Preparation of molecularly imprinted polymer coated magnetic multi-walled carbon nanotubes for selective removal of dibenzothiophene

Novel molecularly imprinted polymers (MIPs) on the surface of magnetic multi-walled carbon nanotubes (MMWCNTs) were prepared using dibenzothiophene (DBT) as template, methacrylic acid (MAA) as functional monomer, ethylene glycol dimethacrylate (EGDMA) as cross-linking agent and ammonium persulfate (APS) as initiator. The synthetic product was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), vibrating sample magnetometer (VSM), and Fourier transform infrared spectroscopy (FTIR). Batch mode adsorption studies were performed to evaluate the adsorption kinetics, adsorption isotherms, and selective recognition of MMWCNTs-MIP. The kinetic data were analyzed using pseudo-first-order and pseudo-second-order equation. The pseudo-second-order exhibited the best fit for the kinetic studies (R2= 0.9985), which indicates that chemisorption process limits adsorption of DBT. The adsorption equilibrium of DBT using MMWCNTs-MIP could be well-defined with the Langmuir isotherm model instead of the Freundlich isotherm model, and the maximum adsorption capacity was calculated as 47.8 mg g-1. Compared with magnetic non-imprinted polymer (MNIP), magnetic MIP (MMIP) possessed a better adsorption property toward DBT, showing its potential for deep desulfurization.