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The byproduct "bio-char" produced by the pyrolysis process was characterized to investigate the properties and its appropriateness for energy application. The pyrolysis reaction was carried out at 300, 350, 400, and 450 °C and 1-h reaction holding time. The analytical techniques TGA/DTG, FT-IR, XRD, SEM, CHNS, and BET were used for the characterization of the different bio-char properties. Results showed that the carbon content in rice straw bio-char increased from 42.20 to 45.33%, with increasing pyrolysis temperatures from 300 to 450 °C. CHNS, XRD, FT-IR, and TGA analysis showed that the bio-char aromatic structure was rich in carbon and it demonstrated higher bio-char carbon stability at 450 °C. With increase in temperature from 300 to 450 °C, the specific surface area of the bio-chars was enhanced (1.17 to 6.60 m2/g). At higher temperatures, biomass macromolecules decomposed completely and bio-char became more porous in nature with voids created within the bio-char matrix. During the pyrolysis of the rice straw biomass, the sharp peaks of the crystalline structure were destroyed and less intensity broader peak appeared in the pyrolysis derived bio-chars. The atomic ratio of H/C and O/C decreased with increase in pyrolysis temperature from 300 to 450 °C. These low values indicate that the reaction temperature promoted the loss of oxygen and hydrogen. [ABSTRACT FROM AUTHOR]

Tamarind seed husk biomass has been explored to study its slow pyrolysis behaviour and potential for bio-oil and biochar production. No study has been reported on the slow pyrolysis of seed husk of tamarind with detailed characterisation of pyrolysis products and in-depth investigations into the breaking pathways using Py-GC/MS. The slow pyrolysis was conducted in a lab-scale glass tubular reactor from 300 to 450 ℃ at a heating rate of 10 ℃/min in a nitrogen atmosphere. An optimised quantity of bio-oil (maximum yield: 38.8 wt.%) was obtained at 400 ℃ at a conversion of 67.1 wt.%, and biochar yield was 32.9 wt.% from slow pyrolysis. Different characterisation techniques were used for slow pyrolysis bio-oil and biochar analysis, such as GC–MS, FTIR, 1HNMR, XRD, SEM and proximate analysis. GC–MS analysis indicated the phenolic-rich nature of the bio-oil with various functionalities. However, more profound insights into its decomposition pattern have been provided using flash pyrolysis via an analytical tool, i.e., Py-GC/MS, which demonstrated breaking patterns of biomass framework and enabled the mechanism to be outlined. [ABSTRACT FROM AUTHOR]

With the extraction of essential oils, a large amount of residual biomass is produced and they can be a good source of functional chemicals/energy. In this study, Py-GC/MS and slow pyrolysis of eucalyptus, mentha, and palmarosa were performed at various temperatures ranging from 300–450 °C to understand the distribution and characterization of the products. Under slow pyrolysis conditions, maximum bio-oil yield for eucalyptus (50.6 wt.%) and palmarosa (42.6 wt.%) was observed at 400 °C; however, for mentha (39.5 wt.%), it was observed at 450 °C. From bio-oil analysis, mentha showed a maximum area% of carbonyls (47.72%); however, phenolics were present in maximum area% in eucalyptus (63.82%) and palmarosa (46.39%). Eucalyptus bio-char showed a higher surface area as compared to the other bio-chars. [ABSTRACT FROM AUTHOR]

Developing efficient process and technologies for the conversion of lignin into valuable functional chemicals is an important aspect of the biorefinery concept. In this study, the effect of low-cost base catalyst (NaOH, KOH, K2CO3 and Na2CO3) and acid catalyst formic acid (FA) was examined for the effective depolymerization of lignin into monomers of phenolic compounds at low temperatures (140, 160 and 180 °C). Also, different reaction residence time (30, 60 and 120 min.), catalyst amounts have been varied to optimize the liquefaction reaction conditions. In the case of non-catalytic experiments, maximum bio-oil yield (14.2 wt.%) was obtained at 160 °C for 30 min. reaction time. With K2CO3 catalysts, maximum bio-oil yield of 26.0 wt.% was observed, whereas in case of formic acid (FA) catalyst lignin depolymerization is very effective as it produced maximum bio-oil yield of 78.0 wt.%. Bio-oils were characterized using GC–MS, FT-IR, NMR analytical methods. Bio-oil analysis showed that it contained higher amount of phenolic monomers after lignin depolymerization. Higher amount of vanillin (41.9%) and isovanillin (44.9%) was found without catalyst and with FA liquefaction reaction. However with base catalyst, dibutyl phthalate (28.8%) was observed as the major compound in lignin depolymerization derived bio-oil. Solid residue analysis shows that base and acid catalyst depolymerized lignin in different ways by breaking of C-O and C–C bonds. [ABSTRACT FROM AUTHOR]

