Dual-Functionalized Fluorescent Cationic Organic Network: Highly Efficient Detection and Removal of Dichromate from Water.

Dichromate is a widespread contaminant in wastewater, threatening the health of humans and other organisms. Therefore, effective detection and removal of dichromate from water is of great significance. Herein, a tetraphenylethylene functionalized cationic organic network (CON-LDU2) was constructed via a facile quaternization reaction. CON-LDU2 was successfully integrated with both detection and removal functionalities toward dichromate. On the one hand, benefiting from the strong fluorescence, CON-LDU2 was employed as a chemosensor, it could efficiently and selectively probe Cr2O72- in water with "turn-off" fluorescent response. On the other hand, the cationic skeleton and free anions inside framework make CON-LDU2 an excellent adsorbent for Cr2O72-, it could capture Cr2O72- from water with rapid kinetics and high capacity. The kinetic constant for adsorption of Cr2O72- can reach up to 1.784 g mg-1 min-1, while the capacity is determined as 325 mg g-1. Furthermore, CON-LDU2 displayed good recyclability and can be reused for at least 5 cycles. Therefore, CON-LDU2 can serve as an ideal candidate not only in detection but also in removal of Cr2O72- in water medium.