Lignin and lignocellulosic materials: A glance on the current opportunities for energy and sustainability

Abstract

Fossil fuels are running out fast. The energy demand is one of the largest challenges humankind has ever faced. Applications targeting renewable resources that are nonpetroleum based are booming. The scientific community is now ever more dedicated to the production of sustainable, green, and bio-based materials. Biomasses have started to realize their potential as a renewable energy source! This sentence is becoming a truth, especially if we know that out of the 2TW energy coming from renewable energy sources and which represent only 21% of the actual current needs, biomasses contribute to more than 70% compared to around 30% from hydropower. Yet, most of the biomass is in the form of fuelwood as well as agricultural and animal wastes. Approximately 70 x 106 tons of lignin are produced in the pulping procedure and only ~2% of this enormous amount is reused! The fate of the rest is either a low-grade fuel or thrust aside as waste. With a high content of functional groups (especially hydroxyl moieties either aliphatic or aromatic) and an elevated carbon content, lignin retains the "considered necessary" properties for energy storage and energy reservation applications. These properties include, for example, liability for chemical modification and thermal stability. Moreover, lignin is of low cost, widely available from different plant sources, promising renewability, biodegradable, and biocompatible with relevant antioxidant and antimicrobial properties. A combination of these properties in one source has opened realms of applications in the fields of material sciences as well as in the associated fields, for example, biology and medicine as readers will see throughout the chapter. To that point, the authors are focusing on lignin in the production of biofuels, polymer-based materials, lignin as a carbon precursor for environmental and catalytic applications, and micro- and nanoscale applications.