title: Immobilization of mercury in field soil and sediment using carboxymethyl cellulose stabilized iron sulfide nanoparticles.
abstract: Mercury (Hg) is one of the most pervasive and bio-accumulative metals in the environment. Yet, effective in situ remediation technologies have been lacking. This study investigated the effectiveness of a class of soil-deliverable FeS nanoparticles for in situ immobilization of Hg in two field-contaminated soils from a New Jersey site and one sediment from an Alabama site. The nanoparticles were prepared using sodium carboxymethyl cellulose (CMC) as a stabilizer. Transmission electron microscopy measurements revealed a particle size of 34.3 ± 8.3 nm (standard deviation), whereas dynamic light scattering gave a hydrodynamic diameter of 222.5 ± 3.2 nm. Batch tests showed that at an FeS-to-Hg molar ratio of 28:1-118:1, the nanoparticles reduced water-leachable Hg by 79%-96% and the TCLP (toxicity characteristic leaching procedure) based leachability by 26%-96%. Column breakthrough tests indicated that the nanoparticles were deliverable in the sediment/soil columns under moderate injection pressure. However, once the external pressure was removed, the delivered nanoparticles remained virtually mobile under typical groundwater flow conditions. When the Hg-contaminated soil and sediment were treated with 52-95 pore volumes of a 500 mg l(-1) FeS nanoparticle suspension, water-leachable Hg was reduced by 90%-93% and TCLP-leachable Hg was reduced by 65%-91%. The results warrant further field demonstration of this promising in situ remediation technology.
authors: Environmental Engineering Program, Department of Civil Engineering, Auburn University, Auburn, AL 36849, USA.
authors: Yanyan
authors: Y
authors: Gong
authors: Yuanyuan
authors: Y
authors: Liu
authors: Zhong
authors: Z
authors: Xiong
authors: Dawn
authors: D
authors: Kaback
authors: Dongye
authors: D
authors: Zhao
mesh_terms: D002266:Carboxymethylcellulose Sodium / Q000737:chemistry*; D052918:Environmental Restoration and Remediation / Q000379:methods*; D019015:Geologic Sediments / Q000032:analysis; D058085:Iron Compounds / Q000737:chemistry*; D008628:Mercury / Q000302:isolation & purification*; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D012987:Soil / Q000032:analysis; D012989:Soil Pollutants / Q000302:isolation & purification*; D013440:Sulfides / Q000737:chemistry
chemical_list: D058085:Iron Compounds; D012987:Soil; D012989:Soil Pollutants; D013440:Sulfides; D008628:Mercury; D002266:Carboxymethylcellulose Sodium