Abstract This paper attempts to test the ionic liquids (ILs) modified Amberlite XAD-4 resins as novel and effective adsorbents for valeric acid (VA) removal from aqueous solutions by adsorption. In this regard, the adsorption performance and mechanism of Amberlite XAD-4 resin with imidazolium-based ILs, namely 1-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF 6 ), and 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (BMIMTf 2 N), were investigated. The unmodified XAD-4 and ionic liquids modified Amberlite XAD-4 resins (XAD-4/IL1 and XAD-4/IL2) have been characterized with FTIR, XRD, and SEM analysis. The characterization results confirmed that the successful IL modification onto the resin surface. In batch adsorption experiments, the influence of initial VA concentrations (1–3% w/w), temperature (25–45 o C), and resin dosage (0.01–0.05 g) on adsorption capacity was conducted. Additionally, adsorption isotherm, kinetics and thermodynamic modeling were carried out to determine the adsorption mechanism. IL modification, specifically with Tf₂N⁻ based anion, significantly improved the adsorption performance of Amberlite XAD-4 for VA. The highest q e values were determined at the conditions of lower temperature (25 °C), maximum initial VA concentration (3% w/w), and minumum adsorbent dosage (0.01 g) as 1006.41 mg.g −1 , 1123.31 mg.g −1 , and 1307.94 mg.g −1 for XAD-4, XAD-4/IL1 and XAD-4/IL2, respectively. Imidazolium-based ILs modified XAD-4 can be an alternative as an innovative and effective adsorbent for VA uptake from aqueous medium.
Yalçın et al. (2026) studied this question.