硫掺杂ZnFe_(2)O_(4)/蒙脱石复合材料的铀酰吸附研究

Study on uranyl adsorption of sulfur-doped ZnFe_(2)O_(4)/MMT composite

为获得铀酰(UO2^(2+))吸附性能高的吸附剂,以蒙脱石(Montmorillonite,MMT)和铁酸盐(ZnFe_(2)O_(4))为原材料与L-半胱氨酸通过水热反应制备了硫掺杂ZnFe_(2)O_(4)(S-ZnFe_(2)O_(4))和ZnFe_(2)O_(4)/MMT(S-ZnFe_(2)O_(4)/MMT),采用XRD、FTIR和SEM对S-ZnFe_(2)O_(4)和S-ZnFe_(2)O_(4)/MMT进行了结构表征,研究了pH、接触时间和UO2^(2+)初始质量浓度对UO2^(2+)吸附效果的影响,结果表明:S-ZnFe_(2)O_(4)呈高分散的纳米颗粒状,并且均匀分布于蒙脱石片层结构表面;S-ZnFe_(2)O_(4)与蒙脱石复合后能明显提高其UO2^(2+)吸附性能,最佳吸附pH为6.0;S-ZnFe_(2)O_(4)和S-ZnFe_(2)O_(4)/MMT复合材料对UO2^(2+)的最大吸附量分别为51.44 mg/g和68.45 mg/g;吸附符合Langmuir等温吸附模型和伪二阶动力学模型,说明吸附过程属于表面单分子层化学吸附。

For obtaining a high uranyl(UO2^(2+))adsorption performance of adsorbent,montmorillonite(MMT)and ferrite(ZnFe_(2)O_(4))were used as raw materials to prepare sulfur-doped ZnFe_(2)O_(4)(S-ZnFe_(2)O_(4))and ZnFe_(2)O_(4)/MMT(S-ZnFe_(2)O_(4)/MMT)by hydrothermal reaction with L-cysteine.The structure of S-ZnFe_(2)O_(4) and S-ZnFe_(2)O_(4)/MMT was characterized by XRD,FTIR and SEM,while the effects of pH,contact time and initial UO 22+concentration on UO2^(2+)adsorption performance were studied.The results show that S-ZnFe_(2)O_(4) is presented as highly dispersed nano-particles and are evenly distributed on the surface of the lamellar structure of montmorillonite.The recombination of S-ZnFe_(2)O_(4) with montmorillonite has improved UO2^(2+)adsorption performance significantly.When pH 6.0 was decided to be the optimum adsorption condition,the maximum UO2^(2+)adsorption capacities of S-ZnFe_(2)O_(4) and S-ZnFe_(2)O_(4)/MMT composite were 51.44 mg/g and 68.45 mg/g respectively.The adsorption process is consistent with the Langmuir isotherm adsorption model and the pseudo second-order kinetic model,which is defined as a monolayer-based surface chemical adsorption.