Processable amidoxime functionalized porous hyper-crosslinked polymer with highly efficient regeneration for uranium extraction

• The HWB-AO adsorbent was a porous, processable and non-biologically toxic monolith. • The HWB-AO exhibited high selectivity and long service life. • The adsorption capacity for uranium was 256.4 mg g -1 at pH = 6. Uranium is not only toxic and radioactive, even more an important resource to ensure the nuclear energy development. This work reported an amidoxime-based hyper-crosslinked polymeric resin adsorbent (HWB-AO) to extract uranium from ocean. The monolithic matrix was prepared by suspension polymerization using styrene (St) and divinylbenzene (DVB), followed by post-polymerization modification to graft diaminomaleonitrile (DAMN) and conduct amidoximation to introduce amidoxime groups (AO) in its interior and surface. AO can enhance the affinity to uranium and hydrophilicity to accelerate the uranium adsorption. The monolithic structure overcome the problem that powder adsorbent is easy to drain in real seawater, so the monolithic is easier to apply. The batch adsorption experiments results showed that HWB-AO has an magnificent uranium removal rate (85%) and the maximum adsorption capacity (q e,max ) is 256.4 mg g -1 . In addition, HWB-AO still maintains a giant adsorption efficiency after eight times adsorption-desorption cycles and is environmentally friendly. Concurrently, HWB-AO exhibits excellent selectivity and removal rate (>88%) in modified seawater. Therefore, HWB-AO is considered as a potential adsorbent to perform uranium extraction from natural seawater.