HCO-(Fe_(3)O_(4))_(x)复合吸附剂吸附去除Sb(Ⅲ)和Sb(Ⅴ)的差异及机理

Difference and mechanism of Sb(Ⅲ)and Sb(Ⅴ)adsorption and removal by HCO-(Fe_(3)O_(4))_(x)

采用共沉淀法将Fe_(3)O_(4)掺杂在富含铈研磨抛光污泥(Hydrous cericoxide,HCO)中制备出一种新型HCO-(Fe_(3)O_(4))_(x)复合吸附剂,分别以Sb(Ⅲ)和Sb(Ⅴ)为处理对象,考察了Ce和Fe的摩尔比、pH、投加量和时间对HCO-(Fe_(3)O_(4))_(x)吸附除锑的影响,并研究了不同n(Ce)/n(Fe)时的等温吸附模型、吸附动力学和吸附机理。结果表明:当n(Ce)/n(Fe)为1:0.67和1:1、pH为3和2、温度为35℃条件下,HCO-(Fe_(3)O_(4))_(x)对Sb(Ⅲ)和Sb(Ⅴ)的最大吸附量分别可以达到46.00 mg/g和58.34 mg/g,能有效去除水中的锑离子;HCO-(Fe_(3)O_(4))_(x)吸附Sb(Ⅲ)和Sb(Ⅴ)过程均符合Langmuir等温吸附模型和准二级反应动力学模型,以化学吸附为主。EDS、XRD和XPS等表征结果显示:HCO与Fe_(3)O_(4)的复合制备提高了比表面积并形成了FeCe_(2)O_(4)、FeOOH、Fe_(3)O_(4)和Fe2O3等无定型铁氧化物,为吸附过程中Fe-O-Sb和Ce-O-Sb络合物的形成提供了条件,从而促进了Sb(Ⅲ)和Sb(Ⅴ)的吸附去除。

A new HCO-(Fe_(3)O_(4))_(x) composite adsorbent was prepared by co-precipitation method in cerium-rich grinding and polishing sludge(hydrous ceric oxide,HCO),with Sb(Ⅲ)and Sb(Ⅴ)as treatment materials,respectively.The effects of molar ratio of Ce and Fe,pH,dosage and time on the adsorption of antimony by HCO(Fe_(3)O_(4))_(x) were investigated.The isothermal adsorption model,adsorption kinetics and adsorption mechanism of HCO-(Fe_(3)O_(4))_(x) were studied.The results show that HCO-(Fe_(3)O_(4))_(x) can effectively remove antimony ions from water,and the maximum adsorption capacities of Sb(Ⅲ)and Sb(Ⅴ)can reach 46.00 mg/g and 58.34 mg/g,respectively,under the conditions of molar ratio of Ce and Fe of 1:0.67 and 1:1,pH of 3 and 2,and temperature of 35℃.The adsorption processes of Sb(Ⅲ)and Sb(Ⅴ)by HCO-(Fe_(3)O_(4))_(x) are both in accordance with Langmuir isothermal adsorption model and quasi-second-order reaction kinetics model,with chemical adsorption as the mainstay.The characterization results of EDS,XRD and XPS show that the composite preparation of HCO and Fe_(3)O_(4) increases the specific surface area and forms amorphous iron oxides,such as FeCe_(2)O_(4),FeOOH,Fe_(3)O_(4) and Fe2O3,which provides conditions for the formation of Fe-O-Sb and Ce-O-Sb complexes in the adsorption process and promotes the adsorption removal of Sb(Ⅲ)and Sb(Ⅴ).