高岭石吸附水溶液中铜离子的研究

Study on the Adsorption of Copper Ions in Kaolinite Aqueous Solutions

研究了高岭石对水溶液中铜离子的吸附行为,进行了吸附等温实验和吸附动力学实验,探讨了振荡时间、温度、溶液pH及吸附剂量等因素对吸附性能的影响。结果表明,高岭石对铜离子的吸附符合Langmuir,Freundlich及Dubinin-Radushkevich(D-R)等吸附等温模型。吸附过程中焓变ΔH>0,表明铜离子的吸附是吸热的,ΔG<0表明该吸附反应是自发的;吸附动力学实验表明高岭石对铜离子的吸附反应更好地符合准二级动力学方程;高岭石对铜离子的吸附随温度的增加而增加,在40℃时最大吸附量为17.01 mg/g;pH从2增加到6时,高岭石对铜离子的吸附量逐渐增大;吸附剂量增大,水溶液中铜离子去除率增加;离子强度增大,高岭石对Cu2+的吸附能力降低。

Kaolinite was used as an adsorbent for removing copper ions from aqueous solutions,and the isothermal and kinetic experiments were performed.Sorption experiments were conducted to evaluate the effects of shaking time,temperature,initial solutions pH and adsorbent doses on the sorption capacities and removal efficiency.The isothermal experimental data were fitted using Langmuir,Freundlich and Dubinin-Radushkevich（D-R） adsorption isotherms.The enthalpy change（ΔH） is more than zero,indicating that the sorption nature is endothermie; the Gibbs free energy change （ΔG） is less than zero, showing that the nature of the adsorption process is spontaneous. The kinetic experimental data followed the second-order kinetic model. As temperature increased, the sorption capacity increased. The maximum sorption capacity was 17.01 mg/g at 40℃. The sorption capacities also increased with the increase of solution pH values ranged from 2 to 6 and the doses of adsorbent from 1 to 5 g/L. However, the sorption capacities decreased with the increase of ion strength.