Catalyst-free synthesis of triazine-based porous organic polymers for Hg2+ adsorptive removal from aqueous solution

Abstract The triazine-based porous organic polymers were synthesized by a one-pot amidation polycondensation reaction and they were applied for Hg 2+ removal from aqueous solution. The results showed that these polymers had high Brunauer-Emmett-Teller (BET) surface area (404–521 m 2 /g) and hierarchical porosity with dominated micropores and mesopores. The equilibrium data for Hg 2+ adsorption followed the Langmuir model with the maximum capacity of 229.9 mg/g. The Hg 2+ concentration at the initial concentration of 6.0 ppm reduced to 6 ppb after 20 min, verifying its fast and deep treatment of Hg 2+ wastewater. The adsorption was rapid and the pseudo-second-order rate model characterized the kinetic data perfectly. Moreover, the polymers exhibited excellent selectivity, easy regeneration, and superior reusability, indicative of their outstanding performance for Hg 2+ removal. Analysis of the adsorption mechanism revealed that the embedded carboxyl, triazine ring, and amino groups played significant role due to the strong chelating coordination of the oxygen and nitrogen with Hg 2+ .