Magnetic sulfide-modified nanoscale zerovalent iron (S-nZVI) for dissolved metal ion removal. (1st May 2015)

• Record Type: Journal Article
• Authors: Su, Yiming; Adeleye, Adeyemi S.; Keller, Arturo A.; Huang, Yuxiong; Dai, Chaomeng; Zhou, Xuefei; Zhang, Yalei
• Is Part Of: Water research. Volume 74(2015)
• Page Start: 47
• Page End: 57
• Publication Date: 2015-05-01
• Subjects: Nanoscale zerovalent iron -- Sulfide-modified nanoscale zerovalent iron -- Heavy metal removal -- Oxygen effect -- pH effect; Water -- Pollution -- Research -- Periodicals; 363.7394
• DOI: 10.1016/j.watres.2015.02.004
• Languages: English
• ISSNs: 0043-1354

Abstract

Abstract: Sulfide-modified nanoscale zerovalent iron (S-nZVI) is attracting a lot of attention due to its ease of production and high reactivity with organic pollutants. However, its structure is still poorly understood and its potential application in heavy metal remediation has not been explored. Herein, the structure of S-nZVI and its cadmium (Cd) removal performance under different aqueous conditions were carefully investigated. Transmission electron microscopy (TEM) with an energy-dispersive X-ray spectroscopy (EDS) analysis suggested that sulfur was incorporated into the zerovalent iron core. Scanning electron microscopy (SEM) with EDS analysis demonstrated that sulfur was also homogeneously distributed within the nanoparticles. When the concentration of Na2 S2 O4 was increased during synthesis, a flake-like structure (FeSx ) increased significantly. S-nZVI had an optimal Cd removal capacity of 85 mg/g, which was >100% higher than for pristine nZVI. Even at pH 5, over 95% removal efficiency was observed, indicating sulfide compounds played a crucial role in metal ion removal and particle chemical stability. Oxygen impaired the structure of S-nZVI but enhanced Cd removal capacity to about 120 mg/g. Particle aging had no negative effect on removal capacity of S-nZVI, and Cd-containing mixtures remained stable in a two months experiment. S-nZVI can efficiently sequester dissolved metal ions from different contaminated water matrices. Graphical abstract: Highlights: The specific core–shell structure of S-nZVI was formulated. S-nZVI had a Cd removal capacity of 85 mg/g. S-nZVI can remove 95% Cd 2+ ions even at pH 5. Dissolved oxygen impaired the structure of S-nZVI but enhanced Cd removal. S-nZVI bound with Cd 2+ is very stable.