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Lignocellulosic Fibers from Renewable Resources Using Green Chemistry for a Circular Economy Khandoker S. Salem, Ved Naithani, Hasan Jameel, Lucian Lucia, and Lokendra Pal*
which are rich in forestry resources. But, in places where the availability of forest is limited, non-wood species and agro-indus- trial waste can be possible alternatives and equally valuable sources of biomass. However, the foremost challenge in pro- ducing sustainable lignocellulosic fibers is ensuring a sustainable source of biomass supply, since lignocellulosic resources are prima facie feedstocks for pulp, lignin, nanocrystals nanofibers, and biopolymers, which have versatile industrial applica- tions, for example, paper products, bio- plastics, biocomposites, biofuels, and bioenergy production, etc. Indeed, lignin has emerged as a potential sustainable bioresource for advanced applications due to high carbon content and renewable character. [5] Researchers have developed techniques to valorize lignin for applica- tions in polymers and composites [6,7] and for producing sustainable thermo–electric
The sustainable development of lignocellulose fibers exhibits significant potential to supplant synthetic polymer feedstocks and offers a global platform for generating sustainable packaging, bioplastics, sanitary towels, wipes, and related products. The current research explores the dynamics of fiber production from wood, non-wood, and agro-residues using carbonate hydrolysis and a mild kraft process without bleaching agents. With respect to carbonate hydrolysis, high yield, and good coarseness fibers are attained using a simple, low-cost, and ecofriendly process. Fibers produced using a mild kraft process have lower Klason lignin, carboxyl content, surface charges, and higher fiber length, and crystallinity. Eucalyptus fibers show the highest crystallinity while softwood carbonate fibers show the lowest crystal- linity. Hemp hurd fibers contain the highest concentration of hard-to-remove water, and thus, suffer maximum flattening visualized by the microscopic images. The relatively high yield sustainable fibers with versatile properties can provide a significant economic benefit since fiber is the dominant cost for producing various bioproducts to meet society’s current and future needs.
materials based on carbon nanofibers (CNFs). [8,9] These CNFs have been successfully used as an alternative to carbon nano- tubes (CNTs) to create high performance anodes for better thermo-mechanical and electrical properties. [10,11] However, to continue to increase its utilization, the circular economy is piv- otal though it has been very difficult to efficiently recycle lig- nocellulosic fibers due to limitations in collection and its high degree of contamination. Thus, extensive research is being car- ried out to produce sustainable feedstock by introducing alter- native pulping methods and/or alternative raw materials that would conserve the usage of chemicals, energy, and water. [12–14] Despite considerable research effort, wood is still the predom- inant resource for pulp production because it has been used to produce 89% of the world’s paper, whereas, only 11% is based on non-woody plants. [15] However, non-woody and agro-residues such as hemp hurds have been emerging as a viable resources to meet growing demand for economic and sustainable paper products. [16] Presently, hemp hurd has been used to meet 5% of the total global paper supply for tissue papers, bio-plastics etc., which has been made possible due to the valorization of the hemp hurd from its original use as animal bedding and hemp-lime construction materials. [16] The high cellulose content ≈ 50%–70%, quick harvesting time (4 months) and requirement of fewer harsh chemicals for processing, with respect to the hardwoods and softwoods, have made hemp hurd a promising candidate for sustainable lignocellulosic resource. [16] Another growing challenge for sustainable fiber sources is the introduction of an environment friendly, low chemical pulping
1. Introduction The world has been moving towards a sustainable, bio-based and circular economy due to social awareness and governmental regulations against single plastic use which could save up to $26 trillion by 2030. [1,2] Global environmental awareness has propelled the bio-based industries, like paper, tissue paper prod- ucts, bioplastics, packaging, renewable lubricants, etc., more so than many other industries to play an important role in sustain- able development because among their chief raw materials are renewable wood and non-wood fibers. [3,4] Appropriate and sus- tainable utilization of bioresources are the major requirements to expand the bio-based economy to produce biochemicals, bio- fuels, bioplastics, and related products to their petroleum ana- logues. Wood has been a major source of biomass for the places
K. S. Salem, Dr. V. Naithani, Prof. H. Jameel, Dr. L. Lucia, Dr. L. Pal Department of Forest Biomaterials NC State University
Raleigh, NC 27695–8005, USA E-mail: lokendra_pal@ncsu.edu
The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/gch2.202000065. © 2020 The Authors. Published by Wiley-VCH GmbH. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
DOI: 10.1002/gch2.202000065
2000065 (1 of 10)
Global Challenges 2020 , 2000065
© 2020 The Authors. Published by Wiley-VCH GmbH
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