辣木籽对水中Cr(Ⅵ)的吸附机理及吸附动力学研究

Study on Adsorption Mechanism and Kinetics of Moringa oleifera Lam. Seeds to Cr(Ⅵ) in Water

本文研究了辣木籽对Cr(Ⅵ)液的吸附机理及吸附动力学。结果表明:辣木籽吸附Cr(Ⅵ)是一个以化学吸附为主的单分子层吸附过程,Langmuir等温线方程对室温下辣木籽吸附Cr(Ⅵ)拟合线性关系良好,相关系数R2=0.9958。FTIR的结果表明位于2914 cm-1、2854 cm-1的-CH2-官能团和1754 cm-1处的C=O官能团是辣木籽吸附Cr(Ⅵ)的主要活性基团,这些活性基团与Cr(Ⅵ)发生络合反应而将其去除。二级动力学方程对室温下辣木籽吸附Cr(Ⅵ)拟合结果最好,相关系数R2为0.9901;内扩散方程也能较好地描述吸附过程,相关系数R2为0.9417,说明吸附过程中内扩散是主要控制步骤。

Biological adsorption mechanism and kinetics of Cr (VI) from aqueous solution onto Moringa oleifera seeds was studied. Experimental results showed that:Cr (VI) adsorption on Moringa oleifera seeds was a chemical and monomolecular layer adsorption process; adsorption isotherm data fitted Langmuir isotherm equation under room temperature and the correlation coefficient R2 was 0.9958. FTIR analytic results indicated that-CH2-groups located at 2914 cm-1, 2854 cm-1 and C=O group located at 1754 cm-1 were the main active groups to adsorb Cr (VI) on Moringa oleifera seeds, and complexing reaction occur between these active groups and Cr (Ⅵ) while Cr (Ⅵ) ion removed from the water;Adsorption kinetics data fitted two order kinetics equation the best , and the correlation coefficient R2 was 0.9901; The diffusion equation whose corresponding correlation coefficient R2 was 0.9417 could describe the adsorption process also, and it illustrated internal diffusion was the main control step of the adsorption process.