烟曲霉胞外聚合物对Pb2+的吸附特性

采用阳离子交换树脂(CER)法提取了烟曲霉胞外聚合物（EPS），并分析了其生物化学成分.同时，考察了烟曲霉EPS对重金属离子Pb2+的去除效果，探讨了其生物吸附机理和动力学特性.结果表明，CER法提取的烟曲霉EPS多糖含量较高，对细胞破坏程度较小.烟曲霉EPS吸附Pb2+的平衡时间约为3h，最佳吸附pH为6.5，吸附平衡时 Pb2+去除率为73.48%.烟曲霉EPS对Pb2+的吸附平衡均能较好地用Langmuir模型和Freundlich模型来描述，而且更适用Langmuir模型，最大吸附量qm为32.22mg·g -1.烟曲霉EPS的FTIR分析结果表明，多聚糖中的羟基、羧基和C—O—C等是与Pb2+发生了作用的基团，而其中蛋白质的作用不明显.

Biosorption of Pb2+ by extracellular polymeric substances produced by Aspergillus fumigatus

CER extraction was used to extract extracellular polymeric substances from Aspergillus fumigatus. The biochemical composition of the EPS was determined. The adsorption of Pb~(2+) by the EPS was investigated and the equilibrium and the mechanism of biosorption of Pb~(2+) by EPS are discussed. The results showed that the CER process extracted high amounts of the EPS carbohydrate with hardly any cell lysis. The biosorption equilibrium time was about 3 hours. At pH 6.5, the lead removal efficiency could reach 73.48%. Both the Langmuir isotherm and Freundlich isotherm models could describe the biosorption equilibrium well, but the Langmuir isotherm fit better. The maximum uptake capacity of lead was estimated to be 32. 22 mg ?g~(-1) EPS. Analysis of FTIR spectra demonstrated that hydroxyl, carboxyl and C-O-C groups of the polysaccharide were the main functional groups in the reaction between Pb~(2+) , and the binding capacity of protein to Pb~(2+) was weak.