In industry, ethylene(C_(2)H_(4))/propylene(C_(3)H_(6)) separations are usually performed by a cryogenic process,which is energy intensive. Membrane separation technology is an alternative separation process that save...In industry, ethylene(C_(2)H_(4))/propylene(C_(3)H_(6)) separations are usually performed by a cryogenic process,which is energy intensive. Membrane separation technology is an alternative separation process that saves energy and is efficient. In this study, blend membranes were prepared by doping polyethylene glycol(PEG600) into a poly(ether-block-amide)(Pebax^(■) 2533) matrix and were used to separate the C_(2)H_(4)/C_(3)H_(6) mixture. The PEG 600 and Pebax^(■) 2533 polymers have good compatibility because they share hydrogen bonds. The addition of PEG600 is conducive to the hydrophilicity and the free volume of blend membranes, and it is also conducive to the solubility of C_(2)H_(4) and C_(3)H_(6) in the membranes, which improves the ability of the membranes to separate this gas pair. The Pebax^(■) 2533/PEG600 blend membrane with 15%(mass) PEG600 showed the highest separation performance in our investigated membranes, with a C_(3)H_(6)/C_(2)H_(4) selectivity of 8.9 and a C_(3)H_(6) permeability of 196 barrer(1 barrer = 1.33×10^(14)m^(3)(STP)·m·m^(-2)·s^(-1)·kPa^(-1)) at 238 K and 0.2 MPa, which is higher than that of the Pebax^(■) 2533/NaY-6%(mass) membrane(α_(C_(3)H_(6)/C_(2)H_(4)) =6.5, P_(C_(3)H_(6))=211 barrer) reported in our previous work. It is confirmed that incorporating PEG600 into the Pebax^(■) 2533 matrix to fabricate blend membranes is an efficient strategy for separating light olefins.展开更多
The soybean （Glycine max） Heihe No. 23 is sensitive to imbibitional chilling injury. Polyethylene glycol （PEG） treatment can improve chilling tolerance of soybean seeds to a certain extent. The changes of hydrolyt...The soybean （Glycine max） Heihe No. 23 is sensitive to imbibitional chilling injury. Polyethylene glycol （PEG） treatment can improve chilling tolerance of soybean seeds to a certain extent. The changes of hydrolytic ATPase in plasma membranes and H^＋-pumping responses in soybean seeds were investigated during PEG treatments. Effects of exogenous calcium and exogenous ABA on the hydrolytic ATPase were also examined in order to understand the mechanism of chilling resistance. Highly purified plasma membranes were isolated by 6.0% aqueous two-phase partitioning from soybean seeds, as judged by the sensitivity of hydrolytic ATPase to sodium vanadate. PEG treatment resulted in a slight increase of the hydrolytic ATPase activity in 12 h. Then the activity decreased gradually, but still higher than the control. The H^＋-pumping activity increased steadily during PEG treatment. Exogenous calcium had both activating and inhibiting effects on the hydrolytic ATPase, but the activity was inhibited in soybean seeds treated with exogenous ABA. Results suggested that PEG treatment, not the exogenous calcium and ABA, up-regulated H^＋-ATPase activities in soybean seeds.展开更多
Preparation and blood compatibility of different shape polyvinyl alcohol（PVA） membrane were investigated. Firstly, the tabular and tubular[polytetrafluoroethylene（PTFE） capillary as supporter] PVA membranes were p...Preparation and blood compatibility of different shape polyvinyl alcohol（PVA） membrane were investigated. Firstly, the tabular and tubular[polytetrafluoroethylene（PTFE） capillary as supporter] PVA membranes were prepared; then, methoxy polyethylene glycol（mPEG） was grafted onto the surface of the PVA membranes. The effects of the shape, structure and properties of the membrane surface on blood compatibility were studied in detail. The experiment results show that mPEG modified PVA membranes, especially mPEG modified tubular membrane, could availably repel the adhesion of the platelets. In addition, the anticoagulant mechanism of mPEG with a steric repulsion effectiveness was confirmed further via different grafting methods.展开更多
Three phase PebaxMH 1657/PEG-ran-PPG/CuBTC（polymer/liquid/solid） was successfully deposited as a selective layer on a porous Polysulfone（PSF） support. In fact, the beneficial properties of PEG（high selectivity） ...Three phase PebaxMH 1657/PEG-ran-PPG/CuBTC（polymer/liquid/solid） was successfully deposited as a selective layer on a porous Polysulfone（PSF） support. In fact, the beneficial properties of PEG（high selectivity） with those of PPG（high permeability, amorphous） have been combined with superior properties of mixed matrix membrane（MMMs）. The membranes were characterized by DSC, TGA and SEM, while CuBTC was characterized by COand CHadsorption test. Statistically based experimental design（central composite design, CCD） was applied to analyze and optimize the effect of PEG-ran-PPG（10–50 wt%） and CuBTC（0–20 wt%） mass contents on the COpermeance and CO/CHideal selectivity. Based on the regression coefficients of the obtained models, the COpermeance was notably influenced by PEG-ran-PPG,while CuBTC has the most significant effect on the CO/CHideal selectivity. Under the optimum conditions（PEG-ran-PPG: 32.76 wt% and CuBTC: 20 wt%）, nearly 620% increase in the COpermeance and43% enhancement in the CO/CHideal selectivity was observed compared to the neat Pebax. The effect of pressure（3, 9 and 15 bar） on the pure and mixed gas separation performance of the composite membranes was also investigated. The high solubility of COin the membranes resulted in the enhancement of COpermeability with increase in gas pressure.展开更多
