INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
·
2022
·Vol. 23
·期 21
·13310
·
IF 6.208
Yi Liu,Baojuan Deng,Jiarui Liang,Jiao Li,Baojie Liu,Fei Wang,Chengrong Qin,Shuangquan Yao
Chlorine dioxide is widely used for pulp bleaching because of its high delignification selectivity. However, efficient and clean chlorine dioxide bleaching is limited by the complexity of the lignin structure. Herein, the oxidation reactions of phenolic (vanillyl alcohol) and non-phenolic (veratryl alcohol) lignin model species were modulated using chlorine dioxide. The effects of chlorine dioxide concentration, reaction temperature, and reaction time on the consumption rate of the model species were also investigated. The optimal consumption rate for the phenolic species was obtained at a chlorine dioxide concentration of 30 mmol·L−1, a reaction temperature of 40 °C, and a reaction time of 10 min, resulting in the consumption of 96.3% of vanillyl alcohol. Its consumption remained essentially unchanged compared with that of traditional chlorine dioxide oxidation. However, the consumption rate of veratryl alcohol was significantly reduced from 78.0% to 17.3%. Additionally, the production of chlorobenzene via the chlorine dioxide oxidation of veratryl alcohol was inhibited. The structural changes in lignin before and after different treatments were analyzed. The overall structure of lignin remained stable during the optimization of the chlorine dioxide oxidation treatment. The signal intensities of several phenolic units were reduced. The effects of the selective oxidation of lignin by chlorine dioxide on the pulp properties were analyzed. Pulp viscosity significantly increased owing to the preferential oxidation of phenolic lignin by chlorine dioxide. The pollution load of bleached effluent was considerably reduced at similar pulp brightness levels. This study provides a new approach to chlorine dioxide bleaching. An efficient and clean bleaching process of the pulp was developed.Keywords:lignin;chlorine dioxide;oxidation;bleaching;pulp
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PubMed
高影响因子
CELLULOSE
·
2018
·Vol. 25
·期 10
·5511-5522
·
IF 3.809
Li Xingkang,Luo Yifan,Daroch Maurycy,Hou Juan,Gui Weiyang
Hemicellulose and lignin act as physical barriers impeding the hydrolysis of lignocellulosic biomass by cellulases. To develop a process which could simultaneously remove most hemicellulose and lignin in biomass, in this study, oxygen-assisted ethanol organosolv pretreatment (O 2 -EOP) of sugarcane bagasse (SCB) was carried out. The effects of temperature, time, oxygen pressure and ethanol concentration on the pH of the hydrolysate, the solubilization and the chemical composition of SCB were investigated. Compared with autocatalytic EOP and acid-catalyzed EOP, O 2 -EOP could remove most xylan and lignin from SCB at much milder conditions. At optimized conditions (40/60 ethanol/water (v/v), 1.5 MPa O 2 , 160 °C and 80 min), 82.9% xylan and 83.3% lignin were removed. Glucan content in the residue reached 86.3%, much higher than results obtained by autocatalytic EOP and acid-catalyzed EOP. In subsequent enzymatic hydrolysis (1% solid loading, 4.96 mg protein/g cellulose, 72 h), O 2 -EOP pretreated SCB produced 3.97 and 1.90 times more glucose than untreated material and N 2 -EOP pretreated SCB, respectively. O 2 -EOP also produced abundant organic acids, total amounts of formic acid and acetic acid in the hemicellulose hydrolysate reached 5.42 g/L. In conclusion, O 2 -assisted EOP was an effective process for the production of pulp with high cellulose purity and good accessibility to cellulases.
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Journal of Biobased Materials and Bioenergy
·
2020
·Vol. 14
·期 1
·20-28
·
IF 1.126
Lei Ming,Luo Bin,Zhang Qingtong,Guo Chenyan,Chi Mingchao,Yun Xiaojing,Min Douyong,Wang Shuangfei
Herein, residual lignin was extracted from unbleached sugarcane bagasse pulp via the sequential enzymatic-weak acid hydrolysis method. Subsequently, chlorine dioxide delignification was applied to the extracted lignin. The structural changes of lignin during chlorine dioxide delignification
were characterized by Fourier transform infrared spectroscopy (FT-IR), 13C-nuclear magnetic resonance (13C NMR), 1H-13C heteronuclear single quantum coherence (2D HSQC), and quantitative 31P-nuclear magnetic resonance (31P-NMR)
spectroscopy. The degradation products of lignin dissolved in the simulated bleaching liquor, extracted, and quantified via gas chromatography-mass spectrometry (GC-MS). Lignin was significantly degraded during the delignification process, showing cleavage of the aromatic ring, removal of
the methoxyl group, and cleavage of major interunit linkages. However, the carboxylic acid content increased and GC-MS analysis indicated that lignin was degraded into several organic substances dissolved in the liquor. However, only a few absorbable organic halides (AOX) were generated, confirming
that chlorine dioxide bleaching is an ideal bleaching method.
