IRON BASED IMMOBILIZATION FOR METAL CONTAMINATED SOILS

Abstract

Remediation of contaminated soils is an important task which aims to reduce the impact of toxic metalloidssuch as Cd, Cu and As on public health. In-situ immobilization via the addition of soil amendments suchas iron based materials reduces the mobility and transport of these toxic metalloids in the environment. Awide range of iron-based materials have been used for metal immobilization in contaminated soilsincluding iron oxides, zerovalent iron, nano-zerovalent iron (nZVI), iron salts, green synthesized iron oxidenanoparticle (GION) or phytogenic iron oxides nanoparticles (PION), Fe-Al layered double hydroxideand CMC (carboxymethylcellulose) based iron. The reactivity and surface area of zerovalent iron isincreased at the nanoscale when utilized as nZVI thereby increasing its effectiveness as demonstrated byprevious studies. The efficiency of nZVI in remediation of contaminated soils is limited by the strongtendency of its particles to agglomerate. In order to overcome this limitation and facilitate the delivery andmobility of nZVI in soils, nZVI is immobilized onto a carrier such as resin, potato starch, zeolite, ormesoporous silica or by increasing colloidal stability with the addition of other soil amendments. Eventhough, there is g rowing concern over the environmental impact of nanoparticles, the use of plant extractsto synthesize iron nanoparticles is environmentally friendly and economical.