rGO、TiO_(2)修饰铁基磁性吸附材料除铊的性能

Removal of thallium by rGO and TiO_(2) modified iron-based magnetic adsorbents

近年来,铊(Tl)污染事件时有发生,对饮用水源造成了严重威胁,含铊废水的高效处理刻不容缓。通过化学共沉淀法制备Fe_(3)O_(4)颗粒,结合水热反应、溶胶凝胶等改性方法,制备了磁性钛铁纳米颗粒(TFNPs)、四氧化三铁/二氧化钛核壳颗粒(Fe_(3)O_(4)@TiO_(2))和还原氧化石墨烯负载四氧化三铁/二氧化钛(rGO-Fe_(3)O_(4)@TiO_(2))复合磁性材料,考察磁性复合材料吸附、氧化去除Tl(Ⅰ)的性能,并阐明其作用机制。结果表明,TFNPs、Fe_(3)O_(4)@TiO_(2)和rGO-Fe_(3)O_(4)@TiO_(2)单位Ti含量条件下Tl(I)最大吸附容量分别为200、271.8和440 mg-Tl·g-Ti^(-1)。TFNPs/过硫酸盐(PS)、Fe_(3)O_(4)@TiO_(2)/PS和rGO-Fe_(3)O_(4)@TiO_(2)/PS耦合体系对Tl的去除率分别为51.7%、47.2%和88.4%,这表明rGO-Fe_(3)O_(4)@TiO_(2)/PS耦合体系能够高效的去除Tl。在Tl(Ⅰ)和PS混合溶液中,Fe_(3)O_(4)、rGO和rGO-Fe_(3)O_(4)@TiO_(2)的电子供给容量(EDC)分别为168.2、225.4和195.4μmol-e^(-)·g^(-1),而电子接受容量(EAC)分别为131.4、746.8和571.3μmol-e^(-)·g^(-1),表明rGO具有优异的电子转移能力。本研究结果可为含铊废水高效处理材料的开发提供参考。

The thallium pollution leading to a serious threat to the safety of drinking water in downstream cities.Therefore,the efficient treatment of thallium containing wastewater is urgently needed.In this study,Fe_(3)O_(4)particles were prepared by chemical coprecipitation method and the surface loading of TiO_(2)nanoparticles was prepared by hydrothermal reaction and sol-gel method.Three different magnetic adsorbents including TFNPs,Fe_(3)O_(4)@TiO_(2)and rGO-Fe_(3)O_(4)@TiO_(2)composite were developed for the removal of thallium from water.The maximum adsorption capacities of Tl(Ⅰ) under unit Ti content on TFNPs,Fe_(3)O_(4)@TiO_(2)and rGO-Fe_(3)O_(4)@TiO_(2)magnetic composites were 200,271.8 and 440 mg-Tl·g-Ti^(-1),respectively.Therefore,the rGO-Fe_(3)O_(4)@TiO_(2)adsorbent achieved the efficient removal of Tl(Ⅰ) from water.The Tl removal rates of TFNPs/PS,Fe_(3)O_(4)@TiO_(2)/PS and rGO-Fe_(3)O_(4)@TiO_(2)/PS hybrid systems were respectively 51.7%,47.2%and 88.4%,indicating that rGO-Fe_(3)O_(4)@TiO_(2)/PS hybrid system could remove Tl quickly and efficiently.The electronic supply capacities (EDC) of Fe_(3)O_(4),rGO and rGO-Fe_(3)O_(4)@TiO_(2)were respectively 168.2,225.4 and 195.4μmole-·g^(-1),when they were added into Tl(Ⅰ) and PS mixed solution.The electron acceptance capacity (EAC) values were respectively,131.4,746.8 and 571.3μmol-e^(-)·g^(-1),which indicated that rGO nanosheets have excellent electron transfer ability.The results of this study can provide a reference for the development of efficient thallium containing wastewater treatment materials.