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1.
Proc Natl Acad Sci U S A ; 117(29): 16776-16781, 2020 07 21.
Artigo em Inglês | MEDLINE | ID: mdl-32636260

RESUMO

A particularly promising approach to deconstructing and fractionating lignocellulosic biomass to produce green renewable fuels and high-value chemicals pretreats the biomass with organic solvents in aqueous solution. Here, neutron scattering and molecular-dynamics simulations reveal the temperature-dependent morphological changes in poplar wood biomass during tetrahydrofuran (THF):water pretreatment and provide a mechanism by which the solvent components drive efficient biomass breakdown. Whereas lignin dissociates over a wide temperature range (>25 °C) cellulose disruption occurs only above 150 °C. Neutron scattering with contrast variation provides direct evidence for the formation of THF-rich nanoclusters (Rg ∼ 0.5 nm) on the nonpolar cellulose surfaces and on hydrophobic lignin, and equivalent water-rich nanoclusters on polar cellulose surfaces. The disassembly of the amphiphilic biomass is thus enabled through the local demixing of highly functional cosolvents, THF and water, which preferentially solvate specific biomass surfaces so as to match the local solute polarity. A multiscale description of the efficiency of THF:water pretreatment is provided: matching polarity at the atomic scale prevents lignin aggregation and disrupts cellulose, leading to improvements in deconstruction at the macroscopic scale.


Assuntos
Biotecnologia/métodos , Lignina/química , Madeira/química , Proteínas de Bactérias/metabolismo , Biomassa , Celulase/metabolismo , Furanos/química , Gluconacetobacter xylinus/enzimologia , Hidrólise , Lignina/metabolismo , Populus/química , Solventes/química , Tensoativos/química
2.
Ecotoxicol Environ Saf ; 201: 110800, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32540617

RESUMO

Surface fires occur naturally or anthropogenically and can raise the temperature at the soil surface up to 600 °C. The heat derived from the surface fire can be subsequently transferred into CO2-enriched subsoils. As a result, the chemical compositions of soil organic matter (SOM) may be altered in fire-impacted anaerobic environments, indirectly influencing the redox transformations of pollutants, such as Cr(VI). In this study, a peat soil was heated up to 600 °C with limited air flow to simulate the effects of heat on the SOM during surface fire events. Then, Cr(VI) removal, including reduction and sorption, by the heat-treated peat soils was determined in relation to changes in the soil organic components. The results showed that the amount of O-containing functional groups, -CH2/-CH3 units of aliphatic groups, and dissolved organic carbon (DOC) in the SOM gradually decreased with an increase in the heating temperature. The removal of 0.1932 mM Cr(VI) did not exhibit a consistent decline along with the changes in these soil components. The heating temperatures of 200 and 250 °C were the thresholds that led to the decomposition of temperature-sensitive soil organic components such as lignin and other labile SOM. Such newly released organic fragments synergized lignin-like substances and carboxyl groups, resulting in up to 99% removal of the initially added Cr(VI). As the heating temperatures were increased from 300 to 600 °C, Cr(VI) reduction decreased from 66% to 20%. The black carbon-like materials and/or aromatic-containing moieties were the major components responsible for Cr(VI) reduction in 600°C-treated peat soils.


Assuntos
Cromo/análise , Temperatura Alta , Substâncias Húmicas/análise , Lignina/química , Poluentes do Solo/análise , Solo/química , Oxirredução
3.
Food Chem ; 329: 127153, 2020 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-32512392

RESUMO

Olive leaves are an under valorized residue of olive tree pruning and olive fruit harvesting and that are usually removed by either burning or grinding and scattering them on fields. However, as plant material easily available, they may be used as raw material in biorefineries, or for the industrial manufacture of many diverse products, given their lignocellulosic composition. Like other lignocellulosic biomasses, the composition of olive leaves depends on cultivar and to know it is essential for an adequate use. Therefore, this work tackles a characterization analysis of the lignocellulosic fraction of some olive leaf cultivars, both commercial and wild. In general, the cultivars studied did not show large differences in their quantitative composition, except for the content of ethanolic extractives and cellulose of the commercial and wild cultivars. In addition, the high lignin content (around 15%) is remarkable.


