Selective photodegradation of 1-methylimidazole-2-thiol by the magnetic and dual conductive imprinted photocatalysts based on TiO2/Fe3O4/MWCNTs

The magnetic and dual conductive imprinted photocatalysts (MCIPs) were synthesized through the suspension polymerization method. TiO2/Fe3O4/MWCNTs, 1-methylimidazole-2-thiol and pyrrole were used as supports, template molecule and functional monomer, respectively. The MCIPs were further characterized by X-ray diffraction (XRD), Fourier transform infrared spectra (FT-IR), scanning electron microscopy (SEM), transmission electron microscope (TEM), UV-visible diffuse reflectance spectra (UV-vis DRS), thermogravimetric analysis (TGA) and vibrating sample magnetometer (VSM). The result revealed that polypyrrole (PPy) was formed and well embedded in the surface imprinted layer of TiO2/Fe3O4/MWCNTs. Owing to PPy and MWCNTs, the MCIPs was equipped with dual conductivity which was particularly useful for photodegradation of 1-methylimidazole-2-thiol in aqueous solution under ultraviolet irradiation. Through a series investigation of factors, it was obvious that when the polymerization time was 24 h and the adding dose of pyrrole was 8 mmol, the resulting MCIPs obtained the highest photocatalytic ability. In addition, the photodegradation process obeyed the pseudo-first-order kinetic reaction and exhibited an excellent selective degradation ability of 1-methylimidazole-2-thiol. The degradation intermediate products and mechanism of 1-methylimidazole-2-thiol were further discussed. (C) 2013 Elsevier B.V. All rights reserved.