Organosolv delignification of rice straw cellulose fiber for functional food packaging

Abstract

Cellulosic fiber from rice straw provides a sustainable alternative to the environmental menace of the field burning problem. Response surface methodology and artificial neural network were applied in the organosolv pulping process to evaluate the responses of total pulp yield (TPY, %), holocellulose content (HC, %), and Klason lignin (KL, %). The optimum input parameters for these reactions were solvent ratio (formic acid: acetone 8:2), chemical doses (68%), time (269 min), and temperature (106 °C) with a response value of TPY (49.8%), HC (80.35%) and KL (3.85%). Artificial neural networks showed better-optimized results as compared to the response surface methodology. An exceptional fiber separation was observed using SEM analysis, while FT-IR analysis confirmed the significant removal of lignin as per drastic reduction in the absorption band at around 1505 cm⁻¹. The cellulose maximization and lignin reduction in the optimized pulp were also confirmed using EDX, XRD, and TGA analysis. Further, the effects of the addition of cationic starch, carboxymethyl cellulose, and xanthan gum were studied for making fiber composite hand sheets. The surface properties were optimum at the bio-additive doses of 3% (oven-dried) in both cases. However, the strength properties reached the maximum with the addition of 2% bio-additives. Nevertheless, cationic starch showed more suitable bio-additive for hand sheet packaging papers with better surface and strength properties. This study determined the optimum organosolv process parameters at the lab scale and further confirmed the suitability of the developed material for packaging applications with improved strength, surface, and optical properties.