Polyacrylamide/EDTA-modified chitosan/graphene oxide hydrogels as an adsorbent and supercapacitor for sustainable applications

Due to high security and versatility, hydrogels have attracted great interest in sustainable applications such as wastewater treatment and energy storage. However, the poor adsorption capacity as an adsorbent and the low conductivity as an electrolyte seriously restrict the sustainable application of hydrogels. Here, we prepare nanocomposite hydrogels (PAAm/CS-EDTA/GO) by mixing ethylene diamine tetraacetic acid (EDTA)-modified chitosan (CS) and graphene oxide (GO) in crosslinking polymerization of acrylamide (AAm). Nanocomposite gives PAAm/CS-EDTA/GO hydrogel excellent mechanical properties (e.g., fracture energy of similar to 1208 kJ center dot m(-3)). EDTA, CS and GO support rich and special adsorption sites for the removal of metal ions and dyes. The addition of lithium chloride (LiCl) makes PAAm/CS-EDTA/GO/Li hydrogel have anti-freezing and anti-dehydration properties. Interestingly, the synergy of CS-EDTA and GO increases the conductivity of the hydrogel. The supercapacitor assembled by PAAm/CS-EDTA/GO/Li hydrogel electrolyte shows high capacitance and temper-ature tolerance. Our work provides a route for the rational development of adsorption materials and energy storage devices for sustainable applications.

Automated summary

Due to their high security and versatility, hydrogels have gained great interest in sustainable applications such as wastewater treatment and energy storage. However, their poor adsorption capacity and low conductivity have limited their sustainable application. In this study, nanocomposite hydrogels (PAAm/CS-EDTA/GO) were prepared by crosslinking polymerization of ethylene diamine tetraacetic acid (EDTA)-modified chitosan (CS) and graphene oxide (GO). The addition of lithium chloride (LiCl) improved the performance of the hydrogel by providing anti-freezing and anti-dehydration properties and enhancing the conductivity. The supercapacitor assembled using PAAm/CS-EDTA/GO/Li hydrogel electrolyte showed high capacitance and temperature tolerance.