In this work, a series of polyethyleneimine （PEI） functionalized commercial silica gel were prepared by wet impregnation method and used as CO2 sorbent. The as-prepared sorbents were characterized by N2 adsorption, ...In this work, a series of polyethyleneimine （PEI） functionalized commercial silica gel were prepared by wet impregnation method and used as CO2 sorbent. The as-prepared sorbents were characterized by N2 adsorption, FT-1R and SEM techniques. CO2 capture was tested in a fixed bed reactor using a simulated flue gas containing 15.1% CO2 in a temperature range of 25-100 ~C. The effects of sorption temperature and amine content on CO2 uptake of the adsorbents were investigated. The silica gel with a 30 wt% PEI loading manifested the largest CO2 uptake of 93.4 mgcoz/gadsorbent （equal to 311.3 mg^oz/gPEI） among the tested sorbents under the conditions of 15.1% （v/v） CO2 in N2 at 75 ~C and atmospheric pressure. Moreover, it was rather low-cost. In addition, the PEI-impregnated silica gel exhibited stable adsorption-desorption behavior during 5 consecutive test cycles. These results suggest that the PEI-impregnated silica gel is a promising and cost-effective sorbent for CO2 capture from flue gas and other stationary sources with low CO2 concentration.展开更多
A new type of the nanometer particles and epoxy/bismaleimide-triazine nanocomposites were prepared using a nanometer silica （nano-SiO2）, a 4,5-epoxycyclohexane 1,2-dicarboxylic acid dilycidyl （TDE-85） epoxy resin,...A new type of the nanometer particles and epoxy/bismaleimide-triazine nanocomposites were prepared using a nanometer silica （nano-SiO2）, a 4,5-epoxycyclohexane 1,2-dicarboxylic acid dilycidyl （TDE-85） epoxy resin, a 4,4＇-bismaleimidodiphenymethane （BMI） and a bisphenol a dicyanate （BADCy）. The properties of nano-SiOJTDE-85/BMI/BADCy composites, such as mechanical and thermal properties, were systemically investigated in detail by mechanical measurement, scanning electron microscope （SEM）, dynamic mechanical analysis （DMA） and thermogravimetric analysis （TGA）. The experimental results showed that the addition of the appropriate amount of nano-SiO： could improve the impact strength and the flexural strength of the nano- SiO2/TDE-85/BMI/BADCy composites. Simultaneously, the thermal stability of the blends was found to be higher than that of the TDE-85/BMI/BADCy copolymers.展开更多
Solid state bio-processing of wheat straw was carried out through an indigenous fungal strain Pleurotus ostreatus IBL-02 under pre-optimized fermentation conditions. The maximum activity, 692±12 U/mL, of the indu...Solid state bio-processing of wheat straw was carried out through an indigenous fungal strain Pleurotus ostreatus IBL-02 under pre-optimized fermentation conditions. The maximum activity, 692±12 U/mL, of the industrially important manganese peroxidase (MnP) enzyme was recorded after five days of still culture incubation. The crude MnP was 2.1-fold purified with a specific activity of 860 U/mg after purification on a Sephadex-G-100 gel column. On native and SDS-PAGE electrophoresis gels, the purified MnP fraction was a single homogenous band of 45 kDa. An active fraction of MnP was immobilized using hydrophobic sol-gel entrapment comprising tetramethoxysilane (T) and propyltrimethoxysilane (P) at different T:P molar ratios. Characterization revealed that after 24 h incubation at varying pH and temperatures, the MnP fraction immobilized at a T:P ratio of 1:2 in the sol-gel retained 82% and 75% of its original activity at pH4 and 70 ℃, respectively. The optimally active fraction at a 1:2 T:P ratio was tested against MnSO4 as a substrate to determine the kinetic catalytic constants KM and Vmax . To explore the industrial applicability of P. ostreatus IBL-02 MnP, both the free and immobilized MnP were used for the decolorization of four different textile industrial effluents. A maximum of 100% decolorization was achieved for the different textile effluents within the shortest time period. A lower KM , higher Vmax , hyper-activation, and enhanced acidic and thermal resistance up to 70 ℃ were the novel catalytic features of the sol-gel immobilized MnP, suggesting that it may be a potential candidate for biotechnological applications particularly for textile bioremediation purposes.展开更多
