Synergistic effect of carboxyl and sulfate groups for effective removal of radioactive strontium ion in a Zr-metal-organic framework
Rapid removal of radioactive strontium from nuclear wastewater is of great significance for environmental safety and human health. This work reports the effective adsorption of strontium ion in a stable dual-group metal-organic framework, Zr6(OH)14(BDC-(COOH)2)4(SO4)0.75 (Zr-BDC-COOH-SO4), which con...
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| Autores principales: | , , , |
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| Formato: | article |
| Lenguaje: | EN |
| Publicado: |
IWA Publishing
2021
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| Materias: | |
| Acceso en línea: | https://doaj.org/article/34abbe8148054fc8b048b71768fc50a5 |
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| Sumario: | Rapid removal of radioactive strontium from nuclear wastewater is of great significance for environmental safety and human health. This work reports the effective adsorption of strontium ion in a stable dual-group metal-organic framework, Zr6(OH)14(BDC-(COOH)2)4(SO4)0.75 (Zr-BDC-COOH-SO4), which contains strontium-chelating groups (-COOH and SO4) and a strongly ionizable group (-COOH). Zr-BDC-COOH-SO4 exhibits very rapid adsorption kinetics (<5 min) and a maximum adsorption capacity of 67.5 mg g−1. The adsorption behaviors can be well fitted to the pseudo-second-order model and the Langmuir isotherm model. Further investigations indicate that the adsorption of Sr2+ onto Zr-BDC-COOH-SO4 would not be obviously affected by solution pH and adsorption temperature. The feasible regeneration of the adsorbent was also demonstrated using a simple elution method. Mechanism investigation suggests that free -COOH contributes to the rapid adsorption based on electrostatic interaction, while the introduction of -SO4 significantly enhanced the adsorption capacity. Thus, these results suggest that Zr-BDC-COOH-SO4 is a potential candidate for Sr2+ removal. They also introduce dual groups as an effective strategy for designing high-efficiency adsorbents. HIGHLIGHTS
A dual-group (-COOH and -SO4) metal-organic framework was used to adsorb radioactive Sr2+.;
Very rapid adsorption kinetics of <5 min was obtained for the adsorbent.;
Large numbers of free carboxyl groups contribute to the fast adsorption.;
Introduction of -SO4 significantly enhances the adsorption capacity.;
The adsorbent exhibits a good anti-interference ability in terms of temperature and pH.; |
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