[Biosorption of Pb2+ and Cu2+ by an exopolysaccharide from the deep-sea psychrophilic bacterium Pseudoalteromonas sp. SM9913].
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 180 min. Qe of Pb2+ decreases with the addition of coexisted-ions such as Ca2+, Mg2+, Na+ and K+. Addition of Ca2+, Mg2+ also decreases the Qe of Cu2+, but low dosage of Na+ and tested dosage of K+ increase the Qe of 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 degrees C) and 36.7 mg/g (40 degrees C), 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.
Zhou
Wei-zhi
WZ
School of Environmental Science and Engineering, Shandong University, Ji' nan 250100, China. wzzhou@sdu.edu.cn
Li
Wei-wei
WW
Zhang
Yu-zhong
YZ
Gao
Bao-yu
BY
Wang
Jing
J
D000327:Adsorption; D001673:Biodegradation, Environmental; D003300:Copper / Q000378:metabolism*; D005109:Extracellular Matrix / Q000378:metabolism; D007854:Lead / Q000378:metabolism*; D011135:Polysaccharides, Bacterial / Q000378:metabolism*; D031161:Pseudoalteromonas / Q000302:isolation & purification / Q000378:metabolism*; D012623:Seawater; D014871:Water Microbiology; D014874:Water Pollutants, Chemical / Q000378:metabolism*
D011135:Polysaccharides, Bacterial; D014874:Water Pollutants, Chemical; D007854:Lead; D003300:Copper