Hydrothermal liquefaction (HTL) is an effective process for bio-oil production. To date, various co-liquefaction studies have been performed using biomasses with significantly different compositions in the presence of various solvents. The present study investigates the co-hydrothermal liquefaction of Prot lignin (PL) and Sargassum tenerrimum macroalgae (ST) in water, ethanol, and water–ethanol solvent mixture in different ratios of feedstocks (1:1, 7:3, and 3:7) at 280 °C for 15-min reaction residence time. The bio-oil and bio-char yields are measured at different operating temperatures, solvent mixture, and biomass blending ratios to understand the compound distribution. Lower bio-oil and higher solid yields were obtained in co-liquefaction experiments as compared to the liquefaction of individual lignin feedstock, whereas the opposite was found with macroalgae feedstock. Individual solvent such as water and ethanol produced bio-oil yield as 5.0 wt% and 13.5 wt% (with 1:1 feedstock), respectively. Maximum bio-oil yield (51.66 wt%) was obtained with 7:3 (lignin: macroalgae feed) under water–ethanol solvent mixture. With an increase in macroalgae feed, the bio-oil yield was reduced by a significant amount (16.1 wt%). Gas chromatography with mass spectrometry (GC–MS) results showed that organic compounds were detected in all bio-oils in the order of phenol derivatives > acids/esters > ketones/aldehydes > nitrogen-containing > aromatics compounds. Furthermore, bio-chars from co-liquefaction have been analyzed using Fourier transform infrared spectroscopy (FTIR) and elemental methods for understanding the carbon and functionality distribution in bio-chars. The present study demonstrated an efficient co-HTL process for the production of functional compounds. [ABSTRACT FROM AUTHOR]

Lignin—an underutilized component of lignocellulosic biomass and an aromatic polymer has an immense potential for the production of valuable chemicals. The ultimate goal of our research is to understand the lignin depolymerization at a lower temperature to obtain valuable chemicals such as vanillin, phenol-2-methoxy in the absence of a solid catalyst. Alkali lignin was depolymerized using polar protic solvents such as methanol, ethanol, and water and with co-solvents methanol-water, ethanol-water, and methanol-ethanol system at 120 °C under nitrogen (N2) and hydrogen (H2) and reaction pressure (1, 5, 10, 15, and 20 bar). The results show that efficient depolymerization can be achieved in an ethanol-water (50/50, W/W) co-solvent system under an N2 environment. The use of H2 enhanced lignin depolymerization and maximum bio-oil yield (51.6 wt.%) was observed under 10 bar H2 pressure with an ethanol-water solvent system. The bio-oil was analyzed using GC-MS, FT-IR, and 1H-NMR. The bio-oil compounds identified from GC-MS analysis were classified into G, H, and other type compounds. Interestingly, higher selectivity (90.77%) of G-type compounds was found in lignin depolymerized bio-oil with a high yield of vanillin. The reaction mechanisms showed that functional compounds are produced from the cleavage of ether C-O (β-O-4) type and C-C (5-5) type bonds. [ABSTRACT FROM AUTHOR]

Lignin is a macro polymer with aromatic structure and is a highly promising renewable carbon source for valuable chemicals and energy. It is available in huge quantities as a by-product from the paper & pulp industry and 2G ethanol industry. Valorization of lignin into useful chemicals can play a vital role in overcoming the demand of diverse chemicals being produced from petroleum feedstock. In the present study, we have examined the oxidative conversion of prot lignin in the presence of Cu/γ-Al2O3, Mn/γ-Al2O3, and Cu-Mn/γ-Al2O3 in water and ethanol-water co-solvent mixture. In water, maximum bio-oil yield of 24.0 wt.% was noticed with Cu/γ-Al2O3. In the case of ethanol-water (50/50) (wt/wt) co-solvent mixture, the maximum bio-oil yield of 74.3 wt.% was obtained with Cu/γ-Al2O3, catalyst. The bio-oil was analysed by GC-MS, 1H-NMR, and FT-IR analyses. The GC-MS compounds were grouped as phenolic (G-, H-, and S-type), heterocyclic, acidic, and other type compounds. Among all the catalysts, Cu/γ-Al2O3 showed the maximum amount of phenolics (84.2%) using 25/75 (wt/wt) ethanol-water solvent. In the case of water as reaction medium, the non-catalytic and catalytic oxidation of lignin showed the maximum selectivity towards acetosyringone with area percentage as 42.0% and 34.4% respectively. In addition, the formation of vanillin (20.7%) was observed in the presence of Cu/γ-Al2O3 using water. [ABSTRACT FROM AUTHOR]

