In traditional in situ polymerization preparation for solid-state electrolytes,initiators are directly added to the liquid precursor.In this article,a novel cellulose paper-based composite separator is fabricated,whic...In traditional in situ polymerization preparation for solid-state electrolytes,initiators are directly added to the liquid precursor.In this article,a novel cellulose paper-based composite separator is fabricated,which employs alumina as the inorganic reinforcing material and is loaded with polymerization initiator aluminum trifluoromethanesulfonate.Based upon this,a separator-induced in situ directional polymerization technique is demonstrated,and the extra addition of initiators into liquid precursors is no longer required.The polymerization starts from the surface and interior of the separator and extends outward with the gradually dissolving of initiators into the precursor.Compared with its traditional counterpart,the separator-induced poly(1,3-dioxolane)electrolyte shows improved interfacial contact as well as appropriately mitigated polymerization rate,which are conducive to practical applications.Electrochemical measurement results show that the prepared poly(1,3-dioxolane)solid electrolyte possesses an oxidation potential up to 4.4 V and a high Li+transference number of 0.72.After 1000 cycles at 2 C rate(340 mA g^(−1)),the assembled Li||LiFePO_(4)solid battery possesses a 106.8 mAh g^(−1)discharge capacity retention and 83.5%capacity retention ratio,with high average Coulombic efficiency of 99.5%achieved.Our work may provide new ideas for the design and application of in situ polymerization technique for solid electrolytes and solid batteries.展开更多
Separators have been gaining increasing attention to improve the performance of lithium ion batteries(LIBs),especially for high safe and long cycle life.However,commercial polyolefin separators still face the problems...Separators have been gaining increasing attention to improve the performance of lithium ion batteries(LIBs),especially for high safe and long cycle life.However,commercial polyolefin separators still face the problems of rapid capacity decay and safety issues due to the poor wettability with electrolytes and low thermal stability.Herein,a novel composite separator is proposed by introducing a surfactant of sodium dodecyl thiosulfate(SDS)into the polytetrafluoroethylene(PTFE)substrate with the binder of polyacrylic acid(PAA)through the suction filtration method.The introduction of PAA/SDS enhances the adsorption energy between PTFE substrate and electrolyte through density functional theory calculations,which improves wettability and electrolyte uptake of the separator significantly.The asachieved composite separator enables the LIBs to own high Li^(+)conductivity(0.64×10^(-3)S cm^(-1))and Li^(+)transference number(0.63),further leading to a high capacity retention of 93.50%after 500 cycles at 1 C.In addition,the uniform and smooth surface morphology of Li metal employed the composite separator after cycling indicates that the lithium dendrites can be successfully inhibited.This work indicates a promising route for the preparation of a novel composite separator for high safe LIBs.展开更多
A composite separator of SiC/PVDF-HFP was synthesized for lithium-ion batteries with high thermal and mechanical stabilities.Benefiting from the nanoscale,high hardness,and melting point of SiC,SiC/PVDFHFP with highly...A composite separator of SiC/PVDF-HFP was synthesized for lithium-ion batteries with high thermal and mechanical stabilities.Benefiting from the nanoscale,high hardness,and melting point of SiC,SiC/PVDFHFP with highly uniform microstructure was obtained.This polarization caused by barrier penetration was significantly restrained.Due to the Si-F bond between SiC and PVDF-HFP,the structural stability has been obviously enhanced,which could suppress the growth of lithium(Li) dendrite.Furthermore,some 3D reticulated Si nanowires are found on the surface of Li anode,which also greatly inhibit Li dendrites and result in irregular flakes of Li metal.Especially,the shrinkage of 6% SiC/PVDF-HFP at 150℃ is only 5%,which is notably lower than those of PVDF-HFP and Celgard2500.The commercial LiFePO_(4) cell assembled with 6% SiC/PVDF-HFP possesses a specific capacity of 157.8 mA h g^(-1) and coulomb efficiency of 98% at 80℃.In addition,the tensile strength and modulus of 6% SiC/PVDF-HFP could reach 14.6 and 562 MPa,respectively.And a small deformation(1000 nm) and strong deformation recovery are obtained under a high additional load(2.3 mN).Compared with PVDF-HFP and Celgard2500,the symmetric Li cell assembled with 6% SiC/PVDF-HFP has not polarized after 900 cycles due to its excellent mechanical stabilities.This strategy provides a feasible solution for the composite separator of high-safety batteries with a high temperature and impact resistance.展开更多
Cadmium(Cd) contamination in soils is a global ecological threat. Conventional powdered biochar added to soil can temporarily immobilize Cd but is difficult to separate from soil, leading to secondary release of Cd an...Cadmium(Cd) contamination in soils is a global ecological threat. Conventional powdered biochar added to soil can temporarily immobilize Cd but is difficult to separate from soil, leading to secondary release of Cd and posing potential ecological and human health risks. The blocky biochar is also difficult to separate from the soil due to its fragile nature. One of the keys to overcome the difficulties in separating biochar from soil is to improve its mechanical strength. Blocky zeolite-biochar composites(ZBC) that have good mechanical strength were obtained after pyrolyzing the mixture of 50% feedstock and 50% zeolite powder at 400 ℃. ZBC and NaOH-activated ZBC(ZBC_a) were applied to remove Cd from soil. After sieving Cd-loaded ZBC and ZBC_a from soil, the bioavailable Cd content in the soil decreased by 59.70% and 68.54%,respectively. Zeolite contributed to improving both adsorption performance and mechanical properties of the composites. After repeating the process of “remediation-sieving-desorption-regeneration” three times, the recoveries of ZBC and ZBC_a were above 97.00%, and regeneration rates were 48.70-83.26%,respectively. Under simulated mechanical sieving conditions, ZBC and ZBC_a lost only 4.06% and 5.40%of their mass and retained their integrity. Remediation of Cd-contaminated soil with blocky zeolitebiochar composite is sustainable and safe because the removal of bioavailable Cd from soil is permanent rather than a temporary decrease of bioavailability. This study provides a reference for the preparation of separable and recyclable adsorbents for the removal of contaminants from soil.展开更多
