title: Magnetic sulfide-modified nanoscale zerovalent iron (S-nZVI) for dissolved metal ion removal.
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 Na2S2O4 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.
authors.affiliation: State Key Laboratory of Pollution Control and Resources Reuse, Tongji University, Shanghai 200092, China; Bren School of Environmental Science & Management, University of California, Santa Barbara, 3420, Bren Hall, CA 93106, USA; University of California Center for Environmental Implications of Nanotechnology, Santa Barbara, CA, USA.
authors.forename: Yiming
authors.initials: Y
authors.lastname: Su
authors.affiliation: Bren School of Environmental Science & Management, University of California, Santa Barbara, 3420, Bren Hall, CA 93106, USA; University of California Center for Environmental Implications of Nanotechnology, Santa Barbara, CA, USA.
authors.forename: Adeyemi S
authors.initials: AS
authors.lastname: Adeleye
authors.affiliation: Bren School of Environmental Science & Management, University of California, Santa Barbara, 3420, Bren Hall, CA 93106, USA; University of California Center for Environmental Implications of Nanotechnology, Santa Barbara, CA, USA. Electronic address: keller@bren.ucsb.edu.
authors.forename: Arturo A
authors.initials: AA
authors.lastname: Keller
authors.affiliation: Bren School of Environmental Science & Management, University of California, Santa Barbara, 3420, Bren Hall, CA 93106, USA.
authors.forename: Yuxiong
authors.initials: Y
authors.lastname: Huang
authors.affiliation: State Key Laboratory of Pollution Control and Resources Reuse, Tongji University, Shanghai 200092, China; College of Civil Engineering, Tongji University, Shanghai 200092, China.
authors.forename: Chaomeng
authors.initials: C
authors.lastname: Dai
authors.affiliation: State Key Laboratory of Pollution Control and Resources Reuse, Tongji University, Shanghai 200092, China.
authors.forename: Xuefei
authors.initials: X
authors.lastname: Zhou
authors.affiliation: State Key Laboratory of Pollution Control and Resources Reuse, Tongji University, Shanghai 200092, China; Key Laboratory of Yangtze Water Environment for Ministry of Education, Tongji University, Shanghai 200092, China. Electronic address: zhangyalei@tongji.edu.cn.
authors.forename: Yalei
authors.initials: Y
authors.lastname: Zhang
mesh_terms: D002104:Cadmium / Q000302:isolation & purification*; D006863:Hydrogen-Ion Concentration; D007501:Iron / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry*; D010100:Oxygen / Q000737:chemistry; D013440:Sulfides / Q000737:chemistry*; D014865:Waste Disposal, Fluid / Q000379:methods*; D014874:Water Pollutants, Chemical / Q000302:isolation & purification*
chemical_list: D013440:Sulfides; D014874:Water Pollutants, Chemical; D002104:Cadmium; D007501:Iron; D010100:Oxygen
keywords: Heavy metal removal; Nanoscale zerovalent iron; Oxygen effect; Sulfide-modified nanoscale zerovalent iron; pH effect