Valorization of Corn Waste: Oil–Water Separation and Fuel Enhancement

Corn waste is an abundant agricultural byproduct with untapped potential for functional reuse. In this work, we demonstrate a simple, low-cost approach to repurpose raw and untreated corn cob and husk for dual applications: oil–water separation and energy generation. Without requiring chemical modification, both materials exhibit strong hydrophobicity toward water (contact angle > 120°) and oleophilicity toward various oils (contact angle ≈ 0°), enabling effective removal of floating and submerged organic liquids from water. Oil absorption capacities ranged from 62 to 234 wt % for corn cob and 127–593 wt % for corn husk across five representative oils. Postabsorption, the gross calorific values of the oil-laden corn waste more than doubled compared to their raw counterparts, reaching up to 9145 cal/g. Structural and chemical analyses reveal that the synergistic effect of porous morphology and lignocellulosic composition underlies their wetting behavior and absorption performance. Furthermore, both materials retained stable functionality under sunlight exposure and thermal stress, confirming their environmental robustness. This study introduces a dual-function pathway for corn waste valorization, enabling both environmental remediation and renewable energy recovery─while requiring no complex instrumentation or processing steps. To the best of our knowledge, this is the first report to demonstrate the direct use of raw and untreated corn cob and husk for both oil–water separation and subsequent fuel enhancement without requiring any chemical or physical modification. The strategy presents a scalable solution for biomass reuse in resource-limited settings.