Effects Of Hydrothermal Conditions Research Articles

Correction: Saafie et al. Effect of Hydrothermal Conditions on Kenaf-Based Carbon Quantum Dots Properties and Photocatalytic Degradation. Separations 2023, 10, 137

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The effect of hydrothermal conditions on the yield of spring soft wheat (Triticum aestivum L.) when using mineral fertilizers in the arid Volga region

The paper reflects the results of the effectiveness of the use of various doses of mineral fertilizers in a long stationary experiment on spring soft wheat for nine rotations of a six-field crop rotation (27 years of cultivation) in the conditions of the steppe zone of the Volga region. The systematic use of medium and high doses of nitrogen-phosphorus fertilizers contributed to obtaining the highest yield increases to control in the experiment throughout the entire research period. The average level of correlation between hydrothermal conditions in the period May-July and crop productivity has been established. Separate calculations by month showed an average level of correlation with June. Based on the results of regression analysis, the degree of influence of hydrothermal conditions as a factorial feature on the productivity of spring soft wheat in the experiment was determined. The analysis showed that the effect of the obtained values of the hydrothermal coefficient in May and July on the production process of vegetating plants was insignificant, and in June it reached 30% according to experience.

Effect of Hydrothermal Conditions on Kenaf-Based Carbon Quantum Dots Properties and Photocatalytic Degradation

The development of biomass-based CQD is highly attentive to enhancing photocatalytic performance, especially in secondary or ternary heterogeneous photocatalysts by allowing for smooth electron-hole separation and migration. In this study, kenaf-based carbon quantum dots (CQD) were prepared. The main objective of the current work was to investigate temperature, precursor mass and time in hydrothermal synthesis treatment to improve the CQD properties and methylene blue photocatalytic degradation. Optimization of kenaf-based CQD for inclusion in hydrothermal treatment was analyzed. The as-prepared CQDs were characterized in detail by Fourier transform infrared (FTIR) spectroscopy, using a Hitachi TEM System (HT7830, RuliTEM, Tokyo, Japan), by photoluminescence (PL), and by ultraviolet-visible (UV-Vis) spectroscopy. It was found that C200-0.5-24 exhibits a higher photocatalytic activity of the methylene blue dye and optimized hydrothermal conditions of 200 °C, 0.5 g and 24 h. Therefore, novel kenaf-based CQD was synthesized for the first time and was successfully optimized in the as-mentioned conditions. During the hydrothermal treatment, precursor mass controls the size and the distribution of CQD nanoparticles formed. The C200-0.5-24 showed a clearly defined and well-distributed CQD with an optimized nanoparticle size of 8.1 ± 2.2 nm. Indeed, the C200-0.5-24 shows the removal rate of 90% of MB being removed within 120 min.

Hydrothermal carbonization of alfalfa: role of processing variables on hydrochar properties.

Hydrothermal carbonization of alfalfa is a potential way to reuse agricultural waste. However, the effects of hydrothermal conditions on the properties of alfalfa-derived hydrochar are not clear. Herein, this study investigated the impact of different synthesis conditions (e.g., heating temperature, heating time, and solid to liquid ratio) on the formation and properties of hydrochar. Characterization and thermogravimetric analysis results revealed that with the increase of hydrothermal temperature and the extension of time, cellulose in alfalfa broken down more completely, and the number of carbon spheres and the aromatization degree increased, while the functional groups decreased. Furthermore, there was a surge in the carbon content, fixed carbon yield, high heating value, reduced oxygen, and volatile content. Additionally, the enhancement solid-liquid ratio could effectively improve the energy and mass yields. In all, by adjusting the process parameters of hydrochar, cleaner and higher productivity products could be obtained. This study provides theory basis for the production of target hydrochar that is used to soil amendments, adsorbents, and energy sources in the future.

