title: Reductive immobilization of chromate in water and soil using stabilized iron nanoparticles.
abstract: Laboratory batch and column experiments were conducted to investigate the feasibility of using a new class of stabilized zero-valent iron (ZVI) nanoparticles for in situ reductive immobilization of Cr(VI) in water and in a sandy loam soil. Batch kinetic tests indicated that 0.08g/L of the ZVI nanoparticles were able to rapidly reduce 34mg/L of Cr(VI) in water at an initial pseudo first-order rate constant of 0.08h(-1). The extent of Cr(VI) reduction was increased from 24% to 90% as the ZVI dosage was increased from 0.04 to 0.12g/L. The leachability of Cr preloaded in a Cr-loaded sandy soil was reduced by nearly 50% when the soil was amended with 0.08g/L of the ZVI nanoparticles in batch tests at a soil-to-solution ratio of 1g: 10mL. Column experiments indicated that the stabilized ZVI nanoparticles are highly deliverable in the soil column. When the soil column was treated with 5.7 bed volumes of 0.06g/L of the nanoparticles at pH 5.60, only 4.9% of the total Cr was eluted compared to 12% for untreated soil under otherwise identical conditions. The ZVI treatment reduced the TCLP leachability of Cr in the soil by 90%, and the California WET (Waste Extraction Test) leachability by 76%. The stabilized ZVI nanoparticles may serve as a highly soil-dispersible and effective agent for in situ reductive immobilization of chromium in soils, groundwater, or industrial wastes.
authors.affiliation: Environmental Engineering Program, Department of Civil Engineering, 238 Harbert Engineering Center, Auburn University, Auburn, AL 36849, USA.
authors.forename: Yinhui
authors.initials: Y
authors.lastname: Xu
authors.forename: Dongye
authors.initials: D
authors.lastname: Zhao
mesh_terms: D001673:Biodegradation, Environmental; D002840:Chromates / Q000737:chemistry*; D005296:Ferrous Compounds; D007501:Iron; D007700:Kinetics; D019216:Metals, Heavy; D053758:Nanoparticles; D010084:Oxidation-Reduction; D012987:Soil; D014867:Water
chemical_list: D002840:Chromates; D005296:Ferrous Compounds; D019216:Metals, Heavy; D012987:Soil; D014867:Water; C020748:ferrous sulfate; D007501:Iron