Assuntos
Lignina/química , Olea/química , Açúcares/química , Biomassa , Extratos Vegetais/química , Folhas de Planta/química
4.
Chemosphere ; 255: 126893, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32402872

RESUMO

Syringol and syringaldehyde are widely present pollutants in atmosphere and wastewater due to lignin pyrolysis and draining of pulp mill effluents. The hydroxylation degradation mechanisms and kinetics and health effect assessment of them under high and low-NOx regimes in atmosphere and wastewater have been studied theoretically. The effect of pH on reaction mechanisms and rate constants in their ·OH-initiated degradation processes has been fully investigated. Results have suggested that aqueous solution played a positive role in the ·OH-initiated degradation reactions by decreasing the energy barriers of most reactions and changing the reactivity order of initial reactions. For Sy- and Sya- (anionic species of syringol and syringaldehyde), most initial reaction routes were more likely to occur than that of HSy and Hsya (neutral species of syringol and syringaldehyde). As the pH increased from 1 to 14, the overall rate constants (at 298 K) of syringol and syringaldehyde with ·OH in wastewater increased from 5.43 × 1010 to 9.87 × 1010 M-1 s-1 and from 3.70 × 1010 to 1.14 × 1011 M-1 s-1, respectively. In the NOx-rich environment, 4-nitrosyringol was the most favorable product, while ring-opening oxygenated chemicals were the most favorable products in the NOx-poor environment. On the whole, the NOx-poor environment could decrease the toxicities during the hydroxylation processes of syringol and syringaldehyde, which was the opposite in a NOx-rich environment. ·OH played an important role in the methoxyphenols degradation and its conversion into harmless compounds in the NOx-poor environment.


Assuntos
Benzaldeídos/química , Pirogalol/análogos & derivados , Atmosfera/química , Concentração de Íons de Hidrogênio , Cinética , Lignina/química , Oxirredução , Oxigênio , Pirogalol/química , Águas Residuárias , Água
5.
Chemosphere ; 256: 127116, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32460161

RESUMO

Anaerobic digestion (AD) of lignocellulosic biomass is appealing because of the abundance and ease of obtaining the biomass locally. However, the recalcitrance of lignocellulosic biomass presents an obstacle in the hydrolysis step of AD and lowers the process efficiency. In this study, sunflower, which is a model lignocellulosic biomass, was pretreated by thermal (hydrothermal pretreatment, HTP) and non-thermal (milling) methods; the methane yield and biodegradability of the pretreated biomass were determined using a series of batch tests. The thermal pretreatment method showed a significantly higher methane yield (213.87-289.47 mL g-1 VS) and biodegradability (43-63%) than those of the non-thermally pretreated biomass, and the optimum pretreatment effect was observed at an HTP temperature of 180 °C. However, at an HTP temperature exceeding 200 °C, the induced formation of 5-hydroxymethylfurfural and furfural significantly lowered the methane yield and biodegradability. This study revealed that the HTP temperature is closely related to the formation of lignocellulosic biomass-degrading byproducts, which potentially hinder the methanogenesis step in AD; severe HTP conditions may have the opposite effect on the AD performance of lignocellulosic biomass.


Assuntos
Biocombustíveis/análise , Temperatura Alta , Lignina/química , Metano/análise , Eliminação de Resíduos/métodos , Anaerobiose , Biodegradação Ambiental , Biomassa , Hidrólise
6.
Chemosphere ; 255: 126805, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32387911

RESUMO

Large amounts of agricultural solid wastes (ASWs) and animal dung are produced annually causing serious environmental problem that requires proper treatment. The present study proposes a strategy for optimizing the anaerobic co-digestion of ASWs and cow dung (CD), identifies the key factors governing the co-digestion performance and evaluates the effect of NaHCO3 alkalinity treatment on improving the economy and performance of anaerobic digestion (AD). The results revealed that the highest cumulative methane production (CMP) of 297.99 NL/kgVS can be generated by co-digestion of ASWs and CD at a ratio of 60:40. Further improvement was achieved via alkalinity treatment with 1.0 g of NaHCO3/gVS leading to decrease in lignin, cellulose, and hemicellulose contents of feedstock by 3.5%, 10.5% and 15.9%, respectively, converting them to soluble fractions and improving the CMP by 11.2-29.7% based on substrate quality. The improved CMP in the chemically treated substrates reflects a 19% increase in the generated revenue. The kinetics of the AD process was successfully fitted to modified Gompertz model with very low standard deviation residuals (SDR) ≤ 5.21 and R2 ≥ 0.979. Results confirm that the proposed strategy is an effective method for producing biogas from co-digestion of ASWs and CD.


