Synthesis and characterization of a highly functionalized cationic porous organic polymer as an efficient adsorbent for removal of hazardous nitrate and chromate ions

Abstract

Due to increasing the pollution of the environment and water resources, the construction of effective adsorbents has vital importance for environmental protection. In this work, an imine-linked triazine-imidazolium-based cationic porous organic polymer (CPOP) with high porosity was synthesized via the catalyst-free Schiff’s base condensation. The structural properties of prepared porous polymer were characterized by FT-IR, XRD, SEM, EDS, HR-TEM, TGA, and Brunauer-Emmett-Teller (BET) surface area analysis. The performance of this synthesized cationic porous organic polymer was evaluated as an adsorbent for hazardous ions which exhibited good removal efficiency for nitrate (77 %), and chromate (92 %) ions. The adsorption process was fitted well with the Freundlich isotherm with high correlation coefficients (R2 = 0.9984 and R2 = 0.9879 for nitrate and chromate respectively. The pseudo-second-order kinetic model better describes the adsorption kinetics behaviour. The aim of this study is the introduction of a new porous organic polymer which can adsorb nitrate and chromate ions with high adsorption capacity. The cationic skeleton and free anions inside this porous polymer suggesting that ion exchange is the driving force for highly efficient removal of hazardous anionic contaminants.