Preparation of modified MXene material and its adsorption performance for Sr²⁺

Ti₃CNT_x/TMAOH was prepared when tetramethylammonium hydroxide(TMAOH) was selected as the intercalating agent. Adsorption performance of Ti₃CNT_x/TMAOH on Sr²⁺ in simulated radioactive wastewater was evaluated. The synthesized Ti₃CNT_x/TMAOH was characterized by SEM-EDS, XRD, BET and FTIR. In the batch experiment, the effects of the dosage of adsorbent Ti₃CNT_x/TMAOH, time, pH and competitive ions on Sr²⁺ removal were investigated. The results show that the removal rate of Sr²⁺ is 99.28% when the dosage is 1.0 g·L⁻¹, pH is 6, and the time is 10 min. The inhibition order of competitive ions is Ca²⁺$ \text{ > > } $Mg²⁺$ \text{ > } $K⁺$ \text{ > } $Na⁺$ \text{ > } $Cs⁺. After four adsorption-desorption cycles, the Sr²⁺ removal rate is 69.56%. The adsorption is consistent with the pseudo-second-order kinetic. The adsorption isotherm data conforms to the R-P model. 93.80% and 68.49% Sr²⁺ can be removed in tap water and lake water, respectively. Sr²⁺ is adsorbed by Ti₃CNT_x/TMAOH via ion exchange, surface chelation, electrostatic adsorption and interlayer interception.