Showing papers on "Sawdust published in 2019"

Natural deep eutectic solvents (DES) for fractionation of waste lignocellulosic biomass and its cascade conversion to value-added bio-based chemicals.

Abstract: Deep eutectic solvents (DES), prepared from choline chloride (ChCl) compound as hydrogen bond acceptor and lactic acid (LA), oxalic acid (OA), potassium hydroxide or urea (UA) as the electrostatic attracting donors in different amount ratios, were synthetized, applied and studied for lignocellulosic biomass fractionation. The mixtures of ChCl with OA or KOH were found to dissolve beech wood polymers more effectively compared to ChCl with LA or UA. In addition to DES screening test experiments, the influences of the process performance parameters, like measurement reaction time (2–24 h), temperature (60–100 °C) and the chip to solution mass relationship (1:100–1:10), on particle size distribution, solid residue's properties, functional cellulose, hemicellulose and lignin contents, the concentration of sugars, polyphenolics and volatile chemical products in raw liquid extract, as well as kinetics were experimentally determined. The further spectroscopic, microscopic and chromatographic analysis of solubilisation demonstrated that ChCl with OA selectively isolated phenols, could potentially be scalable and could be utilized in lignin-first bio-refinery plant. Purified cellulose-rich material was obtained, according to attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR), while polyphenols were above 15 g L−1 (gallic acid equivalent, examined by Folin–Ciocalteu method), revealing predominant dissolution. Conversely, for ChCl with KOH, aromatics were below detection limit value, while polysaccharides dropped for a factor of 10, paralleled to sawdust's fresh sample. The DES recovery by centrifugation, anti-solvent-assisted phase separation and vacuum distillation operation was also performed. While promising, NADES must be additionally developed, especially considering recycling, stability and economics.

Modeling adsorption mechanism of paraquat onto Ayous (Triplochiton scleroxylon) wood sawdust

Abstract: The equilibrium sorption of a local Ayous (Triplochiton scleroxylon) wood sawdust was examined as substitute adsorbent for removal of paraquat from water. Langmuir, Freundlich, Temkin and Dubinin–Radushkevich (DRK) isotherms were used to compare the equilibrium sorption data obtained. The separation factor revealed a constructive sorption experiment since the maximum monolayer coverage (Q0) from Langmuir isotherm model was found out to be 41.66 µmol/g. In addition, the correlation value of Langmuir isotherm model was the maximum among the four adsorption isotherms. From Freundlich isotherm model, the sorption intensity (n) that denotes favorable sorption and the correlation value are 2.402 and 0.929, respectively. Temkin isotherm model was used to calculate the heat of sorption process which corresponds to 18.39 J/mol, and the mean free energy was estimated from DRK isotherm model to be 0.091 kJ/mol which vividly proved that the adsorption experiment was obeyed to a physical process. The results indicate that this local wood sawdust could be employed as an economical material for reducing paraquat from industrial wastewater.

Nitrogen-Doped Biomass-Derived Carbon Formed by Mechanochemical Synthesis for Lithium-Sulfur Batteries.

Abstract: Nitrogen-doped carbons were synthesized by a solvent-free mechanochemically induced one-pot synthesis by using renewable biomass waste. Three solid materials are used: sawdust as a carbon source, urea and/or melamine as a nitrogen source, and potassium carbonate as an activation agent. The resulting nitrogen-doped porous carbons offer a very high specific surface area of up to 3000 m2 g-1 and a large pore volume up to 2 cm3 g-1 . Also, a high nitrogen content of 4 wt % (urea only) up to 12 wt % (melamine only) is generated, depending on the nitrogen and carbon sources. The mechanochemical reaction and the impact of different wood components on the porosity and surface functionalities are investigated by nitrogen physisorption and high-resolution X-ray photoelectron spectroscopy (XPS). These N-doped carbons are highly suitable as cathode materials for Li-S batteries, showing high initial discharge capacities of up to 1300 mAh gsulfur-1 (95 % coulombic efficiency) and >75 % capacity retention within the first 50 cycles at low electrolyte volume.

