球衣菌对Pb^(2+)的吸附及其影响因素研究

On the biosorption of Pb^(2+) by Sphaerotilus natans and the influential factors on such adsorption

采用球衣菌(Sphaerotilus natans)FQ32为生物吸附剂,研究了Pb^(2+)初始浓度、吸附剂用量、菌龄、pH值、温度和吸附时间等理化因素对球衣菌吸附硝酸铅溶液模拟废水中Pb^(2+)的影响。结果表明,球衣菌在Pb^(2+)初始质量浓度为50 mg/L、吸附剂0.6g/L用量、菌龄32 h、pH=7、温度30℃、吸附时间60min的条件下,对Pb^(2+)的吸附率为89.98%,吸附量为74.98 mg/g;该吸附过程是一个快速的过程,在吸附5 min时,吸附量已达总吸附量的94%.90 min达到吸附平衡。球衣菌对Pb^(2+)的吸附基本为细胞表面的被动吸附,吸附条件对吸附效率有较大影响。

This paper is concerned about a renovated method for bioabsorbing Pb^2＋ by using living cells of Sphaerotillts natarzs FQ32 as an agent in aqueous solution simulated wastewater. For the research purpose, we have done a series of experiments to determine and define the imquential factors on the biosorption process, such＇as the initial concentration of Pb^2＋ , the biomass concentration, the bacteria culturing time, pH value, temperature and the adsorbing time to Pb^2＋ . The results have shown that, at the low Pb^2＋ concentration （〈 50 rag/L）, the adsorption efficiency tends to increase with the initml Pb^2＋ concentration. In a solution with Pb^2＋ concentration of 50 mg/L, however, the adsorption efficiency tends to decrease with the increase of the initial biomass level from 0.6 g/L to 3.0 g/L, for pH value and cell age may influence the adsoqption efficieny, though the temperature influence is slight. Actually, the maximum adsorption eapacily for Pb^2＋ of S. natam FQ32 would be gained at the 74.98 mg/g dry biomass and the adsorption efficiency uould reach 89.98% under the optimal conditions, that is to say, when the Pb^2＋ concentration was 50 mg/L, tire bacteria were euhured 32 hrs＇ later with the biomass of 0.6 g/L, and incubation temperature of 30 ℃, as well as file pH 7 for 60 rains. Thus, the kinetic study of the adsorption has shown that Pb^2＋＇ uptake got to 94% of the total uptake in the initial 5 minutes, and ended in 90 ufiuutes, which indicated that the adsorption process was going on fast and properly.