The effect of hydrothermal conditions on the formation of productivity of the facultative barley variety ‘Marusya’ in the southern part of the Rostov region

In the cultivation regions with unstable moisture there are fluctuations in grain crop productivity, which is mainly determined by the definite hydrothermal conditions. The purpose of the current study was to determine the effect of hydrothermal conditions on the formation of barley productivity during autumn and spring sowing periods in the southern part of the Rostov region. When conducting the trial, barley plants experienced a lack of air humidity and were insufficiently provided with precipitation, both in autumn and spring sowing periods, and the coefficient of moisture supply for barley crops was 0.53 and 0.45, respectively. There was found that the longest vegetation period of 235 days was observed during sowing on September 10, when the sum of positive temperatures was also the highest, 2010.4 °C. In the spring sowing periods, these indicators were the smallest: the vegetation period was 83 and 92 days, the sum of positive temperatures was 1555.2 and 1579.3 °C, respectively. There was established that for productivity formation (6.38 t/ha) in autumn sowing, the total moisture consumption of the facultative barley variety ‘Marusya’ was 308.5 mm per 1 ha, and the total moisture consumption per 1 ton of grain was 483.5 m3 on average for 2018-2020. In the total consumption of moisture, precipitation was 95%, and the share of soil moisture was 5%. When sowing in the spring, the variety ‘Marusya’ produced 4.26 t/ha and consumed 211.4 mm of moisture per hectare, and the total moisture consumption per 1 ton of grain was 496.2 m3. In the total consumption of moisture, precipitation was only 34%, and the share of soil moisture was 66%.

Preparations, properties and applications of gallium oxide nanomaterials – A review

AbstractGallium oxide (Ga2O3) is an important wide bandgap transparent conductive oxide with many excellent properties, which is widely used in many fields such as catalysis, electroluminescence, biology, and so on. This review mainly introduces the researches on the preparation, properties and applications of gallium oxide nanomaterials. Initially, the preparation of gallium oxide by hydrothermal method has been highlighted and the effects of hydrothermal conditions on the morphologies and sizes of the final products were summarized. Furthermore, the unique properties of gallium oxide in the fields of electricity, gas, heat, and biomedicine are introduced, and the excellent luminescent properties of gallium oxide are emphasized. Additionally, this review mainly introduces the applications of gallium oxide in the fields of catalysis, gas sensors, optoelectronic devices, high voltage electronic devices and biomedicine. Finally, the problems and shortcomings in current research on gallium oxide nanomaterials are discussed and the opinions and prospects are put forward for the future perspective of the research in gallium oxide nanomaterials.

The effect of temperature fields on soil and plant cover formation in arid ecosystems of the Uvs Nuur basin

Introduction of remote and automated methods into the practice of soil and ecological studies urges for development of the methodological basis for combined analyses of surface and satellite data. The aim of the study was to explore the possibility to identify and typologise the structural and functional borders of soil cover using temperature fields, obtained by combined analysis of the temperature time series obtained by field and remote temperature monitoring. The functional relationships that are expressed within geosystems as the flux of energy and matter are reflected in soil temperature regimes, hydrophysical soil properties and plant cover biological productivity, which were studied in the arid ecosystems of the Uvs Nuur depression in Tuva, Russia. The quantitative characteristic of the temperature fields of the psammophytic soils were obtained, and the effect of hydrothermal conditions and soil hydrophysical properties on above- and belowground phytomass stocks of the sand massif Zuger-Els revealed and discussed.

Solid fuel production from macadamia nut shell: effect of hydrothermal carbonization conditions on fuel characteristics

Hydrothermal carbonization (HTC) was employed to convert macadamia nut shell (MCNS) into solid fuel. The effect of hydrothermal conditions was examined by varying the reaction temperature (170, 200, and 230 °C) and water/biomass ratio (2, 3, and 5). The properties of hydrochar were assessed in term of mass yield, energy recovery, higher heating value (HHV), and atomic H/C and O/C ratios. The results showed that HHV of hydrochar was significantly higher than raw MCNS, and progressively increased with increasing HTC temperature while mass yield showed opposite trend. The solid yield from HTC process varied between 58.38 and 78.43% of the initial dry MCNS with HHV around 22-27 MJ/kg. The energy recovery of hydrochars via HTC was in a range of 82.5-93.2%. Higher HTC temperature also increased the degree of coalification and thermal stability of hydrochar by removing volatile matters from the biomass. The removal of carboxyl and -OH groups reduces the O/C ratio leading to the higher energy densification of hydrochars. Hydrochar produced via HTC at 230 °C possessed the highest HHV of 27 MJ/kg, and had the O/C and H/C ratios close to sub-bituminous coal. The findings indicated that hydrothermal carbonization is a potential method to convert agricultural waste such as macadamia nut shell into solid fuel without pre-drying process.

