoretical reference for designing other self-protected MICs with a long exothermic life-span applied in wide fields of national defense,military industry,etc.展开更多
As an emerging thermal-driven membrane technology,membrane distillation(MD)has attracted immense attention for desalination and water purification.The membranes for MD generally have hydrophobic or superhydrophobic pr...As an emerging thermal-driven membrane technology,membrane distillation(MD)has attracted immense attention for desalination and water purification.The membranes for MD generally have hydrophobic or superhydrophobic properties to enable vapor permeation without liquid passage(e.g.,wetting).However,conventional MD membranes cannot undergo long term stable operations due to gradual wetting in practical applications where the feed solution often contains multiple low-surface tension contaminants(e.g.,oil).Recently,omniphobic membranes repelling all sorts of liquids and typically having ultralow surface energy and re-entrant structures have been developed for robust MD to mitigate wetting and fouling.In this paper,we aim to provide a comprehensive review of recent progress on omniphobic membranes.Fundamentals,desirable properties,advantages and applications of omniphobic membranes are discussed.We also summarize the research efforts and methods to engineer omniphobic membranes.Finally,the challenges and future research directions on omniphobic membranes are discussed.展开更多
Though membrane distillation(MD)has gained more and more attention in the field of desalination,the wetting phenomenon was still a non-negligible problem.In this work,a method combined dip-coating and UV in situ polym...Though membrane distillation(MD)has gained more and more attention in the field of desalination,the wetting phenomenon was still a non-negligible problem.In this work,a method combined dip-coating and UV in situ polymerization for preparing hydrophobic/hydrophilic perfluoropolyether(PFPE)/polyvinylidene fluoride composite membranes.This composite membrane consisted of a top thin hydrophobic coating layer and hydrophilic substrate membrane.In terms of anti-wetting properties,contact angle and liquid entry pressure of all composite membranes(except for those based on 0.45μm)exceeded 160°and 0.3 MPa,respectively.In particular,the desalination performance was tested in vacuum membrane distillation tests by feeding 3.5%(mass)saline solution(NaCl)at 60℃.The composite membranes with larger support pore size and lower PFPE content had higher membrane distillation flux.And for stability tests(testing the 0.22μm membrane coated by 5%(mass)PFPE),the highest MD flux29.08 kg·m^(-2)·h^(-1) and stable salt rejection(over 99.99%)during the period.Except that,the effects of coating material concentration and pore sizes of substrate membrane were also investigated for surface morphology and topography,porosity,mechanical strength and pore size characteristics.This work provided a simple and effective alternative to prepare excellent hydrophobic composite membranes for MD applications.展开更多
This paper conducts a comparative analysis of the anti-wetting properties and degassing performance of both homemade and commercial membranes.Additionally,it introduces a unique approach to hydrophobic modification of...This paper conducts a comparative analysis of the anti-wetting properties and degassing performance of both homemade and commercial membranes.Additionally,it introduces a unique approach to hydrophobic modification of high-flux membranes.The study involved the utilization of Hyflon AD40L for multiple coatings on the surface of polypropylene(PP)hollow fiber membranes.Several variables,including modification solution concentration,temperature,coating duration,number of coating cycles,polymer type,and the choice and concentration of the pore-blocking agent,were systematically investigated to establish the optimal modification process.Characterization of the modified membrane and degassing experiments revealed significant improvements.Specifically,the contact angle increased from 95.5°to 113.1°,while the trans-membrane differential pressure surged from 10.7 kPa to 154.6 kPa,marking a remarkable 14.4-fold enhancement.This enhancement is attributed to the improved antiwetting capabilities of the modified membrane.In the degassing experiments,the modified membrane-based module demonstrated an impressive 95.0%dissolved oxygen removal rate,with a corresponding mass transfer coefficient reaching 18.01×10^(-3)m·h^(-1).These results underscore the substantial potential of the Hyflon AD40 L/PP membrane for applications in membrane degassing.展开更多
