Effect of pH-buffering on Cr(VI) reduction with pyrite in the presence of various organic acids: Continuous-flow experiments

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dc.authoridKantar, Cetin/0000-0001-9747-9115
dc.contributor.authorKantar, Cetin
dc.contributor.authorBulbul, Muhammet Samet
dc.date.accessioned2025-01-27T21:05:47Z
dc.date.available2025-01-27T21:05:47Z
dc.date.issued2016
dc.departmentÇanakkale Onsekiz Mart Üniversitesi
dc.description.abstractThe effects of pH and pH buffering on catalytic hexavalent chromium (Cr(VI)) reduction by pyrite were investigated in a series of column experiments. The experiments show a strong dependence of Cr(VI) removal by pyrite on solution pH, with Cr(VI) removal decreasing with increasing solution pH. While organic buffers e.g., (acetic acid/acetate) showed higher Cr(VI) removal by pyrite under acidic conditions (e.g., pH 4) relative to unbuffered systems, the addition of an organic buffer (MOPS) decreased Cr(VI) removal by pyrite at pH 8 relative to systems buffered with an inorganic buffer (bicarbonate). Similarly, in systems buffered with acetate buffer at pH 4, organic acids (e.g., citrate and tartrate) significantly improved Cr(VI) removal by pyrite due to removal of surface oxidation products (e.g., Fe(OH)(3(s))). Unlike acidic conditions, organic acids such as citrate and EDTA adversely affected Cr(VI) removal under alkaline pH conditions relative to systems containing 0.01 M MOPS buffer only. This inhibitory effect observed under alkaline pH conditions may be explained through competitive adsorption of organic buffers (MOPS) and acids (citrate, EDTA) onto pyrite surface, which, not only, modified pyrite surface properties, but also, blocked access of Cr(VI) to pyrite surface. Overall, it is clear that while pH buffering under acidic conditions may significantly improve the process efficiency of pyrite-based Cr(VI) treatment, it may have adverse effects on process efficiency under alkaline conditions (e.g., pH 8) since organic buffers (e.g., MOPS) and acids (e.g., EDTA) may directly interact with pyrite surface, and change its surface properties. (C) 2015 Elsevier B.V. All rights reserved.
dc.description.sponsorshipScientific and Technological Research Council of Turkey (TUBITAK) [110Y293]
dc.description.sponsorshipThis work is financially supported by the Scientific and Technological Research Council of Turkey (TUBITAK Project No: 110Y293).
dc.identifier.doi10.1016/j.cej.2015.11.019
dc.identifier.endpage180
dc.identifier.issn1385-8947
dc.identifier.issn1873-3212
dc.identifier.scopus2-s2.0-84963938737
dc.identifier.scopusqualityQ1
dc.identifier.startpage173
dc.identifier.urihttps://doi.org/10.1016/j.cej.2015.11.019
dc.identifier.urihttps://hdl.handle.net/20.500.12428/27793
dc.identifier.volume287
dc.identifier.wosWOS:000369461800020
dc.identifier.wosqualityQ1
dc.indekslendigikaynakWeb of Science
dc.indekslendigikaynakScopus
dc.language.isoen
dc.publisherElsevier Science Sa
dc.relation.ispartofChemical Engineering Journal
dc.relation.publicationcategoryinfo:eu-repo/semantics/openAccess
dc.rightsinfo:eu-repo/semantics/closedAccess
dc.snmzKA_WoS_20250125
dc.subjectPyrite
dc.subjectChromate reduction
dc.subjectBicarbonate
dc.subjectMOPS
dc.subjectAcetate
dc.subjectpH-buffering
dc.titleEffect of pH-buffering on Cr(VI) reduction with pyrite in the presence of various organic acids: Continuous-flow experiments
dc.typeArticle

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