A new insight on the core–shell structure of zerovalent iron nanoparticles and its application for Pb(II) sequestration

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

“…According to previous studies, pristine nZVI particles have an almost spherical coreeshell structure and exhibit chain-like particle aggregation (Li and Zhang, 2006;Zhang et al, 2013). TEM images show that S-nZVI has a different morphology compared to nZVI.…”

“…A low IEP implies that SnZVI will be negatively charged in most natural water systems, which may contribute to Cd 2þ removal via electrostatic interaction. Figure S7 shows the XRD patterns of nZVI and S-nZVI, which indicate the presence of Fe 0 (2q ¼ 44.6 ) in S-nZVI, just like nZVI (Adeleye et al, 2013;Zhang et al, 2013). While a small peak of iron oxide (2q ¼ 35.4 ) is detected in S-nZVI, no clear S 0 or any iron sulfide peak is observed.…”

Removal of Lead Ions from Aqueous Solution by Nano Zero-Valent Iron (nZVI)

“…Among these, Lead is an important environmental health concern, because it is nonbiodegradable, and is a toxic metal that is widespread in the world (4), with many industrial applications (3). It can accumulate in human muscles, bones, kidney, brain and cause damage to some human organs such as blood cells and nerve system (5,6). Lead can enter the water system via several pathways, through mining, painting, corrosion of household plumbing, battery industrialized, petroleum industries and so on (2,4).…”

Effects of nitrate on the treatment of lead contaminated groundwater by nanoscale zerovalent iron

“…Pb 2+ pollution results mainly from leakage of leaded gasoline and poor management of wastes from industrial processes such as mining, coal burning, battery production, and smelting [27], while nitrate contamination is mainly from fertilizer application, irrigation with untreated wastewater, and industrial processes [2,28]. Nitrate concentrations as high as 300 mg/L have been detected in groundwater [2].nZVI is easily oxidized on exposure to water, hence the Fe(0) core is surrounded by an oxide layer [6,29]. The core-shell structure is key for Pb 2+ sequestration (partly reduction by core but mainly adsorption and co-precipitation on shell) [15,29,30], but this unique structure is destroyed during the nitrate reduction process as Fe(0) may be oxidized completely [19].…”

“…Nitrate concentrations as high as 300 mg/L have been detected in groundwater [2].nZVI is easily oxidized on exposure to water, hence the Fe(0) core is surrounded by an oxide layer [6,29]. The core-shell structure is key for Pb 2+ sequestration (partly reduction by core but mainly adsorption and co-precipitation on shell) [15,29,30], but this unique structure is destroyed during the nitrate reduction process as Fe(0) may be oxidized completely [19]. The potential effect of the damaged structure on the ability of nZVI to immobilize Pb 2+ has not been investigated to date.…”