Salt-shrinkage resistant poly(amidoxime) adsorbent for improved extraction of uranium from seawater

•A pre-hydrolysis strategy is used to boost the uranium extraction performance.•The strategy is universally applicable for the PAO-based adsorbents.•The pre-treated adsorbent exhibits significant resistance to salt-shrinkage.•The pre-treated adsorbent shows 60.3% enhanced extraction capacity.•The pre-treated adsorbent realizes more than 1-fold accelerated extraction rate.