Modeling surface chemistry and adsorption behavior of biomimetic chitosan/silica hybrid materials
Chitosan/silica hybrid powders, obtained by the sol-gel method (pH 6, 7, 8) are studied for proposing surface chemical models and rationalizing their behaviour as adsorbents. The chitosan and silica exposed groups in dried powders and their protonation state are inferred. Solid-state 29Si-NMR, XPS,...
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| Format: | Article |
| Language: | English |
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Elsevier
2020-07-01
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| Series: | Journal of Materials Research and Technology |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S2238785420313703 |
| _version_ | 1818790683680440320 |
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| author | Johnatan Diosa Juan C Poveda-Jaramillo Frank Ramirez-Rodríguez Monica Mesa |
| author_facet | Johnatan Diosa Juan C Poveda-Jaramillo Frank Ramirez-Rodríguez Monica Mesa |
| author_sort | Johnatan Diosa |
| collection | DOAJ |
| description | Chitosan/silica hybrid powders, obtained by the sol-gel method (pH 6, 7, 8) are studied for proposing surface chemical models and rationalizing their behaviour as adsorbents. The chitosan and silica exposed groups in dried powders and their protonation state are inferred. Solid-state 29Si-NMR, XPS, zeta potential experiments and DFT computational calculations reveal the synthesis pH history of each sample. These details, summarized in surface models, are validated by copper adsorption: The pH 8 sample exhibits the highest hydrophilic and negative character, due to the deprotonated free silanol and neutral amine groups. These favor higher copper adsorption efficiency (30.4%) and loading capacity (0.077 mg Cu(II)/m2), through SiO−-Cu(II) electrostatic interactions and [Cu-(NH2)x]2+ complexation. For lower synthesis-pH samples, the neutral silanol and protonated amine populations increase, and the net surface charge becomes positive. This reduces the copper adsorption through electrostatic repulsions. The protonated amine and deprotonated silanol groups are the main responsible of electrokinetic surface response of materials prepared at lower and higher pH, respectively. The complexation is also involved in copper interactions, especially in surfaces populated by neutral amines. In conclusion, this work helps to understand the pH-dependent surface activity of chitosan/hybrid materials, being helpful for their further functionalization and applications. |
| first_indexed | 2024-12-18T14:59:21Z |
| format | Article |
| id | doaj.art-dab7834e48974b2b9dc16623b643239f |
| institution | Directory Open Access Journal |
| issn | 2238-7854 |
| language | English |
| last_indexed | 2024-12-18T14:59:21Z |
| publishDate | 2020-07-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Journal of Materials Research and Technology |
| spelling | doaj.art-dab7834e48974b2b9dc16623b643239f2022-12-21T21:03:57ZengElsevierJournal of Materials Research and Technology2238-78542020-07-019480928103Modeling surface chemistry and adsorption behavior of biomimetic chitosan/silica hybrid materialsJohnatan Diosa0Juan C Poveda-Jaramillo1Frank Ramirez-Rodríguez2Monica Mesa3Grupo Ciencia de los Materiales, Instituto de Química, FCEN, Universidad de Antioquia UdeA, Calle 70 No. 52-21, Medellín, ColombiaLaboratorio de Espectroscopia Atómica Molecular, Universidad Industrial de Santander, Cra. 27 Calle 9 Bucaramanga, ColombiaGrupo Química-física teorica, Instituto de Química, FCEN, Universidad de Antioquia UdeAGrupo Ciencia de los Materiales, Instituto de Química, FCEN, Universidad de Antioquia UdeA, Calle 70 No. 52-21, Medellín, Colombia; Corresponding author.Chitosan/silica hybrid powders, obtained by the sol-gel method (pH 6, 7, 8) are studied for proposing surface chemical models and rationalizing their behaviour as adsorbents. The chitosan and silica exposed groups in dried powders and their protonation state are inferred. Solid-state 29Si-NMR, XPS, zeta potential experiments and DFT computational calculations reveal the synthesis pH history of each sample. These details, summarized in surface models, are validated by copper adsorption: The pH 8 sample exhibits the highest hydrophilic and negative character, due to the deprotonated free silanol and neutral amine groups. These favor higher copper adsorption efficiency (30.4%) and loading capacity (0.077 mg Cu(II)/m2), through SiO−-Cu(II) electrostatic interactions and [Cu-(NH2)x]2+ complexation. For lower synthesis-pH samples, the neutral silanol and protonated amine populations increase, and the net surface charge becomes positive. This reduces the copper adsorption through electrostatic repulsions. The protonated amine and deprotonated silanol groups are the main responsible of electrokinetic surface response of materials prepared at lower and higher pH, respectively. The complexation is also involved in copper interactions, especially in surfaces populated by neutral amines. In conclusion, this work helps to understand the pH-dependent surface activity of chitosan/hybrid materials, being helpful for their further functionalization and applications.http://www.sciencedirect.com/science/article/pii/S2238785420313703Chitosan/silica hybridsSurface modelingDFT interaction energiesXPS and 29Si-NMR spectroscopiesElectrokinetic behaviour |
| spellingShingle | Johnatan Diosa Juan C Poveda-Jaramillo Frank Ramirez-Rodríguez Monica Mesa Modeling surface chemistry and adsorption behavior of biomimetic chitosan/silica hybrid materials Journal of Materials Research and Technology Chitosan/silica hybrids Surface modeling DFT interaction energies XPS and 29Si-NMR spectroscopies Electrokinetic behaviour |
| title | Modeling surface chemistry and adsorption behavior of biomimetic chitosan/silica hybrid materials |
| title_full | Modeling surface chemistry and adsorption behavior of biomimetic chitosan/silica hybrid materials |
| title_fullStr | Modeling surface chemistry and adsorption behavior of biomimetic chitosan/silica hybrid materials |
| title_full_unstemmed | Modeling surface chemistry and adsorption behavior of biomimetic chitosan/silica hybrid materials |
| title_short | Modeling surface chemistry and adsorption behavior of biomimetic chitosan/silica hybrid materials |
| title_sort | modeling surface chemistry and adsorption behavior of biomimetic chitosan silica hybrid materials |
| topic | Chitosan/silica hybrids Surface modeling DFT interaction energies XPS and 29Si-NMR spectroscopies Electrokinetic behaviour |
| url | http://www.sciencedirect.com/science/article/pii/S2238785420313703 |
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