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INDUSTRIAL CROPS AND PRODUCTS
·
2022
·
IF 6.449
Hao Meng,Yijie Zhao,Shuo Wang,Yonggui Wang,Zefang Xiao,Haigang Wang,Daxin Liang,Yanjun Xie
Well-organized and self-assembled structures with hierarchical surface architectures have recently attracted considerable attention due to their potentially wide application range. Herein, remarkable lignin-based petaloid nanoflakes (LPNFs) were formed via the crystallization of polymeric lignin stearoyl esters (LSEs). A solvent exchange self-assembly technique using Tetrahydrofuran (THF) as a solvent in addition to ethanol, acetone, and water as nonsolvents was used to form LPNFs by the crystallization of the stearyl groups in LSEs during evaporation. The grafting level of the stearoyl groups in the LSEs, the difference of the nonsolvent, and the volume ratios of the solvent/nonsolvent during the solvent exchange process predominantly determined the formation of LPNFs via this process. The self-assembled structures could be constructed as spherical particles and as constituted LPNFs structures with well-organized petaloid nanoflakes. By introducing sufficient amounts of LPNFs patterns on the substrates (e.g., glass slide, paper, and wood), the hydrophilic substrates were successfully transformed into superhydrophobic surfaces. Thus, the synthesis of LSEs and the formation of LPNFs with tunable structures offer a new strategy for the derivation and value-added utilization of lignin.
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高影响因子
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2013
·
IF 2.596
De zhan Ye,Li Jiang,Chao Ma,Ming-hua Zhang,Xi Zhang
The influence of lignin species on the grafting mechanism of lignosulfonate (from eucalyptus and pine, recorded as HLS and SLS, respectively) with acrylic acid (AA) was investigated. The graft polymers were confirmed by the absorption of carbonyl groups in the FTIR spectra. The decreasing phenolic group's content (Ph-OH) is not only due to its participation as grafting site but also to the negative effect of initiator. In the initial period (0–60 min), HLS and SLS both accelerate the polymerization of AA. Additionally, Ph-OH group's content is proportional to product yield ( Y %), monomer conversion ( C %) and grafting efficiency (GE%), strongly indicating that it acts as active center. Nevertheless, compared with HLS, Y % and C % in SLS grafting system are lower though it has higher Ph-OH group's content, which is due to the quinonoid structure formed by the self-conjugated of phenoxy radical in Guaiacyl unit. Finally, the lignosulfonate grafting mechanism was proposed.
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PubMed
高影响因子
HOLZFORSCHUNG
·
2023
·Vol. 77
·期 3
·170-183
·
IF 2.4
Zhizun Gao,Wenjing Wang,Fanjun Yu,Yonggui Wang,Zefang Xiao,Yanjun Xie
Rubberwood was modified using a two-step process involving impregnation with maleated lignin (ML) followed by densification. The effects of ML modification and densification on the physical and mechanical properties of modified wood were studied. The successful preparation of ML was confirmed using Fourier transform infrared spectroscopy and nuclear magnetic resonance spectroscopy. In addition, scanning electron microscopy was used to characterize the densified rubberwood structure, which featured fully compressed cell walls and cell lumina filled with ML. The rubberwood modification resulted in a more uniform structure and increased density compared to untreated wood. Further, water immersion and moisture absorption experiments revealed thickness swelling of only 27.7% and 20.9%, a reduction of nearly 76% and 55%, respectively, compared to the densified wood that was only impregnated with water. The ML modification can alleviate the embrittlement of wood caused by densification. The modulus of rupture and modulus of elasticity of ML-treated and densified wood improved by nearly 54% and 200%, respectively, compared to untreated wood. Therefore, the synergistic treatment strategy can contribute to the high-value utilization of low-quality rubberwood.