New sound absorbent composite materials based on sawdust and polyurethane foam

Abstract: New composite materials based on sawdust as reinforcing material and polyurethane foam as a binder agent, exhibiting sound absorbing proprieties, have been obtained. Due to the sound-absorbent proprieties exhibited by these type of materials, 11 new composite systems have been obtained varying the type and the size of sawdust particles, the percentage of binder and the thickness of material. The sound absorption properties of the new obtained materials are directly correlated with the composition, the thickness of materials as well as the air gap samples and the rigid wall. In addition, the morphological and thermal conductivity proprieties and the mechanical ones, of the new obtained materials, were carried out.

Assessment of energy parameters of biomass and biochars, leachability of heavy metals and phytotoxicity of their ashes

Abstract: The aim of this study was to determine selected energy parameters, leachability of heavy metals and phytotoxicity of biomass ash for different types of plant biomass (wheat straw, miscanthus straw, bark and sawdust) and poultry manure, as well as biochars produced from them. Based on data from proximate and ultimate analysis of the investigated materials, fuel value index (FVI) was calculated to determine their suitability for energy production. The ashes were analyzed for both chemical composition and leaching behavior. The phytotoxicity test of aqueous ash extracts was performed for Lepidium sativum L. It was found that the calorific value of biochars was higher on average by 36% than the value determined for feedstocks used in the pyrolysis process. The pyrolysis of organic materials resulted in the reduction of the volatile matter content. The gross calorific value was determined in biochars formed from miscanthus straw and sawdust which were 26.6 and 23.4 MJ kg−1, respectively. Leachability of heavy metals of biomass ash was highly diverse and depended on the analyzed element and the material type. The phytotoxicity analysis showed that, in general, each of the ash extracts tested had a positive effect on the growth of Lepidium sativum L. compared to the control. The use of ash, fertilizer, or sorbents can be an interesting alternative for materials with high ash content. In all these cases, biochars seem to be very attractive materials that can be used not only in energy production. Given the high carbon content of biochar obtained in the pyrolysis process, it has a high-energy potential and can be used as a biofuel.

Catalytic conversion of lignin in woody biomass into phenolic monomers in methanol/water mixtures without external hydrogen

Abstract: The valorization of lignin in renewable lignocellulosic biomass is an important target in the transition to a more sustainable production of fuels and chemicals. We present here a modification of the “lignin-first” approach that does not hinge on the use of external hydrogen. Instead, we use methanol/water mixtures as a suitable solvent that can be partly reformed into hydrogen. We propose a one-step process in which in planta lignin (wood sawdust) is converted to phenolic monomers over a Pt-based catalyst in an inert atmosphere. The role of the methanol/water mixture is not only to supply hydrogen but also to extract lignin fragments from the biomass matrix. Pt catalyzes methanol reforming to obtain hydrogen and the stabilization of reactive lignin intermediates by hydrogenation of reactive bonds. The latter aspect is crucial to avoid unfavorable condensation of fragments. Under optimized conditions, a yield of phenolic monomers of nearly 50% can be obtained from birch wood at a temperature of 230 °C in 3 h.

Adsorptive Behavior of Methylene Blue onto Sawdust of Sour Lemon, Date Palm, and Eucalyptus as Agricultural Wastes

Abstract: In the present study, to remove methylene blue (MB) from aqueous solution, some agricultural residues and cheap bioadsorbents such as sawdust of palm trees, eucalyptus, and sour lemon were used. To...

Processability and Degradability of PHA-Based Composites in Terrestrial Environments

Abstract: In this work, composites based on poly(3-hydroxybutyrate-3-hydroxyvalerate) (PHB-HV) and waste wood sawdust (SD) fibers, a byproduct of the wood industry, were produced by melt extrusion and characterized in terms of processability, thermal stability, morphology, and mechanical properties in order to discriminate the formulations suitable for injection molding. Given their application in agriculture and/or plant nursery, the biodegradability of the optimized composites was investigated under controlled composting conditions in accordance with standard methods (ASTM D5338-98 and ISO 20200-2004). The optimized PHB-HV/SD composites were used for the production of pots by injection molding and their performance was qualitatively monitored in a plant nursery and underground for 14 months. This study presents a sustainable option of valuation of wood factory residues and lowering the production cost of PHB-HV-based compounds without affecting their mechanical properties, improving their impact resistance and biodegradability rates in terrestrial environments.

