In this paper,the effects of pore-size of SBA-15 on the adsorption kinetics and equilibrium of large protein molecules Bovine serum albumin(BSA)and lysozyme(LYS)have been investigated.The mesoporous molecular sieve SB...In this paper,the effects of pore-size of SBA-15 on the adsorption kinetics and equilibrium of large protein molecules Bovine serum albumin(BSA)and lysozyme(LYS)have been investigated.The mesoporous molecular sieve SBA-15 with six different pore sizes were synthesized with P123 triblock copolymer as the template agent,and 1,3,5-trimethylbenzene(TMB)and isopropyl alcohol as the pore-expanding agent.The samples were characterized by N2 adsorption/desorption,Scanning Electron Microscopy(SEM),Transmission Electron Microscopy(TEM)and X-Ray Diffraction(XRD).It is found that BSA and LYS were adsorbed rapidly on SBA-15 materials with large pores.The BSA adsorption capacity of sieve with the pore diameter of 21.4 nm reached 500 mg·g-1 within 25 minutes.However,if the pore diameter was smaller than 14 nm,the BSA adsorption capacity of the sieve was only about 220 mg·g-1.The adsorption equilibrium data fits in the Langmuir model,where the coefficient of effective use of specific area of mesoporous molecular sieve was found to be 0.03,0.18,0.37 and 0.48,corresponding to the pore diameter of 10.1 nm,13.2 nm,15.4 nm and 21.4 nm,respectively.The equilibrium loading amount of LYS on SBA-15 materials with pore size of 15.4 nm could be up to 1000 mg·g-1.The coefficient of effective use of surface area of mesoporous molecular sieve with diameter of 3.9 nm,7.4 nm,10.1 nm,13.2 nm and 15.4 nm was 0.10,0.47,0.56,0.71 and 0.79,respectively.It is also noted that greater pore size of mesoporous molecular sieve would lead to a higher coefficient of effective use of surface area.展开更多
A functionalized material, PW/SBA-15m, was prepared successfully in diluted H_2SO_4 aqueous solutions by immobilizing 12-tungstophosphates on chemically modified mesoporous silica SBA-15 and characterized by elemental...A functionalized material, PW/SBA-15m, was prepared successfully in diluted H_2SO_4 aqueous solutions by immobilizing 12-tungstophosphates on chemically modified mesoporous silica SBA-15 and characterized by elemental analysis, FTIR, ~ ~31 P MAS NMR, XRD and TEM. The results indicate that the framework of SBA-15 and the Keggin structure of PW_~12 O^3- _~40 were retained, and that 23%-33%(mass fraction) of ~PW_~12 O^3- _~40 was immobilized; the PW_~12 O^3- _~40 anions were finely dispersed on the pore wall of SBA-15. Having been leached in ethanol at 60 ℃ for 7 h, the loss of PW_~12 O^3- _~40 anions was not found.展开更多
Mesoporous silica SBA-15 consists of uniform hexagonal, unconnected cylindrical channels with diameters that can be tuned within a range of 1.5 nm-30 nm, and is thought to have a special thermal conductivity. The theo...Mesoporous silica SBA-15 consists of uniform hexagonal, unconnected cylindrical channels with diameters that can be tuned within a range of 1.5 nm-30 nm, and is thought to have a special thermal conductivity. The theoretical investigation of the shell thermal conductivity of the mesoporous silica is performed in the relaxation time approximation in this paper and an available one-dimensional heat transfer model is used to predict the effective thermal conductivity （ETC） of the mesoporous silica. The experimental result of the ETC is also presented for comparison. The shell thermal conductivity of the mesoporous silica decreases with mesochannel radius increasing or wall thickness decreasing, but does not strictly decrease with porosity increasing. The thermal radiation possibly plays a primary role in heat transfer at the large porosity scale. The predicted ETC of SBA-15 with only conduction considered is quite low at the large porosity, even lower than the thermal conductivity of the silica aerogels. To realize it, doping carbon or other matters which can strongly absorb infrared light into SBA-15 is a possible way.展开更多
Chromium-incorporated mesoporous silica materials （MCrS） have been successfully prepared in strong acidic media by assembly of preformed CrSI precursors with triblock copolymer of the Pluronic type （P123） by a two...Chromium-incorporated mesoporous silica materials （MCrS） have been successfully prepared in strong acidic media by assembly of preformed CrSI precursors with triblock copolymer of the Pluronic type （P123） by a two steps procedure. Various techniques including XRD, N2 adsorption, FT-IR spectroscopy, diffuse reflectance UV-vis （DRUV-vis） and EPR were employed for the materials characterization. MCrS materials have a hexagonal structure with uniform mesopores and contain Cr（V） and Cr（VI） under low and high Cr content and that the mesoporous walls contain the MFI structure building units.展开更多
