Waterborne phenolic, triazine-based porous polymer particles for the removal of toxic metal ions

Abstract

Highly functional and also highly porous materials are presenting great advantages for applications in energy storage, catalysis and separation processes, which is why a continuous development of new materials can be seen. To create a material combining the promising potential interactions of triazine groups with the electrostatic or hydrogen bonding interactions of phenolic groups, a completely new polymeric resin was synthesized. From an eco-friendly dispersion polymerization in water, a copolymer network was obtained, which includes nine hydroxyl groups and one s-triazine ring per repetition unit. The polymer forms highly porous particles with specific surface areas up to 531 ​m²/g and a negative streaming potential over a great pH range. The adsorption isotherms of Ni²⁺, Cd²⁺, and Pb²⁺ were studied in more detail achieving very good adsorption capacities (16 mg Ni²⁺/g, 24 mg Cd²⁺/g, and 90 mg Pb²⁺/g). Demonstrating excellent properties for adsorption applications. The adsorbent exhibited selectivity for the adsorption of Pb²⁺ over more commonly occurring but non-toxic metal ions such as Fe²⁺, Ca²⁺, Mg²⁺, and K⁺. Furthermore, reusability of the material was demonstrated by facile, quantitative desorption of adsorbed Pb²⁺ with a small amount of diluted HCl, circumventing organic chelators. Subsequently, adsorption was carried out without decrease in adsorption performance.