Research on the heavy metal migration and distribution patterns of low permeability copper and zinc contaminated soil during bottom vacuum leaching

With the increasing awareness of environmental protection, the problem of heavy metal pollution in soil has received greater attention. The bottom vacuum leaching remediation method (BVM) is an emerging soil remediation technology that has demonstrated enhanced efficiency and effectiveness in treating soils with low permeability. This experiment employed three soil column models of varying heights to examine the patterns of heavy metal migration and distribution, by conducting a series of experimental studies that investigated changes in soil columns and leaching agents, as well as the distribution of water content, heavy metals, and particle size after the leaching process. The experimental results indicate a correlation between the height of the soil column and the leaching speed, with higher columns exhibiting slower leaching rates. However, the final removal rate is not necessarily the lowest. Particle size analysis reveals that the decomposition of large particles into smaller particles, facilitated by the action of the leaching agent, significantly influences the removal efficiency. The combined effect of particle decomposition and vacuum action demonstrates a pattern of increasing and then decreasing the distribution of heavy metals, forming a distinct zone of heavy metal accumulation.