Exposure to Hg2+-contaminated water poses severe risks to human health. Porous organic polymers (POPs) are known for removing heavy metals efficiently. However, the rapid and simple preparation of POP with efficient and selective adsorption capacities remains challenging. Herein, an effective strategy for the room-temperature preparation of TpPa-1 via a 1-step Schiff-base reaction of 2,4,6-triformylphloroglucinol (Tp) and p-phenylenediamine (Pa-1) using scandium(III) trifluromethanesulfonate as a catalyst is described. Various approaches were used to characterize TpPa-1, including SEM, TEM, XRD, FT-IR, NMR, BET, and TG analysis. TpPa-1 was applied to adsorb trace Hg2+ from aqueous solution, and its adsorption performance was assessed through batch adsorption experiments. The results indicated that over 94% of 100 μg L-1 Hg2+ was removed within 90 min, with the isotherm and kinetics conforming to the Freundlich and the pseudo-second-order models, respectively. Combined with XPS analysis, the Hg2+ adsorption of TpPa-1 was primarily dominated by chelation, competitive, and electrostatic interactions between the carbonyl groups of TpPa-1 and Hg2+. Because of its benefits of facile synthesis, enhanced removal performance, good selectivity, and reusability, the prepared POP material has great potential for Hg2+ removal from aqueous solutions.
Keywords: covalent organic frameworks; mercury adsorption; room-temperature; trace level.