Adsorption of Anionic Dye on the Acid-Functionalized Bentonite
The efficiency of acid treatment on natural calcium bentonite (natural bentonite) for anionic dye adsorption was investigated using methyl orange (MO) as a probe. Additionally, adsorption experiments were accomplished between the natural bentonite, acidified bentonite, and a cationic dye (methylene...
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MDPI AG
2020-08-01
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| Online Access: | https://www.mdpi.com/1996-1944/13/16/3600 |
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| author | Jucielle Veras Fernandes Alisson Mendes Rodrigues Romualdo Rodrigues Menezes Gelmires de Araújo Neves |
| author_facet | Jucielle Veras Fernandes Alisson Mendes Rodrigues Romualdo Rodrigues Menezes Gelmires de Araújo Neves |
| author_sort | Jucielle Veras Fernandes |
| collection | DOAJ |
| description | The efficiency of acid treatment on natural calcium bentonite (natural bentonite) for anionic dye adsorption was investigated using methyl orange (MO) as a probe. Additionally, adsorption experiments were accomplished between the natural bentonite, acidified bentonite, and a cationic dye (methylene blue, MB). Acid functionalization in natural bentonite (RF) was carried out with HCl and H<sub>2</sub>SO<sub>4</sub> acids (RF1 and RF2, respectively). The samples were characterized by chemical analysis, mineralogy, particle size, and thermal behavior with the associated mass losses. The adsorption efficiency of MO and MB dyes was investigated by the effects of the initial concentration of adsorbate (<inline-formula><math display="inline"><semantics><mrow><msub><mi>C</mi><mi>i</mi></msub></mrow></semantics></math></inline-formula>) and the contact time (<inline-formula><math display="inline"><semantics><mrow><msub><mi>t</mi><mi>c</mi></msub></mrow></semantics></math></inline-formula>). The acid treatment was efficient for increasing the adsorption capacity of the anionic dye, and the <inline-formula><math display="inline"><semantics><mrow><msubsup><mi>Q</mi><mrow><mi>m</mi><mi>a</mi><mi>x</mi></mrow><mrow><mi>e</mi><mi>x</mi><mi>p</mi></mrow></msubsup></mrow></semantics></math></inline-formula> values measured were 2.2 mg/g, 67.4 mg/g e 47.8 mg/g to RF, RF1 e RF2, respectively. On the other hand, the acid functionalization of bentonite did not significantly modify the MB dye adsorption. The Sips equation was the best fit for the adsorption isotherms. Thus, we found that the acid-functionalized bentonite increases the anionic dye adsorption by up to 8000%. The increased adsorptive capacity of acidified bentonite was explained in terms of electrostatic attraction between the clay surface and the dye molecule. |
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| issn | 1996-1944 |
| language | English |
| last_indexed | 2024-03-10T17:26:41Z |
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| spelling | doaj.art-b0957ae53cbf4ababac88dce0602a1f32023-11-20T10:10:20ZengMDPI AGMaterials1996-19442020-08-011316360010.3390/ma13163600Adsorption of Anionic Dye on the Acid-Functionalized BentoniteJucielle Veras Fernandes0Alisson Mendes Rodrigues1Romualdo Rodrigues Menezes2Gelmires de Araújo Neves3Programa de Pós-Graduação em Ciência e Engenharia de Materiais (PPG-CEMat), Universidade Federal de Campina Grande, Av. Aprígio Veloso-882, Bodocongó, Campina Grande-PB 58429-900, BrazilPrograma de Pós-Graduação em Ciência e Engenharia de Materiais (PPG-CEMat), Universidade Federal de Campina Grande, Av. Aprígio Veloso-882, Bodocongó, Campina Grande-PB 58429-900, BrazilPrograma de Pós-Graduação em Ciência e Engenharia de Materiais (PPG-CEMat), Universidade Federal de Campina Grande, Av. Aprígio Veloso-882, Bodocongó, Campina Grande-PB 58429-900, BrazilPrograma de Pós-Graduação em Ciência e Engenharia de Materiais (PPG-CEMat), Universidade Federal de Campina Grande, Av. Aprígio Veloso-882, Bodocongó, Campina Grande-PB 58429-900, BrazilThe efficiency of acid treatment on natural calcium bentonite (natural bentonite) for anionic dye adsorption was investigated using methyl orange (MO) as a probe. Additionally, adsorption experiments were accomplished between the natural bentonite, acidified bentonite, and a cationic dye (methylene blue, MB). Acid functionalization in natural bentonite (RF) was carried out with HCl and H<sub>2</sub>SO<sub>4</sub> acids (RF1 and RF2, respectively). The samples were characterized by chemical analysis, mineralogy, particle size, and thermal behavior with the associated mass losses. The adsorption efficiency of MO and MB dyes was investigated by the effects of the initial concentration of adsorbate (<inline-formula><math display="inline"><semantics><mrow><msub><mi>C</mi><mi>i</mi></msub></mrow></semantics></math></inline-formula>) and the contact time (<inline-formula><math display="inline"><semantics><mrow><msub><mi>t</mi><mi>c</mi></msub></mrow></semantics></math></inline-formula>). The acid treatment was efficient for increasing the adsorption capacity of the anionic dye, and the <inline-formula><math display="inline"><semantics><mrow><msubsup><mi>Q</mi><mrow><mi>m</mi><mi>a</mi><mi>x</mi></mrow><mrow><mi>e</mi><mi>x</mi><mi>p</mi></mrow></msubsup></mrow></semantics></math></inline-formula> values measured were 2.2 mg/g, 67.4 mg/g e 47.8 mg/g to RF, RF1 e RF2, respectively. On the other hand, the acid functionalization of bentonite did not significantly modify the MB dye adsorption. The Sips equation was the best fit for the adsorption isotherms. Thus, we found that the acid-functionalized bentonite increases the anionic dye adsorption by up to 8000%. The increased adsorptive capacity of acidified bentonite was explained in terms of electrostatic attraction between the clay surface and the dye molecule.https://www.mdpi.com/1996-1944/13/16/3600bentonitemethylene bluemethyl orangeacid functionalizationadsorptive capacity |
| spellingShingle | Jucielle Veras Fernandes Alisson Mendes Rodrigues Romualdo Rodrigues Menezes Gelmires de Araújo Neves Adsorption of Anionic Dye on the Acid-Functionalized Bentonite Materials bentonite methylene blue methyl orange acid functionalization adsorptive capacity |
| title | Adsorption of Anionic Dye on the Acid-Functionalized Bentonite |
| title_full | Adsorption of Anionic Dye on the Acid-Functionalized Bentonite |
| title_fullStr | Adsorption of Anionic Dye on the Acid-Functionalized Bentonite |
| title_full_unstemmed | Adsorption of Anionic Dye on the Acid-Functionalized Bentonite |
| title_short | Adsorption of Anionic Dye on the Acid-Functionalized Bentonite |
| title_sort | adsorption of anionic dye on the acid functionalized bentonite |
| topic | bentonite methylene blue methyl orange acid functionalization adsorptive capacity |
| url | https://www.mdpi.com/1996-1944/13/16/3600 |
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