Sulfidation extent of nanoscale zerovalent iron controls selectivity and reactivity with mixed chlorinated hydrocarbons in natural groundwater.

Autor: Mangayayam MC; Nano-Science Center, Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark., Perez JPH; GFZ German Research Centre for Geosciences, Telegrafenberg, 14473 Potsdam, Germany; Department of Earth Sciences, Freie Universität Berlin, 12249 Berlin, Germany., Alonso-de-Linaje V; AECOM Environment Madrid, Spain; GIR-QUESCAT, Departamento de Quimica Inorgánica, Universidad de Salamanca, Salamanca, Spain., Dideriksen K; Geological Survey of Denmark & Greenland (GEUS), Øster Voldgade 10, 1350 Copenhagen, Denmark., Benning LG; GFZ German Research Centre for Geosciences, Telegrafenberg, 14473 Potsdam, Germany; Department of Earth Sciences, Freie Universität Berlin, 12249 Berlin, Germany., Tobler DJ; Nano-Science Center, Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark; Department of Plant and Environmental Sciences, University of Copenhagen, 1871 Frederiksberg C, Denmark. Electronic address: dominique.tobler@plen.ku.dk.
Jazyk: angličtina
Zdroj: Journal of hazardous materials [J Hazard Mater] 2022 Jun 05; Vol. 431, pp. 128534. Date of Electronic Publication: 2022 Feb 22.
DOI: 10.1016/j.jhazmat.2022.128534
Abstrakt: Sulfidated nanoscale zerovalent iron (S-nZVI) exhibits low anoxic oxidation and high reactivity towards many chlorinated hydrocarbons (CHCs). However, nothing is known about S-nZVI reactivity once exposed to complex CHC mixtures, a common feature of CHC plumes in the environment. Here, three S-nZVI materials with varying iron sulfide (mackinawite, FeS m ) shell thickness and crystallinity were exposed to groundwater containing a complex mixture of chlorinated ethenes, ethanes, and methanes. CHC removal trends yielded pseudo-first order rate constants (k obs ) that decreased in the order: trichloroethene > trans-dicloroethene > 1,1-dichlorethene > trichloromethane > tetrachloroethene > cis-dichloroethene > 1,1,2-trichloroethane, for all S-nZVI materials. These k obs trends showed no correlation with CHC reduction potentials based on their lowest unoccupied molecular orbital energies (E LUMO ) but absolute values were affected by the FeS m shell thickness and crystallinity. In comparison, nZVI reacted with the same CHCs groundwater, yielded k obs that linearly correlated with CHC E LUMO values (R 2 = 0.94) and that were lower than S-nZVI k obs . The CHC selectivity induced by sulfidation treatment is explained by FeS m surface sites having specific binding affinities towards some CHCs, while others require access to the metallic iron core. These new insights help advance S-nZVI synthesis strategies to fit specific CHC treatment scenarios.
(Copyright © 2022 The Authors. Published by Elsevier B.V. All rights reserved.)
Databáze: MEDLINE
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