The hydrothermal liquefaction (HTL) process is a promising direction for the conversion of waste biomass into valuable chemicals/fuels. Optimization of the process parameters for HTL of biomass has been the research scope in recent years. The study aims to examine the effects of process variables such as the effect of temperature, the role of solvents: water (H2O), methanol (CH3OH), and ethanol (C2H5OH) on hydrothermal liquefaction of the corncob biomass. Hydrothermal liquefaction has been carried out at temperatures of 260, 280, and 300 °C with a reaction holding time of 15 min. The maximum bio-oil yield was obtained (38.0 wt%) at 280 °C in the presence of H2O, whereas in the case of CH3OH and C2H5OH solvents, the maximum bio-oil yield was 18.67 wt.% and 16.83 wt.% at 260 °C and 300 °C, respectively. The solvent efficiency in corncob liquefaction was observed as H2O ˃ CH3OH ˃ C2H5OH for bio-oil production. The obtained bio-oils were characterized in detail using GC-MS, FT-IR, and 1H NMR. From the GC-MS analysis of bio-oil, the phenolic compounds were observed to a higher degree (60%) in the case of H2O solvent than CH3OH and C2H5OH solvent (57% and 46%). Also, FT-IR analysis showed that higher aromatic functional groups present in bio-oil obtained with water solvent while liquefaction with alcoholic solvent showed higher ester functional groups. Moreover, the analysis of bio-residues indicated that the decomposition of the corncob occurred in a different way during HTL with the presence of different solvents. [ABSTRACT FROM AUTHOR]

Photo-electrochemical properties of fluorine-doped tin oxide (FTO)/nickel oxide-nickel (Ni0.98Si0.02O2-Ni) with isolated Si sites are discussed. The Ni0.98Si0.02O2-Ni photo-electrocatalyst without any noble metal was prepared using a one-step chemical reduction precipitation method. Photo-electrochemical properties were investigated by cyclic voltammetry and chronoamperometry techniques in aqueous alkaline solution at pH 8.0. The photo-electrochemical response of the catalyst showed sensitivity to visible and UV light. The catalyst produced hydrogen from water at a rate of 0.5 mmol g−1 h−1 with the reduction of CO2 into CO under visible light in the absence of any light sensitizer or a noble metal. The metallic Ni amount in the catalyst system was optimized to obtain the best photo-electrocatalyst. The first principle DFT study showed that the incorporation of Si sites allowed absorbance of visible light. The catalyst was characterized by powder x-ray diffraction (PXRD), scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), inductively coupled plasma- atomic emission spectroscopy (ICP-AES), Brunauer–Emmett–Teller (BET), cyclic voltammetry, and chronoamperometry. The products were analyzed by gas chromatography- thermal conductivity detector (GC-TCD). [ABSTRACT FROM AUTHOR]

Cotton production is accompanied by generation of huge amounts of residue all over the world. Slow pyrolysis of cotton residue has been carried out under nitrogen atmosphere at temperatures of 300, 350, 400 and 450 °C. Maximum bio-oil yield of 38 wt% was obtained at 400 °C. The organic fraction of bio-oil has been characterised using Fourier transform infrared spectroscopy (FT-IR), proton nuclear magnetic resonance (H-NMR) and gas chromatography-mass spectrometry (GC-MS). Bio-oil contains phenolic compounds which are mostly derived from lignin fraction. The bio-char characterisation using FT-IR, powder X-ray diffraction (XRD) and scanning electron microscope (SEM) indicate the aromatic structure of bio-char. The gas characterisation indicates that decarboxylation and decarbonylation reactions have majorly occurred during pyrolysis. [ABSTRACT FROM AUTHOR]

A case of total urinary incontinence following Y.V. plas y which continued after reverse Y.V. plasty in an 8-year-old boy is presented. A simplified technique of operation at the bladder neck and posterior urethra is described with separation of the symphysis pubis for better exposure of the part. The patient was completely continent and voiding was normal after the operation. Though the follow up period is short, the result is very encouraging and worth a trial in other similar cases. [ABSTRACT FROM AUTHOR]