Magnetic sulfide-modified nanoscale zerovalent iron (S-nZVI) for dissolved metal ion removal

Abstract

Keywords:Nanoscale zerovalent iron Sulfide-modified nanoscale zerovalent iron Heavy metal removalOxygen effect pH effect a b s t r a c t 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 Na 2 S 2 O 4 was increased during synthesis, a flake-like structure (FeS x ) 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.© 2015 Elsevier Ltd. All rights reserved. Available online at www.sciencedirect.com ScienceDirect j ou rnal h ome pag e: www.elsevier.com/loca te/watres w a t e r r e s e a r c h 7 4 ( 2 0 1 5 ) 4 7 e5 7http://dx

Reductive transformation of tetrabromobisphenol A by sulfidated nano zerovalent iron

“…The initial concentrations of TBBPA (5, 10 and 20 mg L À1 ) tested here were comparable to those reported in anoxic sediments (Morris et al, 2004), while those of S-nZVI (0.6, 1.2 and 2.3 mg L À1 ) fell within the concentration range used in other prior studies (Rajajayavel and Ghoshal, 2015;Su et al, 2015).…”

Heteroaggregation of nanoparticles with biocolloids and geocolloids

“…Typical applications include multi-walled carbon nanotubes (MWNTs) for reinforcing the strength of baseball bats [6], and single-walled carbon nanotubes (SWNTs) for biomedical applications, sensors, and electronics [7]; and (3) magnetic particles: magnetic particles have been extensively considered as adsorbents for the removal of various pollutants from water because their inherent superparamagnetic properties result in easy separation by a magnetic field [8][9][10]. Typical magnetic iron oxides are Fe 3 O 4 , and pristine and modified nanoscale zerovalent iron (nZVI) [11][12][13].…”

EDTA functionalized magnetic nanoparticle sorbents for cadmium and lead contaminated water treatment

“…In the past few years, nano-scaled magnetic particles have been proposed as sorbents for environmental decontamination (Huang and Keller, 2013;Su et al, 2015), and due to their superparamagnetic nature as well as their unique physical and chemical properties such as high dispersibility, relatively large surface area, and high ratio of surface-to-volume, they exhibit a high adsorption capacity (Bagheri et al, 2012). With an appropriate coating, which can be either inorganic (e.g., silica or alumina) (Jiang et al, 2012;Karatapanis et al, 2011) or organic (e.g., modified with polymer or surfactant, etc.)…”