Isotactic polypropylene （iPP） hollow fiber microporous membranes were prepared using thermally induced phase separation （TIPS） method. Di-n-butyl phthalate （DBP）, dioctyl phthalate （DOP）, and the mixed solvent...Isotactic polypropylene （iPP） hollow fiber microporous membranes were prepared using thermally induced phase separation （TIPS） method. Di-n-butyl phthalate （DBP）, dioctyl phthalate （DOP）, and the mixed solvent were used as diluents. The effect of α （DOP mass fraction in diluent） on the morphology and performance of the hollow fiber was investigated. With increasing α, the morphology of the resulting hollow fiber changes from typical cellular structure to mixed structure, and then to typical particulate structure. As a result, the permeability of the hollow fiber increases sharply, and the mechanical properties of the hollow fiber decrease obviously. It is suggested that the morphology and performances of iPP hollow fiber microporous membrane can be controlled via adjusting the compatibility between iPP and diluent.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
A systematic study of air gap distance effects on the structure and properties of poly(vinyl butyral)hollow fiber membrane via thermally induced phase separation(TIPS)has been carried out.The results show that the hol...A systematic study of air gap distance effects on the structure and properties of poly(vinyl butyral)hollow fiber membrane via thermally induced phase separation(TIPS)has been carried out.The results show that the hollow fiber membrane prepared at air gap zero has no skin layer; the pore size near the outer surface is larger than that near the inner surface; and the special pore channel-like structure near the outer surface is formed,which is quite different with the typical sponge-like structure caused by TIPS and the finger-like structure caused by non-solvent induced phase separation(NIPS),because of the synergistic action of non-solvent induced phase separation at air gap zero.The pore size gradually decreases from outer surface layer to the intermediate layer,but increases gradually from intermediate layer to the inner surface layer.With the increase of air gap distance,the pore size near the outer surface gets smaller and a dense skin layer is formed,and the pore size gradually increases from the outer surface layer to the inner surface layer.Water permeability of the hollow fiber membrane decreases with air gap distance,the water permeability decreases sharply from 45.50×10-7 to 4.52×10-7 m3/(m2·s·kPa)as air gap increases from 0 to 10 mm at take-up speed of 0.236 m/s,further decreases from 4.52×10-7 to 1.00×10-8 m3/(m2·s·kPa)as the air gap increases from 10 to 40 mm.Both the breaking strength and the elongation increase with the increase of air gap distance.The breaking strength increases from 2.25 MPa to 4.19 MPa and the elongation increases from 33.9% to 132.6% as air gap increases from 0 mm to 40 mm at take-up speed 0.236 m/s.展开更多
Hydrophilic poly(vinyl butyral)(PVB) /Pluronic F127(F127) blend hollow fiber membranes were prepared via thermally induced phase separation(TIPS) ,and the effects of blend composition on the performance of hydrophilic...Hydrophilic poly(vinyl butyral)(PVB) /Pluronic F127(F127) blend hollow fiber membranes were prepared via thermally induced phase separation(TIPS) ,and the effects of blend composition on the performance of hydrophilic PVB/F127 blend hollow fiber membrane were investigated.The addition of F127 to PVB/polyethylene glycol(PEG) system decreases the cloud point temperature,while the cloud point temperature increases slightly with the addition of F127 to 20%(by mass) PVB/F127/PEG200 system when the concentration of F127 is not higher than 5%(by mass) .Light scattering results show that the initial inter-phase periodic distance formed from the phase separation of 20%(by mass) PVB/F127/PEG200 system decreases with the addition of F127,so does the growth rate during cooling process.The blend hollow fiber membrane prepared at air-gap 5mm,of which the water permeability increases and the rejection changes little with the increase of F127 concentration.For the membrane prepared at zero air-gap,both water permeability and rejection of the PVB/F127 blend membrane are greater than those of PVB membrane,while the tensile strength changes little.Elementary analysis shows that most F127 in the polymer solution can firmly exist in the polymer matrix,increasing the hydrophilicity of the blend membrane prepared at air-gap of 5mm.展开更多
The effect of hollow fiber module positions （ horizontal and vertical） on separation performance for PVA solution by using polyethersulfone （PES） hollow fiber ultrafiltration （UF） membrane with the molecular wei...The effect of hollow fiber module positions （ horizontal and vertical） on separation performance for PVA solution by using polyethersulfone （PES） hollow fiber ultrafiltration （UF） membrane with the molecular weight cut-off （MWCO） 30 000 has been discussed. Experimental results illustrated that the suitable operation conditions for PVA solution were as follows： trans-membrane pressure 2.1 bar, solution temperature 75℃ and feed velocity 0.32 m/s. Under these suitable operation conditions, the permeate flux is from 36.8 L/（m^2 ·h·bar） to 42.9 L/（m^2 ·h·bar） for the horizontal module and from 39.8 L/（m^2 ·h·bar） to 66.6 L/（m^2 ·h·bar） for the vertical module. Besides, the Separation performance of PES hollow fiber UF membrane was better by using vertical hollow fiber module than by using horizontal hollow fiber module. When the trans-membrane pressure increased from 1 bar to 2.1 bar, solution temperature from 50 ℃ to 75 ℃, feed solution velocity from 0.16 m/s to 0.32 m/s, the PVA rejection would increase from 95.8% to 99.7%, 95.4 96 to 98.6 %, 95.8 96 to 99.2 96 for horizontal module respectively, and from 98.8 96 to 99.8 %, 98.6 96 to 99.4 96, 98.5 96 to 99.4 96 for vertical module respectively. Therefore, PVA rejection in PES hollow fiber UF process was more than 98.5 96 for vertical module, and it is suitable for PVA recovery from wastewater.展开更多
基金Supported by the National Natural Science Foundation of China （No.20236030）.
