Facile synthesis of dual-functionalized microporous organic network for efficient removal of cationic dyes from water

A facile one-step anhydride hydrolysis strategy was rationally designed to synthesize a novel dual-functionalized microporous organic network (MON-4COOH) with enriched naphthalene and carboxyl groups for efficient removal of cationic dyes. The pre-designed electrostatic, hydrogen bonding , π-π and hydrophobic interaction sites on MON-4COOH led to the complete removal of three typical cationic dyes methylene blue, malachite green and crystal violet (25 mg L −1 for each) within 20 s and gave their maximum adsorption capacities of 2564, 3126 and 1114 mg g −1 , respectively. The adsorption of these cationic dyes fitted well with pseudo-second-order kinetic and Langmuir adsorption models. The adsorption kinetics and capacities of these cationic dyes on MON-4COOH were much faster and higher than many other reported adsorbents. The negatively charged MON-4COOH also gave much faster adsorption kinetic and larger adsorption capacity for cationic (methylene blue, malachite green and crystal violet) dyes than anionic dye. The excellent flow-through water treatment ability and reusability also made MON-4COOH highly potential for the remediation of cationic dyes polluted water. This work provided a feasible way to design and synthesize dual-functionalized MONs for efficient adsorption and elimination of environmental pollutants from water.