Fabrication of bisphenol A molecularly imprinted polymers via Pickering emulsion polymerization stabilized with TiO2 nanoparticles

As a typical endocrine disrupter, bisphenol A (BPA) in the environment could damage the reproductive and endocrine system of humans and mammals. Hence, the precise removal of BPA from the environment becomes increasingly urgent. In this work, we employ Pickering emulsion polymerization to prepare the molecularly imprinted polymer (MIP) microspheres containing specific binding sites for the precise recognition of BPA through the non-covalent molecular imprinting strategy. In the process of polymerization, TiO₂ nanoparticles are used as the sole emulsifier to build the Pickering oil/water emulsion system followed by the radical polymerization. The template molecules of BPA could be eluted from the polymer microspheres by continuous Soxhlet extraction. The obtained MIP microspheres were characterized with the help of optical microscope and field emission scanning electron microscope, respectively. The MIP microspheres present regularly spherical structures with a relative broad size distribution. The chemical structure and thermal stability of MIP and non-imprinted polymer (NIPs) microspheres also were investigated by Fourier transform infrared spectroscopy and thermogravimetry, respectively. The formation of specific imprinted sites on the MIPs was validated through a batch of rebinding experiments, including the binding kinetics, binding isotherm and selective experiment. Moreover, the obtained MIP microspheres could be regenerated and recycled at least five cycles without significant loss of binding capacity. The MIP microspheres would have broad application prospects in the environmental and analytical field.

Graphical abstract

Schematic illustration for the preparation of MIPs microspheres via Pickering emulsion polymerization