Cysteine-functionalization zirconium-organic framework for efficient adsorption 2,4-dichlorophenylacetic acid from water

Abstract

2,4-Dichlorophenoxyacetic acid (2,4-D) is one of the most widely used pesticides in the world, which pose hazardous effects to the aquatic environment and human health due to its long-term and extensive use. In this work, MOF-808-Cys with highly water stable was prepared by one-pot method using L-cysteine modified Zr-based organic framework. Cysteine confers a variety of functional groups to MOF-808, enabling its chemical binding to the target substrate 2,4-dichlorophenylacetic acid (2,4-D). Adsorption experiments reveal that MOF-808-Cys has a higher adsorption efficiency (90%) toward 2,4-D than pristine MOF-808 (75%). Moreover, the adsorption kinetics confirms that the adsorption behavior follows a pseudo-second-order model with intraparticle diffusion. Experimental and characterization analysis show that physical adsorption and chemisorption synergistic improved adsorption capacity and adsorption efficiency. The -NH2 and -SH moiety are introduced into MOF-808 to enhance the adsorption performance by chemical adsorption. This study provides an effectively strategy of functional group modification to enhance the adsorption of pesticides and antibiotic pollutants in wastewater.