Fabrication of Hydroxyl-Carboxyl Bifunctional Hyper-Crosslinked Polymers for Selective Adsorption of Methylene Blue

Abstract

Dyes are usual contaminants in aqueous solution. Some of them are carcinogenic and toxic. Hydroxyl-carboxyl bifunctional hyper-crosslinked polymers (HCHCP) carrying hydroxyl and carboxyl groups on their surface were fabricated for methylene blue (MB) adsorption by Friedel-Crafts alkylation, using 3,4-dihydroxyphenylacetic acid as a monomer. The maximum adsorption amount of MB was 751.88 mg g−1 according to the Langmuir isotherm model. The adsorption kinetics results demonstrated that the adsorption of MB followed the pseudo-second-order kinetic mode. In addition, the results of selective adsorption displayed that the HCHCP could separate MB from Acid Red 91 and methyl orange. Thus, HCHCP are promising adsorbents for cationic dyes.