Selective Reduction of Cr(VI) in Chromium, Copper and Arsenic (CCA) Mixed Waste Streams Using UV/TiO2 Photocatalysis
The highly toxic Cr(VI) is a critical component in the Chromated Copper Arsenate (CCA) formulations extensively employed as wood preservatives. Remediation of CCA mixed waste and discarded treated wood products is a significant challenge. We demonstrate that UV/TiO2 photocatalysis effectively reduce...
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MDPI AG
2015-02-01
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| Series: | Molecules |
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| Online Access: | http://www.mdpi.com/1420-3049/20/2/2622 |
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| author | Shan Zheng Wenjun Jiang Mamun Rashid Yong Cai Dionysios D. Dionysiou Kevin E. O'Shea |
| author_facet | Shan Zheng Wenjun Jiang Mamun Rashid Yong Cai Dionysios D. Dionysiou Kevin E. O'Shea |
| author_sort | Shan Zheng |
| collection | DOAJ |
| description | The highly toxic Cr(VI) is a critical component in the Chromated Copper Arsenate (CCA) formulations extensively employed as wood preservatives. Remediation of CCA mixed waste and discarded treated wood products is a significant challenge. We demonstrate that UV/TiO2 photocatalysis effectively reduces Cr(VI) to less toxic Cr(III) in the presence of arsenate, As(V), and copper, Cu(II). The rapid conversion of Cr(VI) to Cr(III) during UV/TiO2 photocatalysis occurs over a range of concentrations, solution pH and at different Cr:As:Cu ratios. The reduction follows pseudo-first order kinetics and increases with decreasing solution pH. Saturation of the reaction solution with argon during UV/TiO2 photocatalysis had no significant effect on the Cr(VI) reduction demonstrating the reduction of Cr(VI) is independent of dissolved oxygen. Reduction of Cu(II) and As(V) does not occur under the photocatalytic conditions employed herein and the presence of these two in the tertiary mixtures had a minimal effect on Cr(VI) reduction. The Cr(VI) reduction was however, significantly enhanced by the addition of formic acid, which can act as a hole scavenger and enhance the reduction processes initiated by the conduction band electron. Our results demonstrate UV/TiO2 photocatalysis effectively reduces Cr(VI) in mixed waste streams under a variety of conditions. |
| first_indexed | 2024-12-13T07:05:30Z |
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| issn | 1420-3049 |
| language | English |
| last_indexed | 2024-12-13T07:05:30Z |
| publishDate | 2015-02-01 |
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| series | Molecules |
| spelling | doaj.art-3fd39e6cae904e6bb3fd7a497c3b74dd2022-12-21T23:55:49ZengMDPI AGMolecules1420-30492015-02-012022622263510.3390/molecules20022622molecules20022622Selective Reduction of Cr(VI) in Chromium, Copper and Arsenic (CCA) Mixed Waste Streams Using UV/TiO2 PhotocatalysisShan Zheng0Wenjun Jiang1Mamun Rashid2Yong Cai3Dionysios D. Dionysiou4Kevin E. O'Shea5Department of Chemistry and Biochemistry, Florida International University, Miami, FL 33199, USADepartment of Chemistry and Biochemistry, Florida International University, Miami, FL 33199, USADepartment of Chemistry and Biochemistry, Florida International University, Miami, FL 33199, USADepartment of Chemistry and Biochemistry, Florida International University, Miami, FL 33199, USAEnvironmental Engineering and Science Program, University of Cincinnati, Cincinnati, OH 45221-0012, USADepartment of Chemistry and Biochemistry, Florida International University, Miami, FL 33199, USAThe highly toxic Cr(VI) is a critical component in the Chromated Copper Arsenate (CCA) formulations extensively employed as wood preservatives. Remediation of CCA mixed waste and discarded treated wood products is a significant challenge. We demonstrate that UV/TiO2 photocatalysis effectively reduces Cr(VI) to less toxic Cr(III) in the presence of arsenate, As(V), and copper, Cu(II). The rapid conversion of Cr(VI) to Cr(III) during UV/TiO2 photocatalysis occurs over a range of concentrations, solution pH and at different Cr:As:Cu ratios. The reduction follows pseudo-first order kinetics and increases with decreasing solution pH. Saturation of the reaction solution with argon during UV/TiO2 photocatalysis had no significant effect on the Cr(VI) reduction demonstrating the reduction of Cr(VI) is independent of dissolved oxygen. Reduction of Cu(II) and As(V) does not occur under the photocatalytic conditions employed herein and the presence of these two in the tertiary mixtures had a minimal effect on Cr(VI) reduction. The Cr(VI) reduction was however, significantly enhanced by the addition of formic acid, which can act as a hole scavenger and enhance the reduction processes initiated by the conduction band electron. Our results demonstrate UV/TiO2 photocatalysis effectively reduces Cr(VI) in mixed waste streams under a variety of conditions.http://www.mdpi.com/1420-3049/20/2/2622TiO2 photocatalysisCCAchromium(VI)remediationreduction |
| spellingShingle | Shan Zheng Wenjun Jiang Mamun Rashid Yong Cai Dionysios D. Dionysiou Kevin E. O'Shea Selective Reduction of Cr(VI) in Chromium, Copper and Arsenic (CCA) Mixed Waste Streams Using UV/TiO2 Photocatalysis Molecules TiO2 photocatalysis CCA chromium(VI) remediation reduction |
| title | Selective Reduction of Cr(VI) in Chromium, Copper and Arsenic (CCA) Mixed Waste Streams Using UV/TiO2 Photocatalysis |
| title_full | Selective Reduction of Cr(VI) in Chromium, Copper and Arsenic (CCA) Mixed Waste Streams Using UV/TiO2 Photocatalysis |
| title_fullStr | Selective Reduction of Cr(VI) in Chromium, Copper and Arsenic (CCA) Mixed Waste Streams Using UV/TiO2 Photocatalysis |
| title_full_unstemmed | Selective Reduction of Cr(VI) in Chromium, Copper and Arsenic (CCA) Mixed Waste Streams Using UV/TiO2 Photocatalysis |
| title_short | Selective Reduction of Cr(VI) in Chromium, Copper and Arsenic (CCA) Mixed Waste Streams Using UV/TiO2 Photocatalysis |
| title_sort | selective reduction of cr vi in chromium copper and arsenic cca mixed waste streams using uv tio2 photocatalysis |
| topic | TiO2 photocatalysis CCA chromium(VI) remediation reduction |
| url | http://www.mdpi.com/1420-3049/20/2/2622 |
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