Facile synthesis of Melamine-Modified porous organic polymer for mercury (II) removal

Abstract

• A melamine-modified porous organic polymer was successfully prepared. • Melamine endowed the polymer with a high specific surface area. • The polymer possessed a high adsorption capacity and selectivity for Hg 2+ . • High porosity and nitrogen contents of TP-TC-MA contributed to the removal of Hg 2+ . In this study, a novel porous organic polymer modified by melamine (MA-POP) was prepared via a post-modification procedure for the Hg 2+ removal from aqueous solutions. The use of melamine as the rigid crosslinker endowed the polymer with high surface area (669 m 2 g −1 ), total pore volume (0.668 mL g −1 ) and nitrogen content. The material exhibited rapid adsorption kinetic for Hg 2+ , and the adsorption equilibrium can be reached within 10 min. The adsorption progress was more satisfyingly described by the pseudo-second-order kinetic model and the Langmuir isotherm model with a maximum adsorption capacity of 351.6 mg g −1 . XPS and FT-IR spectra suggested that the main adsorption mechanism was chelation between nitrogen groups and Hg 2+ . Besides, the adsorbent possessed high adsorption selectivity towards Hg 2+ in the presence of other eight coexisting metal ions and maintained good adsorption capacity even after five cycles. Therefore, the obtained MA-POP is qualified as a reliable adsorbent for Hg 2+ removal.