Copper distribution for contaminated soils and acid wash efficiency

Abstract

Current application of acid washing is to practice fractionation of soil based on particle size prior to washing. However, there is little published information concerning the relationship between the cost-effectiveness of this practice and soil characteristics; this shortage contributes to less than adequate application of washing in most remediation jobs in Taiwan. This research collected soil samples from a copper-contaminated agricultural field in central Taiwan to study the cleansing efficiency of using acid washing combined with particle sieving for remediating the contaminated soil. The soil texture is a sandy loam. The sandy portion constitutes more than 50% of the total soil mass; and its copper content is below the regulated limitation. Therefore, after separation by sieving, this saves more than 50% of the cost of acid washing. For the sandy portion, the hydrochloric acid solution is more effective but for the silt and clay portions, a mixture of hydrochloric acid and citric acid is most effective to remove copper. This study contributes information valuable to advance the application of acid washing to remediate contaminated soil.

Removal of heavy metals and arsenic from a co-contaminated soil by sieving combined with washing process

“…As a result, heavy metals and arsenic in clays are difficult to remove due to their strong adsorption. Cheng et al (2008) indicated that the concentration of Cu in clays was as high as 670.6 mg/kg, 4.77 times the concentration achieved in gravel. Gong et al (2013) drew a similar conclusion in a soil survey in Hainan, wherein the smallest fraction (<0.053 mm) had the highest heavy metal concentrations.…”