Preparation of a Hydrophobic Attapulgite/Melamine Sponge Composite for Efficient Oil–Water Separation

To enhance the oil–water separation performance and stability of melamine sponge (MS), stearic acid‐grafted attapulgite (SA‐g‐OATP) was synthesized via silanization and amidation grafting. The hydrophobic sponge (MS‐POS) was fabricated by dip‐coating MS in a polydimethylsiloxane (PDMS) solution containing SA‐g‐OATP. Characterization confirmed a grafting rate of 20.73%. The synergy between SA‐g‐OATP and PDMS constructed a hierarchical “micron skeleton‐nanoparticle” rough structure. The optimal sample, MS‐POS1‐1, exhibited superhydrophobicity with a water contact angle of 159.34° and achieved high adsorption capacities for oils and solvents, reaching 112.33 g/g for palm oil. In gravity‐driven tests, it showed separation efficiencies above 98.34% for oil–water mixtures and effectively separated water‐in‐oil emulsions. The sponge demonstrated robust stability, retaining hydrophobicity after 40 cycles of tape‐peeling or sandpaper abrasion, and withstanding prolonged immersion in pH 2–12 solutions. The adsorption capacity remained above 89.70% after 20 consecutive adsorption‐extrusion cycles. Developed from low‐cost materials via a simple process, MS‐POS exhibits high adsorption capacity, excellent selectivity, and robust stability, showing significant potential for oily wastewater remediation.