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To date, concentrated sulfuric acid hydrolysis is the most effective process to recover the maximum yield of monomeric sugars from woody biomass because concentrated sulfuric acid can completely swell and hydrolyze cellulose. During this process, sulfuric acid lignin is quantitatively produced as a by-product, which is difficult to use because of s...
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The alkaline fractionation of rice husk (RH) with NaOH was optimized for the purpose of obtaining a high-yield recovery of glucan and increasing the removal rate for lignin and ash, resulting in a hemicellulose-rich hydrolysate. The determined optimal conditions were a temperature of 150 °C, reaction time of 45 min, and NaOH concentration of 6% (w/...
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... In view of this, technically hydrolyzed lignin (THL) is of particular interest because it is typically generated in large quantities as a hardly utilized by-product of certain industrial processes. According to Shiraki et al. [27], the concentrated sulfuric acid can completely swell and hydrolyze cellulose. The authors consider the concentrated sulfuric acid hydrolysis as the most effective process capable of recovering the maximum yield of monomeric sugars from woody biomass. ...
The present study aimed at utilizing technically hydrolyzed lignin (THL), industrial biomass residue, derived in high-temperature diluted sulfuric acid hydrolysis of softwood and hardwood chips to sugars. The THL was carbonized in a horizontal tube furnace at atmospheric pressure, in inert atmosphere and at three different temperatures (500, 600, and 700 °C). Biochar chemical composition was investigated along with its HHV, thermal stability (thermogravimetric analysis), and textural properties. Surface area and pore volume were measured with nitrogen physisorption analysis often named upon Brunauer–Emmett–Teller (BET). Increasing the carbonization temperature reduced volatile organic compounds (40 ÷ 96 wt. %), increased fixed carbon (2.11 to 3.68 times the wt. % of fixed carbon in THL), ash, and C-content. Moreover, H and O were reduced, while N- and S-content were below the detection limit. This suggested biochar application as solid biofuel. The biochar Fourier-transform infrared (FTIR) spectra revealed that the functional groups were gradually lost, thus forming materials having merely polycyclic aromatic structures and high condensation rate. The biochar obtained at 600 and 700 °C proved having properties typical for microporous adsorbents, suitable for selective adsorption purposes. Based on the latest observations, another biochar application was proposed—as a catalyst.
... The removal of lignin coloring, thereby, is necessary to expand the utilization of C-lignin. Several lignin whitening protocols through the suppression chromophores of G/S-lignin have been demonstrated [38,[52][53][54][55][56], among which the introduction of organic units to the hydroxy groups represented a functionalized and non-destructive route. The arrayed γ-OH in C-lignin benzodioxane units offered convenient active sites for functionalization. ...
... By contrast, uniform laminar structure with smooth surface was detected in a micrometer scale after isocyanation (Fig. 6f). The observed morphologies coincided with the color change of the ChCl/EG/AlCl 3 lignin, that is, the optical properties of dependent on size (Mie scattering) [55,56]. ...
The search for feedstock of catechyl lignin (C-lignin) is great interest and importance, as C-lignin featuring homogeneity and linearity is considered as an "ideal lignin" archetype for valorization and exits in only a few plant seed coats. In this study, naturally occurring C-lignin is first discovered in the seed coats of Chinese tallow, which has the highest content of C-lignin (15.4 wt%) as compared with other known feedstocks. An optimized extraction procedure by ternary deep eutectic solvents (DESs) enables the complete disassembly of C-lignin and G/S-lignin coexisted in Chinese tallow seed coats, and characterizations revealed that the as-separated C-lignin sample is abundant in benzodioxane units with no observation of β-O-4 structures from G/S-lignin. Catalytic depolymerization of C-lignin results in a simplex catechol product in 129 mg per gram seed coats, being higher than other reported feedstocks. Derivatizing the "black" C-lignin via the nucleophilic isocyanation of benzodioxane γ-OH leads to a "whitened C-lignin" with uniform laminar structure and excellent crystallization ability, being conducive to fabricating functional materials. Overall, this contribution showed that Chinses tallow seed coats are suitable feedstock for acquiring C-lignin biopolymer.
... If concentrated acid is used, then cellulose is also hydrolyzed to the liquid phase in monomeric form (most of the time discarding the need for enzymatic hydrolysis) in which case, the formation of degradation products, such as furfural, 5-hydroxy methyl furfural, phenolic acids, and aldehydes, is increased, requiring the process to be performed at low temperatures (< 100 °C) and at longer reaction times [12]. Due to the acid medium, the lignin obtained from acid hydrolysis is, in general highly degraded, as the acidic conditions promote recondensation reactions to occur [34,38] and contaminated with sulfur (when sulfuric acid is used). ...
The increasing demand for greener and sustainable alternatives to fossil-derived fuels, chemicals, and materials has attracted huge attention to lignin, the largest renewable source of aromatic building blocks on earth. This natural polymer accounts for 15 to 40% of all lignocellulosic biomass. As such, in the pulp and paper industries, for example, huge amounts of lignin are produced worldwide. However, most applications for these lignins are of low value, such as their burning for energy. Furthermore, with the introduction of second-generation ethanol biorefineries, the overall lignin production increased. To attain a circular bio-based economy, all side-streams of lignocellulosic biomass and, particularly, lignin should be valorized to as high of a value as possible. Lignin’s rich structure has allowed achieving various high-value products over the years, not only in the production of biofuels but also regarding chemicals and materials. The present paper addresses a broad vision of the several stages of lignin valorization, from the isolation of lignin through pre-treatments of lignocellulosic biomass and the current industrial lignin production to fractionation methodologies that provide homogeneous lignins more adequate for valorization and the conversion of lignin into value-added products via chemical and biological routes.
