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汪赛奇,唐玉朝,黄显怀,伍昌年,薛莉娉,沈珺.还原共沉淀法制备Fe-Ti复合氧化物及其吸附水中As(Ⅴ)的研究[J].环境科学学报,2014,34(8):2014-2021

Arsenate adsorption using Fe-Ti composite oxides synthesized by reduction-co-precipitation method from aqueous solution

基金项目：国家自然科学基金（No.50908001，51078001）；安徽省重大科技专项（No.08010301106）；安徽省国际科技合作项目（No.09080703035）；安徽省优秀青年科技基金（No.10040606Y29）

摘要：采用还原-共沉淀法制备了无定型纳米复合Fe-Ti氧化物（FFT）吸附剂，并研究其对水中低浓度As（Ⅴ）的去除性能.XRD表征结果表明，制备的纳米FFT物相为无定型，BET比表面积达325.3 m²·g^-1，计算得到的BJH吸附平均孔径为2.46 nm（4V/A），颗粒分布均匀.同时，考察了纳米FFT吸附As（Ⅴ）的动力学、热力学、吸附等温线，以及温度、水中共存离子对其去除As（Ⅴ）的影响.结果发现，纳米FFT对As（Ⅴ）的吸附符合拟二级动力学模型，计算出的孔道扩散系数D_P在10^-11~10^-13 cm²·s^-1之间，显示孔扩散是速率限速步骤.Langmuir、Freundlich和Dubinin-Radushkevich（D-R）吸附等温式均可较好地拟合吸附行为，低浓度下Langmuir吸附模型计算出的Q_m达到26.46 mg·g^-1.最后，研究了地下水中常见的共存离子对吸附的影响，发现Ca²⁺、Mg²⁺能够促进吸附，H₂PO₄^-和HCO₃^-则明显抑制吸附过程.

Abstract：In this study, iron(Ⅲ,Ⅱ)-titanium(Ⅳ) composite oxides with amorphous nanostructure named nano-FFT was synthesized and characterized by the X-ray diffraction (XRD) pattern, Brunauer-Emmett-Teller (BET) surface area analysis and Transmission electron microscope (TEM) imagine analyses. It was shown that there were BET surface area of 325.3 m²·g^-1 and BJH average aperture of 2.46 nm (4V/A) for the nano-FFT with amorphous structure and uniform distribution of particles. In general, the kinetic sorption data in different temperatures and co-ions for As(Ⅴ) by nano-FFT were described by the pseudo-second order equation, which indicated that nano-FFT had effective removal ability for As(Ⅴ). Meanwhile, the pore diffusion coefficient D_P values were in the range of 10^-11~10^-13 cm²·s^-1,which proved that pore diffusion was the rate-limiting step. Thermodynamic parameters indicated that sorption reactions on nano-FFT were spontaneous and endothermic. The adsorption process was well consonant with Langmuir, Freundlich and Dubinin-Radushkevich isotherms models, and the Langmuir maximum adsorption capacity calculated in low-concentration of As(Ⅴ) could reach 26.46 mg·g^-1. Furthermore, the effect of common co-ions in groundwater on the adsorption was investigated with promotion function by Ca²⁺ and Mg²⁺, while H₂PO₄^- and HCO₃^- showed distinct inhibitory effects.