Natural Sawdust as Adsorbent for the Eriochrome Black T Dye Removal from Aqueous Solution

Abstract: This paper deals with the adsorption of an anionic dye, Eriochrome Black T (EBT), from aqueous solutions onto sawdust, which is a natural, eco-friendly, widespread, and a low-cost bio sorbent. The aim of the work is to append values to the wood industry waste. Thus, sawdust was used as adsorbent in both batch reactor (BR) and fixed bed column (FBC), and various operating parameters influencing the adsorption process were investigated. The kinetic and the equilibrium adsorption results were found to agree with, respectively, the prediction of the pseudo-second-order equation and the Langmuir model. This latter allowed also the determination of the maximum EBT dye adsorbed amount, which was found to be about 40.96 mg EBT per gram of sawdust at pH = 4, corresponding to % dye removal of about 80%. In addition, the influence of various parameters on the dye adsorption, such as the adsorbent dose, the aqueous phase pH, and the initial dye concentration, was also examined. In batch experiments, The EBT adsorbed amount was found to increase either by increasing the amount of sawdust or by decreasing the aqueous phase pH, whereas, in the fixed bed column, the EBT retention was found to increase by decreasing the flow rate of the dye through the column. The overall data indicate that the EBT adsorption is mainly governed by the electrostatic interactions occurring between the adsorbent material and the dye.

Preparation of Lignin Nanoparticles from Wood Waste for Wood Surface Treatment.

Abstract: Lignin was isolated from wood wastes comprising Iroko sawdust (IR) and mixed sawdust from Iroko and Norway spruce (IRNS), furnished by a local wood houses producer. The respective acidolysis lignin fractions were structurally characterized using pyrolysis (Py)-GCMS, two-dimensional heteronuclear single quantum correlation nuclear magnetic resonance (2D HSQC NMR), Fourier-transform infrared FTIR and ultraviolet-visible (UV-VIS) spectroscopies, size exclusion chromatography, and standard wet-chemistry methods for Klason lignin and polysaccharides determination. The isolated lignin fractions were subsequently used for the preparation of lignin nanoparticles (LNPs) using a non-solvent method. LNPs were then used for wood surface treatment using a dip-coating technique. The coated wood samples were analyzed by colorimetry and scanning electron microscopy (SEM) before and after artificial weathering experiments in a UV chamber to investigate the UV protection potential of the LNPs coatings. Wood samples dip-coated with LNPs showed promising surface modifications resembling a sort of film of fused LNPs. Coatings made from IR-LNPs and IRNS-LNPs performed significantly better in artificial weathering experiments than uncoated reference samples.

Combustion characteristics of fuel briquettes made from charcoal particles and sawdust agglomerates

Abstract: The combustion characteristics of fuel briquettes made from Idigbo (Terminalia ivorensis) charcoal particles, pinewood (Pinus caribaea) sawdust and their agglomerates using gelatinized cassava peels were investigated. The charcoal particles and pine sawdust were blended in the mixing ratios of 90:10, 80:20, 70:30, 60:40, and 50:50, respectively and vice-versa. More so, briquettes were produced from pure charcoal particles and pine sawdust separately for the purpose of comparison with the blended briquettes. The gelatinized binder was 5% of the total briquettes weight. The briquettes were produced using a pressure of 5 MPa with a dwelling time of 5 min in a hydraulic briquetting machine. Proximate, elemental compositions and heating value analyses were carried out on the raw charcoal, sawdust, cassava peel, and their briquettes. The results showed that variations in the mixing ratios of the bio-residues had significant effects on all the properties investigated. An increase in the charcoal particles led to an increase in the fixed carbon content and heating value of the briquettes. Conversely, higher pine sawdust content in the briquette resulted in higher volatile matter content and lower heating value. The briquette made from pure charcoal particles had the highest heating value (24.9 MJ/kg) and ash content (6.0%). Its carbon, hydrogen, and oxygen contents were in the range of 44.6–50.1%, 5.1–5.6% and 34.4–41.5%, respectively. The proximate analysis, elemental composition analysis, and heating values of the produced fuel briquettes depicted that they have better combustion properties when compared to the raw charcoal, pine dust, and cassava peel. Thus, the produced briquettes would serve as good fuel for domestic and industrial applications.