2023 Volume 18 Issue 1 Pages 31-41
The objective of this study was to develop a better understanding of the mechanisms of arsenic adsorption by iron particles in the remediation of arsenic leaching soil. During the study, the following observations were made: 1) in-crease in the addition ratio of iron particles in soil slurry resulted in decrease of arsenic leaching, 2) removal of all iron particles from the slurry by magnetic force resulted in the return to original arsenic leaching value level, and 3) arsenic leaching from the soil appeared to be pH-dependent. From these results, the following conclusions were de-duced: (a) soluble arsenic in soil slurry is adsorbed by amorphous iron oxy-hydroxide produced from the reaction of iron ions eluted from the iron particles, (b) arsenic leaching increased due to lack of available iron oxy-hydroxide, reduced by the removal of iron particles, and (c) arsenic leaching ability of cleaned soil varies in accordance with re-sidual quantity of iron oxy-hydroxide. Furthermore, the following rationale behind the conventional method of add-ing acid together with iron particles was inferred: (a) lowers the slurry pH values resulting in reduced arsenic leach-ing values, and (b) promotes elution of iron ions from iron particles resulting in increased production of iron oxy-hydroxide (adsorbent).
