磁性Fe_(3)O_(4)@SiO_(2)@介孔SiO_(2)空心微球的制备及漆酶固定化

Synthesis and laccase immobilization of magnetic Fe_(3)O_(4)@SiO_(2)@mesoporous SiO_(2) hollow microspheres

磁性介孔二氧化硅复合材料作为酶固定化载体具有优异的酶固定化性能和良好的磁分离性能,受到国内外学术界广泛关注。本文在自制的β-FeOOH空心微球表面上包覆致密的SiO_(2)保护层,在酸性条件下以P123为模板剂,十六烷基三甲基溴化铵(CTAB)为辅助导向剂成功制备出了磁性β-FeOOH@SiO_(2)@介孔SiO_(2)空心复合微球,最后在还原气氛下煅烧得到Fe_(3)O_(4)@SiO_(2)@介孔SiO_(2)空心微球。结果表明,所制备的Fe_(3)O_(4)@SiO_(2)@介孔SiO_(2)微球空心结构未坍塌,具有规整的球形结构,介孔SiO_(2)壳层(平均厚度约为11nm)均匀地包覆在β-FeOOH@SiO_(2)中空微球表面。伴随着CTAB量的增加,微球的最可几孔径由4.30nm减小到3.19nm,比表面积从376m2/g升高到640m2/g,孔容从0.36cm3/g升高到0.56cm3/g。复合微球的饱和磁化强度为11.3emu/g,矫顽力为111.5Oe,外加磁场作用下可以实现样品的快速分离,且样品的再分散性良好。当介孔孔径为4.30nm时,Fe_(3)O_(4)@SiO_(2)@介孔SiO2空心复合微球漆酶固定量高达234mg/g。固定化漆酶在不同pH、温度下的活性显著优于游离酶。

The magnetic mesoporous silica composite material as the enzyme immobilization carrier has excellent enzyme immobilization performance and good magnetic separation performance,and has received extensive attention from academic circles at home and abroad.The surface of the self-madeβ-FeOOH hollow microspheres was coated with a dense SiO_(2) protective layer.Under acidic conditions,β-FeOOH@SiO_(2)@mesoporous SiO_(2 ) hollow composite microspheres were successfully prepared by using P123 as a template and cetyltrimethylammonium bromide(CTAB)as an auxiliary directing agent.Magneticβ-FeOOH@SiO_(2)@mesoporous SiO2 hollow composite microspheres were finally calcined in a reducing atmosphere to obtain Fe_(3)O_(4)@SiO_(2)@mesoporous SiO_(2) hollow microspheres.The results showed that the hollow structure of the prepared Fe_(3)O_(4)@SiO_(2)@mesoporous SiO2 microspheres was not collapsed and had a regular spherical structure.The mesoporous SiO_(2) shell(with a average thickness of about 11nm)was uniformly coated onβ-FeOOH@SiO_(2) hollow microsphere surface.As the amount of CTAB increases,the most probable pore size of the microspheres decreased from 4.30nm to 3.19nm,the specific surface saturation magnetization of the composite microspheres was 11.3emu/g,and the coercivity was 111.5Oe.The rapid separation of the samples could be achieved under the action of an external magnetic field,and the redispersibility of the samples was good.When the mesoporous pore size was 4.30nm,the amount of laccase immobilized in Fe_(3)O_(4)@SiO_(2)@mesoporous SiO_(2) hollow composite microsphere was as high as 234mg/g.The activity of immobilized laccase at different pH and temperature was significantly better than that of free laccase.