Novel molecularly imprinted malachite green bifunctional imprinted microspheres through Pickering emulsion polymerization

Abstract

Novel malachite green molecularly imprinted polymer microspheres (MIP-MGs) were first synthesised using a modified powdered activated carbon-supported Bi₂O₃-doped TiO₂ to stabilise Pickering emulsion polymerisation for removal of malachite green (MG). Adsorption, catalytic properties and effects of pH and dosage on MIP-MGs were studied. The adsorption capacity of MIP-MGs reached 38.20 mg L⁻¹, which was about 1.8 times higher than that of non-molecularly imprinted polymer microspheres (NIP-MGs) and a higher selection coefficient K′ of 4.26 and 3.75 for MG was exhibited. MIP-MGs had the best photocatalytic activity (98.25%) under the optimal conditions of 0.8 g L⁻¹ of MIP-MGs and pH 8. In addition, photo-induced ˙O₂⁻ and h⁺ were considered to be the main active substances in MG photodegradation. According to the research results, the possible photocatalytic reaction mechanism of MIP-MGs was proposed and discussed in detail.