|
Abstract:Soil is not only the major component of ecological system, also the material basis of human livings. In recent years, with our contaminated soil area expending and its extent deepening year by year, the health of mankind, flora and fauna are subjected to threaten. Chemical leaching is a high-efficient remediation technology, which can remove contaminants from soil rapidly and instantly and has a stable remediation effectiveness. It has become one of research hot and development direction for rapid soil remediation means.Considering the arid land and rice land as the research objects which are near a lead-zinc dressing plant in Shuikou Hill, Hu Nan, this paper studied the effective content and chemical speciation of the heavy metal Zn, Pb, Cu by analyzing the speciation distribution of the heavy metal from the tested soils. Research shows that residue is the main existence form of the heavy metal Zn, Pb, Cu from the arid soil, the reducible and oxidable proportion is higher, the acid soluble proportion is lower; Otherwise, in the rice land, the acid soluble proportion is relatively higher, while the residue proportion is low.Based on the above-mentioned results, this paper contrasted the leaching agents’removal effect on the heavy metal of the arid land, including the citric acid, tartaric acid, EDTA, MGDA and saponin, and studied the removal efficiency of the concentration, leaching time, liquid-soil ratio, and leaching times. The results show that the best removal efficiency was gained by the citric acid and tartaric acid with a sound solubility, short leaching time and cheap price; then the EDTA and MGDA is better, but the MGDA is expensive; the saponin is worse. On the other side, considering the saponin having a sound biodegradation, this paper studied the removal effect of the saponin which suggested that it has a good removal efficiency. Therefore, the saponin has a better leaching effect on soils with a high content of acid soluble form.
|