黑曲霉对弱酸性艳兰RAWL的吸附动力学和热力学研究

On kinetic and thermodynamic behavior of biosorption of weak acid brilliant blue RAWL by Aspergillus niger

借助吸附等温线比较了不同pH以及完整细胞与单细胞壁染料生物的吸附性能差异,化学修饰研究了菌体表面不同官能团对染料吸附的贡献,考察了不同温度下染料生物的吸附动力学,并进行了模型拟合。结果表明,黑曲霉的染料吸附较好地符合Freundlich方程(R2>0.99),低pH值有利于染料吸附;染料吸附不仅发生在细胞壁,细胞内部也可发生;表面氨基作为主要的吸附官能团,其质子化导致的菌体正电荷和染料负离子间的静电引力作用是染料吸附的重要机理;吸附动力学可用拟二级速率方程描述(R2=0.9999);吸附活化能Ea=5.21kJ/mol,表明吸附具一定的活化性。

In this paper the authors intend to introduce their research on the biosorption of the brilliant blue weak acid RAWL by Aspergillus niger under different pH and the different biosorption abilities between cell wall and intact cell by means of the adsorption isotherm. The paper also investigates and analyzes the contribution of different groups of the cell to the dye biosorption by using the chemical modification, the kinetic and thermodynamic behavior of dye biosorption. The results of their research show that the Freundlich fits the adsorption process well （ R^2 〉 0. 99）, and the low pH benefits the dye biosorption. The intact cell holds higher biosorption ability than the cell wall, which indicates that the dye adsorption not only occur in the cell wall but also in other cell parts. The amino group might be the main adsorptive site in the cell and the electrostatic attraction between the negative dye molecular and positive amino protonated at the low pH may lead to increase in the capacity of dye biosorption. At the same time, the function of the pseudo second order model reaction rate helps to define the dye biosorption reaction perfectly with the correlation coefficient （R^2） being 0. 999 9. Thus, it can be found that the dye biosorption proves to be active by calculating the activation energy of the sorption （ Ea = 5.21 kJ/mol） with the Arrhenius under different temperatures.