ARTICLE | doi:10.20944/preprints201808.0103.v1
Subject: Environmental And Earth Sciences, Environmental Science Keywords: ammonia nitrogen; bentonite; COD; RSM; sawdust; SBR
Online: 6 August 2018 (09:08:31 CEST)
Water pollutants removal by biomass adsorbent has been considered innovative and cost effective, thus commendable for application in industrial applications. However, certain important aspects have been overlooked by researchers, namely the efficiency in the operation time and pollutant removal. In this research, landfill leachate samples with organic components were treated using bentonite-enriched with sawdust augmented (SBR) process. By modifying the pH, the sawdust samples were categorized into three: the acidic, the alkaline, and the neutral. To bentonite samples, the pH-adjusted sawdust was added at 10%, 20%, and 30% amounts by mass respectively. At the optimum aeration rate of 7.5 L/min and contact period of 22 h, the treatment achieved 99.28% and 95.41% removal of COD and NH3-N with bentonite respectively. For both pollutants, in the presence of sawdust, the removal reduced by about 17% with contact period reduced to 2 h which was a considerable achievement.
ARTICLE | doi:10.20944/preprints201810.0769.v1
Subject: Engineering, Civil Engineering Keywords: Bentonite; Sawdust; Chemically treatment; Heavy metal; Adsorption capacity
Online: 1 November 2018 (18:18:19 CET)
In recent years, the need for safe and modern composite barrier for the prevention of groundwater contamination and the provision of Geo-environmental protection has been studied together with the need of designing low cost and effective liner for isolating landfill contents from the environment. In this study, various mix designs involving two natural adsorbents, the Na-Bentonite and the pH-adjusted sawdust were prepared for a series of Geo-environmental experiments to be carried out to determine the adsorption capacity, buffering capacity, pH changes, and COD changes among others, in the presence of Pb(NO3)2 contaminant concentrations. Generally, the results showed an increase in adsorption capacity in the acidic segment of the treatment. An increase of 58% of the adsorption efficiency of the Na-Bentonite in adsorbing the contaminant at the highest concentration was the most important achievement of the system while in the acidic segment.
ARTICLE | doi:10.20944/preprints202311.0795.v1
Subject: Engineering, Energy And Fuel Technology Keywords: Torrefaction; steam explosion; net present value; pelletization; sawdust; oat straw
Online: 13 November 2023 (10:26:19 CET)
Lignocellulosic biomass has demonstrated great potential as feedstock for pellet production, notwithstanding the fact that the industrial production of pellets is faced with some economic challenges. This study presents a technoeconomic analysis of six case scenarios to develop a process model for pellet production from sawdust and oat straw that employs torrefaction and steam explosion pretreatment prior to pelletization. SuperPro Designer was used to carry out this evaluation. The pellet plants were designed to have a capacity of 9.09 t/h of sawdust and oat straw each. The pellet yield ranged from 59 kt– 72 kt/year. Scenarios analyzed included variations of steam explosion and torrefaction. In some scenarios materials were lost in the form of liquid and gas due to the pretreatment process. The breakdown of equipment purchase cost showed that the torrefaction reactor is the most expensive unit with about 51% of the purchase cost. Facility-dependent and feedstock costs were the major significant contributors to the pellet production cost. The profitability of pellet production as determined by the net present value (NPV), internal rate of return (IRR), and payback period and was found to be sensitive to variations in feedstock cost.
ARTICLE | doi:10.20944/preprints202304.1221.v1
Subject: Chemistry And Materials Science, Paper, Wood And Textiles Keywords: Carbon footprint; Wood residuals; Sawdust; eucalyptol; Odor release; Plywood; carbon footprint
Online: 29 April 2023 (07:27:51 CEST)
A sustainable matrix based on eucalyptol essential oil/sawdust was developed and applied on one-sided laminated plywood. This finish aims to serve as a eucalyptol odor slow release. Eucalyptol odor release was monitored with gas chromatography coupled with a flame ionization detector (GC – FID: Limits of Detection and Quantification of 0.70 g/m3 and 2.11 g/m3, respectively, and with linearity up to 18.6 g/m3). Measurement of the eucalyptol odor released was performed during a six-month period and it was found that the release followed a first-order exponential decay with a decay rate constant of 0.0169 per day. The half-life was determined to be of 48 days. The granulometry and particle size porosity of sawdust were analyzed by Scanning Electron Microscopy. Sawdust size fraction between 112 – 200 μm showed best eucalyptol absorption capacity with 1:3 masses ratio (sawdust:eucalyptol). The time capacity of eucalyptol release depends of composite eucalyptol – sawdust quantity. Where this relation was determined: 15.0 grams of composite eucalyptol-sawdust by 0.8 mm diameter aperture gave 6 months of eucalyptol release, that was considered very positive, understanding high volatility of eucalyptol and a small quantity of composite for further products. The new product is characterized by a carbon footprint (considering the industry frontiers) of 5.94 kg CO2eq/m2 of plywood floor.