Industrial production and domestic discharge produce a large amount of oily wastewater, which seriously affects the stability of the ecological environment. Membrane separation technology provides another path to trea...Industrial production and domestic discharge produce a large amount of oily wastewater, which seriously affects the stability of the ecological environment. Membrane separation technology provides another path to treating oily wastewater. And appropriate surface modification of the membrane helps to achieve high efficiency of treating oily wastewater. With green, economy and stability been more concerned.The focal research reports a completely biodegradable all cellulose composite filter paper(ACCFP) composed of Ⅰ-cellulose macrofibers and Ⅱ-cellulose matrix. It is a simple one-step impregnation method to adjust the surface microstructure of the pristine filter paper(PFP), and it does not involve with chemical reaction. The pre-wetted ACCFP consist of Ⅱ-cellulose hydrogel and Ⅰ-cellulose reinforcement in the process of oil-water separation. This layer of hydrogel is the fundamental to underwater superoleophobicity, which determines their eligibility for applications of efficient oil-water mixture or oil-in-water(oil/water) emulsion separation. The separation efficiency of oil-water mixture and oil/water emulsion exceed 95% and 99.9%, respectively. In addition, excellent mechanical properties of ACCFP in dry and wet conditions ensure its stability in service and prolong service life in applications. The focal study provides a new method for high-performance oil-water separation and it is more in line with sustainable chemistry.展开更多
In this work,a sponge-like polysulfonamide(PSA)/SiO_2 composite membrane is unprecedentedly prepared by the phase inversion method,and successfully demonstrated as a novel separator of lithium-ion batteries(LIBs).Comp...In this work,a sponge-like polysulfonamide(PSA)/SiO_2 composite membrane is unprecedentedly prepared by the phase inversion method,and successfully demonstrated as a novel separator of lithium-ion batteries(LIBs).Compared to the commercial polypropylene(PP) separator,the sponge-like PSA/SiO_2 composite possesses better physical and electrochemical properties,such as higher porosity,ionic conductivity,thermal stability and flame retarding ability.The LiCoO_2/Li half-cells using the sponge-like composite separator demonstrate superior rate capability and cyclability over those using the commercial PP separator.Moreover,the sponge-like composite separator can ensure the normal operation of LiCoO_2/Li half-cell at an extremely high temperature of 90 °C,while the commercial PP separator cannot.All these encouraging results suggest that this phase inversion based sponge-like PSA/SiO_2 composite separator is really a promising separator for high performance LIBs.展开更多
The development of multilayer composite membranes for CO_2 separation has gained increasing attention due to the desire for energy efficient technologies. Multilayer composite membranes have many advantages, including...The development of multilayer composite membranes for CO_2 separation has gained increasing attention due to the desire for energy efficient technologies. Multilayer composite membranes have many advantages, including the possibility to optimize membrane materials independently by layers according to their different functions and to reduce the overall transport resistance by using ultrathin selective layers, and less limitations on the material mechanical properties and processability. A comprehensive review is required to capture details of the progresses that have already been achieved in developing multilayer composite membranes with improved CO_2 separation performance in the past 15-20 years.In this review, various composite membrane preparation methods were compared, advances in composite membranes for CO_2/CH_4 separation,CO_2/N_2 and CO_2/H_2 separation were summarized with detailed data, and challenges facing for the CO_2 separation using composite membranes,such as aging, plasticization and long-term stability, were discussed. Finally the perspectives and future research directions for composite membranes were presented.展开更多
The development of defect-free composite membrane(CM) is often challenging due to poor dispersion and distribution of filler particles in the polymer matrix. Despite the attractive physicochemical properties and gas s...The development of defect-free composite membrane(CM) is often challenging due to poor dispersion and distribution of filler particles in the polymer matrix. Despite the attractive physicochemical properties and gas separation performance of carbon nanotube(CNT) based CM, CNT displayed poor dispersion characteristics in most polymer matrix domain. Instead of incorporating CNT, a viable alternative, carbon nanofiber(CNF) which exhibits similar properties as CNT, but improved dispersion quality in the polymer matrix is found. In this work,CNF particles were incorporated in poly(2,6-dimethyl-1,4-phenylene oxide)(PPOdm) polymer continuous phase for CM development. The optimum gas separation performance of the PPOdm-CNF CM(11.25 at 197.02 barrer of CO_2 permeability) was obtained at 3 wt% of CNF loading. Compared to pristine PPOdmmembrane,CO_2 permeability and CO_2/CH_4 selectivity of PPOdm-3 wt% CNF CM were enhanced by 180% and 55%, respectively.At 3 wt% CNF loading, the filler particles were dispersed and distributed more homogenously, in which no obvious CNF agglomeration was observed. In addition, the incorporation of CNF particles also enhanced the mechanical and thermal properties of the resultant CM.展开更多
This study deals with polydimethylsiloxane(PDMS)/polyvinylidene fluoride(PVDF) composite membranes for propane separation from propane/nitrogen mixtures,which is relevant to the recovery of propane in petroleum and ch...This study deals with polydimethylsiloxane(PDMS)/polyvinylidene fluoride(PVDF) composite membranes for propane separation from propane/nitrogen mixtures,which is relevant to the recovery of propane in petroleum and chemical industry.The surface and cross-section morphology of PDMS/PVDF composite membranes was observed by scanning electron microscope(SEM).The surface morphology of PDMS/PVDF composite membranes is very dense.There are three layers,the thin dense top layer,finger-like porous middle layer and s...展开更多
