Zhang Shuwu, Liu Changjun, Luan Zhaokun, Peng Xianjia, Ren Haijing, Wang Jun
State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, Beijing 100085, PR China.
J Hazard Mater. 2008 Apr 1;152(2):486-92. doi: 10.1016/j.jhazmat.2007.07.031. Epub 2007 Jul 17.
Red mud (RM), a waste tailing from alumina production, was modified with FeCl(3) for the removal of arsenate from water. The RM and modified red mud (MRM) were characterized using scanning electron microscopy (SEM) and X-ray diffraction (XRD) microanalysis. Adsorption of arsenate on modified red mud (MRM) was studied as a function of time, pH, and coexisting ions. Equilibrium time for arsenate removal was 24h. Solution pH significantly affected the adsorption, and the adsorption capacity increased with the decrease in pH. Langmuir and Freundlich isotherms equation were used to fit the adsorption isotherms. The Langmuir isotherm was the best-fit adsorption isotherm model for the experimental data. Adsorption capacity of MRM was found to be 68.5mg/g, 50.6 mg/g and 23.2mg/g at pH 6, 7 and 9, respectively. NO(3)(-) had little effect on the adsorption. Ca(2+) enhanced the adsorption, while HCO(3)(-) decreased the adsorption. MRM could be regenerated with NaOH, and the regeneration efficiency reached 92.1% when the concentration of NaOH was 0.2 mol/L.
赤泥（RM）是氧化铝生产过程中产生的一种废渣，用FeCl₃对其进行改性以去除水中的砷酸盐。采用扫描电子显微镜（SEM）和X射线衍射（XRD）微分析对RM和改性赤泥（MRM）进行了表征。研究了改性赤泥（MRM）对砷酸盐的吸附作用与时间、pH值和共存离子的关系。去除砷酸盐的平衡时间为24小时。溶液pH值对吸附有显著影响，吸附容量随pH值的降低而增加。用Langmuir和Freundlich等温线方程拟合吸附等温线。Langmuir等温线是最适合实验数据的吸附等温线模型。在pH值为6、7和9时，MRM对砷酸盐的吸附容量分别为68.5mg/g、50.6mg/g和23.2mg/g。NO₃⁻对吸附影响很小。Ca²⁺增强了吸附作用，而HCO₃⁻降低了吸附作用。MRM可用NaOH再生，当NaOH浓度为0.2mol/L时，再生效率达到92.1%。
