Chromium Removal with Environmentally Friendly Iron Nanoparticles in a Pilot Scale Study

Nano zero valent iron (nZVI) is highly reactive, targets a wide range of contaminants and is considered as a promising material for the in situ remediation of contaminated aquifers. Injection of nZVI suspension is a remedial option for the in-situ reduction and immobilization of pollutants in aquifers. The goal of the present study was to evaluate the efficiency of iron nanoparticles (GT-nZVI), synthesised by a green synthesis route, for Cr(VI) removal in a pilot scale application. A tank with dimensions 2.5 m (width) × 3.75 m (length) × 1.5 m (height) was constructed and filled with 24 tons of soil. Firstly 3 m³ GT-nZVI suspension was injected and then the supply of contaminated water containing 5 mg/L Cr(VI) was initiated. Samples were analysed for pH, redox potential and electric conductivity, as well as Fe_tot and Cr(VI). The reactive zone operated efficiently for the treatment of contaminated water for 1 year.