The reverse osmosis (RO) separation of aqueous organic solutions, such as alcohols, amines, aldehydes, acids, ketones, and esters etc., by PAA (polyacrylic acid)/PSF (polysulfone) composite membrane has been studied. ...The reverse osmosis (RO) separation of aqueous organic solutions, such as alcohols, amines, aldehydes, acids, ketones, and esters etc., by PAA (polyacrylic acid)/PSF (polysulfone) composite membrane has been studied. It was found that the separation results for aliphatic alcohols, amines and aldehydes are satisfactory, the solute rejection (R-a) and the volume fluxes of solutions (J(V)) for 1000 ppm ethanol, ethylamine and ethyl aldehyde are 66.2%, 61.0%, 84.0% and 0.90 x 10(-6), 0.35 x 10(-6), 0.40 X 10(-6) m(3)/m(2) . s, respectively, at 5.0 MPa and 30 degrees C. R-a increased with increasing molecular weights of alcohols, amines and aldehydes, and the R-a for n-amyl alcohol, n-butylamine and n-butyl aldehyde reached 94.3%, 88.6% and 96.0%, respectively. Satisfactory separation results (R-a > 70%) for ketones, esters, phenols and polyols have been obtained with the PAA/PSF composite membrane. The effect of operating pressure on the properties of reverse osmosis has also been investigated. Analysis of experimental data with Spiegler-Kedem's transport model has been carried out and the membrane constants such as reflection coefficient sigma, solute and hydraulic permeabilities omega and L-p for several organic solutes have been obtained.展开更多
A global-local finite element modeling technique is employed in this paper to predict the separation in steel cord-rubber composite materials of radial truck tires. The local model uses a finite element analysis in co...A global-local finite element modeling technique is employed in this paper to predict the separation in steel cord-rubber composite materials of radial truck tires. The local model uses a finite element analysis in conjunction with a glob-al-local technique in ABAQUS. A 3-dimensional finite element local model calculates the maximum cyclic shear strain of an interface between steel cord and rubber materials at the carcass ply shoulder region. It is found that the maximum cyclic shear strain is reliable as a result of the analysis of carcass ply separation in radial truck tires. Using the analysis of the local model, a study of the cyclic shear strain is performed in the shoulder region and used to deter-mine the carcass ply separation. The effect of the change of carcass ply design on the separation in steel cord-rubber composite materials of radial truck tires is discussed.展开更多
Fouling-resistant ceramic-supported polymer composite membranes were developed for removal of oil-in-water (O/W) microemulsions. The composite membranes were featured with an asymmetric three-layer structure, i.e., a ...Fouling-resistant ceramic-supported polymer composite membranes were developed for removal of oil-in-water (O/W) microemulsions. The composite membranes were featured with an asymmetric three-layer structure, i.e., a porous ceramic membrane substrate, a polyvinylidene fluoride (PVDF) ultrafiltration sub-layer, and a polyam-ide/polyvinyl alcohol (PVA) composite thin top-layer. The PVDF polymer was cast onto the tubular porous ceramic membranes with an immersion precipitation method, and the polyamide/PVA composite thin top-layer was fabricated with an interfacial polymerization method. The effects of the sub-layer composition and the recipe in the interfacial po-lymerization for fabricating the top-layer on the structure and performance of composite membranes were systematically investigated. The prepared composite membranes showed a good performance for treating the O/W microemulsions with a mean diameter of about 2.4μm. At the operating pressure of 0.4MPa, the hydraulic permeability remained steadily about 190L?m-2?h-1, the oil concentration in the permeate was less than 1.6mg·L-1, and the oil rejection coefficient was always higher than 98.5% throughout the operation from the beginning.展开更多
Carbon dioxide(CO_2) is greenhouse gas which originates primarily as a main combustion product of biogas and landfill gas. To separate this gas, an inside coated thin film composite(TFC) hollow fiber membrane was deve...Carbon dioxide(CO_2) is greenhouse gas which originates primarily as a main combustion product of biogas and landfill gas. To separate this gas, an inside coated thin film composite(TFC) hollow fiber membrane was developed by interfacial polymerization between 1,3–cyclohexanebis–methylamine(CHMA) and trimesoyl chloride(TMC). ATR-FTIR, SEM and AFM were used to characterize the active thin layer formed inside the PSf hollow fiber. The separation behavior of the CHMA-TMC/PSf membrane was scrutinized by studying various effects like feed gas pressure and temperature. Furthermore, the influence of CHMA concentration and TMC concentration on membrane morphology and performance were investigated. As a result, it was found that mutually the CHMA concentration and TMC concentration play key roles in determining membrane morphology and performance. Moreover, the CHMA-TMC/PSf composite membrane showed good CO_2/CH_4 separation performance. For CO_2/CH_4 mixture gas(30/70 by volume) test, the membrane(PD1 prepared by CHMA 1.0% and TMC 0.5%) showed a CO_2 permeance of 25 GPU and the best CO_2/CH_4 selectivity of 28 at stage cut of 0.1. The high CO_2/CH_4 separation performance of CHMA-TMC/PSf thin film composite membrane was mostly accredited to the thin film thickness and the properties of binary amino groups.展开更多
Poly (N,N-dimethylaminoethyl methacrylate)-poly (ethylene glycol methyl ether methacrylate) (PDMAEMA-PEGMEMA) and cesium fluoride (CsF) were blended and used as the separation material of composite membranes.H...Poly (N,N-dimethylaminoethyl methacrylate)-poly (ethylene glycol methyl ether methacrylate) (PDMAEMA-PEGMEMA) and cesium fluoride (CsF) were blended and used as the separation material of composite membranes.Hollow fiber composite membranes were fabricated by coating the blend on polysulfone (PSf) hollow fiber substrate.Introduction of fluorine ion improved the separation performance of the membrane.The concentration of coating solution was adjusted to obtain a membrane with high permeance.The composite membrane showed good performance with the CO2 permeance of 30.4 GPU (1 GPU=10-6 cm3 (STP)/(cm 2 s cmHg)),and selectivities to CO2/N2,CO2/CH4,CO2/H2 and O2/N2 of 47.2,37.6,1.75 and 4.70,respectively.Potassium fluoride (KF),due to its low cost,was also used as a substitute of CsF to prepare composite membrane and the permeation data showed that CsF can be replaced by KF.The effect of operating temperature on the permeation properties of the composite membrane was also investigated.展开更多
