Environmental Remediation of Dye-Contaminated Water Using Epoxy Resin-Based Molecularly Imprinted Polymers for Selective Solid-Phase Extraction of Methylene Blue from Binary Dye Systems

Abstract

 In recent years, increasing discharge of dye-containing industrial wastewater has become a major environmental concern because of its adverse effects on aquatic ecosystems and water quality. In this study, epoxy resin-based molecularly imprinted polymers (ER-MIPs) were successfully synthesized and characterized as selective sorbents for the environmental remediation and removal of methylene blue (MB) from aqueous dye systems using molecularly imprinted solid-phase extraction (MISPE). Methylene blue was employed as the template molecule to fabricate selective recognition sites capable of enhancing extraction selectivity and efficiency in binary dye systems. Several operational parameters affecting extraction performance, including eluent type and volume, flow rate, sorbent amount, dye concentration, sample volume, and pH, were systematically optimized to maximize dye removal efficiency. The optimum conditions were achieved using methanol/acetic acid/water (8:1:1, v/v/v) as eluent, 15 mL eluent volume, 0.1 g sorbent mass, 100 mg L⁻¹ MB concentration, and neutral pH conditions (pH 7). Under these conditions, ER-MIP exhibited significantly higher extraction performance than the corresponding non-imprinted polymer (ER-NIP), owing to the formation of selective recognition cavities, with removal efficiencies ranging from 89.13% to 94.76% and imprinting factors between 4.55 and 8.83. The findings demonstrate the potential applicability of ER-MIPs as selective, efficient, and environmentally relevant sorbents for dye-contaminated water treatment and wastewater remediation.