Post-cationic Modification of a Pyrimidine-Based Conjugated Microporous Polymer for Enhancing the Removal Performance of Anionic Dyes in Water

Ionic porous organic polymers have attracted much attention due to their broad applications in catalysis, energy storage/conversion, proton conduction, etc. In this paper, an ionic porous organic polymer, CMP-PM-Me, was synthesized through post-synthetic modification of a pyrimidine-based conjugated microporous polymer, CMP-PM, which was constructed by the palladium catalyzed Sonogashira reaction of 1,3,5-triethynylbenzen and 2,5-dibromopyrimidine. These two polymers are porous with Brunauer-Emmett-Teller surface areas of 416 and 241 m  g for CMP-PM and CMP-PM-Me, respectively. Due to the cationic framework, CMP-PM-Me exhibits a much faster and more efficient adsorption performance to anionic dyes such as Congo red (CR) and methyl orange (MO) than that of CMP-PM with a neutral framework. The uptakes for CR are 400.0 mg g for CMP-PM-Me and 344.8 mg g for CMP-PM, respectively. Furthermore, CMP-PM-Me could quickly and drastically separate anionic dyes from the binary mixed solution of anionic and nonanionic dyes within a short time. This work not only enriches the family of ionic organic porous polymers and widens their synthetic utility, but also demonstrates their applications in the adsorption and separation of anionic dyes in water.