基金the financial support of the National Key Research and Development Program of China (2020YFB0606405)the Basic Research Program of Shanxi Province (20210302123197)+2 种基金the Key Project of the National Natural Science Foundation of China (21336006)the Scientific Research Foundation for Returned Scholars of Ministry of Education (2017047)the Foundation of State Key Laboratory of Highefficiency Utilization of Coal and Green Chemical Engineering (2017-K15)。
文摘In industry, ethylene(C_(2)H_(4))/propylene(C_(3)H_(6)) separations are usually performed by a cryogenic process,which is energy intensive. Membrane separation technology is an alternative separation process that saves energy and is efficient. In this study, blend membranes were prepared by doping polyethylene glycol(PEG600) into a poly(ether-block-amide)(Pebax^(■) 2533) matrix and were used to separate the C_(2)H_(4)/C_(3)H_(6) mixture. The PEG 600 and Pebax^(■) 2533 polymers have good compatibility because they share hydrogen bonds. The addition of PEG600 is conducive to the hydrophilicity and the free volume of blend membranes, and it is also conducive to the solubility of C_(2)H_(4) and C_(3)H_(6) in the membranes, which improves the ability of the membranes to separate this gas pair. The Pebax^(■) 2533/PEG600 blend membrane with 15%(mass) PEG600 showed the highest separation performance in our investigated membranes, with a C_(3)H_(6)/C_(2)H_(4) selectivity of 8.9 and a C_(3)H_(6) permeability of 196 barrer(1 barrer = 1.33×10^(14)m^(3)(STP)·m·m^(-2)·s^(-1)·kPa^(-1)) at 238 K and 0.2 MPa, which is higher than that of the Pebax^(■) 2533/NaY-6%(mass) membrane(α_(C_(3)H_(6)/C_(2)H_(4)) =6.5, P_(C_(3)H_(6))=211 barrer) reported in our previous work. It is confirmed that incorporating PEG600 into the Pebax^(■) 2533 matrix to fabricate blend membranes is an efficient strategy for separating light olefins.
基金Supported by the National Natural Science Foundation of China (Grant No. 30170100)
文摘The soybean （Glycine max） Heihe No. 23 is sensitive to imbibitional chilling injury. Polyethylene glycol （PEG） treatment can improve chilling tolerance of soybean seeds to a certain extent. The changes of hydrolytic ATPase in plasma membranes and H^＋-pumping responses in soybean seeds were investigated during PEG treatments. Effects of exogenous calcium and exogenous ABA on the hydrolytic ATPase were also examined in order to understand the mechanism of chilling resistance. Highly purified plasma membranes were isolated by 6.0% aqueous two-phase partitioning from soybean seeds, as judged by the sensitivity of hydrolytic ATPase to sodium vanadate. PEG treatment resulted in a slight increase of the hydrolytic ATPase activity in 12 h. Then the activity decreased gradually, but still higher than the control. The H^＋-pumping activity increased steadily during PEG treatment. Exogenous calcium had both activating and inhibiting effects on the hydrolytic ATPase, but the activity was inhibited in soybean seeds treated with exogenous ABA. Results suggested that PEG treatment, not the exogenous calcium and ABA, up-regulated H^＋-ATPase activities in soybean seeds.
基金Supported by the National Natural Science Foundation of China(No.29405038)
文摘Preparation and blood compatibility of different shape polyvinyl alcohol（PVA） membrane were investigated. Firstly, the tabular and tubular[polytetrafluoroethylene（PTFE） capillary as supporter] PVA membranes were prepared; then, methoxy polyethylene glycol（mPEG） was grafted onto the surface of the PVA membranes. The effects of the shape, structure and properties of the membrane surface on blood compatibility were studied in detail. The experiment results show that mPEG modified PVA membranes, especially mPEG modified tubular membrane, could availably repel the adhesion of the platelets. In addition, the anticoagulant mechanism of mPEG with a steric repulsion effectiveness was confirmed further via different grafting methods.
文摘Three phase PebaxMH 1657/PEG-ran-PPG/CuBTC（polymer/liquid/solid） was successfully deposited as a selective layer on a porous Polysulfone（PSF） support. In fact, the beneficial properties of PEG（high selectivity） with those of PPG（high permeability, amorphous） have been combined with superior properties of mixed matrix membrane（MMMs）. The membranes were characterized by DSC, TGA and SEM, while CuBTC was characterized by COand CHadsorption test. Statistically based experimental design（central composite design, CCD） was applied to analyze and optimize the effect of PEG-ran-PPG（10–50 wt%） and CuBTC（0–20 wt%） mass contents on the COpermeance and CO/CHideal selectivity. Based on the regression coefficients of the obtained models, the COpermeance was notably influenced by PEG-ran-PPG,while CuBTC has the most significant effect on the CO/CHideal selectivity. Under the optimum conditions（PEG-ran-PPG: 32.76 wt% and CuBTC: 20 wt%）, nearly 620% increase in the COpermeance and43% enhancement in the CO/CHideal selectivity was observed compared to the neat Pebax. The effect of pressure（3, 9 and 15 bar） on the pure and mixed gas separation performance of the composite membranes was also investigated. The high solubility of COin the membranes resulted in the enhancement of COpermeability with increase in gas pressure.
