Optimizing removal of arsenic, chromium, copper, pentachlorophenol and polychlorodibenzo-dioxins/furans from the 1–4 mm fraction of polluted soil using an attrition process

Abstract

ABSTRACTThe objective of this study was to evaluate, at a pilot scale, the performance of an attrition process for removing As, Cr, Cu, pentachlorophenol (PCP) and polychlorodibenzodioxins and furans (PCDDF) from a 1-4 mm soil fraction. A Box-Behnken experimental design was utilized to evaluate the influence of several parameters (temperature, surfactant concentration and pulp density) and to optimize the main operating parameters of this attrition process. According to the results, the concentration of surfactant (cocamidopropylbetaine-BW) was the main parameter influencing both PCP and PCDDF removal from the 1-4 mm soil fraction by attrition. The behavior of each 2,3,7,8-PCDD/F congener during the attrition process was studied. The results indicated that the concentration of surfactant had a significant and positive effect on the removal of almost all of the dioxin and furan. The removal of 56%, 55%, 50%, 67% and 62% of the contaminants were obtained for As, Cr, Cu, PCP and PCDDF, respectively, using the optimized conditions ([BW]= 2% (w.w−1), T = 25°C and PD = 40% (w.w−1)). These results showed that attrition in the presence of a surfactant can be efficiently used to remediate the coarse fractions of soil contaminated by As, Cr, Cu, PCP and PCDDF.