Efficient selective removal of cesium using recyclable Prussian blue/luffa fiber: performance and phytotoxicity assessment insights

Abstract

The treatment of radioactive wastewater has attracted extensive attention. Here, an adsorbent was designed to achieve efficient, stable, and recyclable removal of cesium ion contamination, and its adsorption properties were studied in detail. Prussian blue, a promising adsorbent for radioactive wastewater purification, has been often hindered in application due to its small size and easy agglomeration. To address this issue, the luffa fiber with a large specific surface area was employed to form networks loading Prussian blue particles and enhance adsorption capacity. In this paper, the recyclable Prussian blue/luffa was prepared by an in situ synthesis approach. Means such as XRD, SEM, EDS, FTIR, and XPS were applied to characterize its morphology and physicochemical properties. It exhibited outstanding selective removal efficiency for Cs⁺ ions and the ability to be rapidly separated from wastewater. The equilibrium and adsorption kinetics followed the Langmuir isotherm and pseudo-second-order model with a maximum adsorption capacity of 102.01 mg/g. Both pH and temperature had effects on the adsorption performance. The removal efficiency of Cs⁺ by Prussian blue/luffa still retained 71.2% after the 3-cycle test, and the possible mechanism was ion caging and ion exchange. In addition, the presence of co-existing ions only reduced the removal rate by less than 10.0%. Importantly, phytotoxicity assessment is urgently needed to address the adverse effects of applied nanoparticle composites on environmental and human safety. The phytotoxicity assessment was investigated, and the results indicated that the composite had no obvious biotoxicity. It is expected to be a highly potential material for disposing of radioactive wastewater. Future applications may extend to the treatment of various types of radioactive waste, providing a sustainable and effective solution to the field of nuclear waste management.