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.

Effects of oil dispersant on solubilization, sorption and desorption of polycyclic aromatic hydrocarbons in sediment–seawater systems

“…The dried aggregates were further oven-dried for 6 h at 80°C before use. Sediment analyses were performed by the Soil Testing Laboratory at Auburn University, and the method details have been described elsewhere (Gong et al, 2012). Table S3 gives salient properties of the sediments.…”

Immobilization of mercury (II) from aqueous solution using Al 2 O 3 -supported nanoscale FeS

“…FeS has been widely studied for mercury immobilization [15][16][17][18][19]. Liu et al [18] found that the enrichment capacity of FeS could reach 0.75 mol Hg(II) /mol FeS.…”

Functionalisation of Colloidal Transition Metal Sulphides Nanocrystals: A Fascinating and Challenging Playground for the Chemist

“…In this case, the successful formation of CMC-FeS could be only indirectly assessed by verifying the very low polydispersity index, suggesting a quite monodisperse system. In a previous paper on the topic [414], evidence that attachment of CMC onto the surface of FeS particles induced strong electrostatic repulsion between the negatively charged particles was also provided based on zeta potential measurements [414]. Furthermore, when stored in sealed vials under anaerobic conditions at room temperature, the CMC-FeS NP did not display any visual sedimentation over a period of several weeks.…”

“…Concerning iron sulphides, very few examples could be retrieved in the literature, dealing with their derivatisation. Among these ones, some [414][415][416] report on iron sulphide which was stabilised by using carboxymethyl cellulose as stabilising ligand. In one case [416], the nanoparticles were prepared using a low-cost, food-grade cellulose (sodium carboxymethyl cellulose, CMC) as the stabiliser.…”