【摘要】 系统研究了硝基还原假单胞菌对重金属镉的吸附特性与吸附机理.研究结果表明,此株菌可以耐受200mg/L重金属镉,而进一步提高镉离子的浓度则会显著抑制该菌的生长.将该菌株接种至含20、50和100mg/L Cd²⁺的液体LB培养基中,经过120h的培养,镉的去除率分别能达到94.3%,91.0%和86.0%.系统研究了pH值、温度、盐浓度和多种重金属离子存在下,该菌株对溶液中镉离子去除效果的影响.结果表明,硝基还原假单胞菌可以在pH值为4⁸范围内有效吸附镉离子,当NaCl溶液提升至1mol/L时,该菌株仍可耐受,并且可以吸附除了铅离子之外的多种重金属离子.X射线光电子能谱分析结果显示,吸附后Cd²⁺的结合能发生了变化.扫描电镜结果显示,与正常菌株相比,吸附镉的菌株产生明显形变,且表面有白色颗粒状物质吸附,结合X射线光电子能谱分析结果,可以说明生物矿化是该菌株吸附和钝化重金属的途径之一.更多还原

【Abstract】 The adsorption characteristics and adsorption mechanism of cadmium removal by Pseudomonas nitroreducenswere investigated systematically. The results showed that the strain could tolerate cadmium up to 200mg/L. Further increase the concentration of cadmium led to a significantly inhibition of the growth of Pseudomonas nitroreducens. In a liquid culture of Pseudomonas nitroreducens, where a liquid LB medium containing 20mg/L, 50mg/L or 100mg/L Cd²⁺ was used, the removal rate of cadmium reached 94.3% 91.0% and 86.0%, respectively after 120 h of cultivation. The impact of p H, temperature, salt concentration and various other heavy metal ions on the removal efficiency of cadmium were also explored. The results showed that Pseudomonas nitroreducens effectively adsorbed cadmium with in the p H range from 4 to 8. The osmosis stress test showed that Pseudomonas nitroreducens could tolerate a Na Cl solution of 1mol/L. Under this condition, the strain still adsorbed a variety of heavy metal ions except lead ions. X-ray photoelectron spectroscopy analysis showed that the binding energy of cadmium changed after adsorption. Scanning electron microscopy（SEM） showed that Pseudomonas nitroreducens deformed and has white particles attached on the surface after cadmium treatment, indicating that biomineralization is one of its ways to adsorb heavy metals.更多还原