Eruption pore matrix with cooperative chelating of spatially continued ligands for rapid and selective removal of uranium

Abstract

A simple yet efficient gas-assisted preparation strategy was designed to prepare new kinds of porous copolymers sorbents in order to effectively avoid complex preparation procedure, undesired nonselective physical adsorption and slow permeable transport. Thus, an eruption pore, amidoxime functioned porous copolymers (PAO-PPoly(TA-ADBA-Cu2+)) was designed and synthesized for high-performance separation of uranium. The naturally existing small molecule thioctic acid (TA) was chosen as adsorption matrix owing to the supramolecular networks structure, plasticity and flexible compositions. For obtain the abundant spatially continued accessible recognizing sites of TA based copolymer, the 2-amino-benzonitrile (ADBA) was both selected as skeleton monomer and functional monomer on the TA matrix. Especially, the constructing chelating moieties of ADBA into porous TA copolymer matrix, where the binding motif’s coordinative interaction towards uranyl is enhanced by introducing an assistant amino group. In addition, the amino substituent of PAO-PPoly(TA-ADBA-Cu2+) assists in reducing the charge on uranyl in the copolymer sorbents and meanwhile serves as a hydrogen bond receptor, which is benefit of boosting the overall uranyl affinity of amidoxime. The Cu2+ could effectively improve the the chemical and mechanical properities of TA matrix mainly owing to the secondary ionic bonding of the copper(II)-carboxylate complexes. Benefiting from the porous structure and spatially continued affinity sites, the maximum uranium adsorption capacity of PAO-PPoly(TA-ADBA-Cu2+) is 515.13 mg g−1 at 318 K, which are superior to better than the previously reported copolymer sorbent. The obtained porous PAO-PPoly(TA-ADBA-Cu2+) materials have an excellent selectivity even when the competitive cations, as well as excellent recyclability toward uranium capture. More importantly, this work not only presents a new clue to fabricate porous copolymer sorbents with excellent chemical stability by gas-assisted preparation method, but also provides a novel platform for uranium extraction from an aqueous solution.