Lignin Research Articles

Lignin fractionation from waste wood using organosolv treatment combined with membrane filtration

The purpose of this study was to investigate the characteristics of lignin fractionated from waste wood (WW) using a two-step process of ethanol organosolv pretreatment followed by ultrafiltration with membranes of different molecular weight cut-offs (1, 5 and 20 kDa). The different permeates obtained were characterized by fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance (NMR), thermogravimetric analysis (TGA) and gel permeation chromatography (GPC). The analysis by FT-IR and NMR of these lignins showed that the lignin core was successfully separated from WW. TGA curves confirmed that the thermal properties of lignin fractionated by ultrafiltration were almost identical to each other. The results from GPC confirmed that fractionating of lignin was achieved by ultrafiltration. For the membrane fractionation process, values of molecular weight decreased as the cut-offs used to obtain the fractions became smaller. As a result, fractionating lignin by a two-step process allowed separating different fractions of lignin of different molecular weights yielded high purity without interference from existing pollutants in WW. The two-step process offers the possibility of using fractionated WW as an untapped source of lignin.

Isolamento e Caracterização de Lignina Acetossolve Extraída do Bagaço de Cana-de-Açúcar

Isolamento e Caracterização de Lignina Acetossolve Extraída do Bagaço de Cana-de-Açúcar

Chemical composition of Panicum maximum ‘BRS Zuri’ subjected to levels of salinity and irrigation depths

The study of cultivars with moderate flood tolerance is essential to their use in pastures irrigated with saline water. The aim of this study was to evaluate the chemical composition of Panicum maximum ‘BRS Zuri’ under the effect of different irrigation depths and levels of salinity. A randomised block design of split plots was used with five replications per treatment. The treatments resulted from the combination of three levels of water salinity (S1 = 0.6, S2 = 1.8 and S3 = 3.0 dS m-1) and four levels of irrigation (I1 = 60%, I2 = 80%, I3 = 100% and I4 = 120% of the evapotranspiration). The chemical composition of the grass, Panicum maximum ‘BRS Zuri’, cut at 28 days, was evaluated over two cycles. There was an interaction between the factors (salinity x irrigation depth x cycle) for the dry matter (DM) content. With the increase in irrigation depth, there was a linear reduction in the crude protein (CP) content in both cycles. The neutral detergent fibre (NDF) and cellulose (CEL) content increased linearly as a function of the irrigation depth, while the lignin (LIG) content decreased linearly with irrigation depth. It was concluded that high levels of salinity cause reductions in the dry matter content in response to increased water availability and extension of the cultivar cycles. The reduction in saline levels under low water availability results in a higher CP content. Salinity has a negative effect on the NDF, ADF, HEM, CEL and LIG content as the irrigation depth increases.

Associative effects of lignin-derived biochar and arbuscular mycorrhizal fungi applied to soil polluted from Pb-acid batteries effluents on barley grain safety

While disobeying environmental regulations of Pakistan, several Pb-acid batteries recycling and repairing units discharge their effluents into water canals that irrigate arable fields. Resultantly, serious ecological risks, as well as human health hazards through consumption of edible crops grown on such Pb-polluted soils have been reported. In this experiment, we observed associative effects of amending a soil polluted from Pb-acid batteries effluents (SPB) with arbuscular mycorrhizal fungi (AMF) and lignin-derived biochar (LBC) on barley grain safety to human health. The SPB was treated with AMF inoculum (a consortium of four AMF species), lignin (LN), and LBC, as sole treatments and AMF inoculum with LN and LBC. Barley parameters involving Pb distribution in grain and other parts, grain biochemistry, and nutrition were assessed. Likewise, Pb bioavailability in SPB, AMF root colonization, soil enzymes, microbial biomass carbon (MBC), and AMF produced total glomalin related soil protein (TGSP) were also scoped. Additionally, human renal cells (HEK 293) cytotoxicity test was performed by opting barley grain-related Pb concentrations. Results show that LBC + AMF significantly reduced grain Pb concentrations below the critical limit [4.67 mg kg−1 (WHO/FAO standard)], AMF colonization, MBC, soil enzymology, and TGSP, compared to control. Likewise, rest barley parameters were also improved in this treatment. Contrary to other treatments, grain produced on LBC + AMF did not result in (a) cell apoptosis, (b) cell distortion and (c) cohesion loss. Immobilization of Pb in SPB was due to the dilution effect of Pb adsorption on LBC, AMF mycelium and TGSP which resulted in a significant drop of grain Pb concentrations below the critical limit and ultimately no harm to HEK 293 cells. Our findings endorse that grain produced at LBC + AMF treatment are safer for human consumption and will not pose health risks. The LBC + AMF application can remediate SPB for safer cereal production.

