多胺型阴离子交换纤维吸附铬(Ⅵ)的动力学

Adsorption Kinetics of Chromium (Ⅵ) onto an Anion Exchange Fiber Containing Polyamine

以聚丙烯腈纤维为原料,采用化学改性法,制备了多胺型阴离子交换纤维.研究该纤维对Cr(VI)的吸附特性.在研究的温度及浓度范围内,该纤维对Cr(VI)吸附的平衡数据符合Langmuir和Freundlich吸附等温方程,对Cr(VI)有较强的亲和力,吸附反应易于进行.重点研究了该纤维对Cr(VI)的吸附动力学特性,分别采用Lagergren一级动力学方程、修正伪一级动力学方程、伪二级动力学方程和颗粒内扩散方程进行拟合,计算相应的速率常数.研究表明,该吸附是一个快速吸附过程,20min即可接近吸附平衡,吸附过程符合伪二级动力学方程,以化学吸附为主,该纤维能够多次反复对Cr(VI)进行吸附.

An anion exchange fiber containing polyamine functional group was synthesized by chemical modification using polyacrylonitrile fiber as the raw material. The adsorption behavior of Cr（Ⅵ） using the self-made fiber was studied. Within the observed temperature and concentration range, equilibrium data for the adsorption of Cr（Ⅵ） from aqueous solutions by the fiber were obtained and correlated with Langmuir-type and Freundlich-type isotherm equations. The adsorption is shown to be a favorable type and the polyamine functional group has a strong affinity for Cr（Ⅵ）. We mainly studied the adsorption kinetics of Cr（Ⅵ） onto the self-made fiber and fitted the kinetic data to the Lagergren first-order equation, the pseudo second-order equation, the modified pseudo first-order equation, and the intra-particle diffusion model. The respective characteristic rate constants were calculated and analyzed. Results show that the adsorption process is fast and that it reaches equilibrium at about 20 min. The experimental data for the adsorption systems fit well to a pseudo second-order equation and chemical adsorption is the main adsorption process. The fiber can be regenerated and repeatedly used for the adsorption of Cr（Ⅵ）.