Sodium Dodecyl Sulfate-Reinforced ZIF-67-Based PDMS Hydrophobic Sponge for Efficient and Rapid Oil–Water Separation

Polydimethylsiloxane (PDMS) sponges exhibit low oil adsorption capacity due to their monolithic pore structure and limited surface area. Here, we present SDS-ZIF-67/PDMS composite sponges that overcome these limitations. ZIF-67 particles are incorporated into the PDMS matrix via a soft-templating approach, creating a submicron hierarchical pore structure and increasing the number of accessible adsorption sites. Surface functionalization with sodium dodecyl sulfate (SDS) introduces long alkyl chains, modulating surface chemistry and enhancing selective affinity for oil molecules. The composite sponge exhibits a water contact angle of 135°, reaches adsorption equilibrium within 6 min, and achieves 96% separation efficiency for various oils and oil–water mixtures. After 15 adsorption–desorption cycles, 87% of the initial adsorption capacity is retained, demonstrating exceptional cyclic stability. These findings underscore the potential of SDS-ZIF-67/PDMS composite sponges for efficient treatment of oily wastewater.