Assuntos
Agricultura , Biocombustíveis , Eliminação de Resíduos/métodos , Anaerobiose , Animais , Reatores Biológicos , Bovinos , Celulose , Cinética , Lignina/química , Metano/biossíntese , Resíduos Sólidos/análise
7.
Chemosphere ; 256: 127079, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32450351

RESUMO

Due to the ecological toxicity and environmental residues, how to remove the persistent organic pollutants (POPs), especially of polycyclic-aromatic-hydrocarbons (PAHs) and dichloro-diphenyl-trichloroethanes (DDTs), from agricultural soil has captured the attention of scholars for a long time. To develop an effective and low-cost in situ co-remediation technique, five independent but complementary treatments were used on an over-standard PAHs-DDTs co-contaminated soil in an agricultural greenhouse. Experimental results identified that the combination of microbe (Bacillus methylotrophicus) - plant (Brassica rapa) could remove rhamnolipid activated PAHs and DDTs effectively after enhanced by Staphylococcus pasteuri. Also, the Benzoapyrene and total DDTs residue in Brassica rapa was up to the standard of National (China) food safety. The lignin enhanced the removal of high-rings PAHs and p-p' DDE but reduced soil microbial biomass carbon and soil enzymes activity (polyphenol oxidase, invertase and acid phosphatase). Pearson correlation analysis showed that polyphenol oxidase activity was significantly related to the PAHs/DDTs dissipation rate. Our research suggested a new amendment that could remediate PAHs/DDTs co-contaminated agricultural soil without interrupting crop production, and the polyphenol oxidase activity should be considered as a micro-ecological indicator in this process.


Assuntos
Biodegradação Ambiental , Lignina/química , Hidrocarbonetos Policíclicos Aromáticos/análise , Poluentes do Solo/análise , Agricultura , Biomassa , Compostos de Bifenilo , Carbono , Desenvolvimento Vegetal , Plantas , Solo/química , Microbiologia do Solo , Staphylococcus , Tricloroetanos
8.
J Dairy Sci ; 103(5): 4252-4261, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32147261

RESUMO

Liquid hot water (LHW) treatment can be used to disrupt the fiber structure of rice straw. This in vitro ruminal batch culture study investigated the effect of LHW treatment on feed degradation, methane (CH4) production, and microbial populations. Rice straw was treated by LHW, and in vitro ruminal fermentation was performed using an automatic system with 72 h of incubation. Scanning electron microscopy showed that LHW treatment disrupted the physical structure of rice straw. Liquid hot water treatment decreased neutral detergent fiber and hemicellulose contents of the rice straw and increased neutral detergent solubles, water-soluble carbohydrates, and arabinose contents. Liquid hot water treatment increased dry matter degradation and volatile fatty acid concentration and decreased the acetate:propionate ratio, CH4 production, hydrogen accumulation, neutral detergent fiber degradation, and populations of protozoa, fungi, and cellulolytic bacteria. In summary, LHW treatment disrupted the cellulose-hemicellulose-lignin structure matrix of rice straw, leading to increased substrate degradability and decreased CH4 production. Therefore, the LHW treatment is a potential strategy to improve the nutritive value of forage such as rice straw and decrease the CH4 emissions in ruminants.


Assuntos
Ração Animal , Manipulação de Alimentos/métodos , Cabras , Metano/biossíntese , Oryza , Rúmen/metabolismo , Anaerobiose , Animais , Celulose/química , Fibras na Dieta , Ácidos Graxos Voláteis/metabolismo , Fermentação , Temperatura Alta , Técnicas In Vitro , Lignina/química , Valor Nutritivo , Oryza/química , Propionatos/metabolismo , Água
9.
Chemosphere ; 251: 126335, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32145573

