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- 2017
亚铁铝类水滑石吸附铀的性能与吸附机制
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Abstract:
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-precipitation method and used for the adsorption of uranium (Ⅵ) from aqueous solution. The effects of initial pH, adsorbent dosage, temperature, adsorption time and initial U(Ⅵ) ions concentration on adsorption of U(Ⅵ) were investigated. 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. 国家自然科学基金项目（11175081）；高等学校博士点基金项目（20134324110003）；湖南省高校重点实验室创新基金项目（13K085）；湖南省教育厅优秀青年项目（14B154）
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