黄孢原毛平革菌(Phanerochaete chrysosporium)对Pb~(2+)的生物吸附特性及吸附机理

研究了非活性黄孢原毛平革菌(Phanerochaete chrysosporium)菌丝球对Pb2+的吸附特性及吸附机理.结果表明,菌丝球对Pb2+的吸附是单分子层吸附,Langmuir模型比Freundlich模型更适合于描述Pb2+在菌丝球上的吸附平衡.菌丝球吸附Pb2+的过程可以分为初始的快速吸附和随后的缓慢吸收2个阶段,并可以用二级动力学模型来描述.在菌丝球吸附Pb2+的过程中虽然存在粒内扩散,但它不是吸附过程的限速步骤.Pb2+的生物吸附过程是放热过程,其吸附活化能为-35.78kJ/mol,Pb2+的吸附热与化学反应热相近,为-44.45 kJ/mol.该生物吸附至少存在2种机理:菌体表面一些含氧基团对Pb2+的络合作用;Pb2+与细胞表面H+的离子交换.

Biosorption Characteristics and Mechanism of Pb2+ by Phanerochaete chrysosporium

The adsorption characteristics and mechanism of Pb²⁺ by inactive Phanerochaete chrysosporium mycelial pellets were studied. The results showed that the adsorption of Pb²⁺ by inactive P. chrysosporium belonged to monolayer surface adsorption. The Langmuir model described the biosorption equilibrium of Pb²⁺ on mycelial pellets better than the Freundlich model. The adsorption dynamics suggested that there were two stages in the process of biosorption of Pb²⁺:a faster sorption step followed by slower uptake. The biosorption dynamics of Pb²⁺ by mycelial pellets could be described using pseudo second-order adsorption kinetics, and the intraparticle diffusion was not the rate-controlling step. The biosorption process of Pb²⁺was exothermic, and the activation energy for the biosorption of Pb²⁺ was -35.78 kJ/mol. The enthalpy change of the biosorption of Pb²⁺ was near to that of the chemical reaction, which was -44.45 kJ/mol. The complex reaction between oxygenous functional groups on the cell wall and Pb²⁺ adsorbed on the surface of cells, and the exchange between Pb²⁺ and H⁺ on the cell wall, were proved to exist in the process of biosorption of Pb²⁺.