Study On Pisha Sandstone Repairing Heavy Metal Contaminated Soil In Shanxi, Shaanxi And Inner Mongolia Energy Zone

Finding suitable repaired materials to repair heavy metal contaminated soil caused by coal,oil and natural gas, is one of the significant measures to regional environment. This paperhighlights the new soil remediation material—Pisha sandstone, and it plays advantages role inthe restoration of soil heavy metal pollution in the energy area.Through adsorption experimentand indoor culture experiments, it aimed to analyze the basic physical and chemical propertiesof the three colors Pisha sandstone deeply, as well as the adsorption mechanism of Pishasandstone on lead, and to evaluate remediation effects and advantages of Pisha sandstone toheavy metal contaminated soil in ecologically fragile areas, as well as the effects of Pishasandstone on the physical and chemical properties of soil.(1) Used three kinds of Pisha sandstone with red, white and gray colors as absorbents toinvestigate the effects of absorbent dosage, pH and ionic strength on the absorption of Pb(II)and kinect and isothermal properties. By used dynamic and thermodynamic models, coupledwith infrared spectroscopic (FTIR) analysis to explore the mechanism on the absorption ofPb(II). The results indicated that Pisha sandstone could adsorb Pb(II) effectively and theabsorption were strongly affected by the concentration of Pb(II), absorbent dosage, pH andionic concentration. With the increase of the dosage, the removal efficiency of Pb(II)increased sharply and while the adsorption efficiency decreased. It positively correlated withof the pH and negatively correlated with the ionic concentration. The Pisha sandstones ofthree different colors could reach the absorption equilibrium within30minutes. Theabsorption rates showed an order of grey> white> red and these kinetic process satisfied thepseudo-second order kinetics model. Freundlich and D-R model could simulate the isothermalproperties of the Pisha sandstones adsorbing Pb(II) in the range of tested concentrations. Themodels and FTIR analysis demonstrated that the processes of the Pisha sandstones absorbingPb(II) were mainly electrostatic adsorption and ion exchange, and supplemented by somechemical adsorption and chemical precipitation.(2) Due to its own characteristic, Pisha sandstone has the stronger adsorption and can beseen as repaired material for heavy metal. It is an important approach to repair heavy metalcontaminated soil. Through indoor culture experiments, it aimed to study the effects of Pisha sandstone on the contents of Pb forms and on the contents of Pb TCLP. The results showedthat Pisha sandstone has a certain superiority about repairing lead contaminated soil, andmakes lead stable. Pisha sandstone can reduce the contents of acid extractable lead andreducible lead in soil, and can increase the contents of residual lead with low activitysignificantly. The dosage of Pisha sandstone in soil was positively related to the contents ofresidual lead with low activity and was negatively related to the contents of acid extractablelead and reducible lead. In addition, Pisha sandstone also significantly reduces the contents ofPb TCLP, and the drop degree is proportional to the dosage of Pisha sandstone. It can inhibitbioavailability and migration of lead. The adsorption characters and the enhancing soil pH ofPisha sandstone were the key factors to immobile lead.(3) Through indoor culture experiments, it aimed to explore the effects of Pisha sandstoneon the physical and chemical properties of soil, including soil bulk density, soil porositysoilpH, field capacity, and the influence of soil enzyme activity. The results showed that Pishasandstone not only can repair heavy metal contaminated soil, but also has some impact on soilphysical, chemical and biological properties. It improves and regulates soil in certain extent.Pisha sandstone reduced soil bulk density, increased soil porosity, improved soil structure,increased soil field capacity and soil pH, and Pisha sandstone had a certain impact on soilenzyme activity.In summary, Pisha sandstone has obvious adsorption advantages, has significantrestorative effects for the contaminated soil, and Pisha sandstone also can improve andregulate the contaminated soil to some extent. This shows that the Pisha sandstone haspossibility as a material to repair heavy metal contaminated soil.