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高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2025
·
IF 13.2
Enqing Zhu,Jinyuan Cheng,Leixin Huang,Hangyu Shen,Jiao Meng,Shaoning Wang,Zhengjun Shi,Muhammad Wajid Ullah,Jinxia Ma,Lili Zhang,Zhiguo Wang
The large-scale application of deep eutectic solvents (DESs) in biorefineries has been limited by low biomass loading. This study introduces a novel ZnCl 2 /lactic acid (LA) DES for the efficient isolation of lignin from poplar at ultrahigh solid loading. The results show that 67.41% delignification was achieved under extreme solid loading of 50 wt%. The recovered lignin exhibited unique amphiphilicity, enabling the fabrication of lignin nanospheres (∼123 nm in diameter) with uniform, monodisperse morphology, superior colloidal stability, and excellent Pickering emulsification stability. Reduced density gradient (RDG) analysis demonstrated that the ZnCl 2 /LA DES outperformed the conventional ChCl/LA system due to Zn 2+ coordination with the carboxyl group of LA and stronger noncovalent interactions with lignin, facilitating targeted β-O-4 bond cleavage. Over 95% of cellulose was recovered and processed into lignin-containing cellulose nanofibers, achieving an outstanding tensile strength of 139.17 MPa. The ZnCl 2 /LA DES system demonstrated exceptional recyclability, maintaining 84.41% delignification efficiency even after five consecutive reuse cycles at 33 wt% solid loading.
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产品关联
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高影响因子
GREEN CHEMISTRY
·
2024
·
IF 9.3
Si-Yu Zhu,Shi-Chang Liu,Chuan-Xi Zhang,Xin Xin,Zhi-Hua Liu,Lujia Zhang,Bing-Zhi Li,Ying-Jin Yuan
A sustainable lignin bioconversion depends on the exploitation of the inherent aromaticity of lignin for high-value aromatic products. However, the microbial valorization of lignin is hindered by the lack of established bioconversion routes or the inefficient heterologous expression of key enzymes. Here, an efficient biological lignin conversion route was constructed in a microbial cell factory by tapping inherent aromaticity of lignin to produce aromatic natural compound such as homoeriodictyol. The heterologous biosynthesis pathways were successfully constructed to convert lignin-derived monomers to homoeriodictyol in Saccharomyces cerevisiae. The implementation of combinatorial regulating strategies resulted in enhanced CoA supply, suppression of branch pathways, and upregulation of the rate-liming enzymes, which increased the titer of homoeriodictyol by a remarkable 22.5-fold. After that, engineering cofactor supply and recycling led to a substantial 95% increase in homoeriodictyol production. The rational design and modification of the heterologous rate-limiting enzymes achieved substantial improvement in the homoeriodictyol yield. All these strategies together enabled the record homoeriodictyol titer of 3.2 mmol/l from lignin derivatives by S. cerevisiae. Overall, such innovative conversion route meets the atom-economic concept by converting lignin derivatives into valuable flavonoid, paving a green, sustainable way for both the valorization of lignin and the production of aromatic natural products.
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高影响因子
CELLULOSE
·
2018
·Vol. 25
·期 11
·6479-6494
·
IF 3.809
Jiang Yan,Liu Xiuyu,Yang Qiang,Song Xueping,Qin Chengrong,Wang Shuangfei,Li Kecheng
Abstract High (14.9%), medium (2.4%) and low (0.1%) lignin-containing cellulosic fibers were processed through a micro-grinding method to mechanically produce lignocellulose nanofibrils (LCNFs). Effects of residual lignin on the mechanical defibrillation process were investigated in terms of the nanofibrils yields, the diameters of resultant LCNFs and the micro-grinding energy consumption. The results showed that the residual lignin delayed the initial defibrillation of cellulosic fibers due to its physical barrier. However, the residual lignin eventually facilitated the defibrillation and improved the maximum nanofibrils yields by 17.9–30.8%, and greatly reduced the diameters of the resultant LCNFs from 32.9 ± 7.7 to 9.2 ± 3.3 nm. The effects of lignin on counteracting the recombination reactions between the highly reactive cellulose radicals and hindering the aggregation of defibrillated fibrils through reducing the inter-fibrillar hydrogen bonding presumably resulted in the better eventual defibrillation of cellulosic fibrils. Graphical abstract
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高影响因子
