Experimental study on removal of cadmium from contaminated soil by Acidithiobacillus ferrooxidans via microbial leaching
Microbial leaching is a resource-saving,low-carbon and environment-friendly soil remediation method,and is a promising technique for remediating contaminated soil.The characteristics and leaching mechanism of cadmium leaching from contaminated soil by Acidithiobacillus ferrooxidans were studied through a series of laboratory tests in order to provide theoretical basis for remediation of heavy metal contaminated soil.The characteristics of cadmium leaching from contaminated soil by Acidithiobacillus ferrooxidans were studied by means of oscillatory leaching test,considering the concentration of cadmium,the dosage of energy material Fe2+,the inoculation amount of Acidithiobacillus ferrooxidans and the leaching time.The results show that the lower the initial concentration of cadmium in the contaminated soil,the higher the leaching ratio of cadmium.With the increase of leaching time,the pH of solution and the leaching ratio of cadmium in contaminated soil showes a gradually increasing trend.With the increase of Fe2+concentration,the leaching ratio of cadmium in contaminated soil increases first and then decreases.The best leaching effect is achieved when the concentration of Fe2+is 9 g·L-1.With the increase of Acidithiobacillus ferrooxidans dosage,the leaching effect increases as well.When the nutrient Fe2+dosage is 9 g·L-1,the inoculation amount of Acidithiobacillus ferrooxidans is 25%,the leaching ratio can reach 96.6%when the initial concentration of cadmium is 100 mg·kg-1.Microscopic test showed that the new elongated minerals appeared on the surface of the soil sample after leaching,and the residual cadmium in soil were mainly in weak acid extractable and residual state,with much reduced reducible and oxidizable state.
万方数据
维普
