Adsorptive Removal of Radioactive Cesium from Model Nuclear Wastewater over Hydroxyl-Functionalized Mxene Ti₃C₂T_x

Abstract

Selective removal of 137 Cs from nuclear wastewater is still a challenge due to the issues of efficient adsorbent exploitation and high concentrations of competitive ions. In this study, two-dimensionallayered Mxene Ti 3 C 2 T x achieved the surface alkaline modification with KOH to be used as an efficient adsorbent for Cs + removal from model wastewater. Hydroxyl-modified Ti 3 C 2 T x obtained improved the delamination morphology and surface structure compared with the pristine Ti 3 C 2 T x . In addition, the F species in Ti 3 C 2 T x were efficiently removed and the hydroxyl groups were increased after modification. The adsorption efficiency of Cs + over the hydroxyl-modified Ti 3 C 2 T x was significantly enhanced, being attributed to the improvements in morphology, structure, and properties. 0.05 g of an optimal adsorbent achieved 90% removal of Cs + with 5 mg•L −1 initial concentration in 50 mL of model wastewater within 5 min at ambient temperature and neutral conditions. Hydroxyl-modified Ti 3 C 2 T x also exhibited high adsorption selectivity for Cs + in the presence of competitive metal ions such as K + , Na + , Mg 2+ , and Ca 2+ . The mechanism study revealed that the ion exchange between [Ti−O] − H + /Cs + mainly contributed to Cs + adsorption, and the complexation between the oxygen-containing groups [Ti−O] in modified Ti 3 C 2 T x and Cs was also involved. The hydroxyl-modified Ti 3 C 2 T x was easy to regenerate and exhibited good recyclability for Cs + adsorption.

Self-Polycondensing Hypercross-Linked Polymers from Hydroxybenzyl Alcohols for Efficient Cesium Adsorption

“…It was clearly observed from Figure d–f that the binding energies of phenolic hydroxyl (CHOH) demonstrated obvious shifts (0.14–0.33 eV) after Cs adsorption onto HCP-HBAs, indicating the formation of –OCs . More importantly, the binding energies of −CH 2 OH also significantly shifted (0.41–0.73 eV), confirming that the hydroxymethyl group can boost the Cs adsorption.…”

“…It was clearly observed from Figure 5d−5f that the binding energies of phenolic hydroxyl (�CHOH) demonstrated obvious shifts (0.14−0.33 eV) after Cs adsorption onto HCP-HBAs, indicating the formation of −OCs. 57 More importantly, the binding energies of −CH 2 OH also significantly shifted (0.41−0.73 eV), confirming that the hydroxymethyl group can boost the Cs adsorption. Combined with the results of 13 C CP/MAS NMR, FT-IR, XPS, and selectivity experiments, it can be speculated that the deprotonated phenolic hydroxyl groups were exchanged with Cs + , and the residual hydroxymethyl in the polymer backbone played the role of cooperative coordination, as illustrated in Figure 6.…”

Synthesis of Titanium Carbide MXene Nanosheets by Ecofriendly Technique for Strontium Ion Adsorption

“…[ 12 ] On the other hand, it is reported that the surface termination by −O and −OH can enhance the Sr 2+ capturing efficiency by forming stable bonding with radioisotopes. [ 13 ] Therefore, searching an alternative etchant, which is more efficient in radioisotope removal and ecofriendly than the conventional hazardous chemicals, is needed.…”

Application of MXene for remediation of low-level radioactive aqueous solutions contaminated with 133Ba and 137Cs

“…These radionuclides can cause severe health issues in human cells as well the ecosystem. Since MXenes are novel materials developed in recent years, very few studies have been reported on barium 9,10 and cesium 11,12 ion removal. In addition, none of these studies used radioactive isotopes.…”