Stabilizing Effects of Fe-Ce Oxide on Soil As(Ⅴ) and P

Abstract

The mining and smelting of arsenic-containing metal minerals, and the large-scale use of chemicals and pesticides, has resulted in the widespread pollution of soils in southwestern and southern China. In this study, the stabilizing effect of Fe-Ce oxide (FC) on three representative arsenic-contaminated soils was evaluated. The microscopic adsorption characteristics of FC and As(Ⅴ) were explored by scanning electron microscopy and energy disperse spectroscopy (SEM-EDS) and X-ray photoelectron spectroscopy (XPS). The results showed that FC can significantly reduce arsenic concentrations by 84.1%-98.3% during the Toxicity Characteristic Leaching Procedure (TCLP), and showed strong pH adaptability in alkaline soil. It efficiently transformed (non-)specifically sorbed arsenic (F1+F2) into hydrous oxides phases of Fe and Al (F3+F4). FC also significantly reduced available P by 47.13%-60.32% in different types of soil. FC can not only release As(Ⅴ) adsorption sites occupied by P in soils, but also effectively prevents non-point source pollution of the surrounding water. SEM-EDS and XPS analysis detected Fe, Ce, and As on the surface of As(Ⅴ) adsorption products, and As was mainly adsorbed on the surface of Fe atoms. The results of this study provide a scientific basis for soil arsenic stabilization in China.