Modification of Lignin Extracted from Oil Palm Fronds (OPF) as Mild Steel Corrosion Inhibitors by Mohd. Hazwan Hussin, Afidah Abdul Rahim, Nurul Atiqah Sa`don

MODIFICATION OF LIGNIN EXTRACTED FROM OIL PALM FRONDS (OPF) AS MILD STEEL CORROSION INHIBITORS Lignocellulosic biomass is a biodegradable product, waste or residue originating from agriculture and aquaculture, mainly composed of cellulose, hemicelluloses and lignin. Oil palm frond (OPF) is one of the major sources of lignocellulosic biomass in Malaysia as it has been produced in abundant amounts per year as waste from oil palm milling operations. Lignin, which can be used as antioxidants became the main focus of this study. However, its hydrophobicity limited its capability to be beneficial for any other possible applications. Modification of its complex structure is needed in order to overcome this problem. This research reports on the comparative structural characteristics and antioxidant activity of autohydrolyzed ethanol organosolv lignin (AH EOL) extracted from OPF and modified autohydrolyzed ethanol organosolv lignin via incorporation of m-cresol (AHC EOL) and 4-nitrophenol (AHNP EOL). The chemical modification, by utilizing organic scavenger during the delignification process, enhanced the solubility of the modified lignin by reducing its hydrophobicity properties and transformed the structure into smaller fragments. The inhibitive effect on the corrosion of mild steel in 0.5 M HCl solution was studied by electrochemical impedance (EIS) and potentiodynamic polarization. The studies revealed that the corrosion rate of mild steel can be reduced in the presence of the modified lignin.