Lian Lili, Guo Liping, Guo Chunjing
Faculty of Chemistry, Northeast Normal University, Changchun, 130024, People's Republic of China.
J Hazard Mater. 2009 Jan 15;161(1):126-31. doi: 10.1016/j.jhazmat.2008.03.063. Epub 2008 Mar 21.
The ability of Ca-bentonite to remove Congo red dye from aqueous solutions has been carried out as a function of contact time, temperature (20-50 degrees C), pH (5-10) and concentration (50-200mgL(-1)). An amount of 0.2g of Ca-bentonite could remove more than 90.0% of the dye from 100mgL(-1) Congo red dye solution for the temperature range studied here. The amount of dye adsorbed per unit weight of Ca-bentonite increased from 23.25 to 85.29mgg(-1) with increasing concentration from 50 to 200mgL(-1), but it had a little change with temperature and decreased slightly with increasing pH. The kinetics of adsorption in view of three kinetic models, i.e., the pseudo-first-order Lagergren model, the pseudo-second-order model and the intraparticle diffusion model, was discussed. The pseudo-second-order kinetic model described the adsorption of Congo red on Ca-bentonite very well. Analysis of adsorption results obtained at 20 degrees C showed that the adsorption pattern on Ca-bentonite followed the Freundlich isotherms. It was indicative of the heterogeneity of the adsorption sites on the clay particles. From thermodynamic studies, it was seen that the adsorption was spontaneous and endothermic.
研究了钙基膨润土从水溶液中去除刚果红染料的能力，该能力是接触时间、温度（20 - 50摄氏度）、pH值（5 - 10）和浓度（50 - 200mgL(-1)）的函数。在此研究的温度范围内，0.2g钙基膨润土能够从100mgL(-1)的刚果红染料溶液中去除超过90.0%的染料。随着浓度从50mgL(-1)增加到200mgL(-1)，单位重量钙基膨润土吸附的染料量从23.25增加到85.29mgg(-1)，但随温度变化不大，且随pH值升高略有下降。基于三种动力学模型，即准一级Lagergren模型、准二级模型和颗粒内扩散模型，讨论了吸附动力学。准二级动力学模型很好地描述了刚果红在钙基膨润土上的吸附。对20摄氏度下获得的吸附结果分析表明，钙基膨润土上的吸附模式遵循Freundlich等温线。这表明粘土颗粒上吸附位点的不均匀性。从热力学研究可以看出，吸附是自发的且吸热的。
