MIL-101(Cr)has a special pore cage structure that provides broad channels for the transport of water molecules in the reverse osmosis(RO)water separation and purification.Combining MIL-101(Cr)with Fe_(3)O_(4) nanopart...MIL-101(Cr)has a special pore cage structure that provides broad channels for the transport of water molecules in the reverse osmosis(RO)water separation and purification.Combining MIL-101(Cr)with Fe_(3)O_(4) nanoparticles forms a water transport intermediate layer between the polyamide separation membrane and the polysulfone support base under an external magnetic field.MiL-101(Cr)is stable in both water and air while resistant to high temperature.With the introduction of 0.003 wt.%MIL-101(Cr)/Fe_(3)O_(4),the water flux increased by 93.31%to 6.65 L·m^(-2)·h^(-1)·bar^(-1) without sacrificing the NaCl rejection of 95.88%.The MIL-101(Cr)/Fe_(3)O_(4) multilayer membrane also demonstrated certain anti-pollution properties and excellent stability in a 72-h test.Therefore,the construction of a MIL-101(Cr)/Fe_(3)O_(4) interlayer can effectively improve the permeability of RO composite membranes.展开更多
The impedance matching of absorbers is a vital factor affecting their microwave absorption(MA)properties.In this work,we controllably synthesized Material of Institute Lavoisier 88C(MIL-88C)with varying aspect ratios(...The impedance matching of absorbers is a vital factor affecting their microwave absorption(MA)properties.In this work,we controllably synthesized Material of Institute Lavoisier 88C(MIL-88C)with varying aspect ratios(AR)as a precursor by regulating oil bath conditions,followed by one-step thermal decomposition to obtain carbon-coated iron-based composites.Modifying the precursor MIL-88C(Fe)preparation conditions,such as the molar ratio between metal ions and organic ligands(M/O),oil bath temperature,and oil bath time,influenced the phases,graphitization degree,and AR of the derivatives,enabling low filler loading,achieving well-matched impedance,and ensuring outstanding MA properties.The MOF-derivatives 2(MD_(2))/polyvinylidene Difluoride(PVDF),MD_(3)/PVDF,and MD4/PVDF absorbers all exhibited excellent MA properties with optimal filler loadings below 20 wt%and as low as 5 wt%.The MD_(2)/PVDF(5 wt%)achieved a maximum effective absorption bandwidth(EAB)of 5.52 GHz(1.90 mm).The MD_(3)/PVDF(10 wt%)possessed a minimum reflection loss(RL_(min))value of−67.4 at 12.56 GHz(2.13 mm).A symmetric gradient honeycomb structure(SGHS)was constructed utilizing the high-frequency structure simulator(HFSS)to further extend the EAB,achieving an EAB of 14.6 GHz and a RL_(min) of−59.0 dB.This research offers a viable inspiration to creating structures or materials with high-efficiency MA properties.展开更多
Although widely used in permeation reaction barrier(PRB)for strengthening the removal of various heavy metals,zero-valent iron(ZVI)is limited by various inherent drawbacks,such as easy passivation and poor electron tr...Although widely used in permeation reaction barrier(PRB)for strengthening the removal of various heavy metals,zero-valent iron(ZVI)is limited by various inherent drawbacks,such as easy passivation and poor electron transfer.As a solution,a synergistic system with PRB and electrokinetics(PRB-EK)was established and applied for the efficient removal of Cr(Ⅵ)-contaminated groundwater.As the filling material of PRB,ZVI/Fe_(3)O_(4)/activated carbon(ZVI/Fe_(3)O_(4)/AC)composites were synthesized by ball milling and thermal treatment.A series of continuous flow column experiments and batch tests was conducted to evaluate the removal efficiency of Cr(Ⅵ).Results showed that the removal efficiency of Cr(Ⅵ)remained above 93%even when the bed volume(BV)reached 2000 under the operational parameters(iron/AC mass ratio,2:1;current,5 m A).The mechanism of Cr(Ⅵ)removal by the PRB-EK system was revealed through field emission scanning electron microscopy images,X-ray diffraction,X-ray photoelectron spectroscopy,Fe^(2+) concentration,and redox potential(E h)values.The key in Cr(Ⅵ)reduction was the Fe^(2+)/Fe^(3+) cycle driven by the surface microelectrolysis of the composites.The application of an externally supplied weak direct current maintained the redox process by enhancing the electron transfer capability of the system,thereby prolonging the column lifetime.Cr(Ⅵ)chemical speciation was determined through sequential extraction,verifying the stability and safety of the system.These findings provide a scientific basis for PRB design and the in-situ remediation of Cr(Ⅵ)-contaminated groundwater.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.22308183,21776147,21905153,61604086,22378221,and 52002198)the Natural Science Foundation of Shandong Province(Grant Nos.ZR2023QB070 and ZR2021YQ32)+4 种基金the Taishan Scholar Project of Shandong Province(Grant No.tsqn201909117)the Qingdao Science and Technology Benefit the People Demonstration and Guidance Special Project(Grant No.23-2-8-cspz-11-nsh)the Qingdao Natural Science Foundation(Grant No.23-2-1-241-zyyd-jch)the China Postdoctoral Science Foundation(Grant No.2023M731856)Prof.Lifeng Dong also thanks financial support from the Malmstrom Endowed Fund at Hamline University。
文摘MIL-101(Cr)has a special pore cage structure that provides broad channels for the transport of water molecules in the reverse osmosis(RO)water separation and purification.Combining MIL-101(Cr)with Fe_(3)O_(4) nanoparticles forms a water transport intermediate layer between the polyamide separation membrane and the polysulfone support base under an external magnetic field.MiL-101(Cr)is stable in both water and air while resistant to high temperature.With the introduction of 0.003 wt.%MIL-101(Cr)/Fe_(3)O_(4),the water flux increased by 93.31%to 6.65 L·m^(-2)·h^(-1)·bar^(-1) without sacrificing the NaCl rejection of 95.88%.The MIL-101(Cr)/Fe_(3)O_(4) multilayer membrane also demonstrated certain anti-pollution properties and excellent stability in a 72-h test.Therefore,the construction of a MIL-101(Cr)/Fe_(3)O_(4) interlayer can effectively improve the permeability of RO composite membranes.
