Removal of mercury ions from water by triazine porous organic polymers rich in nitrogen and oxygen groups

Using Knoevenagel condensation reaction, two novel porous organic polymers TMTA-DHa and TMTA-TP with olefins were prepared for the removal of mercury ions from water. The material TMTA-TP among them promotes enol-keto reciprocal isomerization during the adsorption of mercury ions. These two polymers are rich in nitrogen and oxygen atoms, which provide more active sites and enhance the binding of Hg2+. Under the synergistic effect of nitrogen and oxygen, both materials showed good adsorption of Hg2+. The presence of enol-keto reciprocal isomerization form in the TMTA-TP material, as well as the presence of certain crystallinity, resulted in higher adsorption than that of the TMTA-DHa material. The adsorption process was better described by the pseudo-second-order kinetic model and Langmuir isotherm model, and the maximum adsorption amount reached 658.9 mg g−1 and 398.7 mg g−1, respectively. Thus, the two polymeric materials obtained, TMTA-DHa and TMTA-TP, were effective adsorbents for Hg2+ removal.