ARTICLE | doi:10.20944/preprints202306.1552.v1
Subject: Engineering, Chemical Engineering Keywords: eucalypt sawdust; steam explosion; cellulosic ethanol; PSSF; high total solids; biomass moisture content
Online: 21 June 2023 (12:50:48 CEST)
The generation of eucalypt sawdust has increased in Uruguay with the expansion of pulp and paper industrial sites. Currently, most of this readily available feedstock is either not used or applied for producing heat and power by combustion in biomass boilers. In this work, eucalypt sawdust was subjected to steam explosion as the first step for cellulosic ethanol production within the biorefinery concept. The effect of sawdust moisture content, pretreatment temperature and residence time were evaluated, along with the influence of water washing of steam-exploded solids on enzymatic hydrolysis and fermentation yields. After steam explosion, 60% xylans and 97% acetyl groups were recovered mainly as oligomers and acetic acid in the pretreatment liquor. Eucalypt sawdust moisture content affected the enzymatic hydrolysis performance and glucan conversion efficiency. Water washing after pretreatment improved hydrolysis efficiencies and ethanol production yields by 10% with respect to the unwashed pretreated solids at the same experimental condition. The best ethanol yields were obtained using PSSF (pre-saccharification and simultaneous saccharification and fermentation) after pretreatment at 205°C for 10 min, using sawdust with an 8% moisture content. In this case, 227 L ethanol and 40 kg total xylose (including xylo-oligomers) were obtained per ton of dry eucalypt sawdust.
ARTICLE | doi:10.20944/preprints202202.0244.v1
Subject: Chemistry And Materials Science, Biomaterials Keywords: wood combustion; sawdust pellets; solid woods; heat calorific value; ash content; bio-energy; Papua New Guinea
Online: 21 February 2022 (03:23:34 CET)
Burning woody biomass for energy is gaining attention due to environmental issues associated with fossil fuels and carbon emission. The carbon released from burning wood is absorbed by plants and is carbon neutral. The purpose of this study was to investigate the combustion characteristics (heat calorific values and ash contents) of three timbers: Araucaria cunninghamii, Instia bijuga and Pometia pinnata and recommend for fuelwood. The test samples were sawdust particles (treatment) and solid woods (control) extracted from the heartwoods. The sawdust particles were oven-dried, sieved and pelletized into pellets using a hand-held pelletizing device, thus, forming cylindrical dimension (volume 1178.57 mm3, oven dry density 0.0008 g/mm3). While the solid woods were cubed and oven-dried (volume 1000.00 mm3, oven dry density 0.001 g/mm3). Prior to combustion in a semi-automatic bomb calorimeter, 90 test specimens (15 replicates per treatment and control per species) were conditioned to 14 % moisture content (at temperature 105 ºC) and weighed to a constant (unit) mass (1.0 g). The heat energy outputs and ash residues (of treatments) were analyzed statistically. The results indicated variability in heat energy outputs and ash residues between test specimens of the three species. Comparatively, the treatment specimens of A. cunninghamii produced higher calorific value (18.546 kJ/g) than the control (18.376 kJ/g) whilst the treatment specimens of I. bijuga and P. pinnata generated lower heat calorific values (17.124 kJ/g and 18.822 kJ/g) than the control (18.415 kJ/g and 20.659 kJ/g), respectively. According to ash content analysis, A. cunninghamii generated higher residues (6.3%) followed by P. pinnata (4.5%) and I. bijuga (2.8%). The treatment specimens of the three species could not meet the standard heat energy requirement (20.0 kJ/g) and thus, were unsuitable for fuelwood. However, the control specimens of P. pinnata generated equivalent heat energy (20.659 kJ/g) and could be a potential fuelwood.