Decrease of Heavy Metal Availability: Different Approaches for Remediation of Polluted Soil in Red River Delta, Vietnam

Abstract: Heavy metal (HM) contaminations in the topsoil around handicraft villages in the Red River Delta (RRD),Vietnam impose serious threats to the subsoil as well as to the groundwater quality. This work is to decrease the mobility of HM by applying Fe powder, the kaolinite, bentonite and vermiculite to soils.  Organo-clays produced by modifying these above clay minerals with surfactants HDPy and HDPyCl were tested for removing HM. Fe powder exposes a better sorption capacity for HM as compared to vermiculite and bentonite. Application of Fe in 1 w.% can enhance adsorption capacity of Cu up to 170%, while vermiculite and bentonite applied at 5 w.% can only enhance the adsorption capacity up to ~160% and ~140%, respectively. Low charged clays, which were modified with organic cations have shown be a high potential as adsorbents for Cu in these situations (partially ~220%). These tested materials can flexibly be applied for soil and wastewater remediations in order to step by step reduce the impact of HM pollution in the local area.Keywords: Heavy metal, availability, remediation, clay mineral, Fe powder.