Optimal design and characterization of sulfide-modified nanoscale zerovalent iron for diclofenac removal

Song, Shikun; Su, Yiming; Adeleye, Adeyemi S.; Zhang, Yalei; Zhou, Xuefei

doi:10.1016/j.apcatb.2016.07.055

Cited by 178 publications

(105 citation statements)

References 66 publications

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“…The presence of an FeS (mackinawite) phase either coated onto or mixed with the NZVI particles has been reported, but in many cases without strong experimental evidence to support the claim. [ 34–36 ] Two recent studies provided experimental evidence for an FeS phase in SNZVI, for example, X‐ray absorption spectroscopy analyses [ 37 ] or X‐ray total scattering with pair distribution function analyses. [ 38 ] Other S species have not been reported.…”

Section: Figurementioning

confidence: 99%

“…The addition of FeS x structures into the Fe 0 likely apply different “constraints” for the Fe 0 lattice, affecting the d‐spacing observed in the XRD results (Figure 2a). Although FeS was determined to be the main S species in SNZVI either by Fe K‐edge XANES or pair distribution function analyses in previous studies, [ 37,38 ] the complex relationship between the S content and the particle properties has not been captured. In this work, both Fe K‐edge EXAFS and S K‐edge XANES analysis with appropriate references spectra clearly show how mackinawite (FeS) and pyrite (FeS 2 ) species change with S content.…”

Section: Figurementioning

confidence: 99%

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Sulfur Loading and Speciation Control the Hydrophobicity, Electron Transfer, Reactivity, and Selectivity of Sulfidized Nanoscale Zerovalent Iron

et al. 2020

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radionuclides. [12][13][14][15][16][17] However, NZVI is an indiscriminate reductant that also readily reduces water to form hydrogen gas (Fe 0 + 2H 2 O → Fe 2+ + 2OH − + H 2(g) ). [18] This unwanted side reaction consumes the reducing capacity of the NZVI, decreasing its reactive lifetime, and increases the amount and cost of NZVI required for remediation. Several approaches have been proposed to increase the reactivity or stability of NZVI during remediation, including encapsulating them with polymers or into silica matrices, [15,19] doping them with noble metals like Pd or Pt, [20,21] and supporting them onto carbon matrices like carbon nanotubes or graphene. [22,23] While these approaches improve the injectability of the materials into the subsurface, none have improved the selectivity of NZVI for contaminants over water while still maintaining high reactivity with the target groundwater contaminants. An ideal material for groundwater remediation should possess both high reactivity and selectivity, [24] where the contaminant outcompetes water for reactive sites.Recently, it was shown by us and others that the sulfidation of NZVI lowers its reactivity with water and other non-target hydrophilic contaminants (e.g., NO 3 − ), while increasing its reactivity with target contaminants like chlorinated solvents Sulfidized nanoscale zerovalent iron (SNZVI) is a promising material for groundwater remediation. However, the relationships between sulfur content and speciation and the properties of SNZVI materials are unknown, preventing rational design. Here, the effects of sulfur on the crystalline structure, hydrophobicity, sulfur speciation, corrosion potential, and electron transfer resistance are determined. Sulfur incorporation extended the nano-Fe 0 BCC lattice parameter, reduced the Fe local vacancies, and lowered the resistance to electron transfer. Impacts of the main sulfur species (FeS and FeS 2 ) on hydrophobicity (water contact angles) are consistent with density functional theory calculations for these FeS x phases. These properties well explain the reactivity and selectivity of SNZVI during the reductive dechlorination of trichloroethylene (TCE), a hydrophobic groundwater contaminant. Controlling the amount and speciation of sulfur in the SNZVI made it highly reactive (up to 0.41 L m −2 d −1 ) and selective for TCE degradation over water (up to 240 moles TCE per mole H 2 O), with an electron efficiency of up to 70%, and these values are 54-fold, 98-fold, and 160-fold higher than for NZVI, respectively. These findings can guide the rational design of robust SNZVI with properties tailored for specific application scenarios.Highly redox active materials are an important tool for the degradation of refractory organic water and soil contaminants. [1][2][3][4][5][6][7] Nanoscale zero valent (NZVI) has been used for in situ groundwater remediation for more than two decades. [8][9][10][11][12] NZVI is a strong reductant that readily dechlorinates chlorinated solvents and antibiotics, and reduces and immobilizes h...