The effect of hydrothermal conditions on photoluminescence properties of rice husk-derived silica-carbon quantum dots for methylene blue degradation

Carbon quantum dots (CQDs) have potential to replace metal-based quantum dots due to its low-toxicity. However, studies on CQDs preparation were dominated by synthetic carbon precursors. Switching the precursors into natural ingredient is preferred since they are highly abundant and low-cost. In this study, composite of silica-carbon quantum dots (Si-CQDs) were fabricated from rice husk through a hydrothermal process. Si-CQDs with diverse properties are beneficial for its application in the future; therefore, the variation of hydrothermal conditions (i.e., temperature and pH) was performed to investigate their influence on its properties. Investigation using HRTEM, XPS, Raman spectroscopy, and UV-Vis spectroscopy suggested that hydrothermal conditions affect carbonization reaction. Hydrothermal temperature controls carbonization rate of rice husk ash, while acid addition accelerates polymerization and base addition tends to cut more carbons into small particles. The photoluminescence (PL) analysis showed that the obtained Si-CQD samples have emission in the range of 469–552 nm with various intensities. The application of sole Si-CQDs was evaluated in methylene blue (MB) degradation under visible light irradiation.

Productivity and quality of spring bread wheat of Myronivka breading depending on hydrothermal conditions of the year

Purpose. To investigate the differences of new spring bread wheat varieties of Myronivka breeding on yield, physical properties of grain and flour, depending on hydrothermal conditions, and determine which of them are more genotypically conditioned. Methods. The studies were conducted in 2015–2017 on the fields of breeding crop rotation of the V. M. Remeslo Myronivka Institute of Wheat (MIW) and at the Grain Quality Laboratory of MIW. The predecessor is soybeans for grain. Productivity, physical indicators of grain quality (1000 kernel weight, test weight, vitreousness) and flour quality (sedimentation, protein content, gluten content and quality, flour strength) were determined by standard methods. For the analysis, we used grain and flour in spring bread wheat varieties bred at the MIW: Simkoda myronivska, Panianka, MIP Zlata, Bozhena, Oksamyt myronivskyi, Dubravka, MIP Svitlana, the standard variety Elehiia myronivska. Results. A predominant influence of hydrothermal conditions on yield and physical indicators of spring bread wheat quality and a smaller, but still significant, effect of genotype of the variety were established. The highest genotypic conditionality was observed in two quality indicators: gluten deformation index (38 %) and flour strength (40 %). In terms of yield, the varieties Oksamyt myronivskyi, Simkoda myronivska, Dubravka and Bozhena were distinguished (exceeding the standard by 0.24–0.52 t/ha). The most varieties in terms of test weight and vitreousness corresponded to the class I, according to gluten deformation index – to the quality group I. The high values of sedimentation index and flour strength were observed in the varieties Simkoda myronivska, Oksamyt myronivskyi and MIP Zlata. With different effect of hydrothermal conditions, the studies have established an average strength of the relationship of productivity with 1000 kernel weight (r = 0.50) and test weight (r = 0.43–0.51) and the negative correlation with protein and gluten content (from r = -0.36 to r = -0.58). The most stable averaged correlation were noted between test weight and flour strength (r = 0.51); between protein content and gluten content (r = 0.71) and flour strength (r = 0.67); between gluten content and GDI index (r = 0.58) and flour strength (r = 0.47). Conclusions. The determining influence of the hydrothermal conditions of the year on productivity was established, as well as significant genotypic differences in the quality indicators of grain and flour of spring bread wheat in the conditions of the right-bank Forest-Steppe of Ukraine. There were identified the varieties Simkoda myronivska, Bozhena, and Oksamyt myronivskyi with steadily the highest level of productivity over the years. It was determined that all the studied varieties of spring bread wheat corresponded to the class I in terms of grain vitreousness. The varieties Simkoda myronivska, MIP Zlata, Oksamyt myronivskyi in terms of sedimentation, GDI, and flour strength refered to strong wheat cultivars. The two most genotypically determined quality indicators have been identified: gluten deformation index and flour strength. There were established stable correlations between test weight and flour strength; between protein content and gluten content as well as flour strength; between gluten content and GDI index as well as flour strength.

