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Sulfidation kinetics of silver nanoparticles reacted with metal sulfides.
Environ Sci Technol. 2014 May 06; 48(9):4885-92.ES

Abstract

Recent studies have documented that the sulfidation of silver nanoparticles (Ag-NP), possibly released to the environment from consumer products, occurs in anoxic zones of urban wastewater systems and that sulfidized Ag-NP exhibit dramatically reduced toxic effects. However, whether Ag-NP sulfidation also occurs under oxic conditions in the absence of bisulfide has not been addressed, yet. In this study we, therefore, investigated whether metal sulfides that are more resistant toward oxidation than free sulfide, could enable the sulfidation of Ag-NP under oxic conditions. We reacted citrate-stabilized Ag-NP of different sizes (10-100 nm) with freshly precipitated and crystalline CuS and ZnS in oxygenated aqueous suspensions at pH 7.5. The extent of Ag-NP sulfidation was derived from the increase in dissolved Cu(2+) or Zn(2+) over time and linked with results from X-ray absorption spectroscopy (XAS) analysis of selected samples. The sulfidation of Ag-NP followed pseudo first-order kinetics, with rate coefficients increasing with decreasing Ag-NP diameter and increasing metal sulfide concentration and depending on the type (CuS and ZnS) and crystallinity of the reacting metal sulfide. Results from analytical electron microscopy revealed the formation of complex sulfidation patterns that seemed to follow preexisting subgrain boundaries in the pristine Ag-NP. The kinetics of Ag-NP sulfidation observed in this study in combination with reported ZnS and CuS concentrations and predicted Ag-NP concentrations in wastewater and urban surface waters indicate that even under oxic conditions and in the absence of free sulfide, Ag-NP can be transformed into Ag2S within a few hours to days by reaction with metal sulfides.

Authors+Show Affiliations

Eawag, Swiss Federal Institute of Aquatic Science and Technology , Überlandstrasse 133, CH-8600 Dübendorf.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

24678586

Citation

Thalmann, Basilius, et al. "Sulfidation Kinetics of Silver Nanoparticles Reacted With Metal Sulfides." Environmental Science & Technology, vol. 48, no. 9, 2014, pp. 4885-92.
Thalmann B, Voegelin A, Sinnet B, et al. Sulfidation kinetics of silver nanoparticles reacted with metal sulfides. Environ Sci Technol. 2014;48(9):4885-92.
Thalmann, B., Voegelin, A., Sinnet, B., Morgenroth, E., & Kaegi, R. (2014). Sulfidation kinetics of silver nanoparticles reacted with metal sulfides. Environmental Science & Technology, 48(9), 4885-92. https://doi.org/10.1021/es5003378
Thalmann B, et al. Sulfidation Kinetics of Silver Nanoparticles Reacted With Metal Sulfides. Environ Sci Technol. 2014 May 6;48(9):4885-92. PubMed PMID: 24678586.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Sulfidation kinetics of silver nanoparticles reacted with metal sulfides. AU - Thalmann,Basilius, AU - Voegelin,Andreas, AU - Sinnet,Brian, AU - Morgenroth,Eberhard, AU - Kaegi,Ralf, Y1 - 2014/04/15/ PY - 2014/4/1/entrez PY - 2014/4/1/pubmed PY - 2014/10/2/medline SP - 4885 EP - 92 JF - Environmental science & technology JO - Environ Sci Technol VL - 48 IS - 9 N2 - Recent studies have documented that the sulfidation of silver nanoparticles (Ag-NP), possibly released to the environment from consumer products, occurs in anoxic zones of urban wastewater systems and that sulfidized Ag-NP exhibit dramatically reduced toxic effects. However, whether Ag-NP sulfidation also occurs under oxic conditions in the absence of bisulfide has not been addressed, yet. In this study we, therefore, investigated whether metal sulfides that are more resistant toward oxidation than free sulfide, could enable the sulfidation of Ag-NP under oxic conditions. We reacted citrate-stabilized Ag-NP of different sizes (10-100 nm) with freshly precipitated and crystalline CuS and ZnS in oxygenated aqueous suspensions at pH 7.5. The extent of Ag-NP sulfidation was derived from the increase in dissolved Cu(2+) or Zn(2+) over time and linked with results from X-ray absorption spectroscopy (XAS) analysis of selected samples. The sulfidation of Ag-NP followed pseudo first-order kinetics, with rate coefficients increasing with decreasing Ag-NP diameter and increasing metal sulfide concentration and depending on the type (CuS and ZnS) and crystallinity of the reacting metal sulfide. Results from analytical electron microscopy revealed the formation of complex sulfidation patterns that seemed to follow preexisting subgrain boundaries in the pristine Ag-NP. The kinetics of Ag-NP sulfidation observed in this study in combination with reported ZnS and CuS concentrations and predicted Ag-NP concentrations in wastewater and urban surface waters indicate that even under oxic conditions and in the absence of free sulfide, Ag-NP can be transformed into Ag2S within a few hours to days by reaction with metal sulfides. SN - 1520-5851 UR - https://www.unboundmedicine.com/medline/citation/24678586/Sulfidation_kinetics_of_silver_nanoparticles_reacted_with_metal_sulfides_ L2 - https://doi.org/10.1021/es5003378 DB - PRIME DP - Unbound Medicine ER -