Lignin/poly(butylene succinate) composites with antioxidant and antibacterial properties for potential biomedical applications

Lignin (LIG) is a renewable biopolymer with well-known antimicrobial and antioxidant properties. In the present work LIG was combined with poly(butylene succinate) (PBS), a biocompatible/biodegradable polymer, to obtain composites with antimicrobial and antioxidant properties. Hot melt extrusion was used to prepare composites containing up to 15% (w/w) of LIG. Water contact angle measurements suggested that the incorporation of LIG did not alter the wettability of the material. The material density increased slightly when LIG was incorporated (<1%). Moreover, the melt flow index test showed an increase in the fluidity of the material (from 6.9 to 27.7 g/10 min) by increasing the LIG content. The Young's modulus and the tensile deformation of the material were practically unaffected when LIG was added. Infrared spectroscopy and differential scanning calorimeter confirmed that there were interactions between LIG and PBS. The DPPH assay was used to evaluate the antioxidant properties of the materials. The results suggested that all the materials were capable of reducing the DPPH concentrations up to 80% in <5 h. Finally, LIG-containing composites showed resistance to adherence of the common nosocomial pathogen, Staphylococcus aureus. All tested materials showed ca. 90% less bacterial adherence than PBS.

Bentonite and Biochar Mitigate Pb Toxicity in Pisum sativum by Reducing Plant Oxidative Stress and Pb Translocation.

Lead (Pb)-polluted soils pose a serious threat to human health, particularly by transmitting this heavy metal to the food chain via the crops grown on them. The application of novel amendments in Pb-polluted soils can significantly reduce this problem. In this research, we report the effects of various organic and inorganic amendments i.e., bentonite (BN), biochar (BR), lignin (LN), magnesium potassium phosphate cement (CM) and iron hydroxyl phosphate (FeHP), on the Pb bioavailability in Pb-polluted soil, upon Pb distribution in shoots, roots, grain, the translocation factor (TF) and the bioconcentration factor (BCF) of Pb in pea (Pisum sativum L.) grain. Furthermore, effects of the said amendments on the plant parameters, as well as grain biochemistry and nutritional quality, were also assessed. Lead pollution significantly elevated Pb concentrations in roots, shoots and grain, as well as the grain TF and BCF of Pb, while reducing the nutritional quality and biochemistry of grain, plant height, relative water content (RWC), chlorophyll contents (chl a and chl b) and the dry weight (DW) of shoot, root and grain. The lowest Pb distribution in shoots, roots and grain were found with BN, FeHP and CM, compared to our control. Likewise, the BN, FeHP and CM significantly lowered the TF and BCF values of Pb in the order FeHP > CM > BN. Similarly, the highest increase in plant height, shoot, root and grain DW, RWC, chl a and chl b contents, grain biochemistry and the micronutrient concentrations, were recorded with BR amendment. Biochar also reduced grain polyphenols as well as plant oxidative stress. Given that the BR and BN amendments gave the best results, we propose to explore their potential synergistic effect to reduce Pb toxicity by using them together in future research.

New generation of controlled release phosphorus fertilizers based on biological macromolecules: Effect of formulation properties on phosphorus release

The main objective of this work was to study the possibility of using polysaccharides and lignin as a coating material for water-soluble triple superphosphate (TSP) granular fertilizers. In this study, composites based on three polysaccharides (sodium alginate (alginic acid sodium salt): AL, kappa-carrageenan: CR and carboxymethyl cellulose sodium salt: CM) and lignin (LG) were prepared. The lignin used was extracted from olive pomace (OP) biomass using the alkali method. The morphological, mechanical, and surface properties as well as the thermal behavior of the coatings were characterized and compared. Their morphology and thickness revealed by scanning electron microscopy (SEM) showed good adhesion between the fertilizer and coating materials. The results showed that the lignin-carrageenan formulation (LGCR) exhibited the highest water absorbency and elastic modulus. Release tests showed the effect of the TSP/biopolymer mass ratio and that the slowest P release was obtained with the LGCR@TSP formulation composite within 3 day. In addition, 59.5% and 72.5% of P was released after 3 days with the TSP/biopolymer mass ratios of 5/1 and 15/1, respectively, compared to 100% P release with the uncoated TSP.

