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采用溶胶-凝胶伴随相分离法通过原位合成镍铜铁氧体尖晶石纳米颗粒制备出新型磁性复合多孔SiO_2干凝胶,并对其显微结构、磁性和吸附性能进行了表征。结果表明:前驱体中水解缩合的乙醇酸以有机分子链的形式与无机分子相结合并构成骨架,形成双连续孔结构,尖晶石纳米颗粒均匀分布在二氧化硅基体中。随热处理温度的升高,样品的比表面积迅速下降,但磁化强度增强。经过700℃热处理后的样品S3,孔隙率为73.22%,体积密度为0.32 g/cm3,平均粒度为16μm,能够有效吸附溶液中的Ce(IV),最大吸附容量为100.67 mg/g。此外,样品S3呈现出较好的磁性分离特性和重复利用性。
A novel magnetic composite porous SiO_2 xerogel was prepared by in-situ synthesis of nickel-copper ferrite spinel nanoparticles by sol-gel phase separation. The microstructure, magnetic properties and adsorption properties of the composites were characterized. The results showed that the glycolic acid hydrolyzed and condensed in the precursor was combined with the inorganic molecules in the form of organic molecular chains to form the skeleton, forming a bicontinuous pore structure. The spinel nanoparticles were uniformly distributed in the silica matrix. With the increase of heat treatment temperature, the specific surface area of the sample decreased rapidly, but the magnetization increased. After heat treatment at 700 ℃, the sample S3 has a porosity of 73.22%, a bulk density of 0.32 g / cm3 and an average particle size of 16 μm, which can effectively adsorb Ce (IV) in the solution with a maximum adsorption capacity of 100.67 mg / g. In addition, sample S3 showed better magnetic separation and reusability.