Sorption of Selenium(IV) and Selenium(VI) onto Iron Oxide/Hydroxide-Based Carbon Materials: Activated Carbon and Carbon Foam
Selenium pollution in water is a worldwide issue. Se(IV) and Se(VI) are mainly found in contaminated water due to their high solubility and mobility; their presence poses a serious risk as they can severely harm human health. Although iron oxide and hydroxide nanoparticles can be efficient candidate...
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| Format: | Article |
| Language: | English |
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MDPI AG
2023-10-01
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| Series: | Water |
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| Online Access: | https://www.mdpi.com/2073-4441/15/19/3499 |
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| author | Lucia López-Toyos Elena Rodríguez Roberto García Maria Rosa Martínez-Tarazona Maria Antonia López-Antón |
| author_facet | Lucia López-Toyos Elena Rodríguez Roberto García Maria Rosa Martínez-Tarazona Maria Antonia López-Antón |
| author_sort | Lucia López-Toyos |
| collection | DOAJ |
| description | Selenium pollution in water is a worldwide issue. Se(IV) and Se(VI) are mainly found in contaminated water due to their high solubility and mobility; their presence poses a serious risk as they can severely harm human health. Although iron oxide and hydroxide nanoparticles can be efficient candidates for the removal of selenium oxyanions due to their high adsorption capacity, the role of each iron species has not been fully elucidated. Furthermore, iron species are often found to be less effective for Se(VI) than Se(IV). The challenge and novelty of this study was to develop a carbon material impregnated with different iron phases, including oxides (magnetite/hematite) and hydroxides (goethite/lepidocrocite) capable of removing both Se(IV) and Se(VI). Since the phase and morphology of the iron nanoparticles play a significant role in Se adsorption, the study evaluated both characteristics by modifying the impregnation method, which is based on an oxidative hydrolysis with FeSO<sub>4</sub> 7H<sub>2</sub>O and CH<sub>3</sub>COONa, and the type of carbonaceous support (activated carbon or sucrose-based carbon foam). Impregnated activated carbons provide better removal efficiencies (70–80%) than carbon foams (<40%), due to their high surface areas and point zero charges. These results show that the adsorption of Se(VI) is more favorable on magnetic oxides (78%) and hydroxides (71%) than in hematite (<40%). In addition, the activated carbon decorated with magnetite showed a high adsorption capacity for both selenium species, even in alkaline conditions, when the sorbent surface is negatively charged. A mechanism based on the adsorption of inner-sphere complexes was suggested for Se(IV) immobilization, whereas Se(VI) removal occurred through the formation of outer-sphere complexes and redox processes. |
| first_indexed | 2024-03-09T13:50:04Z |
| format | Article |
| id | doaj.art-6046f3b257b84c36afe8fdd3f086d540 |
| institution | Directory Open Access Journal |
| issn | 2073-4441 |
| language | English |
| last_indexed | 2024-03-09T13:50:04Z |
| publishDate | 2023-10-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Water |
| spelling | doaj.art-6046f3b257b84c36afe8fdd3f086d5402023-11-30T20:50:53ZengMDPI AGWater2073-44412023-10-011519349910.3390/w15193499Sorption of Selenium(IV) and Selenium(VI) onto Iron Oxide/Hydroxide-Based Carbon Materials: Activated Carbon and Carbon FoamLucia López-Toyos0Elena Rodríguez1Roberto García2Maria Rosa Martínez-Tarazona3Maria Antonia López-Antón4Instituto de Ciencia y Tecnología del Carbono, INCAR-CSIC, C/Francisco Pintado Fe, 26, 33011 Oviedo, SpainInstituto de Ciencia y Tecnología del Carbono, INCAR-CSIC, C/Francisco Pintado Fe, 26, 33011 Oviedo, SpainInstituto de Ciencia y Tecnología del Carbono, INCAR-CSIC, C/Francisco Pintado Fe, 26, 33011 Oviedo, SpainInstituto de Ciencia y Tecnología del Carbono, INCAR-CSIC, C/Francisco Pintado Fe, 26, 33011 Oviedo, SpainInstituto de Ciencia y Tecnología del Carbono, INCAR-CSIC, C/Francisco Pintado Fe, 26, 33011 Oviedo, SpainSelenium pollution in water is a worldwide issue. Se(IV) and Se(VI) are mainly found in contaminated water due to their high solubility and mobility; their presence poses a serious risk as they can severely harm human health. Although iron oxide and hydroxide nanoparticles can be efficient candidates for the removal of selenium oxyanions due to their high adsorption capacity, the role of each iron species has not been fully elucidated. Furthermore, iron species are often found to be less effective for Se(VI) than Se(IV). The challenge and novelty of this study was to develop a carbon material impregnated with different iron phases, including oxides (magnetite/hematite) and hydroxides (goethite/lepidocrocite) capable of removing both Se(IV) and Se(VI). Since the phase and morphology of the iron nanoparticles play a significant role in Se adsorption, the study evaluated both characteristics by modifying the impregnation method, which is based on an oxidative hydrolysis with FeSO<sub>4</sub> 7H<sub>2</sub>O and CH<sub>3</sub>COONa, and the type of carbonaceous support (activated carbon or sucrose-based carbon foam). Impregnated activated carbons provide better removal efficiencies (70–80%) than carbon foams (<40%), due to their high surface areas and point zero charges. These results show that the adsorption of Se(VI) is more favorable on magnetic oxides (78%) and hydroxides (71%) than in hematite (<40%). In addition, the activated carbon decorated with magnetite showed a high adsorption capacity for both selenium species, even in alkaline conditions, when the sorbent surface is negatively charged. A mechanism based on the adsorption of inner-sphere complexes was suggested for Se(IV) immobilization, whereas Se(VI) removal occurred through the formation of outer-sphere complexes and redox processes.https://www.mdpi.com/2073-4441/15/19/3499inorganic seleniumiron nanoparticlesactivated carboncarbon foamsadsorption mechanism |
| spellingShingle | Lucia López-Toyos Elena Rodríguez Roberto García Maria Rosa Martínez-Tarazona Maria Antonia López-Antón Sorption of Selenium(IV) and Selenium(VI) onto Iron Oxide/Hydroxide-Based Carbon Materials: Activated Carbon and Carbon Foam Water inorganic selenium iron nanoparticles activated carbon carbon foams adsorption mechanism |
| title | Sorption of Selenium(IV) and Selenium(VI) onto Iron Oxide/Hydroxide-Based Carbon Materials: Activated Carbon and Carbon Foam |
| title_full | Sorption of Selenium(IV) and Selenium(VI) onto Iron Oxide/Hydroxide-Based Carbon Materials: Activated Carbon and Carbon Foam |
| title_fullStr | Sorption of Selenium(IV) and Selenium(VI) onto Iron Oxide/Hydroxide-Based Carbon Materials: Activated Carbon and Carbon Foam |
| title_full_unstemmed | Sorption of Selenium(IV) and Selenium(VI) onto Iron Oxide/Hydroxide-Based Carbon Materials: Activated Carbon and Carbon Foam |
| title_short | Sorption of Selenium(IV) and Selenium(VI) onto Iron Oxide/Hydroxide-Based Carbon Materials: Activated Carbon and Carbon Foam |
| title_sort | sorption of selenium iv and selenium vi onto iron oxide hydroxide based carbon materials activated carbon and carbon foam |
| topic | inorganic selenium iron nanoparticles activated carbon carbon foams adsorption mechanism |
| url | https://www.mdpi.com/2073-4441/15/19/3499 |
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