Rapid and highly selective removal of cesium by Prussian blue analog anchored on porous collagen fibers

Abstract

Removing radioactive cesium from wastewaters is necessary for sustainable development of nuclear energy. In this study, a novel adsorbent (PBA-CFs) was successfully fabricated by securely anchoring Prussian blue analog on porous collagen fibers (CFs) crosslinked with Zr4+. PBA-CFs showed low pH sensitivity and high adsorption capacity (qe) for cesium, with an optimal adsorption pH range of 2–10 and a maximum of 1.32 mmol g−1. The novel adsorbent also displayed high selectivity for Cs+ in the presence of competing ions (K+, Na+, Ca2+, Mg2+, Sr2+, or Co2+). They could effectively remove above 98 % Cs+ from tap water, lake water, and mineral water and more than 75 % of Cs+ in seawater at the Cs+ concentration of 10–60 mg/L. The adsorption process could rapidly reach equilibrium within 30 min and satisfy the pseudo-second-order kinetics model. Adsorption thermodynamics further indicated the process was exothermic, feasible, and spontaneous. Significantly, PBA-CFs exhibited superior adsorption performance in the continuous column process, with qo of 1.53 mmol g−1. One gram of PBA-CFs could effectively treat 4.03 L (666 BV) of water at a flow rate of 0.3 mL min−1, with a removal rate beyond 95 %, superior to other common adsorbents. Moreover, 0.1 mol/L NH4Cl solution with pH 2 could rapidly regenerate the saturated PBA-CF column. PBA-CFs demonstrated notable irradiation stability after exposure to 10–350 kGy of 60Co γ-ray. These results demonstrate PBA-CFs are a highly effective and promising adsorbent for the removal of radioactive 137Cs from wastewater. This work not only provides a feasible method for Cs+ removal to facilitate the environmental protection and sustainable development of nuclear energy but also extends the effective application and circular development of CFs as a reproducible biomass resource.