Study On Immobilization Remediation Technology For Heavy Metal Contaminated Soil By Organic-inorganic Complex

In recent decades, the contamination of soils by toxic and hazardous heavy metals is a widespread environmental problem and the removal of heavy metals from contaminated soils is becoming a major concern. The immobilization is an economic, efficient and feasible remediation technique of contaminated soils by heavy metals, and it is suitable for the remediation of slight non-point pollution soils induced by agricultural activity, especially for the combined pollution of heavy metals. The problems of immobilization are still exist . Firstly, most fixatives are chemosynthesis. it is easy to cause secondary pollution. Secondly , a fundamental problem have not been solved .It is metal ions are still in the soil .Their morphology may change with the environment .Thirdly, it must have scientific technical parameters and commercial fixative so as to spread the remediation technology .nowadays , study on specific applying method of fixative is not deeply .In this study, study on important and difficult problem of remediation of soil metal pollution. To passive heavy metal in soil with organic-inorganic complex which is prepared by this laboratory. Studying the passive effects to heavy metal in soil of organic-inorganic complex by incubation experiments . Studying main influence factors on passive effects of organic-inorganic complex by simulation experiments . Studying application technology of organic-inorganic complex used in repairing heavy metal contaminated soil. To provide theoretical basis for developing achieve economical and safety technology of repairing heavy metal contaminated soil. It has important theoretical significance and practical value for developing the remediation of heavy metal contaminated soil.The main results of this paper are as follows:1.The organic-inorganic complex can significantly reduce the DTPA-Cu content in cinnamon soil and alluvia soil, however it has little capability to immobilize Cd. We got the same regularity when the organic-inorganic complex were used to immobilize Cu & Cd contaminated cinnamon soil and alluvia soil, the complex has little efficiency in immobilizing Cu & Cd in acid brown soil. There is one special area for the organic-inorganic complex application in ion immobilization of heavy metal contaminated soil.2.The useless of organic-inorganic complex can enhance the PH of alluvia soil, the more change for cinnamon soil and no change for acid brown soil. It's very useful to reduce DTPA-Cu content when the PH is raised in soil, the negative ion quantity is efficiently increased in soil at the same time. That may be one theory for organic-inorganic complex immobilizing heavy metal ion in contaminated soil.3.Based on the remediation efficiency and economic concern, the organic-inorganic complex optimum quantity is 1.5% of soil weight when it is used for Cu immobilization in contaminated cinnamon soil and alluvia soil; the content of water in soil is 70% of maximum. There is no different for remediation efficiency by bagged complex or used directly, we chance the bagged complex for it's easily to be separated from soil. When there is no ryegrass, the minim DTPA-Cu content appeared in the area 20cm from complex, the area change to 30cm from complex when ryegrass is planted.4.The usage of organic-inorganic complex with optimal parameter not only efficiently increases the quantity of ryegrass but also deeply reduces the Cu content in soil. There is no different by bagged complex and used directly.In summary, the organic-inorganic complex prepared in our lab has the efficiently immobilization of Cu in cinnamon soil and alluvia soil, the complex reduced the Cu content significantly in ryegrass, There is no different by bagged complex and used directly, so we chance the bagged complex for it's easily to be separated from soil. . There is one special area for the organic-inorganic complex application in ion immobilization of heavy metal contaminated soil. The major impact factors include the kinds of heavy metal ion, the parent material of soil etc. it is the important theoretical basis for developing achieve economical and safety technology of repairing heavy metal contaminated soil.