... Hydrolysis of lignocelluloses using concentrated acids achieves near-theoretical sugar yields and fewer degradation products than the more commonly employed dilute acid hydrolysis process (Shiraki et al. 2020). This concentrated acid hydrolysis is a process that has been reported to have been in use since the early twentieth century. ...
... The good sugar yields and low content of fermentation inhibitors indicate that two-stage concentrated acid hydrolysis may be a good alternative for the single-step approach in processing the biomass, especially maize cob, softwood, sugarcane bagasse, and many others (Størker et al., 2012). Moreover, concentrated sulfuric acid hydrolysis has been reported by Shiraki et al. (2020) to be the most effective process to recover the maximum yield of monomeric sugars from woody biomass since concentrated sulphuric acid can completely inflate and hydrolyse cellulose. And during this process, the authors further report that the sulfuric acid lignin is quantitatively produced as a by-product, which is challenging to use because of self-condensation between the lignin molecules under acidic conditions (Shiraki et al., 2020). ...
... Moreover, concentrated sulfuric acid hydrolysis has been reported by Shiraki et al. (2020) to be the most effective process to recover the maximum yield of monomeric sugars from woody biomass since concentrated sulphuric acid can completely inflate and hydrolyse cellulose. And during this process, the authors further report that the sulfuric acid lignin is quantitatively produced as a by-product, which is challenging to use because of self-condensation between the lignin molecules under acidic conditions (Shiraki et al., 2020). ...
This report presents a mini-survey of biomass hydrolysis, which tends to unfold the concept of what the process is all about, categories involved, and reporting concerning the processes involved in each category. The categories entail the chemical and biological means where acid catalysts and enzymes are used, respectively, including reports of some works carried out in the literature.
... On the other hand, concentrated acid hydrolysis uses less energy because it is conducted at a lower temperature. The concentrated sulfuric acid hydrolysis used obtained the maximum yield of sugar from woody biomass [102]. However, the higher acid concentration will inhibit enzymatic activity (furfural, 5-hydroxymethylfurfural) and increase equipment corrosion [103]. ...
The increasing demand for petroleum-based polyethylene terephthalate (PET) grows population impacts daily. A greener and more sustainable raw material, lignocellulose, is a promising replacement of petroleum-based raw materials to convert into bio-PET. This paper reviews the recent development of lignocellulose conversion into bio-PET through bioethanol reaction pathways. This review addresses lignocellulose properties, bioethanol production processes, separation processes of bioethanol, and the production of bio–terephthalic acid and bio–polyethylene terephthalate. The article also discusses the current industries that manufacture alcohol-based raw materials for bio-PET or bio-PET products. In the future, the production of bio-PET from biomass will increase due to the scarcity of petroleum-based raw materials.
... A study in [46] provides enough evidence about the effectiveness of concentrated H 2 SO 4 . The study states that using concentrated H 2 SO 4 recovers maximum use of monomeric sugars (glucose) from woody biomass (e.g., sawdust waste). ...
... The research also provides justification that concentrated H 2 SO 4 can provide maximum recovery without any unique additive. The research in [46] provides a solid affirmation to the findings of this research study which touts concentrated H 2 SO 4 as the acid which provided maximum glucose yield with respect to acid hydrolysis. ...
A large amount of sawdust is generated as municipal waste in Ghana. The poor disposal of sawdust has led to high levels of contamination in the environment. In light of this, the study at hand focuses on the upcycling of sawdust waste (biomass) into bioethanol. The study framework followed three steps which include pretreatment and acid hydrolysis (H2SO4 and HCl at 0.6 M, 6 M, 11 M, and stock concentrations) followed by fermentation in a continuous stir tank reactor (CSTR). The material balance in the fermentation tank is principled on the following key species viz. yeast (Saccharomyces cerevisiae procured from the University of Cape Coast chemical stores), glucose, and ethanol. The highest yield from concentrated H2SO4 produced a glucose yield of 92.9% and ethanol yield of 80.9% after fermentation which was higher as compared to the HCl hydrolysates. To ascertain the purity of the ethanol yields, boiling point test, flammability test, chromic test, and GC–MS studies were carried out; 100 g of sawdust waste has been reported to yield 206 ml of bioethanol. The study concludes with a discussion of Ghana’s potential of adopting, producing, and utilizing bioethanol. It also captures the benefit of bioethanol to the country and the future prospects of bioethanol production.
Here, we present a practical method for whitening lignin derivatives, which is solvent-controlled encapsulation (SCE) to rearrange the chromosphere at the solvent/lignin interface. Water, ethanol, and/or acetone are mixed to adjust the polarity of the solvent, resulting in lignin nanoparticles with hydrophobic chromophores within the core. Whitening lignin derivatives are produced when the hydroxy group is simultaneously modified by a non-chromophoric organic group. The SCE method is used in various organic isocyanates with different substituents and lignin derivatives. The whitened lignin nanoparticle acts as transmittance coating-film, glass/quartz adhesive, and heatproofing additive for poly(ϵ-caprolactam). Our results first demonstrate that lignin can be used as whitened polymers with high design flexibility and material functionality. A broad-range usage of lignin via its whitening is encouraged to realize conversion from oil-based refinery to biomass-based refinery.
