MnO2@矿渣去除废水中的铊

以工业磁性矿渣构建具有二氧化锰包覆层（MnO2@矿渣）的吸附剂，用于去除废水中的重金属铊元素。并探究吸附剂投加量、反应时间、反应pH、离子强度、有机物等影响因素及除铊机理。结果表明：在碱性条件下（pH=10），MnO2@矿渣对水中的铊的吸附率达99.5%以上，10 min 内达到吸附平衡; MnO2@矿渣对铊的吸附容量随投加量的增大而增大，随离子强度的增大而减小，有机物对吸附铊的影响表现出差异性。吸附过程符合拟二级动力学模型，等温吸附适用Langmuuir和Freundlich方程描述；通过X-射线粉末衍射（XRD）、扫描电子显微镜（SEM）-X射线能谱（EDS）表征手段分析，证实成功制备了MnO2@矿渣；傅里叶变换红外（FT-IR）和X射线光电子能谱（XPS）的结果表明MnO2@矿渣对Tl（I）的去除是一个表面羟基络合、氧化和沉淀的过程。重复利用实验表明MnO2@矿渣有很好的脱附与再生能力。

Removal of thallium from waste water using MnO2@slag

The hierarchical MnO2-coated industrial magnetic slag (MnO2@slag) was synthesized and used as adsorbents to remove heavy metal thallium ions from contaminated waste water. The influencing factors including adsorbent dosage, reaction time, reaction pH, ionic strength and organic matter on thallium adsorption were investigated. The involved thallium removal mechanism was also explored. Results show that the equilibrium adsorption efficacy was over 99.5% under alkaline condition (pH=10), and the adsorption equilibrium reached within 10 min. Adsorption capacity increased with the increase in sorbent dosage, and decreased with the increase in ionic strength, the effect of organic matter on adsorption of thallium was different. Adsorption kinetics were fitted well by the pseudo-second-order model, and the adsorption was well fitted with both Langmuir and Freundlich isotherms. Analyses of XRD, SEM-EDS, FT-IR and XPS suggest that surface hydroxyl complexation, oxidation and precipitation were the main process for thallium removal via MnO2@slag. Cyclic reuse experiments showed that MnO2@slag has an excellent adsorption-regeneration ability.