Flax Shives Research Articles

Non-competitive adsorption of polycyclic aromatic hydrocarbons and heavy metals on activated carbon produced from flax shives

Non-competitive adsorption of polycyclic aromatic hydrocarbons and heavy metals on activated carbon produced from flax shives

Moisture Properties, Microstructural and Microbiological Characteristics of Flax and Hemp Shives Used in Construction Industry

ABSTRACT The construction industry is among the largest energy-consumer and waste-generating sectors, and it needs sustainable methods and materials to decrease its carbon footprint. One possible solution is to use secondary raw materials and crops as a basis for thermal insulation materials or passive buffers of moisture. This article presents the results of testing raw hemp and flax shives obtained from Polish crops for use in the construction industry. There are only a few works devoted to the parameters of the raw material itself, and no comparative studies are available on the shives themselves. Therefore, it is of utmost importance to compare the properties of shives obtained from these two fibrous plants, to understand their usability and possibilities. Our research focuses on measuring pore size distribution, hygroscopic sorption moisture, capillary rise, and contact angle. It was shown that both types of shives are characterized by similar porosity and hygroscopic sorption characteristics, but different pore size distribution and ability to absorb water through capillary action. Microbiological tests showed variations in the presence of fungi on the shives surfaces. The article also presents an example of the use of the tested materials as an internal wall covering and compares it to gypsum plaster.

Novel approach to bio-inspired triboelectric nanogenerators employing recycled natural fibres for sustainable energy harvesting

By leveraging nature's ingenuity and adopting a circular economy approach, bio-inspired triboelectric nanogenerators (TENGs) can not only generate clean electricity but also contribute to environmental stewardship and resource conservation. Herein, a novel approach to developing bio-inspired TENGs utilizing recycled natural fibres sourced from agricultural waste is reported. The potential of various natural fibres, including coco peat, sugarcane husk, pistachio shell, and flax shive, for integration into TENG applications is investigated. Natural fibres-based TENGs (NF-TENGs) comprising polyvinyl alcohol and the aforementioned agro-waste composites are fabricated using a straightforward solution casting technique. Structural, elemental, and interaction analyses of these fibres are systematically conducted using analytical techniques such as Scanning Electron Microscopy, Energy Dispersive X-ray Spectroscopy, and Fourier Transform Infrared spectroscopy. Electrical characterizations, encompassing voltage, current, and determination of optimal load resistance, along with device stability assessments, are performed on the NF-TENGs. Furthermore, the optimized NF-TENG, composed of flax-seed husk, is demonstrated for powering small-scale electronics including charging electrolytic capacitors, LEDs, and functioning as a self-powered biomechanical sensor. This research marks a significant advancement in sustainable energy technologies by harnessing the latent potential of agricultural waste-derived natural fibres.

THERMAL PROCESSING OF OIL FLAX BONES INTO ACTIVATED CARBON

Flax shives – waste generated during the primary processing of flax in the textile industry, make up 70% of the total mass of oil flax stalks. The results of an experimental study of the thermal processing of oil flax bonfires by the method of slow conductive pyrolysis in the temperature range of 400–650 °C are presented. An experimental bench for thermal decomposition of flax fire and activation of carbon residue by superheated water vapor is presented. The required temperature regimes of pyrogenetic decomposition were established, which are in the range of 500–600 °C. An analysis of the physicochemical properties of experimental samples of biochar obtained by pyrogenetic decomposition of flax fires has been carried out. At low temperatures of 400–430 °C, the specific gravity of carbon is in the range of 80–82%. Under temperature conditions of 500–600 °C, the specific gravity of carbon was 91–93%. At higher temperature conditions, the yield of gaseous products increases, and the ash content in the solid carbonaceous residue increases. The modes of steam activation of biochar from flax fires have been established, so to achieve the best sorption values, water vapor should be at a temperature of 900 °C. A comparative analysis of the sorption abilities of experimentally obtained activated carbon with BAU-A activated carbon is given. Based on the data obtained, it was concluded that the activated carbon from the fire of flax corresponds to the parameters of GOST 6217-74.

