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

Abstract

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.