Hydrophobic porous membrane is the key to the desalination performance of membrane distillation(MD).However,traditional MD membranes suffer from poor hydrophobicity of pore surfaces,leading to pore wetting and causing...Hydrophobic porous membrane is the key to the desalination performance of membrane distillation(MD).However,traditional MD membranes suffer from poor hydrophobicity of pore surfaces,leading to pore wetting and causing the loss of desalination stability.In this study,we present an ultrathin polyvinylidene fluoride(PVDF)nanocomposite membrane with robust anti-wetting properties and high permeability for stable MD desalination.The improved anti-wetting properties are achieved by enhancing the hydrophobicity of membrane pore surfaces via introducing hydrophobic silica nanoparticles to build nanostructures on the pore surfaces.The hydrophobic nanostructured pore surfaces induce the formation of the nano-Cassie state upon contact with water,thereby enhancing the specific liquid entry pressure of water(LEPw)with 788%compared to commercial PVDF membranes.The resulted porous structure and 10μm membrane thickness(i.e.,20 times thinner than commercial PVDF membranes)enable the stable desalination flux of 20.30 kg m−2 h−1 and high salt rejection of>99.9%with 60°C seawater.Our ultrathin nanocomposite membranes provide a promising solution for long-term MD seawater desalination.展开更多
基金funded by the financial support from National Natural Science Foundation of China(Grant No 21805014 and No82102635)Science and Technology Research Project of Chongqing Education Board(Grant No.KJQN201901428)。
文摘For solving the dilemma of the short exothermic life-span of WO_(3)based metastable interstitial composites(MICs)with extensive application prospect,this paper has firstly designed the promising antiwetting Al/WO_(3)MICs via electrophoresis assembly of nano-Al and WO_(3)particles fabricated by hydrothermal synthesis method,followed by the subsequent fluorination treatment.A combination of X ray diffraction(XRD),field emission scanning electron microscope(FESEM),energy dispersive X-ray spectroscopy(EDX),and Fourier transform infrared spectroscopy(FT-IR)techniques were utilized in order to characterize the crystal structure,microstructure,and elemental composition distribution of target films after different natural exposure tests.The product with uniform distribution and high purity possesses a high contact angle of~170°and a minute sliding angle of~1°,and displays the outstanding anti-wetting property using droplets with different surface tensions.It also shows great moisture stability in high relative-humidity circumstances after one year of the natural exposure experiment.Notably,the heat output of a fresh sample can reach up to 2.3 kJ/g and retain 96%after the whole exposure test,showing outstanding thermo-stability for at least one year.This work further proposed the mechanism of antiwetting Al/WO_(3)MICs considering the variation tendency of their DSC curve,providing a valuable theoretical reference for designing other self-protected MICs with a long exothermic life-span applied in wide fields of national defense,military industry,etc.
文摘As an emerging thermal-driven membrane technology,membrane distillation(MD)has attracted immense attention for desalination and water purification.The membranes for MD generally have hydrophobic or superhydrophobic properties to enable vapor permeation without liquid passage(e.g.,wetting).However,conventional MD membranes cannot undergo long term stable operations due to gradual wetting in practical applications where the feed solution often contains multiple low-surface tension contaminants(e.g.,oil).Recently,omniphobic membranes repelling all sorts of liquids and typically having ultralow surface energy and re-entrant structures have been developed for robust MD to mitigate wetting and fouling.In this paper,we aim to provide a comprehensive review of recent progress on omniphobic membranes.Fundamentals,desirable properties,advantages and applications of omniphobic membranes are discussed.We also summarize the research efforts and methods to engineer omniphobic membranes.Finally,the challenges and future research directions on omniphobic membranes are discussed.