Microporous polyvinylidene fluoride(PVDF)hollow fibre membranes were spun using the dry-wet phaseinversion method.By means of dip-coating technique,a uniform coating with thickness of around 5-12 μm of polyvinyldimet...Microporous polyvinylidene fluoride(PVDF)hollow fibre membranes were spun using the dry-wet phaseinversion method.By means of dip-coating technique,a uniform coating with thickness of around 5-12 μm of polyvinyldimethylsiloxane(PVDMS)was formed on the surface of porous PVDF hollow fibers.The structural parameters of PVDFsubstrate membrane were estimated by gas permeation test.Using N_2/O_2 as the medium,the separation properties ofPVDMS-PVDF composite hollow fiber membranes were also evaluated experimentally.The experimental data of bothpermeability and selectivity are in good agreement with the theoretical results predicted by the presented pore-distributionmodel.In order to obtain the compact composite membrane free of defects by the dip-coating technique,the thickness ofPVDMS skin must be higher than 5 μm.展开更多
MoS2/γ-Al2O3 ceramic composite membrane is successfully synthesized by the sol-gel method based on the inorganic salt route. The aluminum hydrate sol derived from the inorganic salt Al(NO3)3, whose transparence and ...MoS2/γ-Al2O3 ceramic composite membrane is successfully synthesized by the sol-gel method based on the inorganic salt route. The aluminum hydrate sol derived from the inorganic salt Al(NO3)3, whose transparence and viscosity are 97% and 1.2 × 10-3 Pa. s, respectively, can be formed through adjusting the ratio of the peptizing agent H+ to Al3+ to 0.3. The aluminum hydrate gel at 110℃ is amorphous in structure and is heat-treated in air at 800℃ to form γ-Al2O3. The precursor derived from the mixture solution of ammonium molybdate, thioacetamide and a reducing agent, can be transformed into crystal MoS2 under reducing condition at 800℃. MoS2/γ-Al2O3 composite membrane is an organic whole and bps no gradation from MoS2 layer to γ-Al2O3 Iayer. The separation factor a H2/H2S through the MoS2/γ-Al2O3 composite membrane increase with rising temperature and a H2/H2S at 600℃ is 4.45 higher than the theoretical separation factor produced by the ideal Knudsen diffusion.展开更多
It was tried to prepare the biodegradable composite particles by the phase separation method followed by the drying-in-liquid method. The composite particles were made of poly-ε-caprolac-tone, quaternary ammonium, ca...It was tried to prepare the biodegradable composite particles by the phase separation method followed by the drying-in-liquid method. The composite particles were made of poly-ε-caprolac-tone, quaternary ammonium, carbon black and wax. In the experiment, acetone and water were selected as a good solvent and a poor solvent for poly-ε-caprolactone, quaternary ammonium and wax, respectively. The composite particles were prepared by changing the surfactant species and their concentration, the feeding velocity of water and the weight ratio of poly-ε-caprolactone with larger molecular weight to one with smaller molecular weight. The composite particles with the inner structure in which carbon black, quaternary ammonium and wax were coated well with poly-ε-caprolactone could be prepared by the preparation method presented in this study. The structure and the mean diameter of composite particles were strongly affected by the feeding velocity of water. The higher the feeding velocity of water, the larger the mean diameter of composite particles. The mean diameter was drastically decreased with the surfactant concentration and increased with the added amount of poly-ε-caprolactant with larger molecular weight.展开更多
The novel method for preparing the polymer composite particles has been developed. It was tried to prepare polymer composite particles composed of polystyrene and carbon black with the phase separation method followed...The novel method for preparing the polymer composite particles has been developed. It was tried to prepare polymer composite particles composed of polystyrene and carbon black with the phase separation method followed by suspension polymerization. In order to prepare the polymer composite particles with the more uniform diameter, the styrene monomer droplets containing carbon black were formed with phase separation emulsification in which ethyl alcohol and water were used as the good solvent and the poor solvent for styrene monomer, respectively. In the experiment, the surfactant species and their concentrations, the pouring velocity of water and the weight ratio of carbon black to styrene monomer were mainly changed. Water was poured at the given pouring velocity into ethyl alcohol in which styrene monomer and an initiator were dissolved and carbon black was dispersed beforehand. The spherical polymer composite particles containing carbon black were prepared with Tween 20 and Tween 80 of nonionic surfactants and the irregular polymer composite particles were prepared with PVA, SDS and Kotamine. The diameters of polymer composite particles increased with the pouring velocity of water and with the weight ratio of carbon black to styrene monomer.展开更多
To separate salts of metals and non-electrolytes, the approach of dialysis through the composite membranes (CMs) is proposed. CM is a combination of cation and anion exchange areas. In the composite membrane, cations ...To separate salts of metals and non-electrolytes, the approach of dialysis through the composite membranes (CMs) is proposed. CM is a combination of cation and anion exchange areas. In the composite membrane, cations and anions are transferred through the respective exchange areas simultaneously without violation of macroscopic electro-neutrality. This provides a better transfer of salts than conventional ion exchange membranes (IEMs). The dialysis of the ethylene glycol aqueous salt solutions through the CMs was investigated. We have shown that the transport of salts through the composite membranes is more intensive (unlike IEM providing no transfer of salts from weakly mineralized aqueous solutions due to the Donnan exclusion) and the ethylene glycol transfer is not very significant, that is the basis of effective separation. The possibility to use of composite membranes for metal salt and other electrolyte separation is discussed.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.52072105,21676067)the Key R&D Program of Anhui Province(202104a05020044)+2 种基金the Anhui Provincial Natural Science Foundation(2108085J23)Science and Technology Major Project of Anhui Province(202003a05020014)the Fundamental Research Funds for the Central Universities(PA2021KCPY0028,JZ2020YYPY0109).
