| 深海适冷菌Pseudoalteromonas sp. SM9913胞外多糖对Pb2+和Cu2+的吸附性能研究 |
| 摘要点击 3259 全文点击 2180 投稿时间：2008-01-08 修订日期：2008-04-11 |
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| 中文关键词 深海适冷菌 胞外多糖 Pb2+ Cu2+ 生物吸附 |
| 英文关键词 deep-sea psychrophilic bacterium exopolysaccharide Pb2+ Cu2+ biosorption |
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| 中文摘要 |
| 采用深海适冷菌Pseudoalteromonas sp. SM9913分泌的胞外多糖（EPS）分别对Pb2+和Cu2+进行吸附，研究了多糖用量、pH、吸附时间和共存离子对EPS吸附性能的影响及EPS对Pb2+和Cu2+的吸附热力学.结果表明，EPS对Pb2+和Cu2+的吸附量随EPS投加量的增加而减小.EPS对Pb2+和Cu2+的最佳吸附pH分别为4.5～5.5和4.5～6.0. EPS对Cu2+的吸附平衡时间为90 min，对Pb2+的吸附平衡时间则长达180 min.共存离子Ca2+、Mg2+、Na+、K+的加入均降低了EPS对Pb2+的吸附量，Ca2+、Mg2+的加入降低了EPS对Cu2+的吸附量，但低浓度的Na+和实验范围浓度的K+不仅没有降低反而增加了EPS对Cu2+的吸附量.Freundlich和Dubinin-Radushkevich方程均能较好地描述SM9913胞外多糖吸附Pb2+和Cu2+的热力学过程，由Dubinin-Radushkevich方程得到SM9913胞外多糖对Pb2+和Cu2+的最大吸附量分别为243.3 mg/g (10℃) 和36.7 mg/g (40℃).胞外多糖吸附金属离子前后的红外光谱分析表明，多聚糖中C—O—C、乙酰基和羟基是起主要吸附作用的官能团. |
| 英文摘要 |
| Biosorption of Pb2+ and Cu2+ by exopolysaccharide (EPS) from the deep-sea psychrophilic bacterium Pseudoalteromonas sp. SM9913 was investigated. The influence of EPS dosage, pH, equilibrium time and coexisted-ions on adsorption property and the adsorption isotherm of this EPS were studied. The results show that the equilibrium adsorption capacity (Qe) decreases with the increase of EPS dosage. The optimum pH for the adsorption of Pb2+ is 4.5-5.5, and for the adsorption of Cu2+ is 4.5-6.0. The adsorption equilibrium of Cu2+ onto the EPS is attained within 90 min, while the Pb2+ adsorption equilibrium time is 180min. Qeof Pb2+ decreases with the addition of coexisted-ions such as Ca2+, Mg2+, Na+ and K+. Addition of Ca2+， Mg2+ also decreases the Qeof Cu2+, but low dosage of Na+ and tested dosage of K+ increase the Qeof Cu2+. Both Freundlich and Dubinin-Radushkevich isotherm equations could well describe the thermodynamics process of Pb2+ and Cu2+ adsorbed onto the EPS. The maximum adsorption capacity of the EPS determined by Dubinin-Radushkevich isotherm equation for Pb2+ and Cu2+ are 243.3 mg/g (10℃) and 36.7 mg/g (40℃), respectively. IR analysis demonstrates that the group of C—O—C, acetyl and hydroxyl of polysaccharide are the main functional groups for binding metal ions. |