Hydrothermal carbonization of cellulose and xylan into hydrochars and application on glucose isomerization

Abstract: Hydrochar microsphere as clean and facile carbon materials have great potentials to be used in biomass valorization for producing value-added chemicals. In this study, the hydrochars obtained from cellulose and xylan were prepared. The effect of hydrothermal conditions on hydrochars’ chemical composition, thermal stability and the porosity obtained from cellulose and xylan were evaluated. In order to explore the application of the hydrochar in biofuel production, the cellulose derived hydrochar supported Al catalyst (Al-Cel-HTC) was prepared by one-step hydrothermal process for catalysis glucose isomerization. We found distinct physicochemical properties between cellulose and xylan derived hydrochar. The specific surface area (SBET) of cellulose derived hydrochar (118 m2/g) is significantly higher than that of xylan derived hydrochar (28 m2/g). The hydrochars are composed of carbonaceous microspheres as evidenced by SEM. The catalytic performance of Al-Cel-HTC was investigated. Results shown that 77.8 mol/% selectivity of glucose to fructose can be obtained in aqueous by the catalyst. The SEM-EDS images of the catalyst shown the strong crystal-hydrochar microsphere interaction benifit in diminishing the agglomeration of hydrochar microsphere. The BET specific surface area and crystal structure (AlO(OH) and Al2O3) of hydrochar supported aluminum catalyst have positive correlation with the catalytic selectivity.

Evolution of Zeolite Crystals in Self-Supporting Faujasite Blocks: Effects of Hydrothermal Conditions.

In order to prepare self-supporting faujasite (FAU) zeolite, a self-supporting zeolite block was synthesized in situ by hydrothermal treatment of a metakaolin base geopolymer. The effects of hydrothermal conditions such as hydrothermal alkalinity, temperature and time on the phase composition, microstructure and mechanical strength of the hydrothermal samples were investigated and evidenced by a series of characterization methods such as X-ray diffraction (XRD), scanning electron microscopy (SEM), and Brunauer-Emmet-Teller (BET). The results showed that a self-supporting faujasite block could be obtained by hydrothermal treatment of the geopolymer block in 2 M NaOH solution at 90 °C for 24 h, which had high crystallinity, regular morphology and high compressive strength. The self-supporting zeolite block had a compressive strength of 11.7 MPa, a pore volume of 0.24 cm3/g, and an average pore diameter of 7.86 nm. The specific surface area and the microporous specific surface area of the self-supporting faujasite blocks were 80.36 m2/g and 19.7 m2/g, respectively.

Controlled Synthesis of Tb3+/Eu3+ Co-Doped Gd₂O₃ Phosphors with Enhanced Red Emission.

(Gd0.93−xTb0.07Eux)2O3 (x = 0–0.10) phosphors shows great potential for applications in the lighting and display areas. (Gd0.93−xTb0.07Eux)2O3 phosphors with controlled morphology were prepared by a hydrothermal method, followed by calcination at 1100 °C. XRD, FE-SEM, PL/PLE, luminescent decay analysis and thermal stability have been performed to investigate the Eu3+ content and the effects of hydrothermal conditions on the phase variation, microstructure, luminescent properties and energy transfer. Optimum excitation wavelength at ~308 nm nanometer ascribed to the 4f8-4f75d1 transition of Tb3+, the (Gd0.93−xTb0.07Eux)2O3 phosphors display both Tb3+and Eu3+ emission with the strongest emission band at ~611 nm. For increasing Eu3+ content, the Eu3+ emission intensity increased as well while the Tb3+ emission intensity decreased owing to Tb3+→Eu3+ energy transfer. The energy transfer efficiencies were calculated and the energy transfer mechanism was discussed in detail. The lifetime for both the Eu3+ and Tb3+ emission decreases with the Eu3+ addition, the former is due to the formation of resonant energy transfer net, and the latter is because of contribution by Tb3+→Eu3+ energy transfer. The phosphor morphology can be controlled by adjusting the hydrothermal condition (reaction pH), and the morphological influence to the luminescent properties (PL/PLE, decay lifetime, etc.) has been studied in detail.

