Sustainable Multi-Network Cationic Cryogels for High-Efficiency Removal of Hazardous Oxyanions from Aqueous Solutions
It is still a challenge to develop advanced materials able to simultaneously remove more than one pollutant. Exclusive cationic composite double- and triple-network cryogels, with adequate sustainability in the removal of Cr<sub>2</sub>O<sub>7</sub><sup>2−</sup> a...
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| Format: | Article |
| Language: | English |
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MDPI AG
2023-02-01
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| Series: | Polymers |
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| Online Access: | https://www.mdpi.com/2073-4360/15/4/885 |
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| author | Ecaterina Stela Dragan Doina Humelnicu Maria Valentina Dinu |
| author_facet | Ecaterina Stela Dragan Doina Humelnicu Maria Valentina Dinu |
| author_sort | Ecaterina Stela Dragan |
| collection | DOAJ |
| description | It is still a challenge to develop advanced materials able to simultaneously remove more than one pollutant. Exclusive cationic composite double- and triple-network cryogels, with adequate sustainability in the removal of Cr<sub>2</sub>O<sub>7</sub><sup>2−</sup> and H<sub>2</sub>PO<sub>4</sub><sup>−</sup> oxyanions, were developed in this work starting from single-network (SN) sponges. Chitosan (CS), as the only polycation originating from renewable resources, and poly(N,N-dimethylaminoethylmethacrylate) (PDMAEMA) and polyethyleneimine (PEI), as synthetic polycations, were employed to construct multi-network cationic composite cryogels. The properties of the composites were tailored by the cross-linking degree of the first network (SN5 and SN20, which means CS with 5 or 20 mole % of glutaraldehyde, respectively) and by the order of the successive networks. FTIR, SEM-EDX, equilibrium water content and compressive tests were used in the exhaustive characterization of these polymeric composites. The sorption performances towards Cr<sub>2</sub>O<sub>7</sub><sup>2−</sup> and H<sub>2</sub>PO<sub>4</sub><sup>−</sup> anions were evaluated in batch mode. The pseudo-first-order, pseudo-second-order (PSO) and Elovich kinetics models, and the Langmuir, Freundlich and Sips isotherm models were used to interpret the experimental results. The adsorption data were the best fitted by the PSO kinetic model and by the Sips isotherm model, indicating that the sorption mechanism was mainly controlled by chemisorption, irrespective of the structure and number of networks. The maximum sorption capacity for both oxyanions increased with the increase in the number of networks, the highest values being found for the multi-network sponges having SN5 cryogel as the first network. In binary systems, all sorbents preferred Cr<sub>2</sub>O<sub>7</sub><sup>2−</sup> ions, the selectivity coefficient being the highest for TN sponges. The high sorption capacity and remarkable reusability, with only a 4–6% drop in the sorption capacity after five sorption–desorption cycles, recommend these composite cryogels in the removal of two of the most dangerous pollutants represented by Cr<sub>2</sub>O<sub>7</sub><sup>2−</sup> and H<sub>2</sub>PO<sub>4</sub><sup>−</sup>. |
| first_indexed | 2024-03-11T08:14:13Z |
| format | Article |
| id | doaj.art-d34416c9a8d943289e41d3f623adf988 |
| institution | Directory Open Access Journal |
| issn | 2073-4360 |
| language | English |
| last_indexed | 2024-03-11T08:14:13Z |
| publishDate | 2023-02-01 |