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Section: Figurementioning

confidence: 99%

Section: Figurementioning

confidence: 99%

Sulfur Loading and Speciation Control the Hydrophobicity, Electron Transfer, Reactivity, and Selectivity of Sulfidized Nanoscale Zerovalent Iron

et al. 2020

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“…未硫化的 NZVI 主要通过零价铁表面的亚铁氧化物活化分子氧, 而硫化型 NZVI 主要是通过材料表面的 FeS 活化分子氧, 由于 FeS 壳能加速电子流, 并且能在一定程度上抑制与水分子反应, 因此氧化能力也相应强一些 [36] . 并且, 有研究表明硫化作用能抑制氧气与 NZVI 的直接反应, 使得反应更倾向于首先 Fe-S 键的断裂, 随后产生的 Fe 2＋与 S 2-与氧气反应生成氧活性物质 [53] . 图 5 为硫化型 NZVI 在缺氧水体中还原降解对硝基酚在富氧水体中对硝基酚被硫化型 NZVI 产生的羟基自由基(•OH)氧化降解的示意图 [36] .…”

Section: 氧化作用unclassified

Research Progress of Aqueous Pollutants Removal by Sulfidated Nanoscale Zero-valent Iron

Tang¹,

Tang²,

Feng³

et al. 2017

Acta Chim. Sinica

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Nanoscale zero-valent iron (NZVI), an environmental remediation agent derived from wide range of raw materials, has been extensively applied in the field of remedying polluted water environment such as groundwater and wastewater. Although NZVI possesses some advantages such as excellent reaction activity, low cost and low toxicity, the limitation of in-situ remediation and storage concerning this kind of material has not been completely overcome yet. Among methods to improve the practical application of NZVI in water environment, sulfidation has become a research hotspot over recent decade. This means that the focus of modifying NZVI has shifted from reaction activity to electron selectivity. Most of the preparation methods of sulfidated NZVI belong to the chemical approach. These sulfidated materials have been heavily used to degrade organic pollutants and remove heavy metals in water to test their practical reactivity. Reaction mechanisms of pollutants and sulfidated NZVI in different environmental systems have also been extensively investigated. Hereinto, according to the species of organic pollutants and the reaction conditions, these reaction mechanisms can be roughly divided into three categories, including adsorption, reduction, and oxidation. In recent years, it is noted that sulfidated NZVI has made great progress to enhance the reaction activity and electrons selectivity, though it still has some limitations in the practical application. It is necessary to thoroughly review recent research progress about the reaction activities of sulfidated NZVI and its reaction mechanisms with pollutants in water, because it can clearly figure out new directions towards future development of sulfidated NZVI application. Due to the superior properties of sulfidated zero-valent iron, this material and relevant iron sulfide-based materials are going to belong to the most important functional materials in the field of environmental remediation with promising development prospect.

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“…Diclofenac sodium (DS) is a typical non-steroidal anti-inflammatory drug [ 1 , 2 , 3 ]. The usage of DS in China amounts to thousands of tonnes every year.…”

Section: Introductionmentioning

confidence: 99%

Study on the Visible-Light Photocatalytic Performance and Degradation Mechanism of Diclofenac Sodium under the System of Hetero-Structural CuBi2O4/Ag3PO4 with H2O2

Chen

et al. 2018

Materials

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Two kinds of CuBi2O4/Ag3PO4 with different heterojunction structures were prepared based on the combination of hydrothermal and in-situ precipitation methods with surfactant additives (sodium citrate and sodium stearate), and their characteristics were systematically resolved by X-ray Diffraction (XRD), Brunauer–Emmett–Teller (BET), X-ray Photoelectron Spectroscopy (XPS), Scanning Electron Microscope (SEM)/ High-resolution Transmission Electron Microscopy (HRTEM), UV-vis Diffuse Reflectance Spectra (DRS) and Photoluminescence (PL). Meanwhile, the photocatalytic properties of the catalysts were determined for diclofenac sodium (DS) degradation and the photocatalytic mechanism was also explored. The results indicate that both of the two kinds of CuBi2O4/Ag3PO4 exhibit higher photocatalytic efficiency, mineralization rate, and stability than that of pure CuBi2O4 or Ag3PO4. Moreover, the catalytic activity of CuBi2O4/Ag3PO4 can be further enhanced by adding H2O2. The free radical capture experiments show that in the pure CuBi2O4/Ag3PO4 photocatalytic system, the OH• and O2•− are the main species participating in DS degradation; however, in the CuBi2O4/Ag3PO4 photocatalytic system with H2O2, all OH•, h+, and O2•− take part in the DS degradation, and the contribution order is OH• > h+ > O2•−. Accordingly, the photocatalytic mechanism of CuBi2O4/Ag3PO4 could be explained by the Z-Scheme theory, while the catalysis of CuBi2O4/Ag3PO4 with H2O2 follows the heterojunction energy band theory.

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Optimal design and characterization of sulfide-modified nanoscale zerovalent iron for diclofenac removal

Cited by 178 publications

References 66 publications

Sulfur Loading and Speciation Control the Hydrophobicity, Electron Transfer, Reactivity, and Selectivity of Sulfidized Nanoscale Zerovalent Iron

Sulfur Loading and Speciation Control the Hydrophobicity, Electron Transfer, Reactivity, and Selectivity of Sulfidized Nanoscale Zerovalent Iron

Research Progress of Aqueous Pollutants Removal by Sulfidated Nanoscale Zero-valent Iron

Study on the Visible-Light Photocatalytic Performance and Degradation Mechanism of Diclofenac Sodium under the System of Hetero-Structural CuBi2O4/Ag3PO4 with H2O2

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