Wood Biomass from the Model Wastewater and Its Fractionation

The production of veneer in Latvia and many countries of East Europe is accomplished by the hydrothermal treatment of hardwood in special water basins. As a result, formed effluents contain wood-originated pollutants, which are responsible for the enhanced chemical oxygen demand and the intensive colour of the wastewater. Keeping in mind the volume of the polluted effluents formed annually at the Latvian plywood plants, it is very important to extract qualitatively and quantitatively the formed biomass from the effluent. The choose of an effective method of the waste biomass extraction depends on chemical characterisation of the effluent. In this work, for imitating woodworking wastewater, birch sawdust was hydrothermally treated in mild alkaline conditions at 90°C. The yield of the solid biomass did not exceed 7% and contained, mainly, hemicelluloses in the polysaccharide form and lignin. The applied instrumental analysis (FTIR-, UV-, Raman spectroscopy) testify the dominant content of hemicelluloses in the obtained biomass. The fractionation of the biomass was performed using concentrated sulphuric acid and ethanol. As the obtained results have shown, the content of lignin, hemicelluloses and water-soluble degraded wood products in the solid biomass corresponded to the following mass ratio: 1.2 /6.7 /1.0, respectively

Preliminary Study of the Biorefinery Concept to Obtain Furfural and Binder-less Panels from Hemp (Cannabis Sativa L.) Shives

AbstractThe objective of the study was to investigate the preliminary technological parameters for obtaining furfural and binder-less panels depending on hydrothermal pre-treatment temperature, steam explosion treatment and pressing conditions. If the pre- treatment temperatures were 160–180°C and the time 90min, the yield of furfural was 64.8–67.2% from that which was theoretically possible. The furfural obtaining dynamics significantly increases in the first 10minutes, when the yield of furfural at 180°C is almost twice as high as at 160°C. The obtained maximal MOE value (3250N mm-2) and good enough surface of some panels demonstrate that all prepared hemp shives materials can be used for binder-less panel production. The obtained excellent correlation between MOE and MOR values (r = 0.9) demonstrates that the strength of the composites could be predictable

Influence of Biomass Pretreatment Process Time on Furfural Extraction from Birch Wood

Furfural is a biomass derived-chemical that can be used to replace petrochemicals. In this study, dilute sulphuric acid hydrolysis was used for hemicelluloses secession from birch wood. The reaction was investigated at different biomass treatment times (10-90 min, increasing it by 10 min). We found that the greatest amount of furfural 1.4-2.6%, which is 9.7-17.7% from theoretical possible yield, was formed in the first 30 min of the beginning of birch wood pentoses monosaccharide dehydration, but the greatest yield of furfural 10.3%, which is 70.0% from the theoretical yield, can be obtained after 90 min. Given that furfural yield generally does not exceed 50% from the theoretical amount, the result can be considered as very good

Changes in the Birch Wood Lignocellulose Composition in the Pretreatment Process

In the near future, deciduous wood may be a real alternative to oil as a raw material for production of chemicals and motor fuel. Now bioethanol is produced mainly by fermenting starch-containing (wheat, corn) and sugar-containing (sugar beat, sugar cane) materials. However, in the very immediate future, the circumstances of these raw materials and the new situation in the oil market will put up the use of biomass for the production of bioethanol and different chemicals such as furfural and acetic acid. Unfortunately, till now, the joint production of bioethanol and furfural had not been possible because of the 40-50% cellulose degradation during the furfural obtaining process. The aimed change in the mechanism of the process has permitted to solve two problems simultaneously, namely, to increase the furfural yield from 50% up to 70% from the theoretically possible one and to diminish 7 times the degree of cellulose destruction in the lignocellulosic residue. Based on the theoretical studies of this process, a new technology including two-step hydrolysis of hardwood may be developed

Impact of Birch Wood Prehydrolysis Conditions upon the Yield and Properties of Activated CarbonfFrom Lignocellulose

The xylan-rich outer layer of birch veneer blocks making plywood factory residue veneer shorts is an ideal raw material for production of furfural, acetic acid and activated carbon. The aim of our investigation was to find optimum prehydrolysis conditions, within the limits of technological parameters tested at present, and to secure high yield and quality of all intended products. It has been elucidated that a 2% catalyst (H2SO4) concentration at 167–177oC ensures high yield of furfural and the quality of lignocellulose is appropriate for processing into activated carbon. During prehydrolysis, the plasticity of lignocellulose is greatly improved, and it granulates perfectly. The activated carbon yield in comparable conditions is by 10–15% higher; the sorption activity of iodine is practically the same (907 and 953 mg I2/g, respectively) as in the case of the catalyst concentration 3% (o.d. wood basis) even not taking into account the 13% lower activated carbon yield at a 3% catalyst concentration. The superheated steam expenditure is lower, since partly it can be substituted by carbon dioxide

Impact of Water-Soluble Substances of Birch Lignocellulose on the Mechanical and Sorption Properties of Granular Activated Carbon

All characteristic lignocellulose specimens made from birch veneer shorts during prehydrolysis and furfural production were studied as carbonisation starting materials. To elucidate the impact of water-soluble substances of lignocellulose on the potential of pores forming, two parallel samples of lignocellulose were prepared, from which one was leached with water. Cellolignin contained 24.5-27.7% water-soluble substances composed of 6.2-7.5% sulphuric acid, 13.5-16.5% levulinic acid 41-51% reducing substances (sugars) and 26-35% unidentified substances- ash, lignans (maximum in UV spectra at λ = 286.6 nm). It must be noted that the charcoal yield was high from the leached lignocellulose too – up to 42-43% on the oven dry lignocellulose mass basis. Testing of the carbonised granules made from washed lignocellulose demonstrated the same high mechanical strength as in the case of unleached lignocellulose-containing water soluble extractives acting as some kind of binders

Granular Activated Carbon from Deciduous Wood Lignocellulose

Since the capacity of an adsorbent is expressed in terms of the surface area or the amount adsorbed per weight unit, high-density adsorbents are required. The dried leftover lignocellulose of furfural production, due to its good self-binding properties, can be granulated or palletized and used as a potential raw material for production of high-density activated carbon sorbents with double density, in comparison with activated carbon from charcoal. These high-density microporous sorbents are appropriate for purifying gaseous media. The chemical and mechanical pre-treatment of lignocellulose imparts new properties to the porous structure of the carbon material and to the activated carbon prepared from it

Characterisation of Biomass from the Wood Hydrolysate and Its Isolation with Organic and Inorganic Polycation

The hydrolysate of the hydrothermal treatment of birch sawdust in the mild alkaline conditions, imitating industrial wastewater, was derived. An attempt to investigate the chemical and component composition of the dry matter of the hydrolysate using FTIR, HLPC and 13 C NMR was made. The comparative effectiveness of the isolation of wood biomass from the hydrolysate with the known coagulants - poly(ethyleneimine) and polyaluminium chloride was assessed