Sequential two-step fractionation of lignocellulose with formic acid organosolv followed by alkaline hydrogen peroxide under mild conditions to prepare easily saccharified cellulose and value-added lignin
“…1b). From there, downstream sample-washing and -neutralization would be unnecessary as the delignified FA residues on the EFB fibers were sufficiently good for the fractionation of lignocellulosic fibers 8 .Figure 1The flow cycles of cellulose isolation through ( a ) conventional method ( b ) integration method and the effect of lignocellulosic delignification on the control parameters of ( c ) H 2 O 2 concentration, ( d ) Fe(II) dosage on catalytic oxidation and ( e ) delignification kinetics of the integration organosolv and catalytic oxidation.…”
Section: Resultsmentioning
confidence: 99%
“…Advanced organosolvation (organosolv) fractionating technologies for lignocellulosic biomass are able to increase the efficiency of the recovery of individual lignocellulosic components 8 . Specifically, the chemicals extracted via this process can be easily recovered through distillation, hence makes it cost-effective and eco-friendly 9 .…”
The recognition of cellulose nanofibrils (CNF) in the past years as a high prospect material has been prominent, but the impractical cellulose extraction method from biomass remained as a technological barrier for industrial practice. In this study, the telescopic approach on the fractionation of lignin and cellulose was performed by organosolv extraction and catalytic oxidation from oil palm empty fruit bunch fibers. The integration of these techniques managed to synthesize CNF in a short time. Aside from the size, the zeta potential of CNF was measured at −41.9 mV, which allow higher stability of the cellulose in water suspension. The stability of CNF facilitated a better dispersion of Fe(0) nanoparticles with the average diameter size of 52.3–73.24 nm through the formulation of CNF/Fe(0). The total uptake capacity of CNF towards 5-fluorouracil was calculated at 0.123 mg/g. While the synergistic reactions of adsorption-oxidation were significantly improved the removal efficacy three to four times greater even at a high concentration of 5-fluorouracil. Alternatively, the sludge generation after the oxidation reaction was completely managed by the encapsulation of Fe(0) nanoparticles in regenerated cellulose.
“…1b). From there, downstream sample-washing and -neutralization would be unnecessary as the delignified FA residues on the EFB fibers were sufficiently good for the fractionation of lignocellulosic fibers 8 .Figure 1The flow cycles of cellulose isolation through ( a ) conventional method ( b ) integration method and the effect of lignocellulosic delignification on the control parameters of ( c ) H 2 O 2 concentration, ( d ) Fe(II) dosage on catalytic oxidation and ( e ) delignification kinetics of the integration organosolv and catalytic oxidation.…”
Section: Resultsmentioning
confidence: 99%
“…Advanced organosolvation (organosolv) fractionating technologies for lignocellulosic biomass are able to increase the efficiency of the recovery of individual lignocellulosic components 8 . Specifically, the chemicals extracted via this process can be easily recovered through distillation, hence makes it cost-effective and eco-friendly 9 .…”
The recognition of cellulose nanofibrils (CNF) in the past years as a high prospect material has been prominent, but the impractical cellulose extraction method from biomass remained as a technological barrier for industrial practice. In this study, the telescopic approach on the fractionation of lignin and cellulose was performed by organosolv extraction and catalytic oxidation from oil palm empty fruit bunch fibers. The integration of these techniques managed to synthesize CNF in a short time. Aside from the size, the zeta potential of CNF was measured at −41.9 mV, which allow higher stability of the cellulose in water suspension. The stability of CNF facilitated a better dispersion of Fe(0) nanoparticles with the average diameter size of 52.3–73.24 nm through the formulation of CNF/Fe(0). The total uptake capacity of CNF towards 5-fluorouracil was calculated at 0.123 mg/g. While the synergistic reactions of adsorption-oxidation were significantly improved the removal efficacy three to four times greater even at a high concentration of 5-fluorouracil. Alternatively, the sludge generation after the oxidation reaction was completely managed by the encapsulation of Fe(0) nanoparticles in regenerated cellulose.
