【摘要】 研究了纳米γ-Al2O3吸附剂对氟离子的吸附行为,考查了吸附平衡时间、温度、溶液的pH等对吸附过程的影响.结果表明,在室温下,纳米γ-Al2O3对氟离子的吸附在3min基本达到平衡;在pH3～9范围内,吸附率达95%以上;吸附过程符合准二级反应动力学模型,其反应的表观活化能(Ea)为10.99kJ.mol-1;颗粒内扩散过程是吸附的主要控制步骤,而颗粒外扩散过程对吸附也有影响;吸附过程符合Langmuir、D-R等温模型,常温下,纳米γ-Al2O3对氟离子的平均吸附能为11.15kJ.mol-1.吸附反应的ΔGθ<0,ΔHθ>0,说明该吸附过程是自发的吸热反应.共存阴离子HCO3-和PO43-、阳离子Cu2+对氟离子的吸附影响较大.纳米γ-Al2O3在动态和静态吸附实验中的除氟效果相近.更多还原

【Abstract】 The adsorption behavior of fluorine ions on nano γ-Al2O3 was investigated.The influences of contact time,temperature,pH and other parameters on the adsorption efficiency of fluoride were explored.The results showed that equilibrium was reached within 3.0 min at indoor temperature.The adsorption efficiency could reach over 95% at pH 3~9.The kinetic experimental data was well fitted with the second-order kinetic model.The apparent activation energy was calculated to be 10.99 kJ·mol-1.The intraparticle diffusion was the main control step of the rate,while the overall process was also influenced by boundary layer diffusion.The sorption data could be well interpreted by the Langmuir and Dubinin-Radushkevich sorption isotherm.The mean energy of adsorption was 11.15 kJ·mol-1 at room temperature.The thermodynamic parameters for adsorption reaction:ΔHθ>0 and ΔGθ<0,indicated that the adsorption process was a spontaneous and endothermic reaction.The co-existed ions such as HCO-3,PO3-4 and Cu2+ had larger effects on adsorption of fluorine ions.Removal efficiency of nano-γ-Al2O3 obtained by dynamic adsorption was close to that obtained through static adsorption.更多还原