Optimization by Response Surface Methodology of Ethanosolv Lignin Recovery from Coconut Fiber, Oil Palm Mesocarp Fiber, and Sugarcane Bagasse

Abstract

The optimization of lignin recovery from coconut fiber (CF), oil palm mesocarp fiber (OPMF), and sugarcane bagasse (SCB) using ethanol organosolv was investigated as well as the resulting lignin characteristics. Ethanol organosolv lignin recovery was successfully optimized, and the lignin yield (YL) was maximized. Ethanol concentration and temperature higher than 74% and 187 °C maximized the YL, playing a significant role in lignin yield. YL was higher for SCB than for other biomasses. High-purity and high-quality lignins were obtained with slightly different structural characteristics among the raw materials. The obtained lignins were the p-hydroxyphenyl–guaiacyl–syringyl type with a purity higher than 86%. SCB lignin seemed to be a better choice than CF and OPMF lignins for application in aromatic polymerization, because of its higher lignin yield, higher purity, higher thermal stability, and more reactive sites.