Rationally designed pyridinium cationic polymeric network for effective TcO4−/ReO4− remediation.

[Display omitted] • 3D building unit based pyridinium covalent polymeric network was synthesized for the first time. • Highly symmetrical 3D TBPM building unit uniformly disperses the positive charges. • High rigidity of the Py-CPN provides stable ion transmission channels to promote fast ion exchange. • Excellent anions (including SO 4 2−, NO 3 −, PO 4 3−, CO 3 2−, and Cl−) selectivity is achieved due to introduction of pyrene units. The development of highly efficient and reliable adsorbent towards radiactive 99TcO 4 − is of great significance. Here, a covalent polymeric network (Py-CPN) based on pyridinium was rationally designed and synthesized through nucleophilic substitution reaction between 3D building unit tetrakis(4-(bromomethyl) phenyl) methane (TBPM) and 1,3,6,8-tetra(pyridin-4-yl) pyrene (TPyPy). Due to the rigidity and shape-persistence of tetrahedral unit of TBPM, which benefited rapid ion transportation across the polymeric network, Py-CPN provided high adsorption capacity and fast kinetics towards ReO 4 − removal. Owing to the introduction of highly hydrophobic and largely conjugated monomer TPyPy, excellent selectivity towards various coexisting anions was achieved. Moreover, the sorption ability of Py-CPN remained stable over a wide range of pH values, including 3 M HNO 3 solution and simulated Hanford LAW off-gas recycle wastes. Py-CPN also exhibited excellent recyclability for at least four cycles. Overall, this work provided a new strategy for constructing high-performance polymeric materials for sustainable development of environment protection. [ABSTRACT FROM AUTHOR]