RESUMO

Pyrolysis of biomass with phosphate compound is a promising method to improve biochar characteristics. However, how phosphate compound affects the three components of biomass during the biochar formation is still unclear. In this study, a typical phosphate compound, calcium dihydrogen phosphate (Ca(H2PO4)2), was premixed with cellulose, hemicellulose, and lignin reagent, at the ratio of 20% (w/w) for biochar production through pyrolysis, aiming to investigate the effects of Ca(H2PO4)2 addition on biochar formation. Results show that, with Ca(H2PO4)2 additions, carbon retention of biochars from cellulose (MCBC) and hemicellulose (MHBC) increased by 63.4% and 48.3%, respectively, but that of lignin (MLBC) decreased by 6.7% due to the reactions between lignin and Ca(H2PO4)2. Moreover, the stable carbon proportion in the biochar decreased by 10.2% for MCBC, almost unchanged for MHBC, and increased by 6.15% for MLBC based on the potassium dichromate oxidation. During the pyrolysis process, Ca(H2PO4)2 addition fixed more volatile and/or labile carbon in biochar, resulting in greater carbon retention. Declined carbon stability of biochar might be caused by the inhibited formation of aromatic-C, evidenced by the Fourier transform infrared spectroscopy analysis. This study highlights the importance and potential mechanisms of calcium dihydrogen phosphate influencing the carbon retention and stability of biochar derived from three biomass components.


Assuntos
Fosfatos de Cálcio/química , Carvão Vegetal/química , Biomassa , Cálcio , Carbono/química , Sequestro de Carbono , Celulose/química , Lignina/química , Polissacarídeos/química , Espectroscopia de Infravermelho com Transformada de Fourier
10.
Artigo em Inglês | MEDLINE | ID: mdl-32181694

RESUMO

In the past decade, Mexican coasts have received an enormous influx of macroalgae species, producing serious environmental and public health concerns. Here, we developed a green methodology to generate a new polymer from the lignin contained in the macroalgae. The methodology consists in lignin extraction-by-boiling and its subsequent polymerization with a laccase-like enzyme from the green algae Tetraselmis gracilis (Tg-laccase). Mass spectrometry revealed the presence of guaiacyl (G), p-hydroxyphenyl (H), and sinapyl alcohol as the main monolignols in the lignin from Sargassum sp. On the other hand, MALDI-TOF spectra shows an increase in the size of the lignin chain after enzymatic polymerization process with Tg-laccase. Besides, the characterization of the novel polymer -using 1H NMR, FTIR, SEC-FPLC, and UV/Vis- allowed establishing that during the polymerization process there is a decrease in the number of phenolic groups as well as loss of aromatic protons, which allowed proposing a polimerizacion mechanism. This methodology could be promising in the development of a new lignin-based polymer and would open a new direction for the environmental management of the macroalgae on the Mexican beaches.


Assuntos
Clorófitas/enzimologia , Química Verde/métodos , Lacase/química , Lignina/síntese química , Polimerização , Alga Marinha/química , Lignina/química , Peso Molecular , Fenóis/química
11.
Chem Biol Interact ; 318: 108977, 2020 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-32035863

RESUMO

Excess weight and obesity increase the risk of developing major risk factors for chronic kidney disease. Lignin comprises 20%-30% of the global plant biomass; however, it is not well utilized because of its resistance to chemical and biological degradation. We investigated whether low-molecular-weight oxidized lignophenol (LOLP), a lignin derivative, could alter inflammation and fibrosis in the kidneys of a high-fat diet (HFD)-fed mice. Male mice were divided into three treatment groups: HFD; HFD +0.3% LOLP; and HFD +0.6% LOLP. The control mice (Cont) were fed a low-fat diet. Macrophage kinetics, the degree of fibrosis, the extent of phosphorylation of AMP-activated protein kinase (AMPK), and mRNA expression of proinflammatory mediators in the kidneys were examined. The number of macrophages, the percentage of fibrotic area, and the mRNA expression of proinflammatory markers, TNF-α and Ccl2, and a marker of fibrosis, TGF-ß, were significantly higher in the kidneys of mice in the HFD group than those in the Cont group. Conversely, treatment with 0.6% LOLP for 8 weeks significantly suppressed the degree of macrophage infiltration, interstitial fibrotic area, and the increased mRNA expression of proinflammatory and fibrosis markers induced by HFD. In conclusion, LOLP suppressed macrophage infiltration and the increase in fibrotic area, and upregulated AMPK phosphorylation in the kidneys of HFD-fed mice; thus, it may ameliorate HFD-induced kidney injury.