基金financial support of the National Key Research&Development Program of China(2017YFC0403702)the National Natural Science Foundation of China(51861135203)+2 种基金the Jiangsu Provincial Department of Human Resources and Social Security(JNHB-036)the Materials-Oriented Chemical Engineering State Key Laboratory Program(KL19-04)Deputyship for Research and Innovation,Ministry of Education in Saudi Arabia for funding this research work through the project number(632)。
文摘Though membrane distillation(MD)has gained more and more attention in the field of desalination,the wetting phenomenon was still a non-negligible problem.In this work,a method combined dip-coating and UV in situ polymerization for preparing hydrophobic/hydrophilic perfluoropolyether(PFPE)/polyvinylidene fluoride composite membranes.This composite membrane consisted of a top thin hydrophobic coating layer and hydrophilic substrate membrane.In terms of anti-wetting properties,contact angle and liquid entry pressure of all composite membranes(except for those based on 0.45μm)exceeded 160°and 0.3 MPa,respectively.In particular,the desalination performance was tested in vacuum membrane distillation tests by feeding 3.5%(mass)saline solution(NaCl)at 60℃.The composite membranes with larger support pore size and lower PFPE content had higher membrane distillation flux.And for stability tests(testing the 0.22μm membrane coated by 5%(mass)PFPE),the highest MD flux29.08 kg·m^(-2)·h^(-1) and stable salt rejection(over 99.99%)during the period.Except that,the effects of coating material concentration and pore sizes of substrate membrane were also investigated for surface morphology and topography,porosity,mechanical strength and pore size characteristics.This work provided a simple and effective alternative to prepare excellent hydrophobic composite membranes for MD applications.
基金financial support of the National Key Research and Development Program of China(2020YFC0862903)the National Natural Science Foundation of China(22078146)+2 种基金the Key Research and Development program of Jiangsu Province(BE2021022)the Materials-Oriented Chemical Engineering State Key Laboratory Program(KL19-04)the Natural Science Foundation of Jiangsu Province(BK20200091).
文摘This paper conducts a comparative analysis of the anti-wetting properties and degassing performance of both homemade and commercial membranes.Additionally,it introduces a unique approach to hydrophobic modification of high-flux membranes.The study involved the utilization of Hyflon AD40L for multiple coatings on the surface of polypropylene(PP)hollow fiber membranes.Several variables,including modification solution concentration,temperature,coating duration,number of coating cycles,polymer type,and the choice and concentration of the pore-blocking agent,were systematically investigated to establish the optimal modification process.Characterization of the modified membrane and degassing experiments revealed significant improvements.Specifically,the contact angle increased from 95.5°to 113.1°,while the trans-membrane differential pressure surged from 10.7 kPa to 154.6 kPa,marking a remarkable 14.4-fold enhancement.This enhancement is attributed to the improved antiwetting capabilities of the modified membrane.In the degassing experiments,the modified membrane-based module demonstrated an impressive 95.0%dissolved oxygen removal rate,with a corresponding mass transfer coefficient reaching 18.01×10^(-3)m·h^(-1).These results underscore the substantial potential of the Hyflon AD40 L/PP membrane for applications in membrane degassing.
基金supported by Ministry of Science and Technology of the People's Republic of China(2021YFA0715700).
文摘Hydrophobic porous membrane is the key to the desalination performance of membrane distillation(MD).However,traditional MD membranes suffer from poor hydrophobicity of pore surfaces,leading to pore wetting and causing the loss of desalination stability.In this study,we present an ultrathin polyvinylidene fluoride(PVDF)nanocomposite membrane with robust anti-wetting properties and high permeability for stable MD desalination.The improved anti-wetting properties are achieved by enhancing the hydrophobicity of membrane pore surfaces via introducing hydrophobic silica nanoparticles to build nanostructures on the pore surfaces.The hydrophobic nanostructured pore surfaces induce the formation of the nano-Cassie state upon contact with water,thereby enhancing the specific liquid entry pressure of water(LEPw)with 788%compared to commercial PVDF membranes.The resulted porous structure and 10μm membrane thickness(i.e.,20 times thinner than commercial PVDF membranes)enable the stable desalination flux of 20.30 kg m−2 h−1 and high salt rejection of>99.9%with 60°C seawater.Our ultrathin nanocomposite membranes provide a promising solution for long-term MD seawater desalination.