Influence of collagen cross-linkers addition in phosphoric acid on dentin biomodification and bonding of an etch-and-rinse adhesive

ObjectiveTo investigate the effects of natural collagen cross-linkers incorporation in phosphoric acid etchant on dentin biomodification, microtensile bond strength (μTBS) and nanoleakage (NL) of a two-step etch-and-rinse adhesive. MethodsExperimental aqueous solution of 37% ortho-phosphoric acid were prepared with the addition of 2% biomodification agents: Lignin (LIG) from industrial paper production residue, Cardanol (CARD) from cashew-nut shell liquid, and Proanthocyanidin (PAC) from grape-seed extract. Negative control (NC) was acid solution without cross-linker whilst commercial control (CC) was Condac 37 gel (FGM). Dentin specimens were assayed by FTIR after 15s etching to detect collagen cross-linking. Extracted third molars were used for μTBS (n=7) and fracture mode analysis of Optibond S (Kerr), tested after 24h or 1000 thermal cycles. NL was surveyed by SEM. Statistical analysis was performed with two-way ANOVA and Tukey’s test (p<0.05). ResultsFTIR confirmed cross-linking for all agents. μTBS of CC was the highest (46.6±6.2MPa), but reduced significantly after aging (35.7±5.2MPa) (p<0.001). LIG (30.6±3.7MPa) and CARD (28.3±1.8MPa) attained similar μTBS which were stable after aging (p>0.05). Fracture mode was predominantly adhesive. At 24h, all groups showed presence of silver uptake in hybrid layer, except CARD. After aging, CARD- and LIG-treated specimens exhibited little amount of silver penetration. CC, PAC and NC showed gaps, great nanoleakage at hybrid layer and presence of water channels in adhesive layer. SignificanceAltogether, ortho-phosphoric acid incorporated with LIG and CARD promotes stable resin-dentin bond strength with minor nanoleakage after aging, thereby achieving therapeutic impact without additional clinical steps.

Catalytic Hydrogenolysis of Lignin for the Synthesis of Biokerosene

In this work, catalyst consisting of Ru deposited on hypercrosslinked polystyrene (HPS) was investigated in the process of hydrogenolysis of lignin isolated from different substrates. For sawdust, the maximum yield of the desired products was achieved with the use of acetic acid lignin, sunflower husk, and buckwheat husk when using the Klasson lignin. Analysis of hydrogenolysis products showed that the main substances formed in the process are benzene, phenol and their derivatives. In the process of hydrogenolysis of lignins at a pressure of 1 MPa hydrocarbons containing up to 9 hydrocarbon atoms were mainly obtained (78 %). Such hydrocarbons can be used as motor fuels. To increase the yield of hydrocarbons C9+, experiments were conducted to vary the temperature and pressure. The optimal reaction conditions allowing obtaining the highest yield of the target products (C9+ hydrocarbons) were found to be the following: the processing time 1 h, the temperature of 300 °C, the partial pressure of hydrogen of 4 MPa, the stirring speed of 1500 rpm. The 3 % Ru/HPS catalyst showed high stability during hydrogenolysis (up to 5 consecutive cycles without regeneration).

Application of Membrane Separation for Cleaning and Concentration of Nanolignin Suspensions in a Biorefinery Environment

Biorefining is a key technology for the sustainable production of chemicals, fuels and energy from abundant lignocellulosic resources. Within the concept, production of micro- and nanoscaled lignin particles recently gained increasing interest due to their excellent properties and potential application in high-value products. Fabricated via direct precipitation of Organosolv extracts, Nanolignin suspensions need to be increased in concentration and cleaned from impurities. Additionally, solvent background needs to be exchanged from hydroalcoholic solution to pure water for most applications. This work focuses on the application of ultrafiltration in diafiltration mode for this separation task. Experimental operation on lab-scale apparatuses demonstrate the reduction of Ethanol and impurities like sugars, dissolved lignin and sugar degradation products accessed by TOC analysis. Most important, the size of Nanolignin particles is not changed during 9 h of operation. Nevertheless, significant performance degradation due to compaction of polymeric membrane material as well as fouling resulting from deposited lignin particles has been monitored. Consequently, a rigorous optimisation of operating pressure and the development of an adequate membrane regeneration procedure is mandatory.

