Efficient removal of radioactive Th(IV) from nuclear wastewater using phosphate-functionalized Ti3C2Tx

Abstract

In this study, Ti3C2Tx was synthesized from Ti3AlC2 by HF 40% and 12 M LiF + 9 M HCL in 24 hr at temperatures of 313.15 and 333.15 K. Morphology, structure, and functional groups were investigated by the XRD, SEM, EDS, and BET analyses. Under the conditions of thorium (IV) concentration of 150 mg.l−1, pH ∼ 3, temperature of 298.15 K, and contact time of 540 min, the adsorption uptake of thorium (IV) with Ti3C2Tx-HF and Ti3C2Tx-HF in situ was 148 and 346 mg.g−1, respectively. The 3-fold adsorption of Ti3C2Tx-HF in situ was because of the larger interlayer spacing, the larger number of hydroxyl functional groups, and the larger surface area due to the synthesis with 12 M LiF + 9 M HCL. Modification of Ti3C2Tx with phosphate groups was done to increase the adsorption capacity of thorium (IV). The results showed that the adsorption process of thorium (IV) with pristine and modified Ti3C2Tx followed pseudo-second-order kinetics and Freundlich model heterogeneous isotherm. Thermodynamic data revealed that the adsorption process was endothermic. Examining the adsorption mechanism indicated that electrostatic reactions and inner-sphere complexation were the dominant mechanisms of the process.