Adsorptive Removal of Radioactive Cesium from Model Nuclear Wastewater over Hydroxyl-Functionalized Mxene Ti3C2T x

• Published in: Industrial & engineering chemistry research Vol. 61; no. 25; pp. 9054 - 9066
• Main Authors: Chi, Yujing, Xu, Yuan, Xu, Chenxiang, Tian, Jiming, Li, Ying, Gu, Boxiang, Song, Haiyan, Zhang, Han
• Format: Journal Article
• Language: English
• Published: American Chemical Society 29.06.2022
• Subjects: Separations
• ISSN: 0888-5885; 1520-5045
• DOI: 10.1021/acs.iecr.2c01297

Selective removal of 137Cs 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-dimensional-layered Mxene Ti3C2T x achieved the surface alkaline modification with KOH to be used as an efficient adsorbent for Cs+ removal from model wastewater. Hydroxyl-modified Ti3C2T x obtained improved the delamination morphology and surface structure compared with the pristine Ti3C2T x . In addition, the F species in Ti3C2T x were efficiently removed and the hydroxyl groups were increased after modification. The adsorption efficiency of Cs+ over the hydroxyl-modified Ti3C2T 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 Ti3C2T x also exhibited high adsorption selectivity for Cs+ in the presence of competitive metal ions such as K+, Na+, Mg2+, and Ca2+. 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 Ti3C2T x and Cs was also involved. The hydroxyl-modified Ti3C2T x was easy to regenerate and exhibited good recyclability for Cs+ adsorption.