Selective adsorption of ketoconazole from aqueous solutions using a new molecularly imprinted polyurethane coated magnetic multiwall carbon nanotubes

New magnetic molecularly imprinted polyurethanes based on magnetic multi-walled carbon nanotubes (MMWNTs-MIPUs) were synthesized with specific selectivity toward ketoconazole (KTZ) as an anti-fungal drug. First, novel N-(4-carboxyphenyl) trimellitimide diisocyanate (NTDIS) was prepared from the reaction of trimellitic anhydride and 4-amino benzoic acid in two steps. Then, NTDIS was functionalized by β-cyclodextrin and methacrylic acid (MAA-NTDIS-β-CD). MAA-NTDIS-β-CD was used as a functional monomer, KTZ as a template, ethylene glycol dimethacrylate (EGDMA) as a cross-linking agent and 2,2′-azobisisobutyronitrile (AIBN) as initiator. Structure and properties of the prepared compounds were characterized by FTIR, ¹H NMR, FESEM, XRD, VSM, BET, and EDX. The influence of parameters such as solution pH, contact time, temperature, and initial concentrations in controlled absorption of KTZ using MMWCNTs-MIPU and MMWCNTs-NIPU were evaluated. The kinetic data were measured using the pseudo-first-order and pseudo-second-order equation. The pseudo-second-order equation displayed the best fit for the kinetic studies (R² 0.9958). The adsorption equilibrium of KTZ using MMWCNTs-MIPU could be well-defined with the Langmuir isotherm model, and the maximum adsorption capacity was calculated as 52.35 mg g^–1. The prepared MMWCNTs-MIPU can be simply separated by an external magnetic field and, MMWCNTs-MIPU can be used after six filtration-regeneration cycles.