Selective Removal of Nitrophenols from Aqueous Solutions Using Acrylic Acid–Acrylamide Molecularly Imprinted Polymers

Nitrophenols are environmentally persistent and toxic pollutants of global concern due to their harmful effects on ecosystems and human health.This study presents the synthesis of molecularly imprinted polymers (MIPs) based on poly (acrylic acid-coacrylamide) [PAA-co-PAAm], for the selective extraction of nitrophenol isomers from aqueous media for the first time.Characterization by FT-IR, TGA, and UV-Vis spectroscopy confirmed successful incorporation of cross-linking functionalities and enhanced structural integrity in MIPs compared to non-imprinted polymers (NIPs).Extraction efficiency was evaluated by determining the distribution ratio (D) of ortho-, meta-, and para-nitrophenol at pH 2, 7, and 10.D values increased with decreasing pH, with meta-nitrophenol (MNP) showing the highest selectivity.At pH 2, the D for MNP reached 4.6, a sevenfold increase over its value at pH 7.Among the three isomers studied, the MIP synthesized for MNP showed the highest binding efficiency and imprinting factor (I.F.), likely due to the formation of highly specific hydrogen-bonding interactions.Selectivity tests further confirmed the superior recognition of MNP by the MIPs compared to structurally similar compounds such as phenol and m-cresol.These results highlight the potential of PAA-co-PAAm-based MIPs as effective and selective adsorbents for the removal of nitrophenol isomers from contaminated water sources.