Arsenate removal from aqueous solutions using modified red mud.
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.
Zhang
Shuwu
S
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. zhangshuwu@126.com
Liu
Changjun
C
Luan
Zhaokun
Z
Peng
Xianjia
X
Ren
Haijing
H
Wang
Jun
J
D000537:Aluminum Oxide; D001149:Arsenates / Q000302:isolation & purification*; D007220:Industrial Waste; D008669:Metallurgy; D014874:Water Pollutants, Chemical / Q000302:isolation & purification*