Beschreibung:
Selenium (Se) removal from contaminated water has become a major environmental problem in recent years. Designing efficient and selective materials for selenium absorption is urgent and still represents a great challenge. Herein, two novel cationic covalent triazine frameworks (CTFS-Cl and CTFL-Cl) are developed for the first time and employed as a new class of Se adsorbents. The results from systematic adsorption experiments indicate that these materials can adsorb SeO42- in a wide range of pH values (2-11) with fast kinetics (5 min), outstanding adsorption capacity, and excellent selectivity over other competing anions. The maximum adsorption capacity achieved (149.3 mg/g by CTFS-Cl) constitutes one of the highest values among the organic polymeric materials. More importantly, after a single step adsorption, these materials can reduce the Se concentrations to lower than 10 ppb, the lowest drinking water standard in the world. The adsorption mechanism was probed by XPS technique, EDS analysis, adsorption experiments, and DFT calculations, which reveals that anion exchange between Cl- and SeO42- is the main driving force for Se adsorption. This work demonstrates the excellent performance of CTF-based materials with great application prospect for Se removal in contaminated water treatment