Catalysis Science & Technology
·
2022
·Vol. 12
·期 6
·1941-1949
·
IF 6.177
Yunhong Pi,Xiuting Wu,Zefeng Zheng,Liang Ma,Tiejun Wang
Methanol reforming in aqueous solution provides a significantly attractive and promising pathway to release hydrogen with mild H2 release conditions and high H2 storage capacity. Exploring non-noble metal-based catalysts with sufficiently high activity, stability, and selectivity for H2 remains a great challenge. We report here the construction of a chitosan–lignin (CS–LN) carbon framework bio-composite-encapsulated Cu catalyst (Cu@CS–LN) with high loading and dispersion for base-free hydrogen generation from aqueous-phase methanol reforming below 210 °C. With optimized conditions, the hydrogen generation rate of Cu@CS–LN (2.5 × 105 μmolH2 gCu−1 h−1) represents an approximately 2-fold enhancement compared with Cu@CS without lignin incorporation, and more than 3–5 times higher than commercial Cu-based catalysts such as Rainie Cu or CuO/ZnO. The catalyst underwent an intensified water gas shift reaction (WGSR), and it also exhibited extraordinary selectivity toward the CO byproduct. The unique carbon framework structure of CS–LN through electrostatic densification self-assembly not only enhanced the adsorption and dispersion of Cu species, but it also stabilized and further reduced the Cu particles to active phase Cu during the hydrogen generation reaction to promote catalytic activity and stability without obvious catalyst deactivation detected after running for 150 hours. This specific hydrogen production technology exhibits great potential for hydrogen-powered polymer electrolyte membrane (PEMFCs) fuel cells.
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高影响因子
INDUSTRIAL CROPS AND PRODUCTS
·
2015
·
IF 2.837
Peng Zhang,Shi-Jia Dong,Hui-Hui Ma,Bi-Xian Zhang,Yu-Fei Wang,Xiao-Mei Hu
Lignocellulosic biomass is increasingly being promoted as an environmentally and economically sustainable fuel. However, the complex structure of lignocellulose makes it difficult to be fractionated, which limits its conversion into valuable products. In this work, a series of functional acidic ionic liquids (ILs) with a simple synthetic procedure were prepared. Fractionation of corn stover into cellulose, hemicellulose and lignin was successfully performed in ultrasound-assisted ILs at a low reaction temperature of 70 °C for 3 h followed by alkaline extraction. IL-isolated lignin, alkaline lignin, hemicellulose and cellulose were obtained in good yields and their chemical properties were analyzed by FTIR. Significantly, a good yield of IL-isolated lignin was obtained, which accounted for 60.48% of the original lignin. The IL-isolated lignin was S-G-H type indicating by 13 C NMR and 13 C– 1 H correlation 2D NMR (HSQC) analysis. Enzymatic hydrolysis of cellulose was performed successfully. A high yield of 97.77% reducing sugar was achieved. Glucose and cellobiose were measured by HPLC analysis, which accounted for 92.55% of cellulose conversion. Both of the hydrogen bond capability and the acidity of ILs contributed to achieve the effective fractionation. These ILs have a great potential for the preparation of biofuel.
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高影响因子
BIORESOURCE TECHNOLOGY
·
2020
·
IF 7.539
Chongbo Cheng,Pengfei Li,Wenbing Yu,Dekui Shen,Sai Gu
Lignin is the renewable and abundant source of aromatics on earth, and the depolymerization of lignin provides significant potential for producing valuable monophenols. In this work, catalytic hydrogenolysis of organosolv poplar lignin (OPL) in ethanol/isopropanol solvent over monometallic and bimetallic nonprecious catalysts was investigated. Ni/C and a series of NiCu/C catalyst with different Cu loadings were prepared and applied for depolymerization of OPL. The highest yield of phenolic monomers was 63.4 wt% achieved over the Ni 10 Cu 5 /C catalyst at 270 °C without external H 2 . The introduction of Cu in catalysts further promoted the hydrogen donor process of ethanol/isopropanol solvent and facilitated the cleavage of lignin linkages, resulting in the decreased molecular weight of bio-oil. The possible lignin dimer type structures, such as diphenylethane (β-1) type, phenylcoumaran (β-5) type, and pinoresinol (β-β) type structures, were proposed and identified by MALDI-TOF MS, giving a better understanding of the NiCu/C catalyzed lignin depolymerization.
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高影响因子
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