氨基功能化Fe_3O_4@SiO_2的合成及对Pb^(2+)、Hg^(2+)、Cd^(2+)和Cr^(3+)的吸附研究

Synthesis of Amino-functionalized Fe_3O_4@SiO_2 Nanoparticles for Removal of Pb^(2+)、Hg^(2+)、Cd^(2+) and Cr^(3+)

采用化学共沉淀法和溶胶-凝胶法分别合成了Fe_3O_4和核壳式结构Fe_3O_4@SiO_2纳米粒子,然后以聚乙烯亚胺为表面功能化试剂,用化学修饰的方法将其嫁接于Fe_3O_4@SiO_2纳米粒子表面。合成的氨基功能化复合材料具有超顺磁磁性,为重金属离子的富集和分离提供了便利。以氨基功能化的Fe_3O_4@SiO_2-NH_2作为吸附剂,在室温和不调节pH的条件下,研究其对Pb^(2+)、Hg^(2+)、Cd^(2+)和Cr^(3+)(200 ml/L)四种重金属离子的去除效果。Fe_3O_4@SiO_2-NH_2对Pb^(2+)、Hg^(2+)、Cd^(2+)和Cr^(3+)的吸附平衡时间分别为40、50、30和50 min,吸附效率排序为:Cd^(2+)(98.4%)> Pb^(2+)(93.6%)> Hg^(2+)(86.3%)> Cr^(3+)(81.3%)。

The Fe3O4 and Fe3O4@SiO2 nanoparticles were prepared by the chemical co-precipitation and sol-gel methods, respectively, and the surface of Fe3O4@SiO2 nanoparticles was functionalized with polyethyleneimine. The functionalized Fe3O4@SiO2-NH2 particles had the superparamagnetic property, which would favor the magnetic enrichment and separation of these particles after capturing heavy metal ions in solution through an external magnetic field. The adsorption process for Pb^2+,Hg^2+,Cd^2+ and Cr^3+ were mostly complete within 40, 50, 30 and 50 min, respectively. The adsorption efficiencies of Pb^2+、Hg^2+、Cd^2+ and Cr^3+ were 93.6%, 86.3%, 98.4%and 81.3% at room temperature with no pH pre-adjustments.