Development of cellular construction material-based flax shives: Physico-mechanical and thermal characterisation

The reduction of energy consumption in construction, production of thermal insulation materials, and the solution of environmental problems by recycling by-product derived several industrial sectors are becoming greater problems. In this context, vegetable by-products are an excellent alternative product to substitute mineral aggregates because they are easily available and renewable low-cost raw materials, and have higher advantage for economy and environment concerns. The viability of using vegetable materials such as flax shives for developing a sustainable Lightweight Cellular Construction Material (LCCM) is investigated in this paper. The produced material containing different volumes of flax shives (0V (control specimen), 1V, and 2V) was lightened by creating a porous structure in the matrix through a chemical reaction between Aluminium powder and free lime from pre-formulated Tradical PF70 binder. A study conducted on hardened material properties has indicated a significant reduction in sample unit weight, thereby resulting in a level of compressive strength compatible with a load-bearing wall. The reduction in flexural strength was lower than that in compressive strength. This study has also highlighted the effect of the porous structure on the thermal conductivity that lead to provide a high degree of thermal insulation. These results show that the cellular material based on flax particle can be used as suitable insulated load-bearing walls.

Integration of Organic Waste for Soil Stabilization through MICP

Microbial-induced calcite precipitation (MICP) is an innovative technology in civil engineering. However, the high cost of components and the fragility of the treated soil limit its wide use. One of the possible solutions is organic waste incorporation at different stages of the technology. In the present study, we consider the use of spent brewer’s yeast (BSY) to produce bacterial inoculates and wastepaper, flax shives and sawdust as reinforcing additives into the soil. We showed that the replacement of expensive components of LB medium by BSY extract increased biomass growth characteristics of Bacillus subtilis K51, B. cereus 4b and Micrococcus luteus 6 strains by 1.4, 1.5 and 1.8 times, respectively, while for B. subtilis 168, they were comparable to LB medium. The urease activities of all strains were not reduced compared to the control. Among the three kinds of cellulose-containing waste, wastepaper incorporation into MICP-treated soil samples led to an increase in compressive strength by 2.1 times and precipitated calcite percentage by almost 1.5 times compared to a sample without additives. Thus, we showed the potential for soil stabilization through MICP using organic waste.

CHEMICAL PROCESSING OF AGRICULTURE WASTES INTO VANILLIN, PULP AND GLUCOSE

Agrotechnical wastes from processing herbaceous plants consist of lignin and polysaccharides, which can be processed into monomers – phenols and carbohydrates. The prospects of chemical processing of several agrotechnical waste types with a high lignin content (flax shives, sunflower seed husks and buckwheat husks) into vanillin, pulp, and glucose by oxidation and acid hydrolysis were studied. It has been shown that despite the distant phylogenetic relationship of the studied plants, their lignins have a similar structure: they contain a similar amount of methoxyl groups (10–13 wt.% per lignin) and give close yields of aromatic aldehydes upon oxidation with nitrobenzene (17–19%) and oxygen (14–16%). In general, the suitability of agrotechnical wastes for oxidation to aromatic aldehydes determines by the lignin content. Among the studied wastes, flax shives are the most promising feedstock for chemical processing into vanillin and glucose. Cellulose-containing solid residues of oxidation process are more easily hydrolyzed compared to the initial lignocellulosic biomass. The inversion of glucose oligomers during the hydrolysis of cellulose with H2SO4 is limited by the hydrolysis of the tetra- and octamers.

Mass Transfer in the Processes of Native Lignin Oxidation into Vanillin via Oxygen

The influence of mass transfer intensity on the kinetics of the catalytic oxidation of flax shives with oxygen in alkaline media to aromatic aldehydes and pulp was studied. The process was carried out in two autoclaves, with moderate stirring (stirrer engine of 8 W) and intense stirring (stirrer engine of 200 W). The oxidation of flax shives into vanillin, syringaldehyde, and pulp was shown to proceed as a completely diffusion-controlled process under the studied conditions, both moderate and intense stirring. Depending on the process conditions, it can be limited by stages of oxygen transfer through the diffusion boundary layer near the gas–liquid interface (low intensity of mass transfer) as well as by reagents’ inner diffusion in the porous and solid matter of the flax shive particle (high intensity of mass transfer). The results on the influence of the stirring speed and volume of the reaction mass on the rates of oxygen consumption and vanillin accumulation were obtained. They were described using a known simple model connecting the intensity of mass transfer and the stirring power density in the bulk of the liquid phase in terms of algebra equations.