基金financially supported by the National Natural Science Foundation of China(51972049,52073010,and 52373259)the Projects of the Science and Technology Department of Jilin Province(20230201132GX)the Projects of the Education Department of Jilin Province(JJKH20220123KJ)。
文摘The impedance matching of absorbers is a vital factor affecting their microwave absorption(MA)properties.In this work,we controllably synthesized Material of Institute Lavoisier 88C(MIL-88C)with varying aspect ratios(AR)as a precursor by regulating oil bath conditions,followed by one-step thermal decomposition to obtain carbon-coated iron-based composites.Modifying the precursor MIL-88C(Fe)preparation conditions,such as the molar ratio between metal ions and organic ligands(M/O),oil bath temperature,and oil bath time,influenced the phases,graphitization degree,and AR of the derivatives,enabling low filler loading,achieving well-matched impedance,and ensuring outstanding MA properties.The MOF-derivatives 2(MD_(2))/polyvinylidene Difluoride(PVDF),MD_(3)/PVDF,and MD4/PVDF absorbers all exhibited excellent MA properties with optimal filler loadings below 20 wt%and as low as 5 wt%.The MD_(2)/PVDF(5 wt%)achieved a maximum effective absorption bandwidth(EAB)of 5.52 GHz(1.90 mm).The MD_(3)/PVDF(10 wt%)possessed a minimum reflection loss(RL_(min))value of−67.4 at 12.56 GHz(2.13 mm).A symmetric gradient honeycomb structure(SGHS)was constructed utilizing the high-frequency structure simulator(HFSS)to further extend the EAB,achieving an EAB of 14.6 GHz and a RL_(min) of−59.0 dB.This research offers a viable inspiration to creating structures or materials with high-efficiency MA properties.
基金financial support from the National Natural Science Foundation of China(Nos.21906044 and 21477034)the Key Science and Technology Program of Henan Province,China(No.132102210129)+3 种基金the Basic Scientific and Technological Frontier Project of Henan Province(No.162300410046)the Innovation Scientists and Technicians Troop Construction Projects of Henan Province,the Scientific Research Foundation from Soochow University(No.Q416000117)the Technology Department of the Henan Science and Technology Fund Project(No.202102310603)the Cultivating National Scientific Research Project Funds,Henan Normal University(No.5101219170804)。
文摘Although widely used in permeation reaction barrier(PRB)for strengthening the removal of various heavy metals,zero-valent iron(ZVI)is limited by various inherent drawbacks,such as easy passivation and poor electron transfer.As a solution,a synergistic system with PRB and electrokinetics(PRB-EK)was established and applied for the efficient removal of Cr(Ⅵ)-contaminated groundwater.As the filling material of PRB,ZVI/Fe_(3)O_(4)/activated carbon(ZVI/Fe_(3)O_(4)/AC)composites were synthesized by ball milling and thermal treatment.A series of continuous flow column experiments and batch tests was conducted to evaluate the removal efficiency of Cr(Ⅵ).Results showed that the removal efficiency of Cr(Ⅵ)remained above 93%even when the bed volume(BV)reached 2000 under the operational parameters(iron/AC mass ratio,2:1;current,5 m A).The mechanism of Cr(Ⅵ)removal by the PRB-EK system was revealed through field emission scanning electron microscopy images,X-ray diffraction,X-ray photoelectron spectroscopy,Fe^(2+) concentration,and redox potential(E h)values.The key in Cr(Ⅵ)reduction was the Fe^(2+)/Fe^(3+) cycle driven by the surface microelectrolysis of the composites.The application of an externally supplied weak direct current maintained the redox process by enhancing the electron transfer capability of the system,thereby prolonging the column lifetime.Cr(Ⅵ)chemical speciation was determined through sequential extraction,verifying the stability and safety of the system.These findings provide a scientific basis for PRB design and the in-situ remediation of Cr(Ⅵ)-contaminated groundwater.
