富里酸对TNT的吸附-解吸行为

为研究富里酸(FA)对TNT的吸附-解吸规律,采用振荡平衡法进行FA吸附TNT的动力学实验以及吸附-解吸等温实验。结果表明:FA对TNT的吸附可分为快速吸附和慢速吸附2个过程,且吸附在18 h时基本达到平衡;FA对TNT的吸附动力学曲线用准二级动力学曲线描述最为合适,其次是Elovich模型,再次是颗粒内扩散模型;FA吸附TNT的吸附等温线与Freundlich模型有较好的拟合性,其拟合参数<1,说明FA对TNT的吸附为非线性吸附;解吸迟滞指数为1.06,说明TNT在FA上的解吸存在滞后现象。

Adsorption and desorption behaviors of TNT on fulvic acid

In order to study the rules for TNT adsorption/desorption on fulvic acid (FA), the adsorption kinetics and adsorption/desorption were investigated by using batch equilibrium experiments. The results indicated that the adsorption process of TNT on FA was divided into a fast and a slow stage, and that adsorption equilibrium occurred after 18 h. The pseudo-second-order model was the best model to describe the adsorption kinetics of TNT on FA, followed by the Elovich model and intra-particle diffusion model. The adsorption-desorption isotherms of TNT on FA were predicted accurately by the Freundlich model. Nonlinear adsorption occurred in the case of TNT on FA because the parameter 1/n of the adsorption isotherm fitted by the Freundlich model was less than 1. The hysteresis index (HI) value was 1.06, indicating that the desorption process of TNT from FA produced a desorption hysteresis effect.