Preparation of Poly (Vinylimidazole-Co-Polyethylene Glycol Diacrylate) Cryogel and Its Application for Simultaneous Heavy Metal Removal and Oil–Water Separation

The environmental pollution caused by complicated wastewater, such as oily wastewater with various metal ions, is becoming more and more serious, which promotes the rapid development of separation materials and relevant methods. In this paper, poly (vinylimidazole-co-polyethylene glycol diacrylate) (V-co-P) cryogel was synthesized by poly (ethylene glycol) diacrylate and vinylimidazole as monomers via freeze-thawing method, followed by its characterization with SEM, FT-IR, and XPS. It was found that Cu(II) was chemically absorbed on poly (V-co-P) cryogels and the maximum adsorption capacity of the poly (V-co-P) cryogel was determined to be 51.57 mg g −1 . More importantly, the poly (V-co-P) cryogel can effectively separate various oil-in-water emulsions containing Cu(II) in one step, and the micron droplets in the emulsion disappeared completely. The efficiency of Cu(II) removal was determined to be more than 97.5%. Moreover, this cryogel could be reused without significant loss of separation performance after ten cycles. In general, the cryogel prepared by simple freezing polymerization shows both heavy metal removal capacity and oil–water separation ability, which offers considerable potential applications on the disposal of complicated wastewater in the environment.