产黄青霉浸出修复重金属污染土壤

Bioleaching remediation on heavy metal polluted soil using Penicillium Chrysogenum

采集铅锌冶炼厂周边表层土壤,分析其污染情况,并用产黄青霉菌浸出修复,用正交法考察温度、培养基pH值和浸出时间对浸出率的影响,拟寻找最佳修复方案。结果表明:根据GB 15618-95二级土标准值,铅锌冶炼厂周边表层土壤中Zn和Cd已达重度污染程度,Cu达中度污染,Pb为轻度污染,Cr未污染;综合污染指数表明铅锌冶炼厂周边表层土壤已达严重污染程度;Pb和Zn的最适浸出温度为30℃,Cd和Cu的最适浸出温度为20℃;当培养基pH值为7.0时,Pb、Zn、Cd和Cu的浸出率之和最高,Pb和Zn的浸出率之和均在浸出7 d时最高。极差分析表明,培养基pH值和浸出时间是影响产黄青霉浸出修复重金属污染土壤的主要因素;方差分析表明,培养基pH值和浸出时间对Zn的浸出率影响显著,3种因素对Pb、Cd和Cu浸出率的影响均不明显。当温度为30℃,pH值为7.0,浸出7 d时各重金属的浸出率均最高,故产黄青霉浸出修复重金属污染土壤的最优方案为A2B2C3。

The surface soil was sampled around a Pb / Zn smelter to analyze the heavy metal content and determine the pollution level. A 2. 5 g soil sample was added to 50 m L liquid medium and bioleached using Penicillium chrysogenum to determine the best combination of bioleaching factors. A four-factor three-level orthogonal table was applied to investigate the influence of temperature,pH,and bioleaching time on bioleaching rate. The results showed that,according to the GB 15618-95 secondary grade standard,Zn and Cd pollution were at serious levels,Cu pollution was moderate,Pb pollution was mild,and there was no Cr pollution. The overall level of pollution was serious according to both the Neimeiluo and weighting comprehensive indices. The bioleaching rates of Pb and Zn were higher than those of Cd and Cu. The optimum bioleaching temperature for Pb and Zn was30°C,whereas that of Cd and Cu was 20°C. The bioleaching rates of Pb,Zn,Cd,and Cu were highest at a pH value of 7. 0. The bioleaching rates of Pb and Zn were highest when bioleached for 7 days,whereas there was no distinct difference between the bioleaching rates of Cd and Cu on days 5 and 7. Therefore,it is clear that the pH and bioleaching time were the main factors that influenced the bioleaching rate when using P. chrysogenum,according to the results of range analysis. Variance analysis results showed that pH and bioleaching time had a considerable influence on the bioleaching rate of Zn; however,the influence of the three factors on the bioleaching rate of Pb,Cd,and Cu was not obvious,when at a temperature of 30℃,pH of 7. 0,and bioleaching time of 7d,the heavy metal bioleaching rate was the highest. Therefore,the optimal combination of bioleaching remediation of heavy metal contaminated soil by P. chrysogenum was temperature of 30℃,pH value of 7. 0,and bioleaching time of 7 d. Therefore,the optimal combination of bioleaching remediation of heavy metal contaminated soil by P. chrysogenum was A2B2C3.