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90min,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.
Biosorption of Pb^2＋ and Cu^2＋ 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 Pb^2＋ is 4.5-5.5, and for the adsorption of Cu^2＋ is 4.5-6.0. The adsorption equilibrium of Cu^2＋ onto the EPS is attained within 90 min, while the Pb^2＋ adsorption equilibrium time is 180min. Qo of Pb^2＋ decreases with the addition of coexisted-ions such as Ca^2＋ , Mg^2＋, Na ^＋ and K^＋ . Addition of Ca^2＋ , Mg^2＋ also decreases the Qe of Cu^2＋ , but low dosage of Na^＋ and tested dosage of K^＋ increase the Qe of Cu^2＋ . Both Freundlich and Dubinin-Radushkevich isotherm equations could well describe the thermodynamics process of Pb^2＋ and Cu^2＋ adsorbed onto the EPS. The maximum adsorption capacity of the EPS determined by Dubinin-Radushkevich isotherm equation for Pb^2＋ and Cu^2＋ 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 grouos for binding metal ions.
出处
《环境科学》
EI
CAS
CSCD
北大核心
2009年第1期200-205,共6页
Environmental Science
基金
国家高技术研究发展计划(863)项目(2006AA06Z326)
国家自然科学基金项目(50878120)
山东省优秀中青年科学家奖励基金项目(2007BS08004)
山东省博士后创新基金项目(200701006)