Production of Syngas Suitable to be Used in Fermentation to Obtain Biochemical Added-Value Compounds

Lignin-rich residues are a side stream in advanced ethanol biorefineries and they are usually used for heat and power production. However, an alternative is the lignin valorisation by thermochemical and biochemical processes that might be economically more suitable. In this work lignin-rich residues were firstly thermochemical converted to syngas in a fluidised bed gasifier, using steam and oxygen as gasifying agents. The obtained results so far showed that the rise of steam/lignin-rich residues ratio favoured the release of H2 and CO2 and led to a decrease in CO and hydrocarbons content, as steam reforming reactions were favoured. On the other hand, the rise of the equivalent ratio clearly favoured partial oxidation reactions and thus the release of CO and CO2, while H2 and hydrocarbons contents were reduced, due to their partial combustion. The increase of temperature favoured the formation of H2, at the expenses of hydrocarbons and tar release, as both decreased. However, it is fundamental to control gasification temperature to prevent ash melting and consequent bed agglomeration, due to the high ash content in lignin-rich residues, generally with high content of silica and alkali metals. The results led to the selection of gasification conditions (800 °C, equivalent ratio of about 0.13 and steam/lignin ratio of around 0.4) that headed to the following gas ratio CO/CO2/H2=1:0.7:0.7, which was tested for further bacterial fermentation. Fermentation tests with Butyribacterium methylotrophicum showed that the above syngas composition strongly influenced the production levels of acetic and butyric acids. Marked differences in the CO, H2 and CO2 consumption rates were also observed and were correlated with cell growth and metabolites production.

Production of Liquid Compounds by Co-Pyrolysis of Different Pre-Treated Biomasses Mixed With Plastic Wastes

As an innovation to conventional biomass pyrolysis to produce liquid biofuels, different types of biomass wastes were pre-treated by autohydrolysis, prior to pyrolysis. Eucalyptus forestry waste, corn cobs agricultural residue, and miscanthus (an energy crop) were autohydrolysed. Autohydrolysis led to valuable sugar-rich stream that may be used in fermentation and to solids rich in lignin that were pyrolysed. Pyrolysis of autohydrolysed eucalyptus led to an increase in liquids yields of 24 % in relation to untreated eucalyptus, as autohydrolysis weakened initial macromolecular structure and thus helped chemical bonds breakdown during pyrolysis. However, similar pyrolysis liquid yields were obtained by autohydrolysed or untreated corn cobs and miscanthus, thus feedstock composition is an important issue. Nevertheless, the production of added value products by autohydrolysis may still justify this pre-treatment. Otherwise, more severe pre-treatments of these biomasses might improve co-pyrolysis as it happened with eucalyptus. As polyethylene (PE) is easier to pyrolyse than biomass and greatly favours the production of liquid hydrocarbons, autohydrolysed and untreated biomass was mixed with PE wastes to be used in co-pyrolysis. The rise of PE content in the blend clearly favoured the production of liquid products of pre-treated and untreated biomass. 75 %wt. of PE in the blend led to liquid yields of 72 %wt. for untreated eucalyptus and of 82 %wt. for autohydrolysed eucalyptus.

Degradation of biochemical fractions in different temperature of food waste bioevaporation and their contribution to biogenerated heat

Abstract Bioevaporation is a treatment for highly concentrated organic wastewater that uses biogenerated heat from organic matter degradation to remove water from wastewater itself. The degradation of organics is important when investigating bioevaporation process. The aim of this study was to investigate organic compounds degradation in different temperature stages and evaluate their contribution to biogenerated heat during food waste (FW) bioevaporation by using biofilm-developed sponge (BF) as a clean, light and easy-to-prepare bulking agent and microbial carrier. Results showed that amylums were significantly decomposed in all stages and lipids were decomposed a lot except the warming 30 °C to top-temperature stage. Decomposition of amylums and lipids contributed to the main total volatile solids (VS) loss (75.63% and 77.87% in the 1st and 2nd cycle, respectively). Water soluble organic carbon (WSOC) variations were fluctuated especially at the thermophilic phase. The decomposition of hemicellulose (HEM) occurred until cooling 30 °C. However, the degradation of proteins and lignin (LIG) was not significant during the whole process. Carbohydrates and lipids successively served as main substrates for producing biogenerated heat and totally contributed 87.54% and 89.06%, in the 1st and 2nd cycle, respectively. Throughout the process, various organics contained in FW induced extracellular enzymes in different levels, resulting in different degradation performance. The foremost induced enzyme was amylase with activity of 114.50 mg reducing sugar g−1 TS (total solids) min−1 at warming 50 °C of the 2nd cycle, which facilitated amylums to be degraded preferentially. Fluorescence labeling further confirmed significant decrease of amylums and lipids and the slight decrease of proteins. However, decreasing fluorescence intensity of cellulose (CEL) in the top-temperature stage firmly reflected its degradation, which was covered by the content variations caused by readily biodegradable fractions.

