Fe^(0)/Fe_(3)O_(4)复合材料同时去除水中多种重金属的效果  

Simultaneous removal of multiple heavy metals from water using Fe^(0)/Fe_(3)O_(4) composite materials

作　　者：姜维 杨芳俐 吴永红 陈冠忠[1,2] 陈红凤 唐次来 JIANG Wei;YANG Fangli;WU Yonghong;CHEN Guanzhong;CHEN Hongfeng;TANG Cilai(College of Hydraulic&Environmental Engineering,China Three Gorges University,Yichang 443002,China;Engineering Research Center of Eco-environment in Three Gorges Reservoir Region,China Three Gorges University,Yichang 443002,China;State Key Laboratory of Soil and Sustainable Agriculture,Institute of Soil Sciences,Chinese Academy of Sciences,Nanjing 210008,China)

机构地区：[1]三峡大学水利与环境学院,宜昌443002 [2]三峡大学三峡库区生态环境教育部工程研究中心,宜昌443002 [3]中国科学院南京土壤研究所土壤与农业可持续发展国家重点实验室,南京210008

出　　处：《环境工程学报》2022年第4期1186-1198,共13页Chinese Journal of Environmental Engineering

基　　金：国家自然科学基金资助项目(21876097)。

摘　　要：零价铁(Fe^(0))具有中等还原性,可通过还原反应或通过铁腐蚀产物的吸附和共沉淀过程去除水中重金属。但由于铁表面易钝化,导致铁腐蚀反应难以持续,这是限制Fe^(0)应用的关键。因此,本研究通过原位制备零价铁复合体系(Fe^(0)/Fe_(3)O_(4)),并采用批处理和连续流的流化床反应器考察了该复合体系同时去除水中Zn^(2+)、Ni^(2+)和Cr(Ⅵ)的效果。XRD和SEM的结果表明,预处理可以在Fe^(0)表面形成一层晶型完好的Fe_(3)O_(4)。相比Fe^(0),Fe^(0)/Fe_(3)O_(4)体系可显著促进Zn^(2+)、Ni^(2+)和Cr(Ⅵ)的去除。在不同条件下,复合体系均能在几分钟内高效去除Cr(Ⅵ)(>99%),Zn^(2+)的去除率较好(65%~93%),但Ni^(2+)的去除率较差(25%~77%)。Fe^(0)粒径越小、用量越多,重金属去除速率越快。在预处理制备复合体系时,Fe^(2+)含量越高,残留的溶解性Fe^(2+)也越高,由于竞争吸附作用,这会抑制Zn^(2+)和Ni^(2+)的吸附。当3种重金属共存时,少量(10 mg·L−1)的Cr(Ⅵ)会明显促进Zn^(2+)和Ni^(2+)的去除;但过多的Cr(Ⅵ),其促进作用有所减弱。流化床反应器的结果也证明了Fe^(0)/Fe_(3)O_(4)能有效地同时去除Zn^(2+)、Ni^(2+)和Cr(Ⅵ),三者的去除速率为Cr(Ⅵ)>Zn^(2+)>Ni^(2+),与批处理结果一致。Fe^(0)用量越大,处理效果越好。不同氧化剂作为预处理剂时,氧气(曝气)的效果最好,其次是重铬酸钾和硝酸钾。XPS结果表明,Cr(Ⅵ)可全部被还原为Cr(Ⅲ),Ni^(2+)部分被还原为Ni^(0),部分以Ni(Ⅱ)的形式通过吸附或沉淀的方式被固定。本研究提出了一种有效解决Fe^(0)表面钝化的方法,为Fe^(0)用于水体重金属污染的修复方法提供参考。Zero-valent iron(Fe^(0))is a type of metal with moderate reducibility,it can be used to remove heavy metals from water through Fe^(0)reduction,adsorption and/or co-precipitation by iron corrosion products.However,Fe^(0)corrosion reaction is not continuously occurred due to its surface passivation,which is the key step to limit the application of Fe^(0).In this study,Fe^(0)/Fe_(3)O_(4)hybrid system was prepared in situ by simple chemical method.Then simultaneous removal of Zn^(2+),Ni^(2+)and Cr(Ⅵ)from water by this hybrid system was investigated using batch experiment and fluidized bed reactor with continuous flow.The results showed that pretreatment could lead the coating of Fe_(3)O_(4)with good crystal structure on Fe^(0)surface,which was identified by SEM and XRD.Compared with Fe^(0)alone,Fe^(0)/Fe_(3)O_(4)system significantly improved the removal efficiencies of Zn^(2+),Ni^(2+)and Cr(Ⅵ).Under different conditions,Cr(Ⅵ)could be almost completely(>99%)removed by the hybrid system in a few minutes,Zn^(2+)could be well removed with the efficiency of 65%~93%,while Ni^(2+)showed a low removal efficiency of 25%~77%.The smaller particle size and more dosage of Fe^(0)promoted heavy metals removal.During pretreatment,the higher Fe2+concentration,the higher dissolved Fe2+,which could inhibit the adsorption of Zn^(2+)and Ni^(2+)due to competitive effect.The presence of low concentration of Cr(Ⅵ)(10 mg·L−1)could significantly promote the removal of Zn^(2+)and Ni^(2+)in the co-presence of these three heavy metals,but its promotion effect decreased in the presence of excessive Cr(Ⅵ).The results of fluidized bed reactor also proved that Fe^(0)/Fe_(3)O_(4)could effectively remove Zn^(2+),Ni^(2+)and Cr(Ⅵ)simultaneously.The order of removal efficiencies of three heavy metals was Cr(Ⅵ)>Zn^(2+)>Ni^(2+),which was consistent with the results of batch experiment.The higher Fe^(0)dosage,the higher removal efficiencies of heavy metals.Oxygen(aeration)exhibited the best performance as a preconditioning agent during pret

关 键 词：零价铁 重金属 复合体系 流化床反应器 还原 

分 类 号：X703.1[环境科学与工程—环境工程]