文摘In traditional in situ polymerization preparation for solid-state electrolytes,initiators are directly added to the liquid precursor.In this article,a novel cellulose paper-based composite separator is fabricated,which employs alumina as the inorganic reinforcing material and is loaded with polymerization initiator aluminum trifluoromethanesulfonate.Based upon this,a separator-induced in situ directional polymerization technique is demonstrated,and the extra addition of initiators into liquid precursors is no longer required.The polymerization starts from the surface and interior of the separator and extends outward with the gradually dissolving of initiators into the precursor.Compared with its traditional counterpart,the separator-induced poly(1,3-dioxolane)electrolyte shows improved interfacial contact as well as appropriately mitigated polymerization rate,which are conducive to practical applications.Electrochemical measurement results show that the prepared poly(1,3-dioxolane)solid electrolyte possesses an oxidation potential up to 4.4 V and a high Li+transference number of 0.72.After 1000 cycles at 2 C rate(340 mA g^(−1)),the assembled Li||LiFePO_(4)solid battery possesses a 106.8 mAh g^(−1)discharge capacity retention and 83.5%capacity retention ratio,with high average Coulombic efficiency of 99.5%achieved.Our work may provide new ideas for the design and application of in situ polymerization technique for solid electrolytes and solid batteries.
基金supported by the Science Foundation of the National Key Laboratory of Science and Technology on Advanced Composites in Special Environmentsthe National Natural Science Foundation of China(12002109)+1 种基金the China Postdoctoral Science Foundation(2020M670898)the Heilongjiang Postdoctoral Fund(LBH-Z20060)。
文摘Separators have been gaining increasing attention to improve the performance of lithium ion batteries(LIBs),especially for high safe and long cycle life.However,commercial polyolefin separators still face the problems of rapid capacity decay and safety issues due to the poor wettability with electrolytes and low thermal stability.Herein,a novel composite separator is proposed by introducing a surfactant of sodium dodecyl thiosulfate(SDS)into the polytetrafluoroethylene(PTFE)substrate with the binder of polyacrylic acid(PAA)through the suction filtration method.The introduction of PAA/SDS enhances the adsorption energy between PTFE substrate and electrolyte through density functional theory calculations,which improves wettability and electrolyte uptake of the separator significantly.The asachieved composite separator enables the LIBs to own high Li^(+)conductivity(0.64×10^(-3)S cm^(-1))and Li^(+)transference number(0.63),further leading to a high capacity retention of 93.50%after 500 cycles at 1 C.In addition,the uniform and smooth surface morphology of Li metal employed the composite separator after cycling indicates that the lithium dendrites can be successfully inhibited.This work indicates a promising route for the preparation of a novel composite separator for high safe LIBs.
基金supported by the Natural Science Foundation of Science and Technology Department of Sichuan Province, China (23NSFSC6224)the Higher Education Talent Training Quality and Teaching Reform Project of Sichuan Province, China (JG2021-1098)+3 种基金the Industry-university cooperation collaborative education project of the Ministry of Education, China (221001359095358 and 220604738021813)the Development Research Center of Sichuan Cuisine (CC21Z02)the “Sichuang Fusion” Youth Red Dream Building Project of Chengdu University,China (cxcysc2022001)the Solid-state Fermentation Resource Utilization Key Laboratory of Sichuan Province (2020GTJ002)。
文摘A composite separator of SiC/PVDF-HFP was synthesized for lithium-ion batteries with high thermal and mechanical stabilities.Benefiting from the nanoscale,high hardness,and melting point of SiC,SiC/PVDFHFP with highly uniform microstructure was obtained.This polarization caused by barrier penetration was significantly restrained.Due to the Si-F bond between SiC and PVDF-HFP,the structural stability has been obviously enhanced,which could suppress the growth of lithium(Li) dendrite.Furthermore,some 3D reticulated Si nanowires are found on the surface of Li anode,which also greatly inhibit Li dendrites and result in irregular flakes of Li metal.Especially,the shrinkage of 6% SiC/PVDF-HFP at 150℃ is only 5%,which is notably lower than those of PVDF-HFP and Celgard2500.The commercial LiFePO_(4) cell assembled with 6% SiC/PVDF-HFP possesses a specific capacity of 157.8 mA h g^(-1) and coulomb efficiency of 98% at 80℃.In addition,the tensile strength and modulus of 6% SiC/PVDF-HFP could reach 14.6 and 562 MPa,respectively.And a small deformation(1000 nm) and strong deformation recovery are obtained under a high additional load(2.3 mN).Compared with PVDF-HFP and Celgard2500,the symmetric Li cell assembled with 6% SiC/PVDF-HFP has not polarized after 900 cycles due to its excellent mechanical stabilities.This strategy provides a feasible solution for the composite separator of high-safety batteries with a high temperature and impact resistance.
