运用超声共沉淀制备了亚铁铝类水滑石(Fe(Ⅱ)-Al LDH),用于处理含 U(Ⅵ)废水。实验考察了初始pH、吸附剂投加量、温度、吸附时间以及U(Ⅵ)初始浓度对Fe(Ⅱ)-Al LDH 吸附U(Ⅵ)的影响。采用SEM、FTIR、XRD与 XPS等手段分析了相关机制。试验表明,Fe(Ⅱ)-Al LDH 吸附 U(Ⅵ)的最佳 pH 为6,当温度为25℃,投加量为1.0 g/L,U(Ⅵ)初始质量浓度为10 mg/L时,对 U(Ⅵ)的去除率达到99.98%,反应在120 min达到平衡,饱和吸附量为117.13 mg/g。Langmuir等温吸附模型和准二级动力学模型(R2≈1)较好地拟合了吸附过程, Fe(Ⅱ)-Al LDH 对 U(Ⅵ)的吸附是自发的吸热反应。SEM、FTIR、XPS 分析结果表明,吸附前后的 Fe(Ⅱ)-Al LDH 结构没有发生改变,Fe(Ⅱ)-Al LDH 对 U(Ⅵ)的吸附是化学吸附为主,氧化还原作用为辅。
Fe(Ⅱ)-Al layered double hydroxides (Fe-Al LDHs)were prepared by the ultrasound-assisted co-pre-cipitation method and used for the adsorption of uranium (Ⅵ)from aqueous solution.The effects of initial pH,ad-sorbent dosage,temperature,adsorption time and initial U(Ⅵ)ions concentration on adsorption of U(Ⅵ)were in-vestigated.The prepared composites were characterized by SEM,FTIR,XRD and X-ray photoelectron spectroscopy (XPS).The experiment results indicate that the maximum adsorption occur at pH of 6 and the adsorption reach equilibrium within 120 min.Meanwhile the removal rate is up to 99.98% for initial U(Ⅵ)concentration of 10 mg/L and adsorbent dosage of 1.0 g/L at 25 ℃,and the maximum adsorption capacity for U(Ⅵ)ions is 117.13 mg/g. The experimental data fit well with the Langmuir isotherm model and pseudo-second-order kinetic model(R2≈1 ), Adsorption of U (Ⅵ)on Fe (Ⅱ)-Al LDH is primarily due to spontaneous endothermic reaction.The results of SEM、FTIR and XPS show that the structure of Fe(Ⅱ)-Al LDH has no change,chemisorption plays a major role and redox take subsidiary function.
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