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| spelling | doaj.art-d34416c9a8d943289e41d3f623adf9882023-11-16T22:51:16ZengMDPI AGPolymers2073-43602023-02-0115488510.3390/polym15040885Sustainable Multi-Network Cationic Cryogels for High-Efficiency Removal of Hazardous Oxyanions from Aqueous SolutionsEcaterina Stela Dragan0Doina Humelnicu1Maria Valentina Dinu2Department of Functional Polymers, “Petru Poni” Institute of Macromolecular Chemistry, Grigore Ghica Voda Alley 41 A, 700487 Iasi, RomaniaFaculty of Chemistry, Alexandru Ioan Cuza University of Iasi, Carol I Bd. 11, 700506 Iasi, RomaniaDepartment of Functional Polymers, “Petru Poni” Institute of Macromolecular Chemistry, Grigore Ghica Voda Alley 41 A, 700487 Iasi, RomaniaIt is still a challenge to develop advanced materials able to simultaneously remove more than one pollutant. Exclusive cationic composite double- and triple-network cryogels, with adequate sustainability in the removal of Cr<sub>2</sub>O<sub>7</sub><sup>2−</sup> and H<sub>2</sub>PO<sub>4</sub><sup>−</sup> oxyanions, were developed in this work starting from single-network (SN) sponges. Chitosan (CS), as the only polycation originating from renewable resources, and poly(N,N-dimethylaminoethylmethacrylate) (PDMAEMA) and polyethyleneimine (PEI), as synthetic polycations, were employed to construct multi-network cationic composite cryogels. The properties of the composites were tailored by the cross-linking degree of the first network (SN5 and SN20, which means CS with 5 or 20 mole % of glutaraldehyde, respectively) and by the order of the successive networks. FTIR, SEM-EDX, equilibrium water content and compressive tests were used in the exhaustive characterization of these polymeric composites. The sorption performances towards Cr<sub>2</sub>O<sub>7</sub><sup>2−</sup> and H<sub>2</sub>PO<sub>4</sub><sup>−</sup> anions were evaluated in batch mode. The pseudo-first-order, pseudo-second-order (PSO) and Elovich kinetics models, and the Langmuir, Freundlich and Sips isotherm models were used to interpret the experimental results. The adsorption data were the best fitted by the PSO kinetic model and by the Sips isotherm model, indicating that the sorption mechanism was mainly controlled by chemisorption, irrespective of the structure and number of networks. The maximum sorption capacity for both oxyanions increased with the increase in the number of networks, the highest values being found for the multi-network sponges having SN5 cryogel as the first network. In binary systems, all sorbents preferred Cr<sub>2</sub>O<sub>7</sub><sup>2−</sup> ions, the selectivity coefficient being the highest for TN sponges. The high sorption capacity and remarkable reusability, with only a 4–6% drop in the sorption capacity after five sorption–desorption cycles, recommend these composite cryogels in the removal of two of the most dangerous pollutants represented by Cr<sub>2</sub>O<sub>7</sub><sup>2−</sup> and H<sub>2</sub>PO<sub>4</sub><sup>−</sup>.https://www.mdpi.com/2073-4360/15/4/885multi-network cryogelsdichromate ionsphosphate ionssorptionsustainability |
| spellingShingle | Ecaterina Stela Dragan Doina Humelnicu Maria Valentina Dinu Sustainable Multi-Network Cationic Cryogels for High-Efficiency Removal of Hazardous Oxyanions from Aqueous Solutions Polymers multi-network cryogels dichromate ions phosphate ions sorption sustainability |
| title | Sustainable Multi-Network Cationic Cryogels for High-Efficiency Removal of Hazardous Oxyanions from Aqueous Solutions |
| title_full | Sustainable Multi-Network Cationic Cryogels for High-Efficiency Removal of Hazardous Oxyanions from Aqueous Solutions |
| title_fullStr | Sustainable Multi-Network Cationic Cryogels for High-Efficiency Removal of Hazardous Oxyanions from Aqueous Solutions |
| title_full_unstemmed | Sustainable Multi-Network Cationic Cryogels for High-Efficiency Removal of Hazardous Oxyanions from Aqueous Solutions |
| title_short | Sustainable Multi-Network Cationic Cryogels for High-Efficiency Removal of Hazardous Oxyanions from Aqueous Solutions |
| title_sort | sustainable multi network cationic cryogels for high efficiency removal of hazardous oxyanions from aqueous solutions |
| topic | multi-network cryogels dichromate ions phosphate ions sorption sustainability |
| url | https://www.mdpi.com/2073-4360/15/4/885 |
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