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

Chemistry

Industrial Chemistry

Author(s): Kantar C, Ari C, Keskin S, Dogaroglu ZG, Karadeniz A,

Abstract Share this page

Abstract Laboratory 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 S2(2-) to SO4(2-) 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) reduction 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 [SO4(2-)]/[Fe(2+)] 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. Copyright © 2015 Elsevier B.V. All rights reserved. This article was published in J Contam Hydrol and referenced in Industrial Chemistry

Relevant Expert PPTs

Relevant Speaker PPTs

Recommended Conferences

Relevant Topics

Peer Reviewed Journals
 
Make the best use of Scientific Research and information from our 700 + peer reviewed, Open Access Journals
International Conferences 2017-18
 
Meet Inspiring Speakers and Experts at our 3000+ Global Annual Meetings

Contact Us

Agri, Food, Aqua and Veterinary Science Journals

Dr. Krish

[email protected]

1-702-714-7001 Extn: 9040

Clinical and Biochemistry Journals

Datta A

[email protected]

1-702-714-7001Extn: 9037

Business & Management Journals

Ronald

[email protected]

1-702-714-7001Extn: 9042

Chemical Engineering and Chemistry Journals

Gabriel Shaw

[email protected]

1-702-714-7001 Extn: 9040

Earth & Environmental Sciences

Katie Wilson

[email protected]

1-702-714-7001Extn: 9042

Engineering Journals

James Franklin

[email protected]

1-702-714-7001Extn: 9042

General Science and Health care Journals

Andrea Jason

[email protected]

1-702-714-7001Extn: 9043

Genetics and Molecular Biology Journals

Anna Melissa

[email protected]

1-702-714-7001 Extn: 9006

Immunology & Microbiology Journals

David Gorantl

[email protected]

1-702-714-7001Extn: 9014

Informatics Journals

Stephanie Skinner

[email protected]

1-702-714-7001Extn: 9039

Material Sciences Journals

Rachle Green

[email protected]

1-702-714-7001Extn: 9039

Mathematics and Physics Journals

Jim Willison

[email protected]

1-702-714-7001 Extn: 9042

Medical Journals

Nimmi Anna

[email protected]

1-702-714-7001 Extn: 9038

Neuroscience & Psychology Journals

Nathan T

[email protected]

1-702-714-7001Extn: 9041

Pharmaceutical Sciences Journals

John Behannon

[email protected]

1-702-714-7001Extn: 9007

Social & Political Science Journals

Steve Harry

[email protected]

1-702-714-7001 Extn: 9042

 
© 2008-2017 OMICS International - Open Access Publisher. Best viewed in Mozilla Firefox | Google Chrome | Above IE 7.0 version
adwords