A strategy of synergistically using ether oxygen and phenolic hydroxyl groups for Ultra-High selective and fast Cs+ isolation

[Display omitted] •The synergistic effect enhanced the Cs+/K+ selectivity of HCPs.•The Cs+/K+ separation factor of PO-HCPs-6 with more ether oxygen groups reach 57.•The PO-HCPs-6 exhibited an extremely fast kinetic adsorption rate.•The PO-HCPs-6 demonstrated outstanding elution and reusability performance. Hypercrosslinked polymers (HCPs) with synergistic effect of ether oxygen and phenolic hydroxyl groups was designed and fabricated for Cs+ isolation in the salt lake system. The separation factors (S.F.)(Cs+/K+) of the adsorbents were significantly increased through regulating the content of the ether oxygen group in the frameworks. The S.F. of PO-HCPs-6 was increased by nearly 5 times to an ultra-high value (S.F. = 57) compared with the Cs+ adsorbents reported in the literature. Moreover, the mild and sufficient polymerization process endowed PO-HCPs-6 with an extremely fast kinetic adsorption rate. PO-HCPs-6 could quickly reach 90% of the equilibrium adsorption capacity in just 1 min. Finally, after 5 times adsorption–desorption experiments, the remarkable elution rate (>92%) and reusability adsorption capacity (>91%) of PO-HCPs-6 proved it has inspiring application potential for the Cs+ isolation in the salt lake brine system.