A New Generation of Porous Polymer Materials from Polystyrene Waste: Synthesis and Adsorption of Nitrate Anions in Aqueous Media
A simple approach was developed to efficiently graft diethylene triamine onto polystyrene waste using succinic anhydride as a tracer to remove nitrate anions from aqueous solutions. Infrared spectroscopic data showed characteristic signs at 3395 cm<sup>−1</sup> and 1695 cm<sup>−1&l...
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| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2024-11-01
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| Series: | Organics |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2673-401X/5/4/29 |
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| Summary: | A simple approach was developed to efficiently graft diethylene triamine onto polystyrene waste using succinic anhydride as a tracer to remove nitrate anions from aqueous solutions. Infrared spectroscopic data showed characteristic signs at 3395 cm<sup>−1</sup> and 1695 cm<sup>−1</sup> corresponding to N-H and C=O (ester and amide), confirming the grafting of DETA onto PS. The zeta potential study showed that the PS-Succ-DETA adsorbent had a pH<sub>iep</sub> of 8.2, and its charge was positive when the pH was lower than the pH<sub>iep</sub>. Parameters affecting nitrate adsorption, such as dosage, initial concentration, pH, and contact time, were studied. The adsorption data corresponded well to the Langmuir isotherm with an R<sup>2</sup> correlation coefficient of 0.998, and the adsorption capacity was found to be 195.65 mg/g. The adsorption kinetics of NO<sub>3</sub><sup>−</sup> ions by PS-Succ-DETA corresponded perfectly to the PS-II model, with an R<sup>2</sup> coefficient of 0.999. The negative value of ΔG (−10.02 kJ/mol), ΔH (−18.76 kJ/mol), and ΔS (−28.83 J/K/mol) indicates that NO<sub>3</sub>- adsorption is spontaneous exothermic and suggests a decrease in randomness at the solid-liquid interface during the adsorption. The mechanism of adsorption of nitrate ions onto PS-Succ-DETA occurs via electrostatic interactions and hydrogen bonds between the NO<sub>3</sub><sup>−</sup> ions and the -NH<sub>2</sub> and NH functions of PS-Succ-DETA. |
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| ISSN: | 2673-401X |