In this paper, we investigates the concretes respec- tively incorporated with 5% （m ： rn） nano-SiO2 （NS）, 40% （rn ： m） super- fine slag （SS）, as well as 40% （m ： m） SS combining 20% replacement of sand vo...In this paper, we investigates the concretes respec- tively incorporated with 5% （m ： rn） nano-SiO2 （NS）, 40% （rn ： m） super- fine slag （SS）, as well as 40% （m ： m） SS combining 20% replacement of sand volume with RP. The tested mechanical properties include compressive strength, abrasion resistant strength, and elastic modulus. The results indicate that among these concretes, the SS-RP concrete has the highest abrasion re- sistant strength with increment ratios of 1.71 and 1.35 at 28 days and 90 days, respectively; the SS concrete has the highest com- pressive strength with increment ratios of 2.03 and 1.95 at 28 days and 90 days, respectively; the elastic modulus of SS-RP concrete significantly decrease compared with the SS concrete and is slightly higher than that of the reference concrete. It is concluded that NS, SS, and RP all can improve the abrasion resistance of concrete, and it will be significantly improved when SS combining RP is incorporated.展开更多
Li-rich Li[Li0.2Mn0.54Ni0.13Co0.13]02（LMNC） powders were synthesized by a gel-combustion method. The related microstructure, electrochemical performance and electrochemically induced phase evolution were characteriz...Li-rich Li[Li0.2Mn0.54Ni0.13Co0.13]02（LMNC） powders were synthesized by a gel-combustion method. The related microstructure, electrochemical performance and electrochemically induced phase evolution were characterized. The 900℃ calcined powders have a hexagonal layered structure with high ordered degree and low cationic mixing level. The calcined materials as cathode electrode for Li-ion battery deliver the high electrochemical properties with an initial discharge capacity of 243.5 mA. h. g-1 at 25 mA.g-1 and 249.2 mA-h.g-1 even after 50 cycles. The electrochemically induced phase evolution investigated by a transmission electron microscopy indicates that Li＋ ions deintercalated first from the LiMO2 （M = Mn, Co, Ni） component and then from Li2MnO3 component in the LMNC during the charge process, while Li＋ ions intercalated into Li1-xMO2 component followed by into MnO2 component during the discharge process.展开更多
The tribological properties of combinative addition of nano-MoS2 and nano-SiO2 to the base oil have been investigated with a reciprocating ball-on-plate tribotester for magnesium alloy-steel contacts. The results demo...The tribological properties of combinative addition of nano-MoS2 and nano-SiO2 to the base oil have been investigated with a reciprocating ball-on-plate tribotester for magnesium alloy-steel contacts. The results demonstrate that the optimum mass ratio of nano-SiO2 to nano-MoS2 is 0.25：0.75. The optimum combinative addition into the base oil reduces the friction coefficient by 43.8% and the surface roughness （Sa） by 31.7% when compared to that found with the base oil. Meanwhile, the combinative addition of nano-MoS2 and nano-SiO〉 in comparison with single nanoparticles addition, is more pronounced in terms of the lubrication film stability. The excellent tribological properties of the SiO2/MoS2 combinations are attributed to the formation of physical adsorption films and tribochemical products during the rubbing process and the micro-cooperation of various nano- particles with different shapes and lubrication mechanisms.展开更多
文摘In this work, a series of polyethyleneimine （PEI） functionalized commercial silica gel were prepared by wet impregnation method and used as CO2 sorbent. The as-prepared sorbents were characterized by N2 adsorption, FT-1R and SEM techniques. CO2 capture was tested in a fixed bed reactor using a simulated flue gas containing 15.1% CO2 in a temperature range of 25-100 ~C. The effects of sorption temperature and amine content on CO2 uptake of the adsorbents were investigated. The silica gel with a 30 wt% PEI loading manifested the largest CO2 uptake of 93.4 mgcoz/gadsorbent （equal to 311.3 mg^oz/gPEI） among the tested sorbents under the conditions of 15.1% （v/v） CO2 in N2 at 75 ~C and atmospheric pressure. Moreover, it was rather low-cost. In addition, the PEI-impregnated silica gel exhibited stable adsorption-desorption behavior during 5 consecutive test cycles. These results suggest that the PEI-impregnated silica gel is a promising and cost-effective sorbent for CO2 capture from flue gas and other stationary sources with low CO2 concentration.
文摘A new type of the nanometer particles and epoxy/bismaleimide-triazine nanocomposites were prepared using a nanometer silica （nano-SiO2）, a 4,5-epoxycyclohexane 1,2-dicarboxylic acid dilycidyl （TDE-85） epoxy resin, a 4,4＇-bismaleimidodiphenymethane （BMI） and a bisphenol a dicyanate （BADCy）. The properties of nano-SiOJTDE-85/BMI/BADCy composites, such as mechanical and thermal properties, were systemically investigated in detail by mechanical measurement, scanning electron microscope （SEM）, dynamic mechanical analysis （DMA） and thermogravimetric analysis （TGA）. The experimental results showed that the addition of the appropriate amount of nano-SiO： could improve the impact strength and the flexural strength of the nano- SiO2/TDE-85/BMI/BADCy composites. Simultaneously, the thermal stability of the blends was found to be higher than that of the TDE-85/BMI/BADCy copolymers.
