From Computational Screening to Enhanced Adsorption: Optimized Removal of Toxic Congo Red by Nitrogen-rich Triazine Polymers

Abstract

Water pollution is a challenging environmental problem that requires creative and effective remediation strategies. With the relentless increase in the global population and rapid industrialization, our water resources are increasingly threatened. Pollutants from various sources contaminate rivers, lakes, and oceans, thereby affecting ecosystems and human health. In this context, computational and experimental methods have been explored for the adsorption of pollutants, specifically dyes, from water using porous polymers as effective adsorbents. We synthesized an amino-triazine-rich sustainable polymer (CCTAT POP), which was confirmed using various characterization techniques, revealing porous amorphous aggregate structures with a surface area of 99 m². g⁻¹. Computational screening of the various dyes was performed, where Congo Red (CR) exhibited the highest binding energy (−38.38 kcal.mol⁻¹) with the lowest energy gap (2.69 eV), for the selective experimental adsorption studies. The adsorbent CCTAT POP achieved a maximum CR decolorization of 96% at a pH of 5 after optimizing various parameters. Both pseudo-second-order (PSO) kinetics and the Langmuir isotherm model described the adsorption process, with a maximum adsorption capacity of 46.51 mg.g⁻¹ over 240 min. These spontaneous endothermic chemical adsorptions confirmed the stability and reusability of the polymer over three cycles of use. These results suggest that the synthesized polymer offers a promising and cost-effective approach for water purification, advancing the field of polymer-based water treatment technologies.