Assuntos
Proteínas Quinases Ativadas por AMP/metabolismo , Dieta Hiperlipídica/efeitos adversos , Nefropatias/induzido quimicamente , Lignina/química , Fenóis/química , Fenóis/farmacologia , Animais , Proteínas de Ligação ao Cálcio/genética , Proteínas de Ligação ao Cálcio/metabolismo , Ativação Enzimática/efeitos dos fármacos , Fibrose/induzido quimicamente , Inflamação/induzido quimicamente , Inflamação/tratamento farmacológico , Nefropatias/prevenção & controle , Macrófagos/efeitos dos fármacos , Macrófagos/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , RNA Mensageiro , Receptores Acoplados a Proteínas-G/genética , Receptores Acoplados a Proteínas-G/metabolismo
12.
J Agric Food Chem ; 68(10): 3050-3060, 2020 Mar 11.
Artigo em Inglês | MEDLINE | ID: mdl-32069040

RESUMO

Industrial wastewater has brought great disaster to water bodies and soils and seriously affected the growth of crops. It is necessary to prepare a stable, effective, and sustainable treatment agent to control water pollution to obtain clean water. The adsorption effect of a lignosulfonate-lysine hydrogel (CLS-Lys adsorbent) on heavy metal ions (Cu2+ and Co2+) in water is studied. In the synthesis experiment, a response surface method is used to optimize the content of sodium lignosulfonate, lysine, initiator, and cross-linker. The CLS-Lys adsorbent is characterized by Fourier transform infrared spectroscopy, field-emission scanning electron microscopy, thermal analysis, and zeta potential analysis. The performance of the CLS-Lys adsorbent under different influencing factors is studied. The kinetic and isothermal models of the CLS-Lys adsorbent are established. The results show that the main adsorption model of the CLS-Lys adsorbent is chemical adsorption, accompanied by electrostatic adsorption. These two ions have a competitive adsorption relationship, and when the two ions are present at the same time, they inhibit each other. In addition, the CLS-Lys adsorbent has good adsorption and analytical regeneration performance. It is an economic and effective adsorbent and has a broad application prospect.


Assuntos
Hidrogéis/química , Lignina/análogos & derivados , Lisina/química , Metais Pesados/química , Poluentes Químicos da Água/química , Purificação da Água/métodos , Adsorção , Hidrogéis/síntese química , Cinética , Lignina/química , Águas Residuárias/química , Purificação da Água/instrumentação
13.
Biochim Biophys Acta Gen Subj ; 1864(5): 129547, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32032657

RESUMO

BACKGROUND: Lignin, the second most abundant biopolymer on earth, plays a major structural role in plants, conferring mechanical strength and regulating water conduction. Understanding the three-dimensional structure of lignin is important for fundamental reasons as well as engineering plants towards lignin valorization. Lignin lacks a specific primary sequence, making its average chemical composition the focus of most recent studies. However, it remains unclear whether the 3D structure of lignin molecules depends on their sequence. METHODS: We performed all-atom molecular dynamics simulation of three S/G-lignin molecules with the same average composition but different sequence. RESULTS: A detailed statistical analysis of the radius of gyration and relative shape anisotropy reveals that the lignin sequence has no statistically significant effect on the global three-dimensional structure. We found however, that homopolymers of C-lignin with the same molecular weight have smaller radii of gyration than S/G-lignin. We attribute this to lower hydroxyl content of C-lignin, which makes it more compact and rigid. CONCLUSIONS: The 3D structure of lignin is influenced by the overall content of monomeric units and interunit linkages and not by its precise primary sequence. GENERAL SIGNIFICANCE: Lignin is assumed to not have a well-defined primary structure. The results presented here demonstrate there are no significant differences in the global 3D structure of lignin molecules with the same average composition but different primary sequence.


Assuntos
Parede Celular/química , Lignina/química , Plantas/química , Conformação Molecular , Simulação de Dinâmica Molecular
14.
J Agric Food Chem ; 68(7): 2124-2131, 2020 Feb 19.
Artigo em Inglês | MEDLINE | ID: mdl-31985223

RESUMO

Lignin acylated with acetate and/or p-coumarate is common in many herbaceous plants. Herein, the biomimetic oxidation of γ-acylated monolignols with Ag2O was studied to understand the effect of γ-acyl groups on monolignol polymerization. The oxidation of sinapyl acetate gave γ-acylated and α-acylated ß-O-4 dimers in 71 and 9.5% yields, respectively. The oxidation of sinapyl p-coumarate produced γ-acylated ß-O-4 and γ-acylated tetralin ß-ß dimers in 53 and 16% yields, respectively. Only the sinapyl alcohol moiety in sinapyl p-coumarate reacted, and the p-coumarate moiety remained unchanged, suggesting that p-coumaric acid is not incorporated into the lignin backbone in the acylated lignins. All of the γ-acylated monolignols used in this study produced the γ-acylated ß-O-4 dimers, which suggests that the γ-acylated monolignols act as lignin monomers. The relatively high yields of the ß-O-4 dimers indicate that Ag2O oxidation of the monolignols can be used as an easy method for synthesizing the ß-O-4 dimer model compounds.


