Structural modification of oil palm lignin via steam explosion pre-treatment as a potential renewable green substitute in corrosion applications.

This research demonstrates the significance of steam explosion pre-treatment on the structural and antioxidant properties of lignin-derived from oil palm fronds (OPF) biomass via organosolv pulping. The isolated lignin was distinguished as steam explosion acid impregnation ethanol organosolv lignin (SEA EOL), and steam explosion water impregnation ethanol organosolv lignin (SEW EOL), subsequently assessed through complementary analyses such as FTIR, NMR (1H, 13C, and 2D-HQSC), GPC, thermal analyses (TGA and DSC), and FRAP (antioxidant activity). SEA EOL appeared to exhibit superior lignin extraction compared to SEW EOL (% yield SEA EOL: 13.66 ± 0.35 % > % yield SEW EOL: 11.54 ± 0.33 %). Apart from that, SEA EOL also exhibited smaller lignin matrixes (Mw SEW EOL: 4693 gmol-1 > Mw SEA EOL: 1838 gmol-1), resulting in a higher phenolic hydroxyl content, S/G ratio, and enhanced antioxidant activity compared to SEW EOL. The preliminary rust conversion study of the artifact was conducted using SEA EOL, revealing that 7 wt% possessed the highest RT% with 95.45 ± 0.13 %. The XRD and surface analysis of the treated rust artifact indicated that the rust had been converted into an amorphous phase.