Assessment And Performance Test Of A Water-soluble Polymer Heavy Metal Chelating Agent

The heavy metal pollution of soil in China is very serious,which has threatened people's life and health.In the commonly used methods of remediation of soil heavy metals,the use of chemical curing / stabilization of heavy metals has advantages of short treatment cycle and low cost.Polymer containing thiourea group is a kind of excellent stabilization agent,which has very good chelating ability of heavy metal ions,with a water soluble thiourea aldehyde resin of soil solidification/stabilization agent basic conditions have been developed,the performance test and evaluation of its significance in rehabilitation the contaminated soil.This paper mainly through the following aspects of the research on the application of water soluble thiourea aldehyde heavy metal chelating agent in the heavy metal contaminated soil testing and evaluation of the performance.The optimal condition of WTF treatment of heavy metal contaminated soil was analyzed by the poison leaching procedure,and the morphological changes of pollutants in the stabilization process was monitored by Tessier sequential extraction method.Through the analysis of the element content and infrared spectrum of the chelating precipitation of heavy metal chelating agent and heavy metal ions,the microscopic mechanism of the chelating heavy metal ions was deduced.The inhibitory effect of WTF on the growth of microorganisms was evaluated by the microbial toxicity test.The optimum amount of treatment of heavy metal pollution of soil heavy metal chelating agent WTF is 2wt% the best pH is 6.7.Soil samples after stabilization treatment for 7 days,the leaching concentration of Cd and Cr from 0.56 mg/kg and 201.49 mg/kg to 0.12 mg/kg and 20.56 mg/kg were reduced 78.6% and 89.8%,lower than the soil environmental quality standard limits.The results of Tessier sequential extraction showed that the exchangeable heavy metals which are harmful to the environment were transformed to the bound to organic matter.Element content analysis and infrared spectra show that WTF and heavy metal ions through the coordination of the formation of a more stable chelating precipitation.The results of toxicity test showed that WTF,as a new type of soil heavy metal chelating agent,has little toxicity and growth inhibition to indigenous microorganisms.The degradation experiment showed that WTF was not easy to degrade,and the degradation ability of soil microorganism was very limited.