基金a part of a research project entitled “the development of immobilized ligninolytic enzymes for industrial applications” supported by Higher Education Commission (HEC), Islamabad, Pakistan
文摘Solid state bio-processing of wheat straw was carried out through an indigenous fungal strain Pleurotus ostreatus IBL-02 under pre-optimized fermentation conditions. The maximum activity, 692±12 U/mL, of the industrially important manganese peroxidase (MnP) enzyme was recorded after five days of still culture incubation. The crude MnP was 2.1-fold purified with a specific activity of 860 U/mg after purification on a Sephadex-G-100 gel column. On native and SDS-PAGE electrophoresis gels, the purified MnP fraction was a single homogenous band of 45 kDa. An active fraction of MnP was immobilized using hydrophobic sol-gel entrapment comprising tetramethoxysilane (T) and propyltrimethoxysilane (P) at different T:P molar ratios. Characterization revealed that after 24 h incubation at varying pH and temperatures, the MnP fraction immobilized at a T:P ratio of 1:2 in the sol-gel retained 82% and 75% of its original activity at pH4 and 70 ℃, respectively. The optimally active fraction at a 1:2 T:P ratio was tested against MnSO4 as a substrate to determine the kinetic catalytic constants KM and Vmax . To explore the industrial applicability of P. ostreatus IBL-02 MnP, both the free and immobilized MnP were used for the decolorization of four different textile industrial effluents. A maximum of 100% decolorization was achieved for the different textile effluents within the shortest time period. A lower KM , higher Vmax , hyper-activation, and enhanced acidic and thermal resistance up to 70 ℃ were the novel catalytic features of the sol-gel immobilized MnP, suggesting that it may be a potential candidate for biotechnological applications particularly for textile bioremediation purposes.
基金Supported by the National Basic Research Program of China(973 Program)(2009CB623201 and 2013CB035901)the National Natural Science Foundation of China(50972109 and 51109170)the Doctoral Program of Higher Education of China(20090141110021)
文摘In this paper, we investigates the concretes respec- tively incorporated with 5% （m ： rn） nano-SiO2 （NS）, 40% （rn ： m） super- fine slag （SS）, as well as 40% （m ： m） SS combining 20% replacement of sand volume with RP. The tested mechanical properties include compressive strength, abrasion resistant strength, and elastic modulus. The results indicate that among these concretes, the SS-RP concrete has the highest abrasion re- sistant strength with increment ratios of 1.71 and 1.35 at 28 days and 90 days, respectively; the SS concrete has the highest com- pressive strength with increment ratios of 2.03 and 1.95 at 28 days and 90 days, respectively; the elastic modulus of SS-RP concrete significantly decrease compared with the SS concrete and is slightly higher than that of the reference concrete. It is concluded that NS, SS, and RP all can improve the abrasion resistance of concrete, and it will be significantly improved when SS combining RP is incorporated.
文摘Li-rich Li[Li0.2Mn0.54Ni0.13Co0.13]02（LMNC） powders were synthesized by a gel-combustion method. The related microstructure, electrochemical performance and electrochemically induced phase evolution were characterized. The 900℃ calcined powders have a hexagonal layered structure with high ordered degree and low cationic mixing level. The calcined materials as cathode electrode for Li-ion battery deliver the high electrochemical properties with an initial discharge capacity of 243.5 mA. h. g-1 at 25 mA.g-1 and 249.2 mA-h.g-1 even after 50 cycles. The electrochemically induced phase evolution investigated by a transmission electron microscopy indicates that Li＋ ions deintercalated first from the LiMO2 （M = Mn, Co, Ni） component and then from Li2MnO3 component in the LMNC during the charge process, while Li＋ ions intercalated into Li1-xMO2 component followed by into MnO2 component during the discharge process.
基金supported by the National Natural Science Foundation of China(Grant No.51171212)Chongqing Science and Technology Commission(Grant Nos.CSTC2012JJJQ50001,CSTC2013jcyj C60001&cstc2012gg B50003)+2 种基金the National Science and Technology Program of China(Grant No.2013DFA71070)the Fundamental Research Funds for the Central Universities(Grant No.CDJZR13138801)the Fundamental Research Funds for the Yangtze Normal University(Grant No.CJSF2010C025)
文摘The tribological properties of combinative addition of nano-MoS2 and nano-SiO2 to the base oil have been investigated with a reciprocating ball-on-plate tribotester for magnesium alloy-steel contacts. The results demonstrate that the optimum mass ratio of nano-SiO2 to nano-MoS2 is 0.25：0.75. The optimum combinative addition into the base oil reduces the friction coefficient by 43.8% and the surface roughness （Sa） by 31.7% when compared to that found with the base oil. Meanwhile, the combinative addition of nano-MoS2 and nano-SiO〉 in comparison with single nanoparticles addition, is more pronounced in terms of the lubrication film stability. The excellent tribological properties of the SiO2/MoS2 combinations are attributed to the formation of physical adsorption films and tribochemical products during the rubbing process and the micro-cooperation of various nano- particles with different shapes and lubrication mechanisms.
