Purification of original crude glycerol obtained from biodiesel production was conducted in a laboratory scale equipment by means of a combined chemical and physical treatment method based upon repeated cycles of acid...Purification of original crude glycerol obtained from biodiesel production was conducted in a laboratory scale equipment by means of a combined chemical and physical treatment method based upon repeated cycles of acidification of liquid phase to the desired pH value by using 5.85% H3PO4 solution for pH value adjustment, and the mixture was kept at 70 ℃ for 60 rain to make phase separation for obtaining a glycerol-rich middle phase. The yield of crude glycerol reached 81.2%. Subsequently, upon reaction of the obtained glycerol phase with 0.03% of sodium oxalate at 80 ℃ for 30 min the impurity removal rate was equal to 19.8%. The fraction boiling between 164 ℃ and 200 ℃ was collected by vacuum distil- lation followed by decolorization with 2% of active carbon at 80 ℃ for two times to yield the product glycerol with an ac- ceptable purity of 98.10%.展开更多
In this study,the sulfur-doped porous g-C_(3)N_(4) nanosheets(CN-T-U 1.75)were synthesized successfully by onestep calcination utilizing urea and thiourea as precursors.Under visible light irradiation,CN-T-U 1.75 show...In this study,the sulfur-doped porous g-C_(3)N_(4) nanosheets(CN-T-U 1.75)were synthesized successfully by onestep calcination utilizing urea and thiourea as precursors.Under visible light irradiation,CN-T-U 1.75 showed remarkable photocatalytic activity for Rhodamine B(RhB)degradation with a kinetic reaction rate constant of 0.01838 min^(-1).The characterization analysis indicated that CN-T-U 1.75 had a higher specific surface area and the doping altered the energy band structure.This work offers a new viewpoint on modifying the band structure of a photocatalyst using a doping strategy,as well as new insights into the generation routes of active species involved in the photocatalytic process.展开更多
Modified hierarchical porous Hβ zeolite was obtained by metal modification of Hβ zeolite, which was treated with alkaline solution, and the catalysts before and after modification were characterized by means of X-ra...Modified hierarchical porous Hβ zeolite was obtained by metal modification of Hβ zeolite, which was treated with alkaline solution, and the catalysts before and after modification were characterized by means of X-ray diffraction（XRD）, nitrogen adsorption-desorption~ scanning electron microscopy（SEM）, X-ray fluorescence（XRF）, NH3 temperature-programmed desorption and Fourier-transform infrared spectroscopy（FTIR）. The activities of acy- lation of anisole with acetic anhydride were also investigated. The results show that the Hp zeolite, which was treated with alkaline solution has microporous and mesoporous structures that could improve the diffusion performance of chemical reaction. The amount of acid was modulated with metal modification. The Hβ zeolite modified by 5%（mass fraction） metal chromium had the best catalytic performance. The conversion of acetic anhydride acylation was 93.01% under the optimal conditions, which was higher than that of other catalysts. The catalyst not only showed good activity, but also exhibited a stable performance in regeneration tests.展开更多
文摘以三聚氰胺、葡萄糖和氯化铵为原料制备一种具有高比表面积的碳氯共掺杂介孔g-C_(3)N_(4)(C-Cl-CN)光催化剂,并考察其光催化降解罗丹明B(RhB)的性能。采用XRD,XPS,SEM,UV-Vis DRS和PL测试手段表征和分析催化剂的晶型结构、化学组成及微观形貌。结果表明:C-Cl-CN具有最高的比表面积(108.7 m 2/g),降解RhB的速率常数达到0.02290 min^(-1),是纯g-C_(3)N_(4)的9.4倍,且具有良好的催化稳定性。葡萄糖和氯化铵在聚合过程中起到双气泡模板和元素掺杂剂的作用,一方面提升催化剂的比表面积,另一方面减小能带间隙,增强催化剂的光吸收性能。
基金the financial support from Scientific Research Foundation for Doctoral Program of Liaoning Province(20081104)
文摘Purification of original crude glycerol obtained from biodiesel production was conducted in a laboratory scale equipment by means of a combined chemical and physical treatment method based upon repeated cycles of acidification of liquid phase to the desired pH value by using 5.85% H3PO4 solution for pH value adjustment, and the mixture was kept at 70 ℃ for 60 rain to make phase separation for obtaining a glycerol-rich middle phase. The yield of crude glycerol reached 81.2%. Subsequently, upon reaction of the obtained glycerol phase with 0.03% of sodium oxalate at 80 ℃ for 30 min the impurity removal rate was equal to 19.8%. The fraction boiling between 164 ℃ and 200 ℃ was collected by vacuum distil- lation followed by decolorization with 2% of active carbon at 80 ℃ for two times to yield the product glycerol with an ac- ceptable purity of 98.10%.
基金supported by the Liaoning Provincial Natural Fund Mentoring Program Project (2019-ZD-0057)
文摘In this study,the sulfur-doped porous g-C_(3)N_(4) nanosheets(CN-T-U 1.75)were synthesized successfully by onestep calcination utilizing urea and thiourea as precursors.Under visible light irradiation,CN-T-U 1.75 showed remarkable photocatalytic activity for Rhodamine B(RhB)degradation with a kinetic reaction rate constant of 0.01838 min^(-1).The characterization analysis indicated that CN-T-U 1.75 had a higher specific surface area and the doping altered the energy band structure.This work offers a new viewpoint on modifying the band structure of a photocatalyst using a doping strategy,as well as new insights into the generation routes of active species involved in the photocatalytic process.
基金Supported by the Natural Science Foundation of Technology Department of Liaoning Province, China（No.2014020109）.
文摘Modified hierarchical porous Hβ zeolite was obtained by metal modification of Hβ zeolite, which was treated with alkaline solution, and the catalysts before and after modification were characterized by means of X-ray diffraction（XRD）, nitrogen adsorption-desorption~ scanning electron microscopy（SEM）, X-ray fluorescence（XRF）, NH3 temperature-programmed desorption and Fourier-transform infrared spectroscopy（FTIR）. The activities of acy- lation of anisole with acetic anhydride were also investigated. The results show that the Hp zeolite, which was treated with alkaline solution has microporous and mesoporous structures that could improve the diffusion performance of chemical reaction. The amount of acid was modulated with metal modification. The Hβ zeolite modified by 5%（mass fraction） metal chromium had the best catalytic performance. The conversion of acetic anhydride acylation was 93.01% under the optimal conditions, which was higher than that of other catalysts. The catalyst not only showed good activity, but also exhibited a stable performance in regeneration tests.
