Selective Ag⁺ Adsorption of Ureido Polymer Prepared by Cyclopolymerization Giving Large Ring Repeating Units

We report the synthesis of an ureido polymer containing 19-membered rings, prepared by the cyclopolymerization of a bifunctional monomer trans-1,2-bis(acryloyloxyethylureido)cyclohexane (TBAUCH) and studied for the selective adsorption of Ag+. PolyTBAUCH adsorbed Ag+ with an efficiency of 99.8%, and the maximum adsorption capacity was 39.8 mg/g. PolyTBAUCH selectively adsorbed Ag+ from an aqueous solution containing 20 different metal ions in similar concentrations. The selective adsorption depends on the controlling regioselective effect of the ring structure and the ureido groups. PolyTBAUCH could be reused at least for 5 cycles after desorption of Ag+ and maintained an Ag+ adsorption of 95.6% during the 5th cycle.