Cr(VI) removal from aqueous systems using pyrite as the reducing agent: Batch, spectroscopic and column experiments

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dc.authoridDogaroglu, Zeynep Gorkem/0000-0002-6566-5244
dc.authoridKantar, Cetin/0000-0001-9747-9115
dc.contributor.authorKantar, Cetin
dc.contributor.authorAri, Cihan
dc.contributor.authorKeskin, Selda
dc.contributor.authorDogaroglu, Zeynep Gorkem
dc.contributor.authorKaradeniz, Aykut
dc.contributor.authorAlten, Akin
dc.date.accessioned2025-01-27T20:35:11Z
dc.date.available2025-01-27T20:35:11Z
dc.date.issued2015
dc.departmentÇanakkale Onsekiz Mart Üniversitesi
dc.description.abstractLaboratory batch and column experiments, in conjunction with geochemical calculations and spectroscopic analysis, were performed to better understand reaction mechanisms and kinetics associated with Cr(VI) removal from aqueous systems using pyrite as the reactive material under both static and dynamic flow conditions similar to those observed in in situ permeable reactive barriers (PRBs). The X-ray photoelectron spectroscopy (XPS) and geochemical calculations suggest that the Cr(VI) removal by pyrite occurred due to the reduction of Cr(VI) to Cr(III), coupled with the oxidation of Fe(II) to Fe(III) and S-2(2-) to SO42- at the pyrite surface. Zeta potential measurements indicate that although the pyrite surface was negatively charged under a wide pH range in the absence of Cr(VI), it behaved more like a metal oxide surface with the surface potential shifting from positive to negative values at pH values >pH 6 in the presence of Cr(VI). Batch experiments show that increasing solution pH led to a significant decrease in Cr(VI) removal. The decrease in Cr(VI) removal at high Cr(VI) concentrations and pH values can be explained through the precipitation of sparingly soluble Cr(OH)(3(s)), Fe(OH)(3(s)) and Fe(III)-Cr(III) (oxy) hydroxides onto pyrite surface which may, then, lead to surface passivation for further Cr(VI) reduction. Batch results also suggest that the reaction kinetics follow a first order model with rate constants decreasing with increasing solution pH, indicating proton consumption during Cr(VI) reducdon by pyrite. Column experiments indicate that nearly 100% of total Fe in the column effluent was in the form of Fe(II) species with a [[SO42-]/[Fe2+]] stoichiometric ratio of 2.04, indicating that the reduction of Cr(VI) by pyrite produced about 2 mol of sulfate per mole of Fe (II) release under excess surface sites relative to Cr(VI) concentration. Column experiments provide further evidence on the accumulation of oxidation products which consequently led to a significant pressure build up in pyrite packed columns over time. (C) 2015 Elsevier B.V. All rights reserved.
dc.description.sponsorshipTechnological Research Council of Turkey (TUBITAK) [110Y293]
dc.description.sponsorshipThis was fully funded by the Scientific and Technological Research Council of Turkey (TUBITAK) (Project No: 110Y293). The manuscript was greatly improved by comments from two anonymous reviewers.
dc.identifier.doi10.1016/j.jconhyd.2015.01.001
dc.identifier.endpage38
dc.identifier.issn0169-7722
dc.identifier.issn1873-6009
dc.identifier.pmid25644191
dc.identifier.scopus2-s2.0-84921961567
dc.identifier.scopusqualityQ1
dc.identifier.startpage28
dc.identifier.urihttps://doi.org/10.1016/j.jconhyd.2015.01.001
dc.identifier.urihttps://hdl.handle.net/20.500.12428/23593
dc.identifier.volume174
dc.identifier.wosWOS:000350705500003
dc.identifier.wosqualityQ1
dc.indekslendigikaynakWeb of Science
dc.indekslendigikaynakScopus
dc.indekslendigikaynakPubMed
dc.language.isoen
dc.publisherElsevier Science Bv
dc.relation.ispartofJournal of Contaminant Hydrology
dc.relation.publicationcategoryinfo:eu-repo/semantics/openAccess
dc.rightsinfo:eu-repo/semantics/closedAccess
dc.snmzKA_WoS_20250125
dc.subjectPyrite
dc.subjectPermeable reactive barrier (PRB)
dc.subjectReduction
dc.subjectSorption
dc.subjectChromium
dc.subjectTreatment
dc.subjectOxidation
dc.titleCr(VI) removal from aqueous systems using pyrite as the reducing agent: Batch, spectroscopic and column experiments
dc.typeArticle

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