The Microstructure and Growth Behavior of Bi<sub>2</sub>Fe<sub>4</sub>O<sub>9</sub> Superfine Particles Synthesized by Hydrothermal Method

In this work, Bi2Fe4O9superfine particles were prepared by hydrothermal method and effects of hydrothermal conditions on the microstructure of Bi2Fe4O9, especially the concentration of OH-([OH-]) in initial solutions, were investigated. The results showed that [OH-] had obvious influences on the growth of Bi2Fe4O9under the same hydrothermal temperature and hydrothermal time. Phase structure of Bi2Fe4O9unchanged with the increase of [OH-] and maintained orthorhombic structure. Besides, the microstructure of Bi2Fe4O9was carefully studied through transmission electron microscopy (TEM). The results suggested that the mechanism of Bi2Fe4O9growth was Ostwald ripening. In conclusion, Bi2Fe4O9superfine particles with good morphology and microstructure can be successfully synthesized when the concentration of OH-is 2 mol/L and hydrothermal conditions are 240 °C for 6h.Keywords: Bi2Fe4O9, hydrothermal method, phase structure, growth mechanism Topic code numbers: C2

Effect of hydrothermal conditions on superconductivity and magnetism in [Li1−xFexOH]FeS

Recent reports of superconductivity and magnetism in single crystals of [Li1−xFexOH]FeS show unexplained variations in both superconducting and magnetic properties. We investigate the effect of hydrothermal growth conditions on these properties and find that increasing the growth temperature systematically increases the superconducting transition temperature (Tc), sharpens the magnetic transition, and decreases the scattering rate (Γ). The slow rate of Tc suppression with increasing Γ indicates a conventional s-wave superconducting state according to the Abrikosov-Gorkov expression. Samples with higher scattering rate show broader magnetic transitions and a stronger temperature dependence in the magnetic susceptibility. These results identify disorder, due to interstitial iron impurities, as the unique internal parameter responsible for the unexplained variations in Tc and magnetic ordering. We demonstrate the optimal hydrothermal growth conditions to minimize disorder and maximize Tc in [Li1−xFexOH]FeS crystals.

Dynamics of CO2 emission from chernozems under agricultural use

Aim. The comparison of the effect of hydrothermal conditions and various agricultural practices on the emission of CO 2 from chernozems in the Left-Bank Forest-Steppe of Ukraine. Methods. The dynamics of the intensity of carbon dioxide emissions from chernozem calcic (typical chernozem – in Ukrainian classifi cation) was studied during the growing season of 2011–2012. The observations were based on two fi eld experiments with various methods of soil till- age (6–7 years from the beginning of the experiment) and fertilization systems (21–22 years from the beginning of the experiment). Particularly, plowing at 20–22 cm, disking at 10–12 cm, cultivation at 6–8 cm and direct seeding using Great Plains drill were studied among the soil tillage methods. Mineral system (N 45 P 50 K 45 ), organic system (manure 8 t/ha) and combined organic-mineral system (manure 8 t/ha + N 45 P 50 K 45 ) were studied among fertilization systems. The intensity of CO 2 fl ux was determined using the non-stationary respiratory chambers by the alkaline absorption method, with averaging of the results during the day and the frequency of once a month. Results. During the warm period, the emission of carbon dioxide from the soil changes dynamically depending on temperature and humidity. The maximum of emission coincides with the periods of warm summer showers in June-July, the minimum values are characteristic for the late autumn period. The total emission losses of carbon in chernozems over the vegetation period ranged from 480 to 910 kg/ha and varied depending on the methods of tillage ± (4.0–6.0) % and fertilization systems ± (3.8–7.1) %. The changes in the intensity of CO 2 emission from the soil under different methods of soil tillage are associated with hydrothermal regime and the depth of crop residues location. The biggest difference is observed im- mediately after tillage, but in the spring period the differences are only 12–25 %, and after drying of the top layer of soil become even less. Direct seeding technology provides the greatest emission of CO 2 from chernozem, which is fa- cilitated by better water regime and more complete mineralization of plant residues on the soil surface. Annual losses of carbon are the least under disking of soil at 10–12 cm. The changes in the intensity of CO 2 emission from the soil under different fertilization systems are associated with the involvement of the additional organic matter from plant residues and manure to the microbiological decomposition. The greatest emission was observed under the organic- mineral fertilization system, which increased the loss of carbon by 7–8 % in comparison with the mineral system in the unfavorable hydrothermal year and by 11–15 % in the more favorable year. These differences are observed mainly during the fi rst half of the growing season when there is a clear tendency to increase the intensity of soil respiration. Conclusions. The hydrothermal conditions of the warm period of the year are decisive in the formation of the CO 2 emission fl ow from chernozems. Due to the improvement of agricultural practices, emissions might be reduced but not more that by 15 % of natural factor contribution.

