Chapter 7
Resource Utilization
of Agricultural/Forestry Residues
via Fractionation into Cellulose,
Hemicellulose and Lignin
Abstract This chapter reviews advances in the fractionation of lignocellulosic
biomass to its three main components, cellulose, hemicelluloses and lignin, as a
pre-treatment process for resource utilization of agricultural/forestry residues for
biofuels and bio-based chemicals/materials. Different pre-treatment methods such
as physical, chemical, physio-chemical and biological processes are discussed with
their advantages/disadvantages and challenges. Physical pre-treatments are considered eco-friendly methods as they do not require chemicals, but they have high energy
consumption. Chemical methods are more popular owing to their high efficiency for
almost all types of biomass. Among the chemical processes, the Kraft pulping and
organosolv pulping methods have been widely used for biomass delignification and
fractionation to produce lignocellulosic components (cellulose, hemicellulose and
lignin). Kraft pulping is the most popular chemical pulping process applied on industrial scale, operating in water under a high pH condition with alkaline reagents. In
contrast, organosolv pulping operates at mild conditions in organic solvents or their
aqueous solution for fractionation of lignocellulosic biomass. Recently, ionic liquids
have attracted a lot of attention as an alternative to volatile and unstable organic
solvents for biomass fractionation, but they are associated with high cost, difficulty
in recycling and reuse; thus, further investigation is required to make the process
feasible for large scale application. Compared with other pre-treatment methods, the
organosolv pre-treatment has many advantages such as high efficiency, mild operating conditions, easy solvent recovery and recycling, and relatively high purity of
the biomass fractionation products. However, the inevitable loss and flammability of
organic solvents are the main obstacles for industrial applications of these processes.
Whereas, with the development of biorefinery, where the fractionation products (i.e.,
cellulose and lignin) could be valorized for the production of various high-value
bioproducts, e.g., sodium carboxymethyl cellulose (CMC), phenol–formaldehyde
adhesives, epoxy resins, and polyurethane foams, organosolv fractionation offers
immense opportunities for resource utilization of agricultural/forestry residues.
Keywords Agricultural residues · Forestry residues · Lignocellulosic biomass ·
Resource utilization · Fractionation · Physical pre-treatment · Chemical
© Springer Nature Singapore Pte Ltd. 2021
L. Nazari et al., Advanced and Emerging Technologies for Resource Recovery
from Wastes, Green Chemistry and Sustainable Technology,
https://doi.org/10.1007/978-981-15-9267-6_7
179
Resource Utilization
of Agricultural/Forestry Residues
via Fractionation into Cellulose,
Hemicellulose and Lignin
Abstract This chapter reviews advances in the fractionation of lignocellulosic
biomass to its three main components, cellulose, hemicelluloses and lignin, as a
pre-treatment process for resource utilization of agricultural/forestry residues for
biofuels and bio-based chemicals/materials. Different pre-treatment methods such
as physical, chemical, physio-chemical and biological processes are discussed with
their advantages/disadvantages and challenges. Physical pre-treatments are considered eco-friendly methods as they do not require chemicals, but they have high energy
consumption. Chemical methods are more popular owing to their high efficiency for
almost all types of biomass. Among the chemical processes, the Kraft pulping and
organosolv pulping methods have been widely used for biomass delignification and
fractionation to produce lignocellulosic components (cellulose, hemicellulose and
lignin). Kraft pulping is the most popular chemical pulping process applied on industrial scale, operating in water under a high pH condition with alkaline reagents. In
contrast, organosolv pulping operates at mild conditions in organic solvents or their
aqueous solution for fractionation of lignocellulosic biomass. Recently, ionic liquids
have attracted a lot of attention as an alternative to volatile and unstable organic
solvents for biomass fractionation, but they are associated with high cost, difficulty
in recycling and reuse; thus, further investigation is required to make the process
feasible for large scale application. Compared with other pre-treatment methods, the
organosolv pre-treatment has many advantages such as high efficiency, mild operating conditions, easy solvent recovery and recycling, and relatively high purity of
the biomass fractionation products. However, the inevitable loss and flammability of
organic solvents are the main obstacles for industrial applications of these processes.
Whereas, with the development of biorefinery, where the fractionation products (i.e.,
cellulose and lignin) could be valorized for the production of various high-value
bioproducts, e.g., sodium carboxymethyl cellulose (CMC), phenol–formaldehyde
adhesives, epoxy resins, and polyurethane foams, organosolv fractionation offers
immense opportunities for resource utilization of agricultural/forestry residues.
Keywords Agricultural residues · Forestry residues · Lignocellulosic biomass ·
Resource utilization · Fractionation · Physical pre-treatment · Chemical
© Springer Nature Singapore Pte Ltd. 2021
L. Nazari et al., Advanced and Emerging Technologies for Resource Recovery
from Wastes, Green Chemistry and Sustainable Technology,
https://doi.org/10.1007/978-981-15-9267-6_7
179