Contribution of Cross-Linker and Silica Morphology on Cr(VI) Sorption Performances of Organic Anion Exchangers Embedded into Silica Pores
Removal of Cr(VI) from the environment represents a stringent issue because of its tremendous effects on living organisms. In this context, design of sorbents with high sorption capacity for Cr(VI) is getting a strong need. For this purpose, poly(vinylbenzyl chloride), impregnated into porous silica...
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| Format: | Article |
| Language: | English |
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MDPI AG
2020-03-01
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| Series: | Molecules |
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| Online Access: | https://www.mdpi.com/1420-3049/25/5/1249 |
| _version_ | 1818115992977408000 |
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| author | Ecaterina Stela Dragan Doina Humelnicu |
| author_facet | Ecaterina Stela Dragan Doina Humelnicu |
| author_sort | Ecaterina Stela Dragan |
| collection | DOAJ |
| description | Removal of Cr(VI) from the environment represents a stringent issue because of its tremendous effects on living organisms. In this context, design of sorbents with high sorption capacity for Cr(VI) is getting a strong need. For this purpose, poly(vinylbenzyl chloride), impregnated into porous silica (PSi), was cross-linked with either <i>N</i>,<i>N</i>,<i>N</i>’,<i>N</i>’-tetramethyl-1,2-ethylenediamine (TEMED) or <i>N</i>,<i>N</i>,<i>N</i>’,<i>N</i>’-tetramethyl-1,3-propanediamine, followed by the reaction of the free -CH<sub>2</sub>Cl groups with <i>N</i>,<i>N</i>-diethyl-2-hydroxyethylamine to generate strong base anion exchangers (ANEX) inside the pores. The PSi/ANEX composite sorbents were deeply characterized by FTIR spectroscopy, SEM-energy dispersive X-ray spectroscopy (EDX), thermogravimetric analysis (TGA), and water uptake. The sorption performances of composites against Cr(VI) were investigated as a function of pH, contact time, initial concentration of Cr(VI), and temperature. It was found that the cross-linker structure and the silica morphology are the key factors controlling the sorption capacity. The adsorption process was spontaneous and endothermic and well described by pseudo-second-order kinetic and Sips isotherm models. The maximum sorption capacity of 311.2 mg Cr(VI)/g sorbent was found for the composite prepared with mesoporous silica using TEMED as cross-linker. The PSi/ANEX composite sorbents represent an excellent alternative for the removal of Cr(VI) oxyanions, being endowed with fast kinetics, equilibrium in about 60 min, and a high level of reusability in successive sorption/desorption cycles. |
| first_indexed | 2024-12-11T04:15:26Z |
| format | Article |
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| institution | Directory Open Access Journal |
| issn | 1420-3049 |
| language | English |
| last_indexed | 2024-12-11T04:15:26Z |
| publishDate | 2020-03-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Molecules |
| spelling | doaj.art-6992bd17dd6a4cd9bbb78d390d1aa2422022-12-22T01:21:15ZengMDPI AGMolecules1420-30492020-03-01255124910.3390/molecules25051249molecules25051249Contribution of Cross-Linker and Silica Morphology on Cr(VI) Sorption Performances of Organic Anion Exchangers Embedded into Silica PoresEcaterina Stela Dragan0Doina Humelnicu1“Petru Poni” Institute of Macromolecular Chemistry, Grigore Ghica Voda Alley 41 A, 700487 Iasi, RomaniaFaculty of Chemistry, “Al. I. Cuza” University of Iasi, Bd. 11 Carol I, 700506 Iasi, RomaniaRemoval of Cr(VI) from the environment represents a stringent issue because of its tremendous effects on living organisms. In this context, design of sorbents with high sorption capacity for Cr(VI) is getting a strong need. For this purpose, poly(vinylbenzyl chloride), impregnated into porous silica (PSi), was cross-linked with either <i>N</i>,<i>N</i>,<i>N</i>’,<i>N</i>’-tetramethyl-1,2-ethylenediamine (TEMED) or <i>N</i>,<i>N</i>,<i>N</i>’,<i>N</i>’-tetramethyl-1,3-propanediamine, followed by the reaction of the free -CH<sub>2</sub>Cl groups with <i>N</i>,<i>N</i>-diethyl-2-hydroxyethylamine to generate strong base anion exchangers (ANEX) inside the pores. The PSi/ANEX composite sorbents were deeply characterized by FTIR spectroscopy, SEM-energy dispersive X-ray spectroscopy (EDX), thermogravimetric analysis (TGA), and water uptake. The sorption performances of composites against Cr(VI) were investigated as a function of pH, contact time, initial concentration of Cr(VI), and temperature. It was found that the cross-linker structure and the silica morphology are the key factors controlling the sorption capacity. The adsorption process was spontaneous and endothermic and well described by pseudo-second-order kinetic and Sips isotherm models. The maximum sorption capacity of 311.2 mg Cr(VI)/g sorbent was found for the composite prepared with mesoporous silica using TEMED as cross-linker. The PSi/ANEX composite sorbents represent an excellent alternative for the removal of Cr(VI) oxyanions, being endowed with fast kinetics, equilibrium in about 60 min, and a high level of reusability in successive sorption/desorption cycles.https://www.mdpi.com/1420-3049/25/5/1249anion exchangercross-linkerchromium (vi)porous silicasorption kineticssorption isothermreusability |
| spellingShingle | Ecaterina Stela Dragan Doina Humelnicu Contribution of Cross-Linker and Silica Morphology on Cr(VI) Sorption Performances of Organic Anion Exchangers Embedded into Silica Pores Molecules anion exchanger cross-linker chromium (vi) porous silica sorption kinetics sorption isotherm reusability |
| title | Contribution of Cross-Linker and Silica Morphology on Cr(VI) Sorption Performances of Organic Anion Exchangers Embedded into Silica Pores |
| title_full | Contribution of Cross-Linker and Silica Morphology on Cr(VI) Sorption Performances of Organic Anion Exchangers Embedded into Silica Pores |
| title_fullStr | Contribution of Cross-Linker and Silica Morphology on Cr(VI) Sorption Performances of Organic Anion Exchangers Embedded into Silica Pores |
| title_full_unstemmed | Contribution of Cross-Linker and Silica Morphology on Cr(VI) Sorption Performances of Organic Anion Exchangers Embedded into Silica Pores |
| title_short | Contribution of Cross-Linker and Silica Morphology on Cr(VI) Sorption Performances of Organic Anion Exchangers Embedded into Silica Pores |
| title_sort | contribution of cross linker and silica morphology on cr vi sorption performances of organic anion exchangers embedded into silica pores |
| topic | anion exchanger cross-linker chromium (vi) porous silica sorption kinetics sorption isotherm reusability |
| url | https://www.mdpi.com/1420-3049/25/5/1249 |
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