EVALUATION OF CONFINEMENT CONDITIONS AND CONTENT OF LIGNOCELLULOSIC COMPOUNDS ON URBAN SOLID WASTE BIODEGRADATION RATES

The organic fraction (OF) is the main component of urban solid wastes (USW) generated in Mexico and other developing countries. The increasing generation of USW in combination with the long periods required for OF stabilization at confinement sites has exceeded the management capacity of environmental authorities. OF biodegradation has commonly been estimated using theoretical approaches and by characterizing fresh USW, while confinement scenarios have been ignored. This study evaluated the effects of composition, biodegradability and confined conditions on biodegradation of USW in a characteristic dumpsite. Biodegradability was evaluated by the characterization of lignocellulosic compounds, biodegradation by volatile solids (VS) and the confinement conditions by temperature, pH and humidity measurements. On average, the OF represented 56.1 % of the confined USW, and was primarily derived from vegetable wastes (~78 %). The results indicate heterogeneity in the confined USW composition and different degradation stages. Measurement of temperature, pH, moisture and VS suggests that confinement conditions do not promote the establishment of a microbial consortia that degrades the OF. Lignin (LI) and cellulose + hemicellulose (CE + HE) contents suggest low biodegradability of the USW, which was confirmed by inverse correlations between lignocellulosic content and VS. The common use of soil as cover material in dumpsites allows considerable variations in crucial physical and chemical parameters that, when combined with the high percentages of lignocellulosic compounds in the USW, lead to low biodegradation rates.

Dietary threonine prevented stress-related mucosal diseases in rats.

Stress-related mucosal disease (SRMD), or stress ulceration, is a group of conditions ranging from stress-related superficial gastric mucosal damage to deep gastric ulcers that are primarily correlated with mucosal ischemia, and pharmacologic interventions that optimize tissue perfusion or preserve defensive mucus aim to decrease the occurrence of conditions, such as gastric acidity, or enhance gastric defenses. However, the identification of multifactorial pathogenesis may be effective in preventing SMRD, and the use of stress prophylaxis is generally preferred. Since threonine is a component in the polymerization and synthesis of gastric mucin and possibly enhanced defense actions and lignin may provide structural support for defense and antioxidative function, we hypothesized that dietary intake of threonine and/or lignin can enhance defense against SRMD. The water immersion-restraint stress (WIRS) was used in rats and additional groups were pretreated with threonine alone or the combination of threonine and lignin. Based on gross and microscopic evaluations, threonine alone or the combination of threonine and lignin, a natural antioxidant, significantly reduced the development of SRMD (P < 0.05). According to molecular explorations, the levels of inflammatory mediators, such as interleukin (IL)-8, IL-6, IL-1β, inducible nitric oxide synthase (iNOS), tumor necrosis factor alpha (TNF-α), and interferon gamma (IFN-γ), all of which are mediators that play a significant role in controlling WIRS, significantly decreased in the groups pretreated with either threonine alone or the combination of threonine and lignin (P < 0.01). WIRS significantly increased apoptosis in the stomach. However, the apoptotic index significantly decreased with threonine pretreatment. According to periodic acid Schiff staining results, the expression of gastric mucin was significantly preserved in groups pretreated with threonine but remarkedly decreased in the WIRS group. The gastric heme oxygenase-1 levels significantly increased in the group treated with threonine. In conclusion, the dietary intake of threonine or the combination of threonine and lignin is effective in preventing SRMD.

Chemical composition of Urochloa brizantha depending on the seasons and cutting frequencies

The aim of this research was to assess the chemical composition of Brachiaria brizantha cv. Piata variety and to determine which cutting frequency is the most suitable for autumn, winter and spring. The experimental design adopted was the completely randomized in factorial scheme with plots subdivided in time. Each plot consisted of four cutting frequencies (21, 28, 35 and 42 days between cuts) and sub plots were the three seasons (autumn, winter and spring) with 12 replicates per treatment (experimental units). The assessed parameters were; crude protein content, neutral detergent fiber, lignin and in vitro organic matter digestibility. No significant differences were observed in crude protein content between the cutting frequencies of 21, 28 and 35 days for autumn and winter; only the cutting frequency of 42 days showed the lowest values. The cutting frequency of 35 days showed higher crude protein and digestible organic matter for autumn and winter. As for the spring season, the cutting frequency that showed higher production of crude protein and digestible organic matter was 28 days. Key words: Animal nutrition, pastures, Brachiaria brizantha.