Torrefaction of Flax Shives as a Process of Preparation Waste Vegetable Biomass for Energy Purposes

Abstract The use of processed biomass, derived from agricultural crop residues, as a fuel is becoming increasingly important in the energy sector, which additionally allows for the management of excess waste that is a burden on the environment. The aim of this study was to investigate the effect of the torrefaction process conditions in a carbon dioxide atmosphere on the chemical structure of biocarbon and the energy parameters of the produced product, which can be a solid biofuel. The biomass chosen for the experimental work was flax shive. Determinations of the heat of combustion of the produced biocarbon samples were carried out using a KL-10 calorimeter, and identification of the molecular structure of the product and the starting biomass was carried out using infrared spectrometry. It was confirmed that increasing the temperature of biomass torrefaction increases the heat of combustion of the product, with this parameter obtaining the most favourable value for biocarbon obtained during torrefaction at 320°C and for 20 to 30 minutes. The heat of combustion of the biocarbon produced during torrefaction at 320°C and for 30 minutes was 25.92 MJ/kg, with a feedstock mass loss of 41%. Such conditions lead to a significant conversion of the chemical structure of the biomass, with no complete destruction of organic structures.

Application of a newly developed sediment-based binder for rapeseed straw and flax shiv concretes

Based on the need to reduce the carbon footprint of binders used for plant-based concretes, the development of lime–pozzolan binders is on the rise. The carbon emissions due to the binder production have to be reduced in such a way to ensure a high level of carbon storage while improving the thermal resistance of building envelopes. This paper intends to assess the technical feasibility of making plant-based concretes by mixing agricultural by-products (rapeseed straw, hemp and flax shives) with a binder composed of micronized marine sediment (non-calcined) and air lime. The hardening kinetics of the lime–sediment binder with sodium sulfate added was examined as a first step. The effect of various drying conditions on the strength development of lime–sediment mortars was then investigated to help understand the strength performances of plant-based concretes following 7 days of heat curing and 21 days at 65%RH.The results indicate that the newly formed solid products in the binder collected in plant-based concretes were mainly calcium carbonate and CO3-AFm. In spite of the low hydration degree of the binder, it was possible to reach an ultimate strength of 0.5─0.6 MPa at 7 % strain for a stabilized bulk density of 560 kg m−3. The rapeseed straw concrete was characterized by a strain hardening behavior due to the presence of tangled fiber-like particles and showed the lowest thermal conductivity (0.077 W m−1 K−1 in the dry state).

Anaerobic Digestion of Hemp and Flax Straw and Shives and Rapeseed Straw by the Ruminal Microbiota

To mitigate greenhouse gas emissions and improve energy supply security, there is an increasing effort toward the use of non-fossil energy sources. Crop residues have a great potential to be exploited as biomass for biogas production. However, due to their lignocellulosic structures they are difficult to degrade and do not reach competitive performance. A feasible option to mine these substrates is present in the forestomach of ruminants. Therefore, the aim of the present study was to use rumen microorganisms to improve anaerobic digestion (AD) of crop residues. For this purpose, hemp straw, mechanically pre-treated hemp fibers and shives, flax straw, flax shives, and aged and fresh rapeseed straw were evaluated using the rumen simulation technique. The AD of the substrates was divided into three batches. In two batches, hay was added as a control substrate. In summary, none of the analyzed substrates had an equivalent performance as the control hay, but pre-treated hemp fibers and shives had better AD parameters compared to all other alternative substrates, with the lowest pH (mean: 6.81), highest short chain fatty acid (20.0 mmol/day) and H2 production (25.6 mM) and highest degradability (25.2%). Flax straw had the second-best performance (6.81, 17.4 mmol/day, 20.6 mM and 22.2%, respectively), followed by fresh rapeseed straw, hemp straw, aged rapeseed straw and flax shives. Therefore, hemp fibers and shives demonstrated to be the most suitable substrates for AD. However, since pre-treatment can represent significant additional costs for biogas production, flax straw also demonstrated to be a good alternative.

Investigating co-production of syngas, biochar, and bio-oil from flax shives biomass by pyrolysis and in-line catalytic hybrid reforming

Investigating co-production of syngas, biochar, and bio-oil from flax shives biomass by pyrolysis and in-line catalytic hybrid reforming

Reductive Fractionation of Flax Shives in Ethanol Medium over RuNi Bimetallic Catalysts.

