介孔TiO_2的孔结构调控及其蛋白质固定化性能

Pore structure modification of mesoporous TiO_2 for immobilization of protein

以水合二钛酸(H2Ti2O5·xH2O)为前驱体,通过改变热处理条件制备不同孔径尺寸的介孔TiO2。采用X线衍射仪、场发射扫描电子显微镜、N2吸附-脱附方法对TiO2的结构进行表征,同时以牛血清蛋白(BSA)为模型蛋白,考察介孔TiO2的孔结构对BSA固定化性能的影响。结果表明:介孔TiO2的孔径可实现9～30 nm范围内可调,其中650℃焙烧得到的介孔TiO2孔径为21.6 nm,对BSA的吸附量达69.6 mg/g,优于其他孔径尺寸的介孔TiO2,且与纳米TiO2(P25)的吸附量相当。吸附的BSA分子进入TiO2的孔道内,介孔TiO2比P25具有较好的吸附稳定性,经过6次循环后吸附的BSA残余量仍有65%,而P25上BSA的残余量仅为17%。介孔TiO2为微米级颗粒,有利于从反应体系中分离回收,是一种极有潜力的生物分子固定化载体。

The mesoporous TiO2 with different pore sizes was synthesized by changing calcined temperature using H2Ti2O5·xH2O as the precursor.TiO2 samples were characterized by X-ray diffraction（XRD）,field-emission scanning electron microscopy（FESEM） and N2 adsorption-desorption measurements.The effects of pore size of mesoporous TiO2 on the immobilization of bovine serum albumin（BSA） were investigated.The results indicated that the pore size of mesoporous TiO2 was adjustable from 9 nm to 30 nm.The BSA adsorption capacity was up to 69.6 mg/g for the sample（TiO2-650） calcined at 650 ℃,which had the pore size of 21.6 nm.The corresponding adsorption capacity of TiO2-650 was better than other mesoporous TiO2 materials and similar with titanium dioxide nanoparticles（P25）.Nitrogen adsorption-desorption isotherms of mesoporous TiO2 before and after BSA adsorption and their pore size distributions demonstrated that BSA molecules entered the pores.BSA adsorbed on mesoporous TiO2 was more stable than that on P25 and its amount on mesoporous TiO2 maintained 65% of initial value after reusing 6 times,while BSA on P25 was only 17%.Furthermore,micron-sized mesoporous TiO2 was more likely to be separated than P25 from the reaction system.The materials exhibited a potential application in the immobilization for biomolecules.