Chen Hao, Wang Aiqin
Center of Eco-Material and Green Chemistry, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou, PR China.
J Hazard Mater. 2009 Jun 15;165(1-3):223-31. doi: 10.1016/j.jhazmat.2008.09.097. Epub 2008 Oct 2.
Batch adsorption experiments were carried out to remove Cu(II) ions from its aqueous solutions using a poly(acrylamide)/attapulgite composite. The different parameters effecting on the adsorption capacity such as contact time, initial metal ion concentration, temperature and pH of the solution have been investigated. The adsorption kinetic experiments revealed that there are three stages in the whole adsorption process. It was found that Cu(II) adsorption onto the composite followed pseudo-second-order kinetics and were mainly controlled by the film diffusion mechanism, along with a considerable contribution of the intra-particle diffusion mechanism. Analysis of adsorption results obtained at different temperatures showed that the adsorption pattern on the composite well followed the Langmuir, Freundlih and D-R isotherms, and the characteristic parameters for each adsorption isotherm were also determined. The adsorption process has been found endothermic in nature and thermodynamic parameters have been calculated. The analysis for variations of IR spectra and the values of the mean free energies of adsorption (E(a)) demonstrated that the chelation model should be the dominating adsorption mechanism. The species of copper salts can affect the adsorption capacity of the composite, which are in the order of CuSO(4)>CuCl(2)>Cu(NO(3))(2)>>Cu(CH(3)COO)(2).
采用聚丙烯酰胺/凹凸棒石复合材料对水溶液中的Cu(II)离子进行了批量吸附实验。研究了接触时间、初始金属离子浓度、温度和溶液pH值等影响吸附容量的不同参数。吸附动力学实验表明，整个吸附过程分为三个阶段。结果表明，Cu(II)在复合材料上的吸附遵循准二级动力学，主要受膜扩散机制控制，同时颗粒内扩散机制也有相当大的贡献。对不同温度下的吸附结果分析表明，复合材料上的吸附模式符合Langmuir、Freundlih和D-R等温线，并确定了各吸附等温线的特征参数。发现吸附过程本质上是吸热的，并计算了热力学参数。红外光谱变化分析和吸附平均自由能(E(a))值表明，螯合模型应为主要的吸附机制。铜盐种类会影响复合材料的吸附容量，顺序为CuSO(4)>CuCl(2)>Cu(NO(3))(2)>>Cu(CH(3)COO)(2)。
