Solar driven enhanced adsorption of radioactive Cs+ and Sr2+ from nuclear wastewater by chitosan-based aerogel embedded with Prussian blue analog

Abstract

The rational use of solar energy to achieve photothermal conversion is an attractive strategy to promote the efficient removal of radioactive Cs⁺ and Sr²⁺ from nuclear wastewater. Herein, a photothermal adsorbent of composite aerogel with three-dimensional porous structure is fabricated by integrating prussian blue analogues (PBAs) and straw biochar into the chitosan (CS) and waste leather scrap hydrolysate (WLSH) aerogel matrix (CS/WLSH/C/PBAs). The local heating effect generated by CS/WLSH/C/PBAs aerogel induce to generate steam, accelerating the enrichment of Cs⁺ and Sr²⁺ in the solution, which increase their interaction with the CS/WLSH/C/PBAs and improves their adsorption rates and capacities. Under simulated sunlight, the adsorption equilibrium times for Cs⁺ and Sr²⁺ by CS/WLSH/C/PBAs are shortened from 5 h in the dark condition to 2 h, with maximum adsorption capacities of 156.0 and 95.1 mg/g for Cs⁺ and Sr²⁺, respectively. Meanwhile, the CS/WLSH/C/PBAs aerogel also exhibits excellent reusability. Notably, the Cs⁺ and Sr²⁺ still can be efficiently removed in simulated seawater. Encouragingly, the CS/WLSH/C/PBAs aerogel also exhibits excellent adsorption properties for dyes and oils. This work provides insights for the design of multifunctional and efficient composite adsorbents, and paving a promising way for enhancing the adsorption of Cs⁺ and Sr²⁺ through solar energy.