A study on the removal of pollutants from soil contaminated with high concentrations of heavy metals

Abstract

Heavy metal contaminated soil remediation methods are mostly chemical washing, fixed stabilization, and bioremediation techniques. However, chemical drenching can cause secondary pollution; fixation stabilization remediation is incomplete and may fail; and bioremediation has a long time period. Therefore, in this study, we synthesized a stable millimeter-scale gel spherical adsorbent, UIO-66-NH₂@SA, to remove the pollutants from the soil contaminated with high concentrations of heavy metals by a combination of aqueous leaching and adsorption without the addition of additional chemical leaching agents. The UIO-66-NH₂@SA can be recovered by sieving, and it still has the capacity of removing the heavy metals after four adsorption–desorption cycles. The analysis of soil properties before and after adsorption proved that the remediation process would not affect the physicochemical properties and fertility of the soil, and the characterization of x-ray diffraction, Fourier transform infrared, and XPS proved that the adsorption mechanism was mainly ion exchange and functional group complexation.