巯基改性煤矸石去除废水中镉离子的研究

Study on cadmium ions removal from wastewater by sulfydryl modified coal gangue

利用巯基改性热活化煤矸石制备巯基改性煤矸石,采用SEM、XRD、FT-IR、Zeta potential分析方法分析了巯基改性煤矸石的结构和表面官能团等特性,考察了废水pH值、共存离子、巯基改性煤矸石投加量对其吸附Cd^(2+)的影响,探讨了其吸附动力学和吸附等温线。结果表明,巯基改性煤矸石具有丰富的孔道和片状结构,在废水pH值为9.0时对Cd^(2+)的吸附效果最好;Na^(+)、K^(+)、Mg^(2+)与Cd^(2+)存在吸附竞争,抑制了对Cd^(2+)的去除,F^(-)、CO_(3)^(2-)与Cd^(2+)形成化合物,促进Cd^(2+)的去除;巯基改性煤矸石对Cd^(2+)的吸附更符合伪二级动力学和Freundlich吸附等温式,其对Cd^(2+)的吸附以化学吸附为主,呈现多分子层吸附。在巯基改性煤矸石投加量为5 g/L,pH值为9.0,温度为50℃的条件下对Cd^(2+)的吸附率为98.33%,吸附量为65.32 mg/g,巯基改性煤矸石对镉离子具有良好的吸附性能。

Using sulfydryl modified thermal activation to prepare sulfydryl modified coal gangue,the structure and surface functional groups of the sulfydryl modified coal gangue were analyzed by SEM,XRD,FT-IR,Zeta potential methods;besides,the effect of wastewater pH value,coexisting ions and sulfydryl modified coal gangue dosage on adsorption of Cd^(2+)was investigated,and the adsorption kinetics and adsorption isotherms were discussed.The results showed that,sulfydryl modified coal gangue has rich pore channels and sheet-like structure,the best adsorption effect on Cd^(2+)was obtained when the wastewater pH value was 9.0.Na^(+),K^(+),Mg^(2+)compete with Cd^(2+)for adsorption,inhibiting the removal of Cd^(2+).A compound was formed with F^(-),CO_(3)^(2-)and Cd^(2+),which promoting the removal of Cd^(2+).The adsorption of Cd^(2+)by sulfydryl modified coal gangue fits pseudo second order kinetics and Freundlich adsorption isotherm,which is mainly chemical adsoption exhibiting multi-layered adsorption.Under the condition that the sulfydryl modified coal gangue dosage was 5 g/L,the pH value we 9.0,the temperature was 50℃,the adsorption rate of Cd^(2+)was 98.33%,the adsorption capacity was 65.32 mg/L,it was indicated that sulfydryl modified coal gangue had good adsorption performance on cadmium ions.