振荡时间、离子强度、温度和pH值对GMZ膨润土中Cr（Ⅲ解）吸特性的影响

对吸附在高庙子（GMZ）膨润土上的Cr（III）进行解吸实验，研究振荡时间、解吸溶液离子强度、温度和pH值等因素对解吸特性的影响规律。结果表明：高庙子膨润土上Cr（III）的解吸过程较易发生；Cr（III）的解吸动力学过程较吸附过程慢，实验条件下解吸过程在3 h后达到平衡；当使用0.1 mol/L HCl、1 mol/L NaCl和1 mol/L CaCl 2作为解吸液时，Cr（III）的最终解吸率分别达89.4%,56.5%和77.2%；增大解吸溶液的离子浓度能够促进解吸过程的发生；pH值对Cr（III）解吸过程有重要影响；吸附/解吸过程较符合Freundlich等温模型。GMZ膨润土在处理Cr（III）废水时具有较好的再生能力，可以多次重复利用。

Effect of shaking time,ionic strength,temperature and pH value on desorption of Cr（III） adsorbed onto GMZ bentonite

The Cr（III） desorption experiments of Gaomiaozi （GMZ） bentonite in aqueous solutions were performed. The variables affecting the desorption behaviors, such as contact time, concentration of the desorbent, pH value of the solution, temperature and desorption isotherms, were investigated by the batch experiments. The results show that the adsorbed Cr（III） on GMZ bentonite can be easily extracted by the desorbent. Kinetics examination shows that desorption is slower than adsorption, and the desorption rate increases with time and reaches the equilibrium after 3 h. The final desorption ratios of Cr（III） are 89.4%, 56.5%and 77.2%in the desorption solution with 0.1 mol/L HCl, 1 mol/L NaCl, and 1 mol/L CaCl2, respectively, and the concentration can promote the desorption progress. Furthermore, the results of successive regeneration cycles indicate that the bentonite has a good regeneration ability and reusability. The pH value is an important factor in the Cr（III） desorption from the GMZ bentonite. The results of adsorption and desorption isotherms show that both adsorption and desorption isotherms are consistent with the Freundlich equation. The comparison of adsorption and desorption isotherms implies that the adsorption/desorption hysteresis is negligible and the transport of Cr（III） in bentonite can be described by a reversible adsorption process.