Photocatalysis is one of the most promising methods owing to its great potential to relieve environmental issue. To construct efficient photocatalyst with low energy consumption, mild catalytic conditions, and stable ...Photocatalysis is one of the most promising methods owing to its great potential to relieve environmental issue. To construct efficient photocatalyst with low energy consumption, mild catalytic conditions, and stable chemical properties are highly desired. In this work, a novel, highly active and environmental friendly mesoporous photocatalyst Bi4O5Br2/SBA-15 was synthesized by hydrothermal method, and its characteristics and visible-light catalytic activity were investigated. The synthesized photocatalyst consisted of Langmuir type IV hysteresis loops, which was confirmed to be a composite material with mesoporous structure. It exhibited a high visible-light absorption intensity and a low recombination rate of photo-generated electrons and holes. When the mass ratio of Bi/SiO2 was 30/100 during the synthesis, the obtained photocatalyst (Bi30/SBA-15) reflected the fastest Rhodamine B (RhB) removal rate and achieved 100% decolorization of RhB by both adsorption and degradation process. This high decolorization efficiency can also be maintained and realized by recycling the used composite in practice. The enhanced visible-light photocatalytic activity of novel Bi4O5Br2/SBA-15 photocatalyst can be ascribed to the existing active sites both inside and outside SBA-15 which enhanced the separation of photo-generated electrons and holes.展开更多
The biggest challenge for organic phase change materials(PCMs)used in cold energy storage is to maintain high heat storage capacity while reducing the leakage risk of PCMs during the phase transition process.This is c...The biggest challenge for organic phase change materials(PCMs)used in cold energy storage is to maintain high heat storage capacity while reducing the leakage risk of PCMs during the phase transition process.This is crucial for expanding their applications in the more demanding cold storage field.In this study,novel formstable low-temperature composite PCMs are prepared with mesoporous materials,namely SBA-15 and CMK-3(which are prepared using the template method),as supporting matrices and dodecane as the PCM.Owing to the combined effects of capillary forces within mesoporous materials and interactions among dodecane molecules,both dodecane/SBA-15 and dodecane/CMK-3 exhibit outstanding shape stability and thermal cycling stability even after 200 heating/cooling cycles.In comparison to those of dodecane/SBA-15,dodecane/CMK-3 exhibits superior cold storage performance and higher thermal conductivity.Specifically,the phase transition temperature of dodecane/CMK-3 is-8.81℃ with a latent heat of 122.4 J·g^(-1).Additionally,it has a thermal conductivity of 1.21 W·m^(-1)·K^(-1),which is 9.45 times that of dodecane alone.All these highlight its significant potential for applications in the area of cold energy storage.展开更多
基金Supported by the National Basic Research Program of China(2007CB714302)the Outstanding Young Teacher Visiting Scholar Program of Shandong Province
文摘In this paper,the effects of pore-size of SBA-15 on the adsorption kinetics and equilibrium of large protein molecules Bovine serum albumin(BSA)and lysozyme(LYS)have been investigated.The mesoporous molecular sieve SBA-15 with six different pore sizes were synthesized with P123 triblock copolymer as the template agent,and 1,3,5-trimethylbenzene(TMB)and isopropyl alcohol as the pore-expanding agent.The samples were characterized by N2 adsorption/desorption,Scanning Electron Microscopy(SEM),Transmission Electron Microscopy(TEM)and X-Ray Diffraction(XRD).It is found that BSA and LYS were adsorbed rapidly on SBA-15 materials with large pores.The BSA adsorption capacity of sieve with the pore diameter of 21.4 nm reached 500 mg·g-1 within 25 minutes.However,if the pore diameter was smaller than 14 nm,the BSA adsorption capacity of the sieve was only about 220 mg·g-1.The adsorption equilibrium data fits in the Langmuir model,where the coefficient of effective use of specific area of mesoporous molecular sieve was found to be 0.03,0.18,0.37 and 0.48,corresponding to the pore diameter of 10.1 nm,13.2 nm,15.4 nm and 21.4 nm,respectively.The equilibrium loading amount of LYS on SBA-15 materials with pore size of 15.4 nm could be up to 1000 mg·g-1.The coefficient of effective use of surface area of mesoporous molecular sieve with diameter of 3.9 nm,7.4 nm,10.1 nm,13.2 nm and 15.4 nm was 0.10,0.47,0.56,0.71 and 0.79,respectively.It is also noted that greater pore size of mesoporous molecular sieve would lead to a higher coefficient of effective use of surface area.