基金supported by the National Key Research and Development Program of China, China (2019YFC1904102)。
文摘Cadmium(Cd) contamination in soils is a global ecological threat. Conventional powdered biochar added to soil can temporarily immobilize Cd but is difficult to separate from soil, leading to secondary release of Cd and posing potential ecological and human health risks. The blocky biochar is also difficult to separate from the soil due to its fragile nature. One of the keys to overcome the difficulties in separating biochar from soil is to improve its mechanical strength. Blocky zeolite-biochar composites(ZBC) that have good mechanical strength were obtained after pyrolyzing the mixture of 50% feedstock and 50% zeolite powder at 400 ℃. ZBC and NaOH-activated ZBC(ZBC_a) were applied to remove Cd from soil. After sieving Cd-loaded ZBC and ZBC_a from soil, the bioavailable Cd content in the soil decreased by 59.70% and 68.54%,respectively. Zeolite contributed to improving both adsorption performance and mechanical properties of the composites. After repeating the process of “remediation-sieving-desorption-regeneration” three times, the recoveries of ZBC and ZBC_a were above 97.00%, and regeneration rates were 48.70-83.26%,respectively. Under simulated mechanical sieving conditions, ZBC and ZBC_a lost only 4.06% and 5.40%of their mass and retained their integrity. Remediation of Cd-contaminated soil with blocky zeolitebiochar composite is sustainable and safe because the removal of bioavailable Cd from soil is permanent rather than a temporary decrease of bioavailability. This study provides a reference for the preparation of separable and recyclable adsorbents for the removal of contaminants from soil.
基金the financial support from the National Key R&D Program of China (no. 2018YFB1501602)Science Foundation of Shanxi Province, China (Grant no. 201901D111006ZD)+1 种基金Fund for Shanxi “1331 project”Shanxi Province Platform Base and Talent Special Fund (no. 201705D211023)。
文摘Industrial production and domestic discharge produce a large amount of oily wastewater, which seriously affects the stability of the ecological environment. Membrane separation technology provides another path to treating oily wastewater. And appropriate surface modification of the membrane helps to achieve high efficiency of treating oily wastewater. With green, economy and stability been more concerned.The focal research reports a completely biodegradable all cellulose composite filter paper(ACCFP) composed of Ⅰ-cellulose macrofibers and Ⅱ-cellulose matrix. It is a simple one-step impregnation method to adjust the surface microstructure of the pristine filter paper(PFP), and it does not involve with chemical reaction. The pre-wetted ACCFP consist of Ⅱ-cellulose hydrogel and Ⅰ-cellulose reinforcement in the process of oil-water separation. This layer of hydrogel is the fundamental to underwater superoleophobicity, which determines their eligibility for applications of efficient oil-water mixture or oil-in-water(oil/water) emulsion separation. The separation efficiency of oil-water mixture and oil/water emulsion exceed 95% and 99.9%, respectively. In addition, excellent mechanical properties of ACCFP in dry and wet conditions ensure its stability in service and prolong service life in applications. The focal study provides a new method for high-performance oil-water separation and it is more in line with sustainable chemistry.
基金Supported by the funding from "135" Projects Fund of CAS-QIBEBT Director Innovation FoundationThink-Tank Mutual Fund of Qingdao Energy Storage Industry Scientific Research+3 种基金Qingdao Key Lab of Solar Energy Utilization and Energy Storage Technologythe Strategic Priority Research Program of the Chinese Academy of Sciences(XDA09010105)National Natural Science Foundation of China(51502319)Shandong Provincial Natural Science Foundation(ZR2016BQ18)
文摘In this work,a sponge-like polysulfonamide(PSA)/SiO_2 composite membrane is unprecedentedly prepared by the phase inversion method,and successfully demonstrated as a novel separator of lithium-ion batteries(LIBs).Compared to the commercial polypropylene(PP) separator,the sponge-like PSA/SiO_2 composite possesses better physical and electrochemical properties,such as higher porosity,ionic conductivity,thermal stability and flame retarding ability.The LiCoO_2/Li half-cells using the sponge-like composite separator demonstrate superior rate capability and cyclability over those using the commercial PP separator.Moreover,the sponge-like composite separator can ensure the normal operation of LiCoO_2/Li half-cell at an extremely high temperature of 90 °C,while the commercial PP separator cannot.All these encouraging results suggest that this phase inversion based sponge-like PSA/SiO_2 composite separator is really a promising separator for high performance LIBs.
基金supported by the Research Council of Norway through the CLIMIT program(MCIL-CO_2 project,215732)the European Union Seventh Framework Programme(FP7/2007-2013)in HiPerCap project under grant agreement n°608555
文摘The development of multilayer composite membranes for CO_2 separation has gained increasing attention due to the desire for energy efficient technologies. Multilayer composite membranes have many advantages, including the possibility to optimize membrane materials independently by layers according to their different functions and to reduce the overall transport resistance by using ultrathin selective layers, and less limitations on the material mechanical properties and processability. A comprehensive review is required to capture details of the progresses that have already been achieved in developing multilayer composite membranes with improved CO_2 separation performance in the past 15-20 years.In this review, various composite membrane preparation methods were compared, advances in composite membranes for CO_2/CH_4 separation,CO_2/N_2 and CO_2/H_2 separation were summarized with detailed data, and challenges facing for the CO_2 separation using composite membranes,such as aging, plasticization and long-term stability, were discussed. Finally the perspectives and future research directions for composite membranes were presented.
基金Yayasan Universiti Teknologi PETRONAS (YUTP-FRG grant 0153AA-E08)CO_2 Research Centre (CO_2RES) for supporting this work
文摘The development of defect-free composite membrane(CM) is often challenging due to poor dispersion and distribution of filler particles in the polymer matrix. Despite the attractive physicochemical properties and gas separation performance of carbon nanotube(CNT) based CM, CNT displayed poor dispersion characteristics in most polymer matrix domain. Instead of incorporating CNT, a viable alternative, carbon nanofiber(CNF) which exhibits similar properties as CNT, but improved dispersion quality in the polymer matrix is found. In this work,CNF particles were incorporated in poly(2,6-dimethyl-1,4-phenylene oxide)(PPOdm) polymer continuous phase for CM development. The optimum gas separation performance of the PPOdm-CNF CM(11.25 at 197.02 barrer of CO_2 permeability) was obtained at 3 wt% of CNF loading. Compared to pristine PPOdmmembrane,CO_2 permeability and CO_2/CH_4 selectivity of PPOdm-3 wt% CNF CM were enhanced by 180% and 55%, respectively.At 3 wt% CNF loading, the filler particles were dispersed and distributed more homogenously, in which no obvious CNF agglomeration was observed. In addition, the incorporation of CNF particles also enhanced the mechanical and thermal properties of the resultant CM.
