Experimental and Theoretical Studies of Methyl Orange Uptake by Mn–Rich Synthetic Mica: Insights into Manganese Role in Adsorption and Selectivity
Manganese–containing mica (Mn–mica) was synthesized at 200 °C/96 h using Mn–carbonate, Al–nitrate, silicic acid, and high KOH concentration under hydrothermal conditions. Mn–mica was characterized and tested as a new adsorbent for the removal of methyl orange (MO) dye from aqueous solutions. Compare...
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MDPI AG
2020-07-01
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| author | Mohamed A. Barakat Ali Q. Selim Mohamed Mobarak Rajeev Kumar Ioannis Anastopoulos Dimitrios Giannakoudakis Adrián Bonilla-Petriciolet Essam A. Mohamed Moaaz K. Seliem Sridhar Komarneni |
| author_facet | Mohamed A. Barakat Ali Q. Selim Mohamed Mobarak Rajeev Kumar Ioannis Anastopoulos Dimitrios Giannakoudakis Adrián Bonilla-Petriciolet Essam A. Mohamed Moaaz K. Seliem Sridhar Komarneni |
| author_sort | Mohamed A. Barakat |
| collection | DOAJ |
| description | Manganese–containing mica (Mn–mica) was synthesized at 200 °C/96 h using Mn–carbonate, Al–nitrate, silicic acid, and high KOH concentration under hydrothermal conditions. Mn–mica was characterized and tested as a new adsorbent for the removal of methyl orange (MO) dye from aqueous solutions. Compared to naturally occurring mica, the Mn–mica with manganese in the octahedral sheet resulted in enhanced MO uptake by four times at pH 3.0 and 25 °C. The pseudo–second order equation for kinetics and Freundlich equation for adsorption isotherm fitted well to the experimental data at all adsorption temperatures (i.e., 25, 40 and 55 °C). The decrease of Langmuir uptake capacity from 107.3 to 92.76 mg·g<sup>−1</sup> within the temperature range of 25–55 °C suggested that MO adsorption is an exothermic process. The role of manganese in MO selectivity and the adsorption mechanism was analyzed via the physicochemical parameters of a multilayer adsorption model. The aggregated number of MO ions per Mn–mica active site (<inline-formula> <math display="inline"> <semantics> <mi>n</mi> </semantics> </math> </inline-formula>) was superior to unity at all temperatures signifying a vertical geometry and a mechanism of multi–interactions. The active sites number (<i>D</i><sub>M</sub>) of Mn–mica and the total removed MO layers (<i>N</i><sub>t</sub>) slightly changed with temperature. The decrease in the MO adsorption capacities (<i>Q<sub>sat</sub></i> = <i>n·D<sub>M</sub></i>·<i>N</i><sub>t</sub>) from 190.44 to 140.33 mg·g<sup>−1</sup> in the temperature range of 25–55 °C was mainly controlled by the <i>n</i> parameter. The results of adsorption energies revealed that MO uptake was an exothermic (i.e., negative Δ<i>E</i> values) and a physisorption process (Δ<i>E</i> < 40 kJ mol <sup>−1</sup>). Accordingly, the adsorption of MO onto Mn–mica was governed by the number of active sites and the adsorption energy. This study offers insights into the manganese control of the interactions between MO ions and Mn–mica active sites. |
| first_indexed | 2024-03-10T18:11:56Z |
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| last_indexed | 2024-03-10T18:11:56Z |
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| spelling | doaj.art-509824d6a195429c9cf098a042fbbcb32023-11-20T08:00:39ZengMDPI AGNanomaterials2079-49912020-07-01108146410.3390/nano10081464Experimental and Theoretical Studies of Methyl Orange Uptake by Mn–Rich Synthetic Mica: Insights into Manganese Role in Adsorption and SelectivityMohamed A. Barakat0Ali Q. Selim1Mohamed Mobarak2Rajeev Kumar3Ioannis Anastopoulos4Dimitrios Giannakoudakis5Adrián Bonilla-Petriciolet6Essam A. Mohamed7Moaaz K. Seliem8Sridhar Komarneni9Department of Environmental Sciences, Faculty of Meteorology, Environment and Arid Land Agriculture, King Abdulaziz University, Jeddah 21589, Saudi ArabiaFaculty of Earth Science, Beni-Suef University, Beni Suef 62511, EgyptPhysics Department, Faculty of Science, Beni-Suef University, Beni Suef 62511, EgyptDepartment of Environmental Sciences, Faculty of Meteorology, Environment and Arid Land Agriculture, King Abdulaziz University, Jeddah 21589, Saudi ArabiaDepartment of Chemistry, University of Cyprus, P.O. Box 20537, Nicosia