Development of sulfonic acid-functionalized covalent organic polymer towards efficient adsorption of cationic dyes

Abstract

Organic dyes, often found in textile wastewater and soft drinks, are a threat to environmental and human well-being. Considering that adsorbents could be used to alleviate such threats, the present work is focused on the design of a covalent organic polymer (COP) for the adsorption of cationic dyes. For this, a COP was synthesized via a Friedel-Crafts reaction and subsequently functionalized with chlorosulfonic acid groups to form a sulfonated COP, denoted TC-COP-SO3H. Next, the material's adsorption capacity, kinetics, and recyclability were assessed. The adsorption capacity of TC-COP-SO3H for Basic Blue 41 and Basic Blue 46 is higher than it was before the modification with sulfonic groups. The improved adsorption efficiency and the high adsorption capacity for cationic dyes is attributed to the increased density of adsorption sites, which stems from favourable electrostatic interactions that is achieved via post-synthetic modification of the COP.

Keywords

• Sulfonated porous organic polymer
• Friedel–Crafts reaction
• Wastewater
• Covalent organic polymer