Using polysulfone （PSF） hollow fiber ultrafiltration membranes as the substrate, sodium alginate （SA） and polyvinyl alcohol （PVA） blend solutions as the coating solution, and maleic anhydride （MAC） as the cros...Using polysulfone （PSF） hollow fiber ultrafiltration membranes as the substrate, sodium alginate （SA） and polyvinyl alcohol （PVA） blend solutions as the coating solution, and maleic anhydride （MAC） as the cross-linked agent, SAPVA/PSF hollow fiber composite membranes were prepared for the dehydration of ethanol-water. The effects of different sodium alginate concentration in the coating solutions and different operating temperatures on pervaporation performance were investigated. The experimental results showed that pervaporation performance of the SA-PVA/PSF composite membranes for ethanol-water solution exhibited a high separation factor although they had a relatively low permeation flux. As SA concentration in SA-PVA coating solution was 66.7% and the operating temperature was 40 ℃, SA-PVA/PSF hollow fiber composite membrane （PS4） had a separation factor of 886 and flux of 12.6 g/（m^2·h）. Besides, SA-PVA/PSF hollow fiber composite membranes （PS3 and PS4） were used for the investigation of the effect of ethanol concentration in the feed solution on pervaporation performance.展开更多
The viability of polyvinyl acetate (PVA) membranes blended with acrylic ester-co-acrylic acid copolymers (AE-co-AA), for ethanol dehydration was examined. The effects of the operating temperature on the permeate flux ...The viability of polyvinyl acetate (PVA) membranes blended with acrylic ester-co-acrylic acid copolymers (AE-co-AA), for ethanol dehydration was examined. The effects of the operating temperature on the permeate flux and separation factor of the membranes were investigated. The pervaporation separation characteristics of PVA/(AE-co-AA) membranes were related to the blend ratio, the dose of crosslinking agents and the operating temperature.展开更多
A high performance composite membrane was prepared under the inspiration of bioadhesion principles for pervaporative dehydration of ethanol.Chitosan(CS)and polyacrylonitrile(PAN)ultrafiltration membranes were used as ...A high performance composite membrane was prepared under the inspiration of bioadhesion principles for pervaporative dehydration of ethanol.Chitosan(CS)and polyacrylonitrile(PAN)ultrafiltration membranes were used as the active layer and the support layer,respectively.Guar gum(GG),a natural bioadhesive,was introduced as the intermediate bonding layer to improve the separation performance and stability of the fabricated CS/GG/PAN composite membranes.The contact angle of the GG layer was just between those of the CS layer and the PAN layer,minimizing the difference of hydrophilicity between the active layer and the support layer.The peeling strength of the composite membrane was significantly enhanced after the introduction of the GG layer.The effects of preparation conditions and operation conditions including GG concentration,operating temperature and ethanol concentration in feed on the pervaporation performance were investigated.The as-fabricated CS/GG/PAN composite membrane showed the optimum performance with a permeation flux of up to804 g·m-2·h-1and a separation factor higher than 1900.Besides,the composite membranes exhibited a desirable long-term operational stability.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
OBJECTIVE:To examine the antioxidative and hepatoprotective activities of the effective fraction separated from the fruit of Livistona chinensis(FLC)and to explore the possible mechanism.METHODS:The antioxidative acti...OBJECTIVE:To examine the antioxidative and hepatoprotective activities of the effective fraction separated from the fruit of Livistona chinensis(FLC)and to explore the possible mechanism.METHODS:The antioxidative activities of the various fractions separated from FLC were analyzed by in vitro DPPH(1,1-diphenyl-2-picrylhydrazyl radical 2,2-diphenyl-1-(2,4,6-trinitrophenyl) hydrazyl,DPPH) radical and superoxide anion free radical(O^(2-)) scavenging assays.The potential hepatoprotective effects of the ethyl acetate fraction separated from FLC(EFLC) were examined in LO_2 cells and mice.LO_2 cells were incubated with EFLC and exposed to H_2O_2-induced oxidative stress.BABL/C mice were orally administered EFLC for consecutive7 d,and fulminant hepatitis was induced by cauda vein injection of Con A on day 7.RESULTS:EFLC showed prominent antioxidative effects in DPPH-and O^(2-) scavenging assays.EFLC pretreatment effectively protected LO_2 cells from H_2O_2-induced oxidative stress by decreasing apoptosis and raising the levels of antioxidant enzymes.Additionally,EFLC protected mice against Con A-induced fulminant hepatitis by markedly reducing the serum levels of alanine transaminase and aspartate aminotransferase,attenuating histological damage of the mouse liver,and elevating the levels of glutathione peroxidase and total superoxide dismutase,while decreasing the contents of methane dicarboxylic aldehyde,tumor necrosis factor-α,and interleukin-1β in the mouse liver.Furthermore,EFLC pretreatment downregulated the protein expression of B-cell lymphoma 2(Bcl-2) associated X protein,caspase-3,caspase-8,Fas,and Fas L,while upregulating the protein expression of Bcl-2 in the mouse liver.CONCLUSION:These findings revealed that EFLC effectively protected against in vivo and in vitro liver injury,and the mechanism is closely associated with its antioxidative and anti-apoptotic properties.展开更多
基金Project supported by the National Basic Research Program of China (Grant No.2003CB615705)
文摘Using polysulfone （PSF） hollow fiber ultrafiltration membranes as the substrate, sodium alginate （SA） and polyvinyl alcohol （PVA） blend solutions as the coating solution, and maleic anhydride （MAC） as the cross-linked agent, SAPVA/PSF hollow fiber composite membranes were prepared for the dehydration of ethanol-water. The effects of different sodium alginate concentration in the coating solutions and different operating temperatures on pervaporation performance were investigated. The experimental results showed that pervaporation performance of the SA-PVA/PSF composite membranes for ethanol-water solution exhibited a high separation factor although they had a relatively low permeation flux. As SA concentration in SA-PVA coating solution was 66.7% and the operating temperature was 40 ℃, SA-PVA/PSF hollow fiber composite membrane （PS4） had a separation factor of 886 and flux of 12.6 g/（m^2·h）. Besides, SA-PVA/PSF hollow fiber composite membranes （PS3 and PS4） were used for the investigation of the effect of ethanol concentration in the feed solution on pervaporation performance.
