硫掺杂ZnFe2O4/蒙脱石复合材料的铀酰吸附研究

为获得铀酰(UO2²⁺)吸附性能高的吸附剂,以蒙脱石(Montmorillonite,MMT)和铁酸盐(ZnFe₂O₄)为原材料与L-半胱氨酸通过水热反应制备了硫掺杂ZnFe₂O₄(S-ZnFe₂O₄)和ZnFe₂O₄/MMT(S-ZnFe₂O₄/MMT),采用XRD、FTIR和SEM对S-ZnFe₂O₄和S-ZnFe₂O₄/MMT进行了结构表征,研究了pH、接触时间和UO2²⁺初始质量浓度对UO2²⁺吸附效果的影响,结果表明:S-ZnFe₂O₄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-ZnFe₂O₄与蒙脱石复合后能明显提高其UO2²⁺吸附性能,最佳吸附pH为6.0;S-ZnFe₂O₄和S-ZnFe₂O₄/MMT复合材料对UO2²⁺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。

Study on uranyl adsorption of sulfur-doped ZnFe2O4/MMT composite

For obtaining a high uranyl(UO2²⁺)adsorption performance of adsorbent,montmorillonite(MMT)and ferrite(ZnFe₂O₄)were used as raw materials to prepare sulfur-doped ZnFe₂O₄(S-ZnFe₂O₄)and ZnFe₂O₄/MMT(S-ZnFe₂O₄/MMT)by hydrothermal reaction with L-cysteine.The structure of S-ZnFe₂O₄ and S-ZnFe₂O₄/MMT was characterized by XRD,FTIR and SEM,while the effects of pH,contact time and initial UO 22+concentration on UO2²⁺adsorption performance were studied.The results show that S-ZnFe₂O₄ is presented as highly dispersed nano-particles and are evenly distributed on the surface of the lamellar structure of montmorillonite.The recombination of S-ZnFe₂O₄ with montmorillonite has improved UO2²⁺adsorption performance significantly.When pH 6.0 was decided to be the optimum adsorption condition,the maximum UO2²⁺adsorption capacities of S-ZnFe₂O₄ and S-ZnFe₂O₄/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.