Effect of hydrothermal conditions on microstructures of pure and doped CeO2 nanoparticles and their photo-catalytic activity: degradation mechanism and pathway of methylene blue dye

CeO2, Sm and Gd doped CeO2 were synthesized using the hydrothermal route. The influence of synthesis conditions on the crystal structure, particle size and microstructure was investigated. The prepared nanoparticles were characterized using X-ray powder diffraction, FT-Raman spectroscopy, transmission electron microscopy and scanning electron microscopy. The photo-catalytic degradation of methylene blue was examined under UV light using the prepared nanoparticles at different conditions (pH, dye concentration, catalyst dosage). The photo-catalytic activity of CeO2 was kinetically enhanced by trivalent cations (Gd+3 and Sm+3) doping. The results displayed the excellent catalytic activity of the Gd doped CeO2 as compared to that Sm doped CeO2 and the undoped one. The degradation pathways of MB were followed using liquid chromatography/mass spectroscopy (LC/MS), it was found that MB was degraded completely into safe byproducts. The total organic carbon content measurements confirmed the results obtained by LC/MS.

Synergistic effect of sodium ions and fluoride ions on synthesis of pure-phase TiO2(B) nanorings

TiO2(B) has received growing interest as negative electrode materials for Li-ion batteries in recent years. However, its metastability is an intrinsic obstacle for obtaining highly pure-phase TiO2(B). In this study, we reported the synthesis of pure-phase TiO2(B) nanorings with high crystallinity via one-pot hydrothermal method in the presence of sodium fluoride (NaF) solution. The as-prepared TiO2(B) nanorings were systematically characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscope (SEM), and X-ray photoelectron spectroscopy (XPS). The TiO2(B) nanorings had an outer diameter of about 400 nm and inner diameter of about 150 nm. Sodium fluoride was used as phase and morphology control agent. The growth mechanism revealed that sodium ions (Na+) and fluoride ions (F−) had a synergistic effect on the synthesis of pure-phase TiO2(B) nanorings. The morphologies and crystalline phases were easily tailored by tuning the concentration of NaF. The effect of hydrothermal condition on growth of TiO2(B) nanorings was investigated in detail. The as-prepared TiO2(B) nanorings displayed high performance as negative electrode materials in Li-ion batteries.

Cobalt nanoparticles imbedded into zeolite crystals: A tailor-made catalyst for one-step synthesis of gasoline from syngas

The cobalt-imbedded zeolite catalysts in which Co3O4 particles were compatibly imbedded or confined into the zeolite crystals were prepared with the conventional Co/SiO2 catalyst as the precursor and the silica source by a hydrothermal synthesis method. The effect of hydrothermal condition on the catalyst properties and the catalytic performance for the direct synthesis of gasoline-range hydrocarbons was comparatively investigated in this work. And the formation mechanism for the synthesis of this kind of catalyst was proposed. The coincidence of the rate of the silica dissolving process and the zeolite crystallization process was proved to be the key to the rational design of this imbedment-structured catalyst. Compared with the conventional Co/SiO2 catalyst and the zeolite-supported catalyst, the optimized cobalt-imbedded zeolite catalysts present significantly higher gasoline selectivity and produce more iso-paraffins, which can be reasonably attributed to the confined reaction environment, the high diffusion efficiency, the proper reduction behavior, and the suitable acidic properties.

Hydrothermal Degradation of Enzymatic Hydrolysis Lignin in Water-Isopropyl Alcohol Co-Solvent

The effect of hydrothermal conditions on enzymatic hydrolysis lignin (EHL) degradation in water-isopropyl alcohol co-solvent and optimal conditions were investigated. The yields and reactivity toward formaldehyde of degraded enzymatic hydrolysis lignin (DEL) were determined. The optimal conditions of temperature, time, and ratio of solids to liquids were 250 °C, 60 min, and 1:10 (w/v), respectively. The EHL and DEL were characterized by gel permeation chromatography (GPC), Fourier transform infrared spectroscopy (FT-IR), 1H nuclear magnetic resonance (1H NMR), thermal gravity (TG), and differential scanning calorimetry (DSC) analyses. The results revealed that the molecular weight and polydispersity of DEL were lower than that of EHL. Although the fundamental structure of lignin before and after hydrothermal degradation was retained, the ether (β-O-4, α-O-4, etc.) content decreased, while that of hydroxyl (phenolic and aliphatic) increased. The DTGmax and Tg values shifted from 334 and 117 °C to 304 and 105 °C, respectively.