一步法制备体心立方结构的介孔碳/氧化硅纳米复合材料

以酚醛树脂预聚体(Resol)为碳源前驱体,嵌段共聚物聚氧乙烯-聚氧丙烯-聚氧乙烯(PEO–PPO–PEO,F127)和聚二甲基硅氧烷-聚氧乙烯(PDMS–PEO)为混合模板剂,采用溶剂挥发诱导自组装(EISA)方法制备了有序介孔碳-氧化硅纳米复合材料,并进一步采用小角X射线散射(SAXS)、透射电子显微镜(TEM)和氮气吸脱附分析对所制备样品的结构和组成进行表征.结果表明,所制备的介孔碳/氧化硅纳米复合材料具有体心立方Im3m结构,其BET比表面积、总孔容和孔径分别为1 410 m2g,1.12 cm3g和5.4 nm.

碳硅介孔材料对水中Cr^(6+)和苯酚的吸附性能研究

以正硅酸乙酯(TEOS)为硅源,十六烷基三甲基溴化铵(CTAB)为模板和碳源,用水热合成法制备介孔氧化硅(MCM-41),再加浓硫酸,经过干燥、煅烧、水洗,得到介孔碳硅复合材料。考察其对环境水体中Cr^(6+)和苯酚的吸附性能。结果表明,吸附苯酚的最适条件:30℃,pH=5,吸附时间24 h,此时饱和吸附量为7~11 mg/g;吸附Cr^(6+)的最适条件:20℃,pH=8,吸附时间24 h,饱和吸附量为15~20 mg/g。用材料吸附微污染水中Cr^(6+)和苯酚,去除率分别达到70%和79.77%。

Characterization and adsorption behaviors of a novel synthesized mesoporous silica coated carbon composite

A novel mesoporous silica coated carbon composite(denoted SEG) with hierarchical pore structure has been successfully prepared in an aqueous solution that contains triblock copolymer template, aluminum chloride, siliceous source and expanded graphite. Textural property and morphology of the SEG composite were characterized by the combination of X-ray diffraction, N_2 adsorption–desorption, scanning electron microscopy,transmission electron microscopy and Fourier transform infrared measurements. Results show that mesoporous silica is steadily and uniformly grown on the surface of the graphite slices and the thickness of the silica layer can be finely tuned according to the silica/C molar ratio in the initial reaction solution. This newly synthesized SEG composite shows greatly increased adsorption capacity to methylene blue than the pristine expanded graphite in the batch tests. Both Langmuir and Frendlich models were further used to evaluate the adsorption isotherms of methylene blue over expanded graphite and SEG samples with different silica contents. Finally, pseudosecond-order model was used to describe the kinetics of methylene blue over expanded graphite and the silica-carbon composites.