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

Biosorption Characteristics and Mechanism of Pb^(2+) by Phanerochaete chrysosporium

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.

The adsorption characteristics and mechanism of Pb^（2＋） by inactive Phanerochaete chrysosporium mycelial pellets were studied.The results showed that the adsorption of Pb^（2＋） by inactive P.chrysosporium belonged to monolayer surface adsorption.The Langmuir model described the biosorption equilibrium of Pb^（2＋） on mycelial pellets better than the Freundlich model.The adsorption dynamics suggested that there were two stages in the process of biosorption of Pb^（2＋）：a faster sorption step followed by slower uptake.The biosorption dynamics of Pb^（2＋） 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 Pb^（2＋）was exothermic,and the activation energy for the biosorption of Pb^（2＋） was-35.78（kJmol.） The enthalpy change of the biosorption of Pb^（2＋） 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 Pb^（2＋） adsorbed on the surface of cells,and the exchange between Pb^（2＋） and H~＋ on the cell wall,were proved to exist in the process of biosorption of Pb^（2＋）.