Recovery of Cellulose Nanofiber from Lignocellulosic Biomass: Recent Trends and Applications

Background: Plants are considered an important feedstock for cellulose, although algae can be used as a reservoir for the extraction of cellulose in its pure form. Cellulose nanofiber extracted from plant and algae gains more attention among researchers due to their size in the nano range, low cost for preparation, higher surface area available for tuning, outstanding mechanical properties and eco-friendly nature. However, the quality of nanofiber depends on the extraction procedure and feedstock used for their extraction. Furthermore, the extracted nanofiber from lignocellulosic biomass is not compatible with liquid and polymeric matrices due to less amount of functional groups present on their surface. Therefore, it is urged to comprehend the explicit protocol required for the extraction of highly resourceful nanofibers from specific lignocellulosic biomass and surface tuning strategy, which can augment their application in various fields. The present review targets to understand the various polysaccharides, lignin and production of cellulose nanofibers in an economical & efficient way with special attention on its implementation in environmental applications to mitigate the toxic pollutants from our surroundings. Methods: Research articles related to the cellulose types, feedstocks, physico-chemical features, various extraction and conversion techniques, functionalization methods, and applications on mitigating environmental pollution were collected and reviewed. This review article comprises sections which present various cellulose and nanocellulose types, feedstocks, followed by their extraction, characterization and applications in mitigation of environmental issues such as heavy metal contaminations. Results: Studies highlighted in the article detailed types of extraction protocols, so far developed and strategies applied to improve the salient properties of nanofibers for specific applications are enlightened. Conclusion: The functionalized or modified cellulose and nanocellulose have gained significant attention attributed to their unique characteristics, physico-chemical characteristics and efficiency in recovery of environmental pollutants. Thus, further exploitation of such natural resources in mitigation of various environmental issues and other related applications are to be maximized.