摘要
采用共沉淀法制备出Fe_3O_4纳米微粒,再以甘油和水的混合液作溶剂,通过溶胶凝胶法制得介孔SiO_2/Fe_3O_4复合材料,利用XRD、SEM和BET对材料的结构进行表征,结果表明合成的SiO_2/Fe_3O_4复合材料的表面为无定型的介孔SiO_2层,窗口孔径和腔体孔径分别为18.8 nm和30.0nm。通过将合成的介孔SiO_2/Fe_3O_4复合材料在500℃热处理3h后,材料的窗口孔径和腔体孔径分别减少为17.6nm和22.3 nm,而腔体孔径的分布则明显变宽。将未经热处理和已经热处理的介孔SiO_2/Fe_3O_4复合材料分别用于漆酶的固定化,结果表明:经过热处理的复合材料固定化漆酶的表观活性(8.79OD·g^(-1))较未经热处理的复合材料固定化漆酶的表观活性(6.0OD·g^(-1))要高,且在经过8次循环使用以后,前者固定化漆酶的操作稳定性(72.47%)也远远高过后者固定化漆酶的操作稳定性(44.83%)。以上研究表明所合成的介孔SiO_2/Fe_3O_4复合材料经热处理后是一种固定化漆酶的优良载体。
Fe3O4 nanoparticles have been synthesized by co-deposition method,and coated with mesoporous silica by sol-gel method using glycerol and water as mixed solvent.The morphology and structure of the SiO2/Fe3O4 composites were characterized by XRD,SEM and BET.Results showed that the mesoporous silica was coated on the surface of Fe3O4 nanoparticles,and the diameters of its windows and cells were 18.8 nm and 30.0 nm,respectively.After the composite was annealed at 500℃for 3 h,the diameters of its windows and cells decreased to 17.6 nm and 22.3 nm,respectively.Moreover, the pore size distribution of the cells of the annealed composite became broader remarkably.The composites were used as supports to immobilize laccase.The results showed that the apparent activity of laccase immobilized on the annealed composite（8.79 OD·g^-1） was higher than that of laccase immobilized on the unannealed composite（6.0OD·g^-1）.Furthermore, when both of them were recycled for 8 times,the operational stability of the laccase immobilized on the annealed composite （72.47%） was still higher than that of the laccase immobilized on the unannealed composite（44.83%） greatly.All results show that the annealed mesoporous SiO2/Fe3O4 composite is a good carrier for laccase immobilization.
基金
国家自然科学基金(50772001)
安徽省教育厅自然科学基金重点项目(KJ2008A148)
安徽省优秀青年科技基金(08040106822)
