Efficient and environmentally friendly techniques for extracting lignin from lignocellulose biomass and subsequent uses: A review

The development of sustainable and effective methods for extracting lignin is crucial for achieving the advantages and promoting the shift towards a more sustainable and circular bioeconomy. This study addresses the use of environmentally friendly processes, including organosolv technique, supercritical fluid (SCF), non-thermal plasma (NTP), ionic liquids (ILs), deep eutectic solvents (DES), and microwave assisted extraction (MAE) techniques for lignin extraction. Organosolv treatment offers high selectivity and purity of lignin make this process economically feasible. Using supercritical water, carbon dioxide, or ethanol to extract lignin without harmful solvents is successful and customizable. NTP technologies break down lignin, simplifying processing and increasing its value. Whereas ILs may boost lignin synthesis and change its properties via solvent design. DES-based extraction methods can efficiently and specifically extract lignin. The rapid and effective MAE method employs microwave radiation to reduce extraction times and boost yields for lignin extraction. These methods feature high selectivity, little environmental impact, and the capacity to target lignin fractions. The study describes the fundamentals, benefits, and drawbacks of each extraction process, focusing on their ability to extract lignin on a large scale and its future usage. Additionally, this review explores the most recent advancements in the application sector, as well as the challenges and potential advantages of valorizing streams derived from extraction, thereby fostering the development of environmentally friendly and sustainable solutions. This research concludes that to overcome future challenges, need to address scale concerns, cost, emissions, and efficient lignin use.