文摘The viability of polyvinyl acetate (PVA) membranes blended with acrylic ester-co-acrylic acid copolymers (AE-co-AA), for ethanol dehydration was examined. The effects of the operating temperature on the permeate flux and separation factor of the membranes were investigated. The pervaporation separation characteristics of PVA/(AE-co-AA) membranes were related to the blend ratio, the dose of crosslinking agents and the operating temperature.
基金Supported by the New Century Excellent Talents in University(NCET-10-0623)the National Natural Science Foundation for Distinguished Young Scholars(21125627)+1 种基金the National Basic Research Program of China(2009CB623404)State Key Laboratory for Modification of Chemical Fibers and Polymer Materials(Dong Hua University)
文摘A high performance composite membrane was prepared under the inspiration of bioadhesion principles for pervaporative dehydration of ethanol.Chitosan(CS)and polyacrylonitrile(PAN)ultrafiltration membranes were used as the active layer and the support layer,respectively.Guar gum(GG),a natural bioadhesive,was introduced as the intermediate bonding layer to improve the separation performance and stability of the fabricated CS/GG/PAN composite membranes.The contact angle of the GG layer was just between those of the CS layer and the PAN layer,minimizing the difference of hydrophilicity between the active layer and the support layer.The peeling strength of the composite membrane was significantly enhanced after the introduction of the GG layer.The effects of preparation conditions and operation conditions including GG concentration,operating temperature and ethanol concentration in feed on the pervaporation performance were investigated.The as-fabricated CS/GG/PAN composite membrane showed the optimum performance with a permeation flux of up to804 g·m-2·h-1and a separation factor higher than 1900.Besides,the composite membranes exhibited a desirable long-term operational stability.
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.
基金the Science and Technology Plan Projects of Guangdong(No.2013A022100002)
文摘OBJECTIVE:To examine the antioxidative and hepatoprotective activities of the effective fraction separated from the fruit of Livistona chinensis(FLC)and to explore the possible mechanism.METHODS:The antioxidative activities of the various fractions separated from FLC were analyzed by in vitro DPPH(1,1-diphenyl-2-picrylhydrazyl radical 2,2-diphenyl-1-(2,4,6-trinitrophenyl) hydrazyl,DPPH) radical and superoxide anion free radical(O^(2-)) scavenging assays.The potential hepatoprotective effects of the ethyl acetate fraction separated from FLC(EFLC) were examined in LO_2 cells and mice.LO_2 cells were incubated with EFLC and exposed to H_2O_2-induced oxidative stress.BABL/C mice were orally administered EFLC for consecutive7 d,and fulminant hepatitis was induced by cauda vein injection of Con A on day 7.RESULTS:EFLC showed prominent antioxidative effects in DPPH-and O^(2-) scavenging assays.EFLC pretreatment effectively protected LO_2 cells from H_2O_2-induced oxidative stress by decreasing apoptosis and raising the levels of antioxidant enzymes.Additionally,EFLC protected mice against Con A-induced fulminant hepatitis by markedly reducing the serum levels of alanine transaminase and aspartate aminotransferase,attenuating histological damage of the mouse liver,and elevating the levels of glutathione peroxidase and total superoxide dismutase,while decreasing the contents of methane dicarboxylic aldehyde,tumor necrosis factor-α,and interleukin-1β in the mouse liver.Furthermore,EFLC pretreatment downregulated the protein expression of B-cell lymphoma 2(Bcl-2) associated X protein,caspase-3,caspase-8,Fas,and Fas L,while upregulating the protein expression of Bcl-2 in the mouse liver.CONCLUSION:These findings revealed that EFLC effectively protected against in vivo and in vitro liver injury,and the mechanism is closely associated with its antioxidative and anti-apoptotic properties.
