研究报告
孙天一,赵志伟,时文歆,崔福义.磁性CeO2-Fe3O4复合材料光催化/吸附去除水中As(III)[J].环境科学学报,2018,38(8):3108-3117
磁性CeO2-Fe3O4复合材料光催化/吸附去除水中As(III)
- Removal of As(III) through photocatalytic oxidation and adsorption by CeO2-Fe3O4 magnetic composites
- 基金项目：城市水资源与环境重点实验室（哈尔滨工业大学）（No.2016DX11）
- 作者
- 单位
- 孙天一
- 哈尔滨工业大学市政环境工程学院, 哈尔滨 150090
- 赵志伟
- 1. 哈尔滨工业大学市政环境工程学院, 哈尔滨 150090;2. 重庆大学城市资源与环境工程学院, 重庆 400044
- 时文歆
- 哈尔滨工业大学市政环境工程学院, 哈尔滨 150090
- 崔福义
- 哈尔滨工业大学市政环境工程学院, 哈尔滨 150090
- 摘要：原水砷污染问题严重威胁饮用水水质安全，随着生活饮用水标准的提高，致使多地饮用水中砷超标问题突显.本研究利用CeO2半导体的光催化活性及CeO2和Fe3O4对As（V）的强亲和力，合成了双组份磁性CeO2-Fe3O4复合材料，并采用SEM、XRD、BET和VSM等手段进行表征，考察复合材料的光催化/吸附除砷效果；研究了初始pH值、共存离子等因素对吸附除砷效果的影响；采用等温吸附模型、吸附动力学模型等手段进行吸附特性研究.实验结果表明，在光催化过程中，·OH和·O2-为主要的活性氧化物种.在紫外照射下，As（Ⅲ）能完全被氧化为毒性较低的As（V），同时将As（V）高效吸附于CeO2-Fe3O4粒子表面.在中性条件下，CeO2-Fe3O4粒子对砷的饱和吸附量为122.19 mg·g-1.共存离子Cl-和SO42-对As（V）的吸附没有显著影响，而CO32-、SiO32-和PO43-与As（V）存在明显的竞争吸附，使As（V）的吸附去除效果明显降低.吸附动力学和吸附等温线模拟分别符合准二级动力学方程和Freundlich吸附等温线，表明As（V）的吸附以化学吸附为主导.CeO2-Fe3O4复合吸附剂可快速实现固液分离，容易再生且重复利用性较好，具有广泛的应用前景.
- Abstract：Arsenic contamination in raw water causes a serious threat to drinking water safety. With the improvement of the national standard of drinking water, the arsenic exceeding problem in drinking water is serious in many areas. Combined the photocatalytic property of CeO2 and the high adsorption capacity of both CeO2 and Fe3O4, the bifunctional CeO2-Fe3O4 magnetic composites were synthesized and characterized by using SEM, XRD, BET and VSM, to remove As(Ⅲ) through photocatalyic oxidation and adsorption. The effects of initial pH and coexisting ions on the As(Ⅲ) removal were investigated. The adsorption isotherms and adsorption kinetics were studied to better understand the adsorption characters. The results show that·OH and·O2- are regarded as the main role of the photocatalytic process. As(Ⅲ) could be completely oxidized to the less toxic As(V) under UV light, and As(V) could be adsorbed onto the CeO2-Fe3O4 composites surface with high efficiency simultaneously. The maximum adsorption capacities of composites was 122.19 mg·g-1 in the neutral condition. Except for chloride and sulfate, the coexisting of carbonate, silicate and phosphate decreased the As(Ⅲ) removal by competing with arsenic species. The adsorption kinetics and isotherms of arsenic are well fitted with the pseudo-second-order model and the Freundlich isotherm model, respectively, which indicates that the adsorption process belongs to chemisorption. The CeO2-Fe3O4 composites could be rapidly separated from solutions with a simple magnetic process, and easy to be regenerated and reused, which make it has significant application potential in the As(Ⅲ)-contaminated water treatment.
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