Preparation and performance of a novel magnetic conductive imprinted photocatalyst for selective photodegradation of antibiotic solution

Abstract

In order to achieve the treatment of antibiotic pollutants by solid waste, and for the purpose of improving the selectivity while enhancing the photocatalytic efficiency, this work used fly-ash cenospheres (FC) (obtained from coal fly ash, a typical solid waste) as the carrier, o-phenylenediamine (OPD) as the imprinted functional monomer, a conductive polymerizable monomer, enrofloxacin hydrochloride (EH) as the molecular template and TiO₂@magnetic floating fly-ash cenospheres (TMFFC) as the matrix material. A magnetic conductive imprinted photocatalyst (MCIP) was synthesized via surface imprinting technology and a one-pot photo-induced method. The as-prepared MCIP was extensively characterized by SEM, N₂ adsorption–desorption analysis with the Brunauer–Emmett–Teller (BET) method, FT-IR, elemental analysis, TGA, UV-vis and vibrating sample magnetometry (VSM). The results showed that the MCIP possessed a hollow spherical structure, floating and magnetic separation properties (Ms = 9.16 emu g⁻¹), the conductive polymer (POPD) was successfully introduced into the surface-imprinted layer, and the electrical conductivity of MCIP was 0.359 us cm⁻¹. The photodegradation rate, pseudo-first-order constant and coefficient of selection were calculated in detail, and all these data indicated that the MCIP not only had higher photocatalytic efficiency for the degradation of EH compared with other photocatalysts (such as the traditional surface-imprinted photocatalysts and TMFFC), but also possessed better selection for adsorption and photodegradation of EH in single/binary antibiotic solution. The mechanism of selective photodegradation of EH was also investigated.