Preparation and characterization of hydrophobic sodium alginate/coconut fiber aerogels via GDL–CaCO₃ internal gelation and MTMS surface modification

Oil spills pose serious environmental threats, necessitating the development of efficient and sustainable oil-absorbent materials. This study aims to prepare and evaluate sodium alginate (SA)/coconut coir fiber aerogels with hydrophobic surface characteristics, prepared using a sol–gel internal gelation method with CaCO 3 and GDL and subsequently surface-modified with methyltrimethoxysilane (MTMS). The effects of SA concentration (0.3–0.5 g) and MTMS content (0.5–2 mL) on the structure and oil absorption performance were investigated. The results showed that the optimum oil absorption capacity of 288.10% was achieved at 0.4 g SA and 0.5 mL MTMS. Higher SA concentration led to a denser structure with reduced pore accessibility, resulting in lower absorption capacity, while excessive MTMS caused pore blockage and decreased performance. FTIR analysis indicated successful surface modification, and SEM observations revealed a more uniform porous structure after treatment. These structural characteristics contributed to improved oil absorption performance. The developed aerogel demonstrates potential as an environmentally friendly material for oil spill remediation.