Reduction of Cr(VI) in simulated groundwater by FeS-coated iron magnetic nanoparticles

Chemical Engineering Journal

Jin

et al. 2019

144

Section: Introductionmentioning

confidence: 99%

Insight into pH dependent Cr(VI) removal with magnetic Fe3S4

Chemical Engineering Journal

Jin

et al. 2019

144

“…The adsorption isotherm model, reveals the relationship between adsorption amount of Fe 3 O 4 @PCBA for Cr(VI) and residual Cr(VI) concentration at equilibrium, is of cardinal significance in studying surface properties of adsorbent and optimizing the adsorption performance of adsorbents . The experimental equilibrium data of Fe 3 O 4 @PCBA for Cr(VI) were analyzed by the Langmuir and Freundlich models [Figure (a,b)].…”

Section: Resultsmentioning

confidence: 99%

Mussel‐inspired magnetic adsorbent: Adsorption/reduction treatment for the toxic Cr(VI) from simulated wastewater

Dong¹,

J of Applied Polymer Sci

Wei³

et al. 2018

A novel magnetic adsorbent, poly(catechol‐1,4‐butanediamine)‐coated Fe3O4 composite (Fe3O4@PCBA), was successfully fabricated via an easy and gentle method according to the mussel‐inspired adhesion property of polydopamine. Effects of many factors on the adsorption performance of Fe3O4@PCBA for Cr(VI) were investigated, including temperature, pH value, contacting time, adsorbent dosage, and initial Cr(VI) concentration. The thermodynamics, adsorption isotherm, kinetics, and intraparticle diffusion of adsorption were also studied systematically. Results indicated that the removal rate of Cr(VI) was approximately close to 100% when the initial concentration was less than 120 mg/L, and the maximum uptake capacity of Fe3O4@PCBA for Cr(VI) was 280.11 mg/g complied with Langmuir isotherm model. Accordingly, the nocuous Cr(VI) could be partially reduced to Cr(III) during the adsorption period. Hopefully, this strategy could be extended to prepare series of magnetic Fe3O4@catechol–amine adsorbents with different amino and phenolic hydroxyl groups for Cr(VI) removal. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46530.

“…The above results were also verified by the XPS results (Figure 9). Fe species including Fe(II)-S, Fe(III)-O, and Fe(II)-O/Fe(III)-S existed in both pH environments (Gan et al, 2015;Gong et al, 2017), but there are marked differences between samples. The Fe(II)-S species was the main component of the optimal pH environment pyrite.…”

Section: Pyrite Dissolution and Bacteria Proliferation Under Differenmentioning

confidence: 95%

“…The potential of sulfide minerals such as pyrite or reduced sulfur in redox-sensitive contaminant remediation has attracted great interest in recent years (He and Traina, 2005). However, the pyrite surface is usually passivated due to the formation of Fe-Cr compounds, resulting pyrite Frontiers in Microbiology | www.frontiersin.org 2 February 2020 | Volume 10 | Article 3082 utilization being blocked and thus inhibiting further Cr(VI) reduction (He and Traina, 2005;Gong et al, 2017). Strengthening measures that have been applied in pyrite or iron-containing material-based Cr(VI) reduction mainly focus on thermal modification, mechanical crushing, and organic acid/chelating agent addition, etc.…”

Section: Introductionmentioning

confidence: 99%

Pyrite-Based Cr(VI) Reduction Driven by Chemoautotrophic Acidophilic Bacteria

Gan

et al. 2020

Front. Microbiol.

Cr(VI) is considered as a priority pollutant, and its remediation has attracted increasing attention in the environmental area. In this study, the driving of pyrite-based Cr(VI) reduction by Acidithiobacillus ferrooxidans was systematically investigated. The results showed that pyrite-based Cr(VI) reduction was a highly proton-dependent process and that pH influenced the biological activity. The passivation effect became more significant with an increase in pH, and there was a decrease in Cr(VI) reduction efficiency. However, Cr(VI) reduction efficiency was enhanced by inoculation with A. ferrooxidans. The highest reduction efficiency was achieved in the biological system with a pH range of 1-1.5. Pyrite dissolution and reactive site regeneration were promoted by A. ferrooxidans, which resulted in the enhanced effect in Cr(VI) reduction. The low linear relevancy between pH and Cr(VI) dosage in the biological system indicated a complex interaction between bacteria and pyrite. Secondary iron mineral formation in an unfavorable pH environment inhibited pyrite dissolution, but the passivation effect was relieved under the activity of A. ferrooxidans due to S/Fe oxidization. The balance between Cr(VI) reduction and biological activity was critical for sustainable Cr(VI) reduction. Pyrite-based Cr(VI) remediation driven by chemoautotrophic acidophilic bacteria is shown to be an economical and efficient method of Cr(VI) reduction.