文摘A functionalized material, PW/SBA-15m, was prepared successfully in diluted H_2SO_4 aqueous solutions by immobilizing 12-tungstophosphates on chemically modified mesoporous silica SBA-15 and characterized by elemental analysis, FTIR, ~ ~31 P MAS NMR, XRD and TEM. The results indicate that the framework of SBA-15 and the Keggin structure of PW_~12 O^3- _~40 were retained, and that 23%-33%(mass fraction) of ~PW_~12 O^3- _~40 was immobilized; the PW_~12 O^3- _~40 anions were finely dispersed on the pore wall of SBA-15. Having been leached in ethanol at 60 ℃ for 7 h, the loss of PW_~12 O^3- _~40 anions was not found.
基金supported by the National Basic Research Program of China (973 Program) (Grant No. 2012CB720404)the National Natural Science Foundation of China (Grant No. 50836001)+1 种基金the FOK Ying Tong Education Foundation,China (Grant No. 121055)the Fundamental Research Funds for the Central Universities,China (Grant Nos. FRF-AS-12-002 and FRF-TP-11-001B)
文摘Mesoporous silica SBA-15 consists of uniform hexagonal, unconnected cylindrical channels with diameters that can be tuned within a range of 1.5 nm-30 nm, and is thought to have a special thermal conductivity. The theoretical investigation of the shell thermal conductivity of the mesoporous silica is performed in the relaxation time approximation in this paper and an available one-dimensional heat transfer model is used to predict the effective thermal conductivity （ETC） of the mesoporous silica. The experimental result of the ETC is also presented for comparison. The shell thermal conductivity of the mesoporous silica decreases with mesochannel radius increasing or wall thickness decreasing, but does not strictly decrease with porosity increasing. The thermal radiation possibly plays a primary role in heat transfer at the large porosity scale. The predicted ETC of SBA-15 with only conduction considered is quite low at the large porosity, even lower than the thermal conductivity of the silica aerogels. To realize it, doping carbon or other matters which can strongly absorb infrared light into SBA-15 is a possible way.
文摘Chromium-incorporated mesoporous silica materials （MCrS） have been successfully prepared in strong acidic media by assembly of preformed CrSI precursors with triblock copolymer of the Pluronic type （P123） by a two steps procedure. Various techniques including XRD, N2 adsorption, FT-IR spectroscopy, diffuse reflectance UV-vis （DRUV-vis） and EPR were employed for the materials characterization. MCrS materials have a hexagonal structure with uniform mesopores and contain Cr（V） and Cr（VI） under low and high Cr content and that the mesoporous walls contain the MFI structure building units.
文摘Photocatalysis is one of the most promising methods owing to its great potential to relieve environmental issue. To construct efficient photocatalyst with low energy consumption, mild catalytic conditions, and stable chemical properties are highly desired. In this work, a novel, highly active and environmental friendly mesoporous photocatalyst Bi4O5Br2/SBA-15 was synthesized by hydrothermal method, and its characteristics and visible-light catalytic activity were investigated. The synthesized photocatalyst consisted of Langmuir type IV hysteresis loops, which was confirmed to be a composite material with mesoporous structure. It exhibited a high visible-light absorption intensity and a low recombination rate of photo-generated electrons and holes. When the mass ratio of Bi/SiO2 was 30/100 during the synthesis, the obtained photocatalyst (Bi30/SBA-15) reflected the fastest Rhodamine B (RhB) removal rate and achieved 100% decolorization of RhB by both adsorption and degradation process. This high decolorization efficiency can also be maintained and realized by recycling the used composite in practice. The enhanced visible-light photocatalytic activity of novel Bi4O5Br2/SBA-15 photocatalyst can be ascribed to the existing active sites both inside and outside SBA-15 which enhanced the separation of photo-generated electrons and holes.
基金supported by the National Natural Science Foundation of China(Grant No.51906230)the Key scientific and technological projects in Henan Province(Grant No.212102210007)the Project of Zhongyuan Science and Technology Innovation Talents(Grant No.234200510011).
文摘The biggest challenge for organic phase change materials(PCMs)used in cold energy storage is to maintain high heat storage capacity while reducing the leakage risk of PCMs during the phase transition process.This is crucial for expanding their applications in the more demanding cold storage field.In this study,novel formstable low-temperature composite PCMs are prepared with mesoporous materials,namely SBA-15 and CMK-3(which are prepared using the template method),as supporting matrices and dodecane as the PCM.Owing to the combined effects of capillary forces within mesoporous materials and interactions among dodecane molecules,both dodecane/SBA-15 and dodecane/CMK-3 exhibit outstanding shape stability and thermal cycling stability even after 200 heating/cooling cycles.In comparison to those of dodecane/SBA-15,dodecane/CMK-3 exhibits superior cold storage performance and higher thermal conductivity.Specifically,the phase transition temperature of dodecane/CMK-3 is-8.81℃ with a latent heat of 122.4 J·g^(-1).Additionally,it has a thermal conductivity of 1.21 W·m^(-1)·K^(-1),which is 9.45 times that of dodecane alone.All these highlight its significant potential for applications in the area of cold energy storage.
