Semi-IPN Hydrogel-Modified Stainless-Steel Mesh Mixed with SiO2 is Used for Oil–water Separation

The exceptional oil–water selectivity and low oil adhesion of hydrogel materials have garnered considerable attention within the realm of oil–water separation. In this paper, semi-interpenetrating polymer networks (semi-IPN) were introduced into polyvinyl alcohol (PVA)/polyacrylamide (PAM) hydrogels, which improved the mechanical properties of the hydrogels due to the presence of physical and chemical crosslinking. The incorporation of SiO2 nanoparticles into the hydrogel improved the surface energy and roughness, which resulted in superhydrophilic and underwater superoleophobic properties of PVA/PAM/SiO2 semi-IPN hydrogel-coated stainless-steel mesh (SSM). The SSM coated with hydrogel demonstrated excellent resistance to underwater oil, as evidenced by a contact angle of 156°. The oil–water separation flux was as great as 1.2 × 104 L m−2 h−1, and the separation efficiency exceeded 98