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. TiO 2 /Fe 3 O 4 /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 TiO 2 /Fe 3 O 4 /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.