【摘要】 研究了纳米γ-Al2O3吸附剂对Ge(Ⅳ)的吸附行为,考察了吸附平衡时间、温度和溶液的pH值等因素对吸附过程的影响.结果表明,纳米Al2O3对Ge(Ⅳ)的吸附在2min时基本达到平衡,在pH=4～11范围内,Ge(Ⅳ)可以被纳米Al2O3定量富集,吸附率大于95%;吸附于纳米Al2O3上的Ge(Ⅳ)可以用0.3mol/LK3PO4和1mol/LH2SO4混合溶液洗脱,5min后基本达到解析平衡,解析率能达到97%;该吸附过程符合准二级反应动力学模型,计算了不同温度下的吸附速率常数,并求得纳米Al2O3对Ge(Ⅳ)的吸附活化能(Ea)为11.63kJ/mol;该体系的吸附过程符合Freundlich等温式,由D-R等温式求得常温下纳米Al2O3对Ge(Ⅳ)的平均吸附能为10.87kJ/mol.Ge(Ⅳ)吸附反应的ΔG0为负值,焓变ΔH0为正值,说明该吸附过程是自发的吸热反应.更多还原

【Abstract】 The effects of various equilibrium time,temperature and pH on the adsorption of Ge(Ⅳ) on nano-Al2O3 were studied. The results show that the adsorption is fast to reach equilibrium within 2 min. It was found that the adsorption efficiency of Ge(Ⅳ) was more than 95% with pH from 4 to 11. Almost all of Ge(Ⅳ) ions adsorpted onto nano-Al2O3 can be eluted with 0.3 mol/L K3PO4-1 mol/L H2SO4 mixed solution within 5 min,the desorption percentage can reach 97%. The sorption of Ge(Ⅳ) ions onto nano-Al2O3 followed the second-order rate equation,the kinetic experimental data properly correlate with the second-order kinetic model and the values of activation energy(Ea) was 11.63 kJ/mol. The adsorption data are fitted to the Freundlich and the magnitude of sorption energy computed from D-R equation is 10.87 kJ/mol,thus,the type of the adsorption of germanium on nano-Al2O3 is a chemical adsorption. The ΔG0 and ΔH0 values is negative and positive respectively which indicate the adsorption of Ge(Ⅳ) on nano-Al2O3 is spontaneous and endothermic.更多还原