硅烷化改性沸石对重金属离子的吸附性能

制得一种用于重金属废水处理的新型硅烷化改性沸石吸附剂,成本低、效果显著且稳定。通过对改性沸石表征,分析了改性对沸石结构的影响。结果表明,改性一定程度降低了原沸石的晶体特征,但基本上保持了其结构组成;硅烷化改性成功地在沸石上接枝了氨基。对硅烷化沸石的特性研究,得出硅烷化沸石对Ni2+、Cu2+、Zn2+和Pb2+吸附最佳投加量为1、1、1.6和0.6 g/L,且此时对4种离子的去除率也较好;吸附动力学研究得出,其吸附过程可用二级动力学方程较好地拟合;吸附达到平衡时,4种金属离子的平衡吸附量分别为11.23、17.41、15.45和59.42 mg/g;硅烷化沸石对金属离子的吸附行为更符合Langmuir模型,为化学吸附;在酸性条件下(pH=2～6),硅烷化沸石仍保持一定的吸附能力,具有一定的耐酸性。

Adsorption of heavy metal ions by silylation modified zeolite

A new kind of zeolite modified by silylation used for heavy metal ion adsorption was developed in this study. The modification and adsorption character of silylanized zeolite was investigated via SEM, FTIR spectrum, XRD and adsorption experiments. It was revealed that NH₂ was grafted on surface of zeolite and the optimum dosages of the adsorbents for Ni²⁺, Cu²⁺, Zn²⁺ and Pb²⁺ were 1 g/L, 1 g/L, 1.6 g/L and 0.6 g/L. The results of sorption kinetic study show that the adsorption fits pseudo-second-order model better. And the adsorption was inferred to be chemisorption with good fit of Langmuir adsorption isotherm. The silylation zeolite removed heavy metal effectively over the pH range 2~6, therefore the adsorbent could be applied in acid heavy metal wastewater treatment.