Recyclable Prussian Blue/Luffa Fiber for Efficient Selective Removal of Cesium and its Phytotoxicity Assessment

The emergency and safe treatment of radioactive substances leakage wastewater has attracted extensive attention. Prussian blue was used as an adsorbent for the purification of radioactive wastewater. However, easy agglomeration due to its small size often limits the application. With a large specific surface area, the lignocellulosic material– luffa fiber could 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 excellent selective removal efficiency of Cs ⁺ and rapid separation from wastewater. The equilibrium and adsorption kinetics followed the Langmuir isotherm and pseudo-second-order model with a maximum adsorption capacity of 102.01mg/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, the phytotoxicity assessment was investigated and the results indicated that the composite had no obvious biotoxicity. It is expected to be a potential material for disposing of radioactive wastewater.