“…The photocatalytic activity of 2 % MoS 2 /TiO 2 photocatalyst exceeds some other TiO 2 ‐based photocatalyst (Table S1). The photocatalytic activity of 2 % 2D‐2D MoS 2 /TiO 2 photocatalyst was much higher than those previously‐reported photocatalysts, such as MoS 2 /g‐C 3 N 4 and Pt/P25, [24,26] owing to the fact that little lignocellulose can dissolve into alkaline aqueous solution and the acid can catalyze the hydrolysis of α‐cellulose to glucose [33,34] . Therefore, the initial pH of the photocatalytic system could affect the photocatalytic lignocellulose‐to‐H 2 conversion performance of MoS 2 /TiO 2 photocatalysts.…”
Section: Figurementioning
confidence: 85%
“…The photocatalytic activity of 2 % 2D-2D MoS 2 /TiO 2 photocatalyst was much higher than those previously-reported photocatalysts, such as MoS 2 /g-C 3 N 4 and Pt/P25, [24,26] owing to the fact that little lignocellulose can dissolve into alkaline aqueous solution and the acid can catalyze the hydrolysis of αcellulose to glucose. [33,34] Therefore, the initial pH of the photocatalytic system could affect the photocatalytic lignocelluloseto-H 2 conversion performance of MoS 2 /TiO 2 photocatalysts. As shown in Figure 3c, the pH value can efficiently affect the photocatalytic H 2 production: the photocatalytic H 2 evolution activity of 2 % MoS 2 /TiO 2 photocatalyst maximizes at pH 7 and decreases obviously when the pH is below or above 7.…”
As an alternative strategy for H2 production under ambient conditions, solar‐driven lignocellulose‐to‐H2 conversion provides a very attractive approach to store and utilize solar energy sustainably. Exploiting efficient photocatalyst for photocatalytic lignocellulose‐to‐H2 conversion is of huge significance and remains the key challenge for development of solar H2 generation from lignocellulose. Herein, 2D‐2D MoS2/TiO2 photocatalysts with large 2D nanojunction were constructed for photocatalytic lignocellulose‐to‐H2 conversion. In this smart structure, the 2D nanojunctions acted as efficient channel for charge transfer from TiO2 to MoS2 to improve charge separation efficiency and thus enhance photocatalytic lignocellulose‐to‐H2 conversion activity. The 2 % MoS2/TiO2 photocatalyst showed the highest photocatalytic lignocellulose‐to‐H2 conversion performance with the maximal H2 generation rate of 201 and 21.4 μmol h−1 g−1 in α‐cellulose and poplar wood chip aqueous solution, respectively. The apparent quantum yield at 380 nm reached 1.45 % for 2 % 2D‐2D TiO2/MoS2 photocatalyst in α‐cellulose aqueous solution. This work highlights the importance of optimizing the interface structures of photocatalyst for solar‐driven lignocellulose‐to‐H2 conversion.
“…Inspired by the well-researched peroxide-involved pretreatment that lignocellulose could be well deconstructed through the facile oxidation process either in acidic or alkaline conditions [ 23 – 25 ], this work assumed that peroxyacetic acid, an intermediate product that could be self-generated at acidic conditions, was responsible for the efficient delignification of PHP pretreatment. It was proposed that peroxyacetic acid was synthesized through H 2 O 2 oxidation of acetic acid, which was released from biomass acetyl groups and lignin degradation.…”
Background
Peroxyacetic acid involved chemical pretreatment is effective in lignocellulose deconstruction and oxidation. However, these peroxyacetic acid are usually artificially added. Our previous work has shown that the newly developed PHP pretreatment (phosphoric acid plus hydrogen peroxide) is promising in lignocellulose biomass fractionation through an aggressive oxidation process, while the information about the synergistic effect between H3PO4 and H2O2 is quite lack, especially whether some strong oxidant intermediates is existed. In this work, we reported the PHP pretreatment system could self-generate peroxyacetic acid oxidant, which mediated the overall lignocellulose deconstruction, and hemicellulose/lignin degradation.
Results
The PHP pretreatment profile on wheat straw and corn stalk were investigated. The pathways/mechanisms of peroxyacetic acid mediated-PHP pretreatment were elucidated through tracing the structural changes of each component. Results showed that hemicellulose was almost completely solubilized and removed, corresponding to about 87.0% cellulose recovery with high digestibility. Rather high degrees of delignification of 83.5% and 90.0% were achieved for wheat straw and corn stalk, respectively, with the aid of peroxyacetic acid oxidation. A clearly positive correlation was found between the concentration of peroxyacetic acid and the extent of lignocellulose deconstruction. Peroxyacetic acid was mainly self-generated through H2O2 oxidation of acetic acid that was produced from hemicellulose deacetylation and lignin degradation. The self-generated peroxyacetic acid then further contributed to lignocellulose deconstruction and delignification.
Conclusions
The synergistic effect of H3PO4 and H2O2 in the PHP solvent system could efficiently deconstruct wheat straw and corn stalk lignocellulose through an oxidation-mediated process. The main function of H3PO4 was to deconstruct biomass recalcitrance and degrade hemicellulose through acid hydrolysis, while the function of H2O2 was to facilitate the formation of peroxyacetic acid. Peroxyacetic acid with stronger oxidation ability was generated through the reaction between H2O2 and acetic acid, which was released from xylan and lignin oxidation/degradation. This work elucidated the generation and function of peroxyacetic acid in the PHP pretreatment system, and also provide useful information to tailor peroxide-involved pretreatment routes, especially at acidic conditions.
Graphical abstract
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