Cy-1678, CyprusInstitute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, PolandDepartamento de Ingeniería Química, Instituto Tecnológico de Aguascalientes, Aguascalientes 20256, MexicoFaculty of Earth Science, Beni-Suef University, Beni Suef 62511, EgyptFaculty of Earth Science, Beni-Suef University, Beni Suef 62511, EgyptDepartment of Ecosystem Science and Management and Materials Research Institute, 204 Energy and the Environment Laboratory, The Pennsylvania State University, University Park, PA 16802, USAManganese–containing mica (Mn–mica) was synthesized at 200 °C/96 h using Mn–carbonate, Al–nitrate, silicic acid, and high KOH concentration under hydrothermal conditions. Mn–mica was characterized and tested as a new adsorbent for the removal of methyl orange (MO) dye from aqueous solutions. Compared to naturally occurring mica, the Mn–mica with manganese in the octahedral sheet resulted in enhanced MO uptake by four times at pH 3.0 and 25 °C. The pseudo–second order equation for kinetics and Freundlich equation for adsorption isotherm fitted well to the experimental data at all adsorption temperatures (i.e., 25, 40 and 55 °C). The decrease of Langmuir uptake capacity from 107.3 to 92.76 mg·g<sup>−1</sup> within the temperature range of 25–55 °C suggested that MO adsorption is an exothermic process. The role of manganese in MO selectivity and the adsorption mechanism was analyzed via the physicochemical parameters of a multilayer adsorption model. The aggregated number of MO ions per Mn–mica active site (<inline-formula> <math display="inline"> <semantics> <mi>n</mi> </semantics> </math> </inline-formula>) was superior to unity at all temperatures signifying a vertical geometry and a mechanism of multi–interactions. The active sites number (<i>D</i><sub>M</sub>) of Mn–mica and the total removed MO layers (<i>N</i><sub>t</sub>) slightly changed with temperature. The decrease in the MO adsorption capacities (<i>Q<sub>sat</sub></i> = <i>n·D<sub>M</sub></i>·<i>N</i><sub>t</sub>) from 190.44 to 140.33 mg·g<sup>−1</sup> in the temperature range of 25–55 °C was mainly controlled by the <i>n</i> parameter. The results of adsorption energies revealed that MO uptake was an exothermic (i.e., negative Δ<i>E</i> values) and a physisorption process (Δ<i>E</i> < 40 kJ mol <sup>−1</sup>). Accordingly, the adsorption of MO onto Mn–mica was governed by the number of active sites and the adsorption energy. This study offers insights into the manganese control of the interactions between MO ions and Mn–mica active sites.https://www.mdpi.com/2079-4991/10/8/1464hydrothermal synthesisMn–micamethyl orangestatistical physics adsorption modeling |
| spellingShingle | Mohamed A. Barakat Ali Q. Selim Mohamed Mobarak Rajeev Kumar Ioannis Anastopoulos Dimitrios Giannakoudakis Adrián Bonilla-Petriciolet Essam A. Mohamed Moaaz K. Seliem Sridhar Komarneni Experimental and Theoretical Studies of Methyl Orange Uptake by Mn–Rich Synthetic Mica: Insights into Manganese Role in Adsorption and Selectivity Nanomaterials hydrothermal synthesis Mn–mica methyl orange statistical physics adsorption modeling |
| title | Experimental and Theoretical Studies of Methyl Orange Uptake by Mn–Rich Synthetic Mica: Insights into Manganese Role in Adsorption and Selectivity |
| title_full | Experimental and Theoretical Studies of Methyl Orange Uptake by Mn–Rich Synthetic Mica: Insights into Manganese Role in Adsorption and Selectivity |
| title_fullStr | Experimental and Theoretical Studies of Methyl Orange Uptake by Mn–Rich Synthetic Mica: Insights into Manganese Role in Adsorption and Selectivity |
| title_full_unstemmed | Experimental and Theoretical Studies of Methyl Orange Uptake by Mn–Rich Synthetic Mica: Insights into Manganese Role in Adsorption and Selectivity |
| title_short | Experimental and Theoretical Studies of Methyl Orange Uptake by Mn–Rich Synthetic Mica: Insights into Manganese Role in Adsorption and Selectivity |
| title_sort | experimental and theoretical studies of methyl orange uptake by mn rich synthetic mica insights into manganese role in adsorption and selectivity |
| topic | hydrothermal synthesis Mn–mica methyl orange statistical physics adsorption modeling |
| url | https://www.mdpi.com/2079-4991/10/8/1464 |
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