Coordination/cation exchangeable dual sites intercalated multilayered T3C2Tx MXene for selective and ultrafast removal of thallium(I) from water
Thallium (Tl) is an extremely toxic trace element with high bioaccumulation. Selective and ultrafast Tl+ removal from water is critical to the safety of water resources but remains a grand challenge. Here, by intercalating KOH into multilayered Ti3C2Tx MXene, an efficient adsorbent with coordination/cation exchangeable sites (KOH@Ti3C2Tx) has been developed for Tl+ removal. Almost 99.6% of Tl+ could be removed over optimal KOH@Ti3C2Tx in just 10 s, and the maximal uptake capacity was up to 238.1 mg g−1, which is 3.8-fold larger than that of the pristine Ti3C2Tx (61.4 mg g−1). Moreover, benefitting from a wider working pH window and excellent selectivity, KOH@Ti3C2Tx could quickly remove almost all Tl+ from actual wastewater, demonstrating great potential for water purification. Control experiments and calculations jointly demonstrated that the boosted performance can be attributed to the synergistic effect of the abundant hydroxyl groups and exchangeable K+ sites, in which the hydroxyl groups can capture Tl+via coordination while the K+/Tl+ cation exchange contributes to selectivity and fast uptake kinetics. This work highlights the interaction mechanism of active sites and metal ions, providing fundamental guidance to the selective and rapid removal of heavy metals from water, especially in emergency disposal of heavy metal pollution accidents.
危险品化学品经营许可证（带存储）