Lignin and Cellulose Blends as Pharmaceutical Excipient for Tablet Manufacturing via Direct Compression.

Extensive efforts are being made to find alternative uses for lignin (LIG). In the present work the use of this biopolymer as excipient to prepare tablets was studied. For this purpose, LIG was combined with microcrystalline cellulose (MCC) and used as excipients to prepare directly compressed tablets containing a model drug, tetracycline (TC). The excipients contained different concentrations of LIG: 100%, 75%, 50%, 25% and 0% (w/w). Two different compression forces were used (two and five tonnes). When formulations were prepared using LIG as the only excipient, tablets were formed, but they showed lower densities and crushing strength than the ones obtained with only MCC or LIG/MCC blends. Moreover, tablets prepared using five tonnes of compression force showed TC releases ranging from 40% to 70% of the drug loading. On the other hand, the tablets prepared using two tonnes of compression force showed a faster and more efficient TC release, between 60% and 90%. The presence of LIG in the tablets modified significantly the release profile and the maximum amount of TC released. Finally, a DPPH (2,2-diphenyl-1-picrylhydrozyl) assay was performed to confirm that the presence of LIG provided antioxidant properties to the formulations. Accordingly, LIG has potential as a pharmaceutical excipient.

Rheological Behavior of Lignin Based Dispersions Intended for Composite Fuel Production

Rheological Behavior of Lignin Based Dispersions Intended for Composite Fuel Production

Prediction of methane production performances based on determination of organic components for different vegetable wastes

The rapid development of the economy has led to rapid consumption of fossil fuels, which results in extremely serious environmental problems. Biomass energy has been accepted as a way to reduce the usage of fossil fuels due to its cleanliness and renewability. In this study, vegetable wastes (VWs), an abundant kind of biomass resource, were treated by anaerobic digestion (AD) to be converted into methane. The total solids (TS), volatile solids (VS), elemental contents, and organic components of 17 kinds of typical VWs were systematically determined. The methane production performances were then measured and ranged from 120.1 mL/g VS (for pepper stem) to 377.7 mL/g VS (for bok choy). To easily and quickly predict the methane yields of VWs, a curvilinear relationship between different organic compositions (e.g., cellulose, hemicellulose, lignin, non-structural carbohydrate, protein, and VFA contents) and methane production was established and proved to be a useful tool for methane prediction. Four kinetic models (first-order model, Fitzhugh model, Cone model, modified Gompertz model) were applied to simulate the process of AD, and Cone and modified Gompertz models were shown to describe the AD process well. This study will not only provide basic data about the characteristics and methane production of 17 kinds of VWs but also contribute a method for predicting the methane yields of vegetable wastes, which is also valuable in future agro-industrial applications. Keywords: naerobic digestion, organic components, methane production, vegetable waste, kinetic models DOI: 10.25165/j.ijabe.20191203.4705 Citation: Cai F F, YanH, Zhang R H, Liu G Q, Chen C. Prediction of methane production performances based on the determination of organic components for different vegetable wastes. Int J Agric & Biol Eng, 2019; 12(3): 154–159.

Lignin Conversion Into Hydrogen and Biochar Under Microwave Irradiation

Utilization of Kraft lignin is a complex challenge and effective approaches to its solution have not yet been found. One of the promising ways in this area is the processing of lignin into syn-gas and carbon residue, which can be used to obtain sorbents. Processing of lignin into synthesis gas by dry reforming (LDR) under the action of MWI allows for the efficient processing of large-scale waste - lignin and carbon dioxide into an important product of petroleum chemistry like syn-gas with a selectivity exceeding 90%. MWI on the one hand is the source of heat in the reaction volume, on the other hand its effect leads to an increase in the vibrations of the substrate molecules and their polarization, which significantly increases the intensity of the release of hydrogen from the lignin compared to convective heating. Graphite-like conversion of carbon is a valuable raw material for the production of porous carbon sorbents for the treatment of industrial wastewater. It is followed by the fact that it has been measured that it has reached 0.5–0.8 nm. In the case of heat treatment, it is recommended that you follow the short-term heat treatment.