Continuous fixed-bed adsorption of radioactive cesium using PVDF-encapsulated Ti3C2Tx MXene-derived sodium titanate beads

초록

To remove radioactive cesium from aqueous solutions, Ti3C2Tx MXene-derived sodium titanate (MST) was synthesized via in situ alkalization and oxidation and then immobilized in polyvinylidene fluoride (PVDF) polymer. Characterization results confirmed that the MST/PVDF beads exhibit remarkable cesium adsorption performance, attributed to their porous structure, large specific surface area, and diverse surface functional groups. Continuous fixed-bed column experiments were also conducted under various operating parameters, including solution pH, influent cesium concentration, temperature, flow rate, bed height, and competing cations. The dynamic adsorption behavior of cesium was best described by the Thomas and Yoon-Nelson models. Notably, the maximum adsorption capacity of the MST/PVDF beads was determined to be 125.88 mg/g at an influent cesium concentration of 100 mg/L, a flow rate of 0.5 mL/min, and a bed height of 10 cm at pH 7, and 35 degrees C. This adsorption capacity exceeds those reported in previous studies on column systems, highlighting the material's superior performance. The adsorption process is likely governed by both cation exchange between Na+/H+ and Cs+ ions and electrostatic attraction. Given their unique surface properties and superior cesium adsorption capacity, MST/PVDF beads can offer significant potential for the continuous purification of liquid radioactive waste in practical applications.

키워드