基金supported by the China Postdoctoral Science Foundation(No20060400436)the Major State Basic Research Program of China(No2009CB623404)+3 种基金National Natural Science Foundation of China(Nos20736003,20676067)National High Technology Research and Development Program of China(No2007AA06Z317)Foundation of Ministry of Education of China(No20070003130) Foundation of the State Key Laboratory of Chemical Engineering(SKL-ChE-08A01)
文摘This study deals with polydimethylsiloxane(PDMS)/polyvinylidene fluoride(PVDF) composite membranes for propane separation from propane/nitrogen mixtures,which is relevant to the recovery of propane in petroleum and chemical industry.The surface and cross-section morphology of PDMS/PVDF composite membranes was observed by scanning electron microscope(SEM).The surface morphology of PDMS/PVDF composite membranes is very dense.There are three layers,the thin dense top layer,finger-like porous middle layer and s...
文摘The reverse osmosis (RO) separation of aqueous organic solutions, such as alcohols, amines, aldehydes, acids, ketones, and esters etc., by PAA (polyacrylic acid)/PSF (polysulfone) composite membrane has been studied. It was found that the separation results for aliphatic alcohols, amines and aldehydes are satisfactory, the solute rejection (R-a) and the volume fluxes of solutions (J(V)) for 1000 ppm ethanol, ethylamine and ethyl aldehyde are 66.2%, 61.0%, 84.0% and 0.90 x 10(-6), 0.35 x 10(-6), 0.40 X 10(-6) m(3)/m(2) . s, respectively, at 5.0 MPa and 30 degrees C. R-a increased with increasing molecular weights of alcohols, amines and aldehydes, and the R-a for n-amyl alcohol, n-butylamine and n-butyl aldehyde reached 94.3%, 88.6% and 96.0%, respectively. Satisfactory separation results (R-a > 70%) for ketones, esters, phenols and polyols have been obtained with the PAA/PSF composite membrane. The effect of operating pressure on the properties of reverse osmosis has also been investigated. Analysis of experimental data with Spiegler-Kedem's transport model has been carried out and the membrane constants such as reflection coefficient sigma, solute and hydraulic permeabilities omega and L-p for several organic solutes have been obtained.
基金Supported by the National Basic Research Program of China (2009CB623406), the National Natural Science Foundation of China (20990222) and the Natural Science Foundation of Jiangsu Province (BK2009021, SBK200930313).
文摘A global-local finite element modeling technique is employed in this paper to predict the separation in steel cord-rubber composite materials of radial truck tires. The local model uses a finite element analysis in conjunction with a glob-al-local technique in ABAQUS. A 3-dimensional finite element local model calculates the maximum cyclic shear strain of an interface between steel cord and rubber materials at the carcass ply shoulder region. It is found that the maximum cyclic shear strain is reliable as a result of the analysis of carcass ply separation in radial truck tires. Using the analysis of the local model, a study of the cyclic shear strain is performed in the shoulder region and used to deter-mine the carcass ply separation. The effect of the change of carcass ply design on the separation in steel cord-rubber composite materials of radial truck tires is discussed.
基金Supported by the Trans-century Training Programme Foundation for the Talents by the Ministry of Education of China (No.2002-48).
文摘Fouling-resistant ceramic-supported polymer composite membranes were developed for removal of oil-in-water (O/W) microemulsions. The composite membranes were featured with an asymmetric three-layer structure, i.e., a porous ceramic membrane substrate, a polyvinylidene fluoride (PVDF) ultrafiltration sub-layer, and a polyam-ide/polyvinyl alcohol (PVA) composite thin top-layer. The PVDF polymer was cast onto the tubular porous ceramic membranes with an immersion precipitation method, and the polyamide/PVA composite thin top-layer was fabricated with an interfacial polymerization method. The effects of the sub-layer composition and the recipe in the interfacial po-lymerization for fabricating the top-layer on the structure and performance of composite membranes were systematically investigated. The prepared composite membranes showed a good performance for treating the O/W microemulsions with a mean diameter of about 2.4μm. At the operating pressure of 0.4MPa, the hydraulic permeability remained steadily about 190L?m-2?h-1, the oil concentration in the permeate was less than 1.6mg·L-1, and the oil rejection coefficient was always higher than 98.5% throughout the operation from the beginning.
基金Supported by the National Research Council of Science&Technology(NST)grant by the Korea government(MSIP)(No.CRC-15-07-KIER)
文摘Carbon dioxide(CO_2) is greenhouse gas which originates primarily as a main combustion product of biogas and landfill gas. To separate this gas, an inside coated thin film composite(TFC) hollow fiber membrane was developed by interfacial polymerization between 1,3–cyclohexanebis–methylamine(CHMA) and trimesoyl chloride(TMC). ATR-FTIR, SEM and AFM were used to characterize the active thin layer formed inside the PSf hollow fiber. The separation behavior of the CHMA-TMC/PSf membrane was scrutinized by studying various effects like feed gas pressure and temperature. Furthermore, the influence of CHMA concentration and TMC concentration on membrane morphology and performance were investigated. As a result, it was found that mutually the CHMA concentration and TMC concentration play key roles in determining membrane morphology and performance. Moreover, the CHMA-TMC/PSf composite membrane showed good CO_2/CH_4 separation performance. For CO_2/CH_4 mixture gas(30/70 by volume) test, the membrane(PD1 prepared by CHMA 1.0% and TMC 0.5%) showed a CO_2 permeance of 25 GPU and the best CO_2/CH_4 selectivity of 28 at stage cut of 0.1. The high CO_2/CH_4 separation performance of CHMA-TMC/PSf thin film composite membrane was mostly accredited to the thin film thickness and the properties of binary amino groups.
