The treatment of cesium-contaminated wastewater has become one of the biggest issues. The selective Cs⁺ removal from wastewater containing competitive alkali metal ions such as Na⁺ is desired to reduce the volume of sludge. Therefore, the present work focused on water-soluble calix[4]arene-bis-crown-6 (W-BisC6) to selectively capture Cs⁺. For characterization of the complex, UV–vis spectroscopy is commonly used, however, due to the limited availability of information it can be hard to quickly identify the specific structures of some complexes. In this work, the electrospray ionization time of flight spectrometry (ESI-TOF-MS) is successfully utilized to identify the number and type of cations in W-BisC6-cation complexes. ESI-TOF-MS accurately recognized 4 types of complex (W-BisC6–Na⁺, W-BisC6–Cs⁺, W-BisC6–2Na⁺, W-BisC6–Na⁺–Cs⁺), and the experimental and simulated results were almost perfectly matched. It also revealed the difficulty of W-BisC6–2Cs⁺ complex formation under the present conditions. Thus, this technique is significantly helpful for rapid identification of the specific structures of complexes during Cs⁺-contaminated wastewater treatment.

铯污染废水的处理已成为最大的问题之一。希望从含有竞争性碱金属离子（例如Na ⁺）的废水中选择性去除Cs ⁺，以减少污泥的体积。因此，目前的工作集中在水溶性杯[4]芳烃双冠-6（W-BisC6）上，以选择性地捕获Cs ⁺。对于复合物的表征，通常使用紫外-可见光谱法，但是，由于信息的可用性有限，可能难以快速识别某些复合物的特定结构。在这项工作中，成功地利用电喷雾电离飞行时间质谱仪（ESI-TOF-MS）来识别W-BisC6-阳离子络合物中阳离子的数量和类型。ESI-TOF-MS可以准确识别四种类型的复合物（W-BisC6-Na ⁺，W-BisC6-Cs ⁺，W-BisC6-2Na ⁺，W-BisC6-Na ⁺ -Cs ⁺），以及实验和模拟结果几乎完美匹配。这也揭示了W-BisC6–2Cs ⁺的困难在当前条件下形成复合物。因此，该技术对于在受Cs ⁺污染的废水处理过程中快速鉴定复合物的特定结构非常有用。