Sandwich-structured graphene composite sponge with multiple cyclic compression for waste liquid treatment under dynamic electrical stimulation response

3D porous graphene nanosponge has broad application prospects in intelligent sensing, wastewater treatment, environmental remediation and other fields. However, the previously reported graphene-based 3D structure sponge column usually has difficulty achieving compression resistance and excellent adsorption effect. In this study, a novel, simple and low-cost sandwich structure is assembled. The carbon fiber/reduced graphene oxide/ polydimethylsiloxane (CF/rGO/P) with excellent compression electrical properties is used as the intermediate layer, and the flexible polyvinylidene fluoride/rGO/P (PV/rGO/P) is used as the upper and lower layers. A composite assembled graphene sponge column with outer pressure resistance and middle compression resistance is prepared. Results show that this composite sponge has a small resistance(30-100 omega/cm). Under 60% compression deformation, the resistance sensitivity could reach 36.44. The physical adsorption of methylene blue (MB) dye has reached more than 93.7% after 24 h, and the electrochemical adsorption rate is 3.12 times faster than the physical adsorption rate. This sandwich assembly structure exhibits an excellent positive synergistic effect, maintaining high adsorption and desorption properties for MB dyes under high compression cycles. It can be applied to the recovery of cationic dyes in the dynamic flow waste liquid, thereby broadening the application of hydrogel graphene nanosponge in the field of environmental protection.