电化学方法下的聚β-环糊精吸附苯胺特征

Characterization of poly β-cyclodextrin adsorption aniline under electrochemistry

聚β-环糊精(聚β-CD)是通过电化学合成法制备的一形状类似β-环糊精(β-CD)锥筒型的β-环糊精聚合物。苯胺是一种危害较大的环境污染物之一,聚β-CD包合吸附苯胺(An)的机制研究对今后聚β-CD去除苯胺具有重要的意义。在298.15~323.15 K的温度范围内,以电聚合法合成的聚β-CD/聚苯胺(PANI)复合材料的荷电量为吸附量,通过6种吸附等温模型(Langmuir、Freundlich、Langmuir-Freundlich、Temkin、Henry和BET)和4种动力学方程(准一级动力学、准二级动力学、颗粒内扩散及Elovich方程)的拟合,考察了聚β-CD包合吸附苯胺过程中的等温模型及其吸附动力学特征。结果显示,在此温度范围内,Langmuir-Freundlich、Temkin等温吸附模型适合描述聚环糊精对苯胺的包合吸附,说明聚β-CD包合苯胺是单分子层与多分子层吸附共存,且其吸附热与温度呈线性关系,吸附热随表面覆盖率增加而下降;准一级动力学模型更适合模拟聚β-CD包合吸附苯胺的反应过程,表明聚β-CD包合吸附苯胺以物理吸附为主,因此聚β-CD可以应用于苯胺的去除。

Poly β-cyclodextrin is a β-cyclodextrin polymer prepared by the electrochemical method,which shape is similar to β-cyclodextrin cone.Aniline is a kind of harm one of the large environmental pollutants.It is of great significance to study the mechanism of inclusion adsorption between poly β-cyclodextrin and aniline for the removal of aniline by poly β-cyclodextrin in the future.In the temperature range of 293.15-323.15 K,the charge of the poly β-cyclodextrin/polyaniline composite synthesized by electropolymerization is used as the adsorption amount.The isothermal model and its adsorption kinetics in the process of adsorption inclusion were investigated by the fit of 6 adsorption isothermal models(Langmuir,Freundlich,Langmuir-Freundlich,Temkin,Henry and BET) and 4 kinetic equations(quasi-primary dynamics,quasi-secondary dynamics,intraparticle diffusion and Elovich equations) using charges.The results show that in this temperature range,the Langmuir-Freundlich and Temkin isothermal adsorption models are suitable for describing the inclusion adsorption of poly β-cyclodextrin with aniline.This indicates that poly β-cyclodextrin inclusion aniline is a monomolecular layer and multi-molecular layer adsorption coexistence,and its adsorption heat and temperature are linearly related,and the adsorption heat decreases with the increase of surface coverage.The quasi-primary kinetic model is more suitable for simulating the reaction process of poly β-cyclodextrin inclusion adsorption aniline,indicating that this adsorption is mainly physical adsorption,which suggestes that poly β-cyclodextrin can be applied for the removal of aniline.