Sulfonated Hollow Covalent Organic Polymer: Highly‐Selective Adsorption toward Cationic Organic Dyes over Anionic Ones in Aqueous Solution

Abstract A sulfonated hollow covalent organic polymer (sh‐COP‐P) was prepared by post sulfonation of hollow covalent organic polymer (h‐COP‐P) synthesized through poly‐condensation of tetrabiphenylporphyrin (TBPP). In comparison with h‐COP‐P, sh‐COP‐P exhibits significantly enhanced adsorption capacity of organic cationic dyes in aqueous solutions accompanied with notably reduced adsorption capacity of anionic dyes. This gives sh‐COP‐P a satisfactory performance in selectively separating cationic organic dyes from anionic ones, mainly attributed to the electrostatic interaction between polymer backbone and the guest molecules.