Preparation of lignin-containing porous microspheres through the copolymerization of lignin acrylate derivatives with styrene and divinylbenzene

A novel method for synthesizing microspheres from lignin or lignin acrylate derivatives through copolymerization with styrene (St) and divinylbenzene (DVB) has been developed. The copolymers were obtained by the emulsion-suspension polymerization with a constant molar ratio of DVB to St of 1: 1 (w/w) and different amounts of lignin or its derivatives. The morphologies of the obtained materials were examined by scanning electron microscopy. Two types of lignin modifications were performed to introduce vinyl groups into the lignin molecules: modification with acrylic acid and modification with epichlorohydrin plus acrylic acid. The course of modification was confirmed by attenuated total reflectance Fourier transform infrared spectroscopy. The thermal stability and degradation behavior of the obtained microspheres were investigated by thermogravimetric analysis, and the pore structure was characterized via nitrogen sorption experiments. Owing to the presence of specific functional groups and the well-developed pore structure, the obtained Lignin-St-DVB microspheres may have potential application as specific sorbents for the removal of phenolic pollutants from water, as demonstrated by the solid-phase extraction technique.