Assuntos
Ácidos Cumáricos/química , Dioxanos/química , Lignina/química , Óxidos/química , Compostos de Prata/química , Acetatos/química , Biomimética , Oxirredução
15.
Phys Chem Chem Phys ; 22(5): 2878-2886, 2020 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-31950118

RESUMO

Keggin-type polyoxometalate derived ionic liquids (POM-ILs) have recently been presented as effective solvent systems for biomass delignification. To investigate the mechanism of lignin dissolution in POM-ILs, the system involving POM-IL ([C4C1Im]3[PW12O40]) and guaiacyl glycerol-ß-guaiacyl ether (GGE), which contains a ß-O-4 bond (the most dominant bond moiety in lignin), was studied using quantum mechanical calculations and molecular dynamics simulations. These studies show that more stable POM-IL structures are formed when [C4C1Im]+ is anchored in the connecting four terminal oxygen region of the [PW12O40]3- surface. The cations in POM-ILs appear to stabilize the geometry by offering strong and positively charged sites, and the POM anion is a good H-bond acceptor. Calculations of POM-IL interacting with GGE show the POM anion interacts strongly with GGE through many H-bonds and π-π interactions which are the main interactions between the POM-IL anion and GGE and are strong enough to force GGE into highly bent conformations. These simulations provide fundamental models of the dissolution mechanism of lignin by POM-IL, which is promoted by strong interactions of the POM-IL anion with lignin.


Assuntos
Líquidos Iônicos/química , Lignina/química , Simulação de Dinâmica Molecular , Teoria Quântica , Compostos de Tungstênio/química , Guaifenesina/análogos & derivados , Guaifenesina/química , Ligação de Hidrogênio , Lignina/metabolismo , Solubilidade , Eletricidade Estática
16.
J Agric Food Chem ; 68(8): 2493-2505, 2020 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-31976665

RESUMO

Lignin content, composition, and linkage types were investigated in pear fruit cultivars and related species. Lignin content increased during early stages and then decreased toward ripening in the core and flesh of "Gold Nijisseiki" and "Alexandrine Douillard". The lignin content was highest at harvest in Chinese quince. Only trace amounts of lignin were detected in apple flesh. The lignin content was low in Japanese pears "Ohshu", "Hosui", and "Kosui", and the noncondensed lignin index was high in flesh. The lignin type was guaiacyl-syringyl (GS) in these pears and related species. The S/G ratio at harvest varied widely (0.75-2.64) and increased during early stages and remained constant toward harvest in "Gold Nijisseiki" and "Alexandrine Douillard". "Gold Nijisseiki" and "Alexandrine Douillard" were determined to be G- and S-lignin-rich types, respectively. ß-Aryl ether, phenylcoumaran, and resinol interunit linkage types were detected among monolignol bonds, and ß-Aryl ether units were the main linkages in the pear.


Assuntos
Lignina/química , Extratos Vegetais/química , Pyrus/química , Frutas/química , Frutas/classificação , Estrutura Molecular , Pyrus/classificação
17.
Chemosphere ; 246: 125756, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-31918088

RESUMO

The increasing demand for energy all around the world has led to a rise in greenhouse gases (GHGs), of which carbon dioxide (CO2) is the most important. CO2 is largely responsible for global warming and climate change. Processes such as carbon dioxide capture and storage (CCS), which have an effective role in climate mitigation, seem to be promising. In recent years, porous carbons, particularly activated carbons (ACs), have rapidly emerged as one of the most effective adsorbents of CO2. However, the implementation of pristine ACs in the real world is still hindered due to their physical and weak adsorption, which makes these adsorbents sensitive to temperature and relatively poor in selectivity. Hence, the surface modification of ACs is essential in order to improve their surface area, pore structure and alkalinity. Numerous studies have reported lignocellulose-based ACs as very promising adsorbents of CO2. In this review, the sources, health and environmental effects of CO2, and the abatement methods of GHGs are described. In addition, the capture and separation of CO2 from gas stream using various types of lignocellulose-based ACs are summarized. Furthermore, the key factors controlling the adsorption of CO2 by ACs (characteristics of adsorbents, preparation conditions, as well as adsorption conditions) are comprehensively and critically discussed. Finally, future research needs and prospective research challenges are summarized.