The reductive catalytic fractionation of flax shives in the presence of bimetallic NiRu catalysts supported on oxidized carbon materials (CM) such as mesoporous Sibunit and carbon mesostructured by KAIST (CMK-3) was studied. The catalysts based on CMK-3 were characterized by a higher surface area (1216 m2/g) compared to the ones based on Sibunit (315 m2/g). The catalyst supported on CMK-3 (10Ni3RuC400) was characterized by a more uniform distribution of Ni particles, in contrast to the Sibunit-based catalyst (10Ni3RuS450), on the surface of which large agglomerated particles (300-400 nm) were presented. The bimetallic catalysts were found to be more selective towards propanol-substituted methoxyphenols compared to monometallic Ru/C and Ni/C catalysts. A high yield of monomers (up to 26 wt%, including 17% 4-propanol guaiacol) was obtained in the presence of a 10Ni3RuC400 catalyst based on CMK-3.

Influence of sawdust and flax shives on the high temperature mechanical behavior of earthen materials

Earthen materials have recently made headlines due to their high potential reuse in the construction industry. The growing request of earth-based materials is hampered by the lack of information on the fire behaviour of these materials, in particular for issues of instability. Vegetal additions are frequently used in earth construction because they stabilize the clay fraction’s shrinkage property and improve their insulating capacity. The current study focuses on the role the vegetal additions could play in their implementation inside earthen materials, specifically in terms of the latter's high temperature behavior. At various percentages, sawdust and flax shives were added to a raw earth mix. The percentages of those vegetal additions in the earthen matrix ranged between 0 and 7.5 percent of the dry weight of soil. The used additions were characterized before being mixed with soil that was itself characterized also. The manufactured specimens were therefore made up of a mix of raw earth soil mixed with water and vegetal additions, with the characteristics of each addition considered. The specimens were then heated to high temperatures in a furnace programmed to achieve target temperatures of 150 °C, 300 °C, 500 °C, 600 °C and 800 °C at a heating rate of 1 °C/min. The specimen’s residual mechanical properties were then examined. In the absence of vegetal additions, the compressive strength of the specimens increased with temperature. But, the addition of vegetal additions led to a decrease in strength between 150° and 300 °C, which is greater as the percentage of vegetal additions increased. For a lower mass percentage of vegetal additions (2.5%), the compressive strength increased again between 300 °C and 500 °C; and then between 600 °C and 800 °C for all the tested dosages. The comparison between the two types of vegetal additions illustrated the unfavourable influence of a larger size of additions on the residual properties of specimens. In terms of their contribution to the previously determined properties, the sawdust addition outperformed flax shives.

Magnetic Carbon Nanocomposites: Preparation from Cellulose via Chemical Activation with FeCl3 and Characterization

We have studied the preparation of magnetic graphitic carbon composites, which combine the adsorption properties of activated carbon with magnetic properties and properties intrinsic to graphite. The preparation method is efficient; it comprises modifying flax shive cellulose with citric acid to enhance the chelating ability of the flax shive cellulose matrix, impregnating the modified cellulose with iron chloride, and pyrolysis in an inert atmosphere to control the composition, morphology, specific surface, and porosity of hybrid carbon materials. The scenario of cellulose matrix pyrolysis was suggested using thermogravimetry. X-ray structural analysis was used to characterize the graphitic composites. The citric acid modification of cellulose helps to prepare a high-graphite (74%) carbon composite where the graphitization level of the graphite structure approaches the graphitization level of commercially available graphite at 700°С. Low-temperature N2 adsorption–desorption and ζ-potential measurements helped to suggest the adsorption mechanism for environmentally hazardous dyes. The greatest equilibrium adsorption of Methylene Blue (MB) and Methyl Orange (MO) dyes was 127.4 and 23.7 mg/g, respectively. The prepared composites can be used as adsorbents and fillers in polymer composite materials.

