Insight to the batch reactor design and sorption potential profiling of polymer grafted chitosan embedded silanated halloysite for Th(IV) recovery from aqueous system

Abstract

The removal of Th(IV) from wastewater stands as a pivotal step towards advancing cleaner energy, mitigating radioactive contamination, and fostering sustainable nuclear fuel practices. In this research endeavor, a pioneering adsorbent, polymethacrylic acid-grafted-chitosan embedded silanated halloysite (PMAA-g-CT/sHNT), has been synthesized to effectively remove Th(IV) from aqueous solutions. The study meticulously optimized process parameters for the adsorption of Th(IV) onto PMAA-g-CT/sHNT, employing both pseudo-second-order and intra-particle diffusion models. Remarkably, the Langmuir isotherm model exhibited exceptional fitting, revealing a remarkable Th(IV) uptake capacity of 320.99 mg/g at 30 ℃. Thermodynamic analyses underscored the spontaneous and endothermic nature of Th(IV) sorption, as evidenced by the negative ΔG° (-43.73 kJ/mol), positive ΔH° (398.71 kJ/mol), and positive ΔS° (0.0123 kJ/mol/K) values. The desorption process exhibited significant promise, with over 90% Th(IV) recovery even after four cycles of use. In a stride towards practical applicability, a two-stage batch reactor has been devised for commercial implementation of the adsorbent, with operating lines delineated. The efficacy and practicality of the sorbent were further corroborated through investigations conducted using simulated seawater, where a dosage of 2.5 g/L proved optimal for treating 1 L of water. This groundbreaking research not only elucidates the potential of PMAA-g-CT/sHNT as a potent Th(IV) adsorbent but also heralds a promising avenue for addressing critical challenges in wastewater treatment and nuclear waste management.