Since 2010, Prof. Chai and co-workers committed to develop advanced solid and liquid phase extraction techniques for radiochemical separation. They pioneered the environmental remediation of various radionuclides with functional nanoporous adsorbents including metal-organic frameworks (MOFs) and covalent organic frameworks (COFs) [
109-
111]. A series of stable MOFs, COFs and cationic polymeric networks (CPNs) were reported with superior adsorption capacities, kinetics, and selectivity for
99TcO
4−/ReO
4− [
112-
115]. Two base-resistant adsorbents can directly remove
99TcO
4− from simulated alkaline nuclear waste solution with high distribution coefficients [
116,
117]. They unraveled the adsorption mechanism
via the structural illustration of the TcO
4−-incorporated single crystal [
118]. They also provided a rare capture strategy for uranyl combined with complexation, chemical reduction, and photocatalytic reduction [
119,
120]. In addition, a layered coordination polymer can selectively remove Sr
2+ from seawater with the aid of the donor atoms in adjacent layers [
121]. They also developed several adsorbents for gaseous nuclides [
122].