Assuntos
Dióxido de Carbono/química , Lignina/química , Modelos Químicos , Adsorção , Carvão Vegetal , Mudança Climática , Gases de Efeito Estufa , Porosidade , Estudos Prospectivos , Temperatura
18.
Sci Total Environ ; 713: 136573, 2020 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-31955087

RESUMO

Lignin is a highly complex, plant-derived natural biomass component, the analysis of which requires significant demands on the analytical platform. Fourier transform ion cyclotron mass spectrometry (FT-ICR MS) has been shown to be able to readily assess the complexity of lignin and lignin degradation products by assigning tens of thousands of compounds with elemental formulae. Nevertheless, many experimental and instrumental parameters introduce discrimination towards certain components, which limits the comprehensive MS analysis. As a result, a complete characterization of the lignome remains a challenge. The present study investigated a degraded lignin sample using FT-ICR MS and compared several atmospheric pressure ionization methods, e.g., electrospray ionization, atmospheric-pressure chemical ionization, and atmospheric-pressure photoionization. The results clearly show that the number of heteroatoms (e.g., N, S, P) in the sample greatly increases the chemical diversity of lignin, while at the same time also providing potentially useful biomarkers. We demonstrate here that FT-ICR MS was able to directly isolate isotopically pure single components from the ultra-complex mixture for subsequent structural analysis, without the time-consuming chromatographic separation. CAPSULE: Various ionization techniques coupled to FT-ICR MS provide a powerful tool to assess the lignome coverage.


Assuntos
Pressão Atmosférica , Lignina/química , Análise de Fourier , Íons , Espectrometria de Massas
19.
Chemosphere ; 246: 125757, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-31896011

RESUMO

Magnetic lignosulfonate functional materials that were known to remove several types of dye from water effectively were prepared. The surface of an iron (II,III) oxide (Fe3O4) sample was coated with a layer of organic carbon, and magnetic lignosulfonate (FCS) was synthesised by a crosslinking agent. The morphology, structure, stability and magnetic properties of the materials were characterised by various testing methods. Under experimental conditions, the solution's acidity, alkalinity, contact time, temperature, desorption and dye concentration were measured. The experimental results show that the material reached the highest adsorption capacity at pH = 7. In addition, the adsorption data was similar to that of a single layer, Langmuir adsorption model. The maximum adsorption capacities were 198.24 mg g-1 (Congo Red) and 192.51 mg g-1 (Titan Yellow), respectively. Based on its desorption performance, the material had good recyclability. Therefore, these studies could be used in wastewater treatment. Hopefully, the proposed magnetic composites will inspire more scholars to investigate solutions to the problem of contaminated water resources.


Assuntos
Corantes/química , Lignina/química , Poluentes Químicos da Água/química , Purificação da Água/métodos , Adsorção , Vermelho Congo/química , Concentração de Íons de Hidrogênio , Fenômenos Magnéticos , Magnetismo , Temperatura , Águas Residuárias/química , Água/química
20.
Carbohydr Polym ; 230: 115626, 2020 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-31887859

RESUMO

Lignin containing cellulose nanofibrils (LCNF) were obtained by mechanically fibrillating unbleached tree bark after alkaline extraction and used as a reinforcement in thermoplastic starch (TPS) to develop novel biodegradable composite films. With the addition of 15 wt % LCNF, the tensile strength and modulus of the composites increased by 319 % and 800 % compared to neat TPS films, respectively. The crystalline property of cellulose and the high interaction between TPS and LCNF improved the mechanical property of the composite films. The composite film Tonset and Tmax were 263.1 °C and 316.5 °C, respectively, compared to 250.5 °C and 297.3 °C for neat TPS. The composite films also showed higher water barrier property. Experimental results showed that LCNF features a high lignin content. Lignin, a natural polymer, contains hydrophobic and aromatic groups and, thus, can increase the water barrier property and thermal stability of TPS/LCNF composite films.


Assuntos
Lignina/química , Nanocompostos/química , Nanofibras/química , Temperatura Alta , Interações Hidrofóbicas e Hidrofílicas , Estresse Mecânico , Resistência à Tração
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