Synthesis of a porous amidoxime modified hypercrosslinked benzil polymer and efficient uranium extraction from water

Benzil was hypercrosslinked to produce a novel hypercrosslinked porous organic polymer skeleton (HCP-CO) with an ultrahigh Brunauer-Emmett-Teller (BET) surface area of 605.4 m(2)& BULL;g(-1). The skeleton was grafted with diaminomaleonitrile (DAMN) via a simple Schiff base reaction, and then reacted with hydroxylamine hydrochloride (NH2OH & BULL;HCl) to produce an amidoxime-modified hypercrosslinked benzil polymer (HCP-AO) possessing many amidoxime groups. The chelation of the amidoxime group and uranium (VI) and porous structure provided HCPAO with excellent adsorption performance. The maximum adsorption capacity for the uranium of HCP-AO can reach 370.9 mg & BULL;g(-1) at pH = 6. Moreover, the adsorption process agreed well with the Langmuir and pseudo second-order models, thus indicating it was monolayer chemical adsorption. HCP-AO demonstrated excellent selectivity and recyclability; furthermore, the removal rate for uranium still remained at 66.35% in the coexistence of metal ions in simulated seawater. Furthermore, after five adsorption-desorption cycles, the adsorption capacity of HCP-AO slightly reduced. To summarize, we synthesized an efficient adsorbent that possesses high adsorption capacity, selectivity, and recyclability; it has good potential for uranium extraction from water.