Self-Healing Hydrogel toward Metal Ion Rapid Removal via Available Solar-Driven Fashion

Heavy metal ion pollution has been considered a big issue because of the high harmful and destructive effects to human beings. Hydrogel adsorption has received considerable interest in this aspect. However, the challenge still exists because the adsorption process is time-consuming. Herein, we designed and prepared poly(HPA-co-AA-co-NVP) hydrogels (HPA = hydroxypropyl acrylate, AA = acrylic acid, NVP = N-vinyl-2-pyrrolidone) via frontal polymerization (FP) for heavy ion removal. By virtue of high reaction rate of FP, the whole process of polymerization could be accomplished within 10 min without further energy. The as-prepared hydrogels exhibited pH sensitivity, excellent self-healing properties (a self-healing efficiency up to 90.9%), and heavy metal ion adsorption behavior. More importantly, we developed a new solar-driven method for rapid ion uptake, where solar energy was used to facilitate the adsorption rate. As compared to general adsorption in water without any treatment, this new solar-driven method provides a great efficient adsorption process toward heavy metal ions, which increases by 6 times. Furthermore, the application in desalination of seawater was also realized by the solar-driven method. This work not only provides a time-saving and low-energy synthesis pathway for multifunctional hydrogels via FP but also gives a new insight into rapid removal of ions by a new solar-driven method.