基金supported by the Chinese Ministry of Science and Technology(973 Program,No. 2009CB623405)the National Natural Science Foundation of China(NSFC program,20706051 and 20836006)
文摘Poly (N,N-dimethylaminoethyl methacrylate)-poly (ethylene glycol methyl ether methacrylate) (PDMAEMA-PEGMEMA) and cesium fluoride (CsF) were blended and used as the separation material of composite membranes.Hollow fiber composite membranes were fabricated by coating the blend on polysulfone (PSf) hollow fiber substrate.Introduction of fluorine ion improved the separation performance of the membrane.The concentration of coating solution was adjusted to obtain a membrane with high permeance.The composite membrane showed good performance with the CO2 permeance of 30.4 GPU (1 GPU=10-6 cm3 (STP)/(cm 2 s cmHg)),and selectivities to CO2/N2,CO2/CH4,CO2/H2 and O2/N2 of 47.2,37.6,1.75 and 4.70,respectively.Potassium fluoride (KF),due to its low cost,was also used as a substitute of CsF to prepare composite membrane and the permeation data showed that CsF can be replaced by KF.The effect of operating temperature on the permeation properties of the composite membrane was also investigated.
基金This work was supported by the National Natural Science Foundation of China(No.20076025).
文摘Microporous polyvinylidene fluoride(PVDF)hollow fibre membranes were spun using the dry-wet phaseinversion method.By means of dip-coating technique,a uniform coating with thickness of around 5-12 μm of polyvinyldimethylsiloxane(PVDMS)was formed on the surface of porous PVDF hollow fibers.The structural parameters of PVDFsubstrate membrane were estimated by gas permeation test.Using N_2/O_2 as the medium,the separation properties ofPVDMS-PVDF composite hollow fiber membranes were also evaluated experimentally.The experimental data of bothpermeability and selectivity are in good agreement with the theoretical results predicted by the presented pore-distributionmodel.In order to obtain the compact composite membrane free of defects by the dip-coating technique,the thickness ofPVDMS skin must be higher than 5 μm.
文摘MoS2/γ-Al2O3 ceramic composite membrane is successfully synthesized by the sol-gel method based on the inorganic salt route. The aluminum hydrate sol derived from the inorganic salt Al(NO3)3, whose transparence and viscosity are 97% and 1.2 × 10-3 Pa. s, respectively, can be formed through adjusting the ratio of the peptizing agent H+ to Al3+ to 0.3. The aluminum hydrate gel at 110℃ is amorphous in structure and is heat-treated in air at 800℃ to form γ-Al2O3. The precursor derived from the mixture solution of ammonium molybdate, thioacetamide and a reducing agent, can be transformed into crystal MoS2 under reducing condition at 800℃. MoS2/γ-Al2O3 composite membrane is an organic whole and bps no gradation from MoS2 layer to γ-Al2O3 Iayer. The separation factor a H2/H2S through the MoS2/γ-Al2O3 composite membrane increase with rising temperature and a H2/H2S at 600℃ is 4.45 higher than the theoretical separation factor produced by the ideal Knudsen diffusion.
文摘It was tried to prepare the biodegradable composite particles by the phase separation method followed by the drying-in-liquid method. The composite particles were made of poly-ε-caprolac-tone, quaternary ammonium, carbon black and wax. In the experiment, acetone and water were selected as a good solvent and a poor solvent for poly-ε-caprolactone, quaternary ammonium and wax, respectively. The composite particles were prepared by changing the surfactant species and their concentration, the feeding velocity of water and the weight ratio of poly-ε-caprolactone with larger molecular weight to one with smaller molecular weight. The composite particles with the inner structure in which carbon black, quaternary ammonium and wax were coated well with poly-ε-caprolactone could be prepared by the preparation method presented in this study. The structure and the mean diameter of composite particles were strongly affected by the feeding velocity of water. The higher the feeding velocity of water, the larger the mean diameter of composite particles. The mean diameter was drastically decreased with the surfactant concentration and increased with the added amount of poly-ε-caprolactant with larger molecular weight.
文摘The novel method for preparing the polymer composite particles has been developed. It was tried to prepare polymer composite particles composed of polystyrene and carbon black with the phase separation method followed by suspension polymerization. In order to prepare the polymer composite particles with the more uniform diameter, the styrene monomer droplets containing carbon black were formed with phase separation emulsification in which ethyl alcohol and water were used as the good solvent and the poor solvent for styrene monomer, respectively. In the experiment, the surfactant species and their concentrations, the pouring velocity of water and the weight ratio of carbon black to styrene monomer were mainly changed. Water was poured at the given pouring velocity into ethyl alcohol in which styrene monomer and an initiator were dissolved and carbon black was dispersed beforehand. The spherical polymer composite particles containing carbon black were prepared with Tween 20 and Tween 80 of nonionic surfactants and the irregular polymer composite particles were prepared with PVA, SDS and Kotamine. The diameters of polymer composite particles increased with the pouring velocity of water and with the weight ratio of carbon black to styrene monomer.
文摘To separate salts of metals and non-electrolytes, the approach of dialysis through the composite membranes (CMs) is proposed. CM is a combination of cation and anion exchange areas. In the composite membrane, cations and anions are transferred through the respective exchange areas simultaneously without violation of macroscopic electro-neutrality. This provides a better transfer of salts than conventional ion exchange membranes (IEMs). The dialysis of the ethylene glycol aqueous salt solutions through the CMs was investigated. We have shown that the transport of salts through the composite membranes is more intensive (unlike IEM providing no transfer of salts from weakly mineralized aqueous solutions due to the Donnan exclusion) and the ethylene glycol transfer is not very significant, that is the basis of effective separation. The possibility to use of composite membranes for metal salt and other electrolyte separation is discussed.