Adsorption of Chromium (VI) Using an Activated Carbon Derived from Petroleum Coke Feedstock
This study aims to determine the main adsorption mechanism by which chromium (VI) is adsorbed onto the surface of a petroleum-coke sourced activated carbon, a feedstock not prevalent in current literature. The study also aims to produce an activated carbon adsorbent that is both cost-effective and e...
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| Format: | Article |
| Language: | English |
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MDPI AG
2022-12-01
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| Series: | International Journal of Molecular Sciences |
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| Online Access: | https://www.mdpi.com/1422-0067/23/24/16172 |
| _version_ | 1797457195812519936 |
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| author | Kyle S. Fisher Andrew J. Vreugdenhil |
| author_facet | Kyle S. Fisher Andrew J. Vreugdenhil |
| author_sort | Kyle S. Fisher |
| collection | DOAJ |
| description | This study aims to determine the main adsorption mechanism by which chromium (VI) is adsorbed onto the surface of a petroleum-coke sourced activated carbon, a feedstock not prevalent in current literature. The study also aims to produce an activated carbon adsorbent that is both cost-effective and efficient for the removal of chromium (VI) in neutral waters. The efficacy of thermally-treated petroleum coke-activated carbon and nitrogenated petroleum coke-activated carbon using ammonium chloride is compared to the efficacy of commercially available activated carbon. X-ray photoelectron spectroscopy of the activated carbons was obtained both before and after exposure to chromium (VI) for characterization of the materials and confirmation of chromium adsorption. The thermally-treated and nitrogenated activated carbons showed significant enhancement of chromium (VI) removal compared to the non-treated petroleum coke-activated carbon (22.4 mg/g, 21.9 mg/g, and 17.0 mg/g, respectively). However, there was no significant difference observed between the thermally-treated and nitrogenated materials. This indicates that the nitrogenation of the surface does not improve the adsorption capacity of the activated carbon, but rather the thermal treatment itself. X-ray photoelectron spectroscopy showed a significant increase in the alcohol functional groups on the surface of the activated carbon material as a result of the heat-treatment process; from 16.02 atomic percent in the non-treated activated carbon to 26.3 atomic percent in the thermally-treated activated carbon. The alcohol functional groups present on the surface allow for chromium (VI) to undergo reduction to chromium (III) under a similar mechanism to the well-known Jones Oxidation Reaction where the reduced chromium (III) species are then physisorbed to the surface of the activated carbon. XPS results are consistent with this as the chromium species present on the surface of the adsorbent is primarily Cr(OH)<sub>3</sub> (85.6% in the standard AC and 82.5% in the thermally-treated AC). Pseudo-first-order and pseudo-second-order kinetic modeling of the adsorbents indicate that they follow a pseudo-second-order reaction where the rate-limiting step is the chemical sorption of the adsorbate itself. |
| first_indexed | 2024-03-09T16:18:42Z |
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| institution | Directory Open Access Journal |
| issn | 1661-6596 1422-0067 |
| language | English |
| last_indexed | 2024-03-09T16:18:42Z |
| publishDate | 2022-12-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | International Journal of Molecular Sciences |
| spelling | doaj.art-4c8e403fd0264c5d9826fb472e7499aa2023-11-24T15:34:13ZengMDPI AGInternational Journal of Molecular Sciences1661-65961422-00672022-12-0123241617210.3390/ijms232416172Adsorption of Chromium (VI) Using an Activated Carbon Derived from Petroleum Coke FeedstockKyle S. Fisher0Andrew J. Vreugdenhil1Materials Science Graduate Program, Trent University, 1600 W Bank Drive, Peterborough, ON K9L 0G2, CanadaMaterials Science Graduate Program, Trent University, 1600 W Bank Drive, Peterborough, ON K9L 0G2, CanadaThis study aims to determine the main adsorption mechanism by which chromium (VI) is adsorbed onto the surface of a petroleum-coke sourced activated carbon, a feedstock not prevalent in current literature. The study also aims to produce an activated carbon adsorbent that is both cost-effective and efficient for the removal of chromium (VI) in neutral waters. The efficacy of thermally-treated petroleum coke-activated carbon and nitrogenated petroleum coke-activated carbon using ammonium chloride is compared to the efficacy of commercially available activated carbon. X-ray photoelectron spectroscopy of the activated carbons was obtained both before and after exposure to chromium (VI) for characterization of the materials and confirmation of chromium adsorption. The thermally-treated and nitrogenated activated carbons showed significant enhancement of chromium (VI) removal compared to the non-treated petroleum coke-activated carbon (22.4 mg/g, 21.9 mg/g, and 17.0 mg/g, respectively). However, there was no significant difference observed between the thermally-treated and nitrogenated materials. This indicates that the nitrogenation of the surface does not improve the adsorption capacity of the activated carbon, but rather the thermal treatment itself. X-ray photoelectron spectroscopy showed a significant increase in the alcohol functional groups on the surface of the activated carbon material as a result of the heat-treatment process; from 16.02 atomic percent in the non-treated activated carbon to 26.3 atomic percent in the thermally-treated activated carbon. The alcohol functional groups present on the surface allow for chromium (VI) to undergo reduction to chromium (III) under a similar mechanism to the well-known Jones Oxidation Reaction where the reduced chromium (III) species are then physisorbed to the surface of the activated carbon. XPS results are consistent with this as the chromium species present on the surface of the adsorbent is primarily Cr(OH)<sub>3</sub> (85.6% in the standard AC and 82.5% in the thermally-treated AC). Pseudo-first-order and pseudo-second-order kinetic modeling of the adsorbents indicate that they follow a pseudo-second-order reaction where the rate-limiting step is the chemical sorption of the adsorbate itself.https://www.mdpi.com/1422-0067/23/24/16172adsorptionchromium (VI)activated carbonadsorption mechanismnitrogenationfunctionalization |
| spellingShingle | Kyle S. Fisher Andrew J. Vreugdenhil Adsorption of Chromium (VI) Using an Activated Carbon Derived from Petroleum Coke Feedstock International Journal of Molecular Sciences adsorption chromium (VI) activated carbon adsorption mechanism nitrogenation functionalization |
| title | Adsorption of Chromium (VI) Using an Activated Carbon Derived from Petroleum Coke Feedstock |
| title_full | Adsorption of Chromium (VI) Using an Activated Carbon Derived from Petroleum Coke Feedstock |
| title_fullStr | Adsorption of Chromium (VI) Using an Activated Carbon Derived from Petroleum Coke Feedstock |
| title_full_unstemmed | Adsorption of Chromium (VI) Using an Activated Carbon Derived from Petroleum Coke Feedstock |
| title_short | Adsorption of Chromium (VI) Using an Activated Carbon Derived from Petroleum Coke Feedstock |
| title_sort | adsorption of chromium vi using an activated carbon derived from petroleum coke feedstock |
| topic | adsorption chromium (VI) activated carbon adsorption mechanism nitrogenation functionalization |
| url | https://www.mdpi.com/1422-0067/23/24/16172 |
| work_keys_str_mv | AT kylesfisher adsorptionofchromiumviusinganactivatedcarbonderivedfrompetroleumcokefeedstock AT andrewjvreugdenhil adsorptionofchromiumviusinganactivatedcarbonderivedfrompetroleumcokefeedstock |