Green synthesis of water-compatible molecularly imprinted resin on graphene oxide for highly selective extraction of chlorogenic acid in aqueous systems

Abstract

This study presents a novel environmentally friendly approach for synthesizing a water-compatible superhydrophilic molecularly imprinted resin on graphene oxide (SMIR/PGO). In the design of SMIR/PGO, dopamine (DA) serves a dual role: (1) self-polymerizing on the GO surface to form polydopamine, which acts as an environmentally friendly bridge for covalently grafting SMIR and (2) acting as green hydrophilic monomers, replacing traditional phenolic monomers to obtain SMIR. The dual role of DA eliminates the need for tedious steps such as separation, washing, and drying of intermediate materials, facilitating a simple one-pot synthesis. Additionally, hexamethylenetetramine (HMTA) replaces the traditional crosslinker formaldehyde, thereby avoiding direct contact with the carcinogenic formaldehyde. The NH₃ produced by HMTA decomposition acts as a catalyst, obviating the need for additional catalysts in the synthesis of SMIR/PGO. This one-pot synthesis occurs in an aqueous matrix and entirely avoids the use of organic solvents, aligning with green chemistry principles and ensuring compatibility with aqueous solutions. Consequently, SMIR/PGO combines the high specific surface area of GO, the multifunctionality of polydopamine, and the excellent water compatibility and high selectivity of SMIR. This combination provides multiple adsorption interactions to achieve selective extraction of chlorogenic acid in the aqueous matrix. This environmentally friendly synthetic strategy offers an efficient means of designing superhydrophilic molecularly imprinted materials with exceptional recognition and adsorption capabilities in aqueous environments.