文摘Isotactic polypropylene （iPP） hollow fiber microporous membranes were prepared using thermally induced phase separation （TIPS） method. Di-n-butyl phthalate （DBP）, dioctyl phthalate （DOP）, and the mixed solvent were used as diluents. The effect of α （DOP mass fraction in diluent） on the morphology and performance of the hollow fiber was investigated. With increasing α, the morphology of the resulting hollow fiber changes from typical cellular structure to mixed structure, and then to typical particulate structure. As a result, the permeability of the hollow fiber increases sharply, and the mechanical properties of the hollow fiber decrease obviously. It is suggested that the morphology and performances of iPP hollow fiber microporous membrane can be controlled via adjusting the compatibility between iPP and diluent.
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Project(21176264)supported by the National Natural Science Foundation of ChinaProject(11JJ2010)supported by the Natural Science Foundation of Hunan Province,China
文摘A systematic study of air gap distance effects on the structure and properties of poly(vinyl butyral)hollow fiber membrane via thermally induced phase separation(TIPS)has been carried out.The results show that the hollow fiber membrane prepared at air gap zero has no skin layer; the pore size near the outer surface is larger than that near the inner surface; and the special pore channel-like structure near the outer surface is formed,which is quite different with the typical sponge-like structure caused by TIPS and the finger-like structure caused by non-solvent induced phase separation(NIPS),because of the synergistic action of non-solvent induced phase separation at air gap zero.The pore size gradually decreases from outer surface layer to the intermediate layer,but increases gradually from intermediate layer to the inner surface layer.With the increase of air gap distance,the pore size near the outer surface gets smaller and a dense skin layer is formed,and the pore size gradually increases from the outer surface layer to the inner surface layer.Water permeability of the hollow fiber membrane decreases with air gap distance,the water permeability decreases sharply from 45.50×10-7 to 4.52×10-7 m3/(m2·s·kPa)as air gap increases from 0 to 10 mm at take-up speed of 0.236 m/s,further decreases from 4.52×10-7 to 1.00×10-8 m3/(m2·s·kPa)as the air gap increases from 10 to 40 mm.Both the breaking strength and the elongation increase with the increase of air gap distance.The breaking strength increases from 2.25 MPa to 4.19 MPa and the elongation increases from 33.9% to 132.6% as air gap increases from 0 mm to 40 mm at take-up speed 0.236 m/s.
基金Supported by the National Natural Science Foundation of China（20776161）
文摘Hydrophilic poly(vinyl butyral)(PVB) /Pluronic F127(F127) blend hollow fiber membranes were prepared via thermally induced phase separation(TIPS) ,and the effects of blend composition on the performance of hydrophilic PVB/F127 blend hollow fiber membrane were investigated.The addition of F127 to PVB/polyethylene glycol(PEG) system decreases the cloud point temperature,while the cloud point temperature increases slightly with the addition of F127 to 20%(by mass) PVB/F127/PEG200 system when the concentration of F127 is not higher than 5%(by mass) .Light scattering results show that the initial inter-phase periodic distance formed from the phase separation of 20%(by mass) PVB/F127/PEG200 system decreases with the addition of F127,so does the growth rate during cooling process.The blend hollow fiber membrane prepared at air-gap 5mm,of which the water permeability increases and the rejection changes little with the increase of F127 concentration.For the membrane prepared at zero air-gap,both water permeability and rejection of the PVB/F127 blend membrane are greater than those of PVB membrane,while the tensile strength changes little.Elementary analysis shows that most F127 in the polymer solution can firmly exist in the polymer matrix,increasing the hydrophilicity of the blend membrane prepared at air-gap of 5mm.
文摘The effect of hollow fiber module positions （ horizontal and vertical） on separation performance for PVA solution by using polyethersulfone （PES） hollow fiber ultrafiltration （UF） membrane with the molecular weight cut-off （MWCO） 30 000 has been discussed. Experimental results illustrated that the suitable operation conditions for PVA solution were as follows： trans-membrane pressure 2.1 bar, solution temperature 75℃ and feed velocity 0.32 m/s. Under these suitable operation conditions, the permeate flux is from 36.8 L/（m^2 ·h·bar） to 42.9 L/（m^2 ·h·bar） for the horizontal module and from 39.8 L/（m^2 ·h·bar） to 66.6 L/（m^2 ·h·bar） for the vertical module. Besides, the Separation performance of PES hollow fiber UF membrane was better by using vertical hollow fiber module than by using horizontal hollow fiber module. When the trans-membrane pressure increased from 1 bar to 2.1 bar, solution temperature from 50 ℃ to 75 ℃, feed solution velocity from 0.16 m/s to 0.32 m/s, the PVA rejection would increase from 95.8% to 99.7%, 95.4 96 to 98.6 %, 95.8 96 to 99.2 96 for horizontal module respectively, and from 98.8 96 to 99.8 %, 98.6 96 to 99.4 96, 98.5 96 to 99.4 96 for vertical module respectively. Therefore, PVA rejection in PES hollow fiber UF process was more than 98.5 96 for vertical module, and it is suitable for PVA recovery from wastewater.
