Development and Screening of Molecularly Imprinted Polymers for Triclosan Removal from Water Using Different Functional Monomers

Background: Triclosan (TCS), an antimicrobial compound released into aquatic environments, is an emerging contaminant for which selective sorbents are being investigated. Molecularly imprinted polymers (MIPs) can provide template-specific binding sites, but their adsorption behaviour depends on the functional monomer used during synthesis. Aim: This study compared five functional monomers for preparing triclosan-imprinted polymers. Methods: MIPs and corresponding non-imprinted polymers (NIPs) were synthesised by precipitation polymerisation using methacrylic acid, methyl methacrylate, acrylic acid, acrylamide and 4-vinylpyridine. The polymers were screened by batch adsorption and imprinting factor. The selected acrylamide-based polymer was characterised by Fourier-transform infrared spectroscopy, scanning and transmission electron microscopy, and Brunauer–Emmett–Teller surface-area analysis. Adsorption isotherms, selectivity against bisphenol A and regeneration behaviour were also examined. Results: The acrylamide-based MIP showed the highest reported triclosan adsorption efficiency (94.61%) and imprinting factor (5.29) among the five functional-monomer systems. Its specific surface area was 22.664 m² g⁻¹, compared with 14.538 m² g⁻¹ for the corresponding NIP. The reported selectivity parameters were a separation factor of 21.53 and a relative separation factor of 18.07. The sorption efficiency declined over successive regeneration cycles, reaching 75.76% after the fifth reuse. Conclusion: Within the reported batch conditions, acrylamide provided the most favourable functional-monomer formulation for selective triclosan adsorption.