Development of a composite product from fibre yielding crop residues

Particleboard is one of the wood-based composite products, developed from wood and wood industry waste in admixture with an adhesive by thermos-compression. Wood is gradually becoming scarce due to deforestation and it leads to search for an alternative raw material. Jute, flax, and hemp plants are important fibre yielding industrial crops since their respective farming provides economic support to the developing nations from the rural areas. After the extraction of fibres from them, a lot of biomasses in terms of shives and sticks are generated as agricultural waste, and recently, these lignocellulosic biomasses have attained a special attention for the development of medium density particleboard. In this present work, an attempt has made to study the effect of flax shive and jute stick particle blends in admixture with phenol formaldehyde resin on the performance of the particleboard in terms of density, modulus of rupture and water swelling. The particle size distribution, bulk density, chemical composition, thermal properties, and surface chemistry of jute stick and flax shive have studied to assess their compatibility. Results inferred that a 50% jute stick: 50% flax shive combination based particleboard met the desirable properties of a medium density particleboard and showed higher performance than other combinations. It could be concluding that the combined use of biomass residuals for the development of a potential industrial product like packaging box, furniture, false ceilings etc, and it could open a new avenue to their farmers for the creation of wealth from the waste.

Coupled Biogas and Fiber Production from Agricultural Residues and Energy Crops with Steam Explosion Treatment

The global demand for packaging materials and energy is constantly increasing, requiring the exploration of new concepts. In this work, we presented a bioeconomic concept that uses steam explosion and phase separation to simultaneously generate fibers for the packaging industry and biogas substrate for the energy sector. The concept focused on fiber-rich residues and fiber-rich ecological energy crops from agriculture. Feasibility of the concept in the laboratory using feedstocks, including Sylvatic silphia silage, Nettle silage, Miscanthus, Apple pomace, Alfalfa stalks, and Flax shives was confirmed. Our results showed that we were able to separate up to 26.2% of the methane potential while always extracting a smaller percentage of up to 17.3% of organic dry matter (ODM). Specific methane yields of 297–486 LCH4 kgODM−1 in the liquid and 100–286 LCH4 kgODM−1 in the solid phase were obtained. The solid phases had high water absorption capacities of 216–504% due to the steam explosion, while the particle size was not significantly affected. The concept showed high potential, especially for undried feedstock.

Short Flax Fibres and Shives as Reinforcements in Bio Composites: A Numerical and Experimental Study on the Mechanical Properties.

The complete flax stem, which contains shives and technical fibres, has the potential to reduce the cost, energy consumption and environmental impacts of the composite production process if used directly as reinforcement in a polymer matrix. Earlier studies have utilised flax stem as reinforcement in non-bio-based and non-biodegradable matrices not completely exploiting the bio-sourced and biodegradable nature of flax. We investigated the potential of using flax stem as reinforcement in a polylactic acid (PLA) matrix to produce a lightweight, fully bio-based composite with improved mechanical properties. Furthermore, we developed a mathematical approach to predict the material stiffness of the full composite part produced by the injection moulding process, considering a three-phase micromechanical model, where the effects of local orientations are accounted. Injection moulded plates with a flax content of up to 20 V% were fabricated to study the effect of flax shives and full straw flax on the mechanical properties of the material. A 62% increase in longitudinal stiffness was obtained, resulting in a 10% higher specific stiffness, compared to a short glass fibre-reinforced reference composite. Moreover, the anisotropy ratio of the flax-reinforced composite was 21% lower, compared to the short glass fibre material. This lower anisotropy ratio is attributed to the presence of the flax shives. Considering the fibre orientation in the injection moulded plates predicted with Moldflow simulations, a high agreement between experimental and predicted stiffness data was obtained. The use of flax stems as polymer reinforcement provides an alternative to the use of short technical fibres that require intensive extraction and purification steps and are known to be cumbersome to feed to the compounder.

Synthesis, properties, and application of a graphitized magnetic carbon composite made from FeCl3-activated flax shive

Magnetic graphitized materials were synthesized in the temperature range T = 600–1000° With the method of single-stage pyrolysis of microcrystalline flax cellulose (MCC) modified with citric acid and homogeneously impregnated with FeCl3. The modification of the MCC with citric acid and the use of FeCl3 as a graphitization catalyst reduces the graphitization temperature from 800 to 600 °C and increases the degree of graphitization to 95%. Morphological and physicochemical properties of carbon composites were studied by scanning electron microscopy, infrared spectroscopy with Fourier transform, low-temperature adsorption-desorption of N2, X-ray diffraction analysis and zeta potential. A possible mechanism of pyrolysis of the cellulose matrix has been established by thermogravimetry. The carbon composite obtained at 700 °C has the highest adsorption capacity of the dyes methylene blue (МВ) and methyl orange (МО) was 127.4 mg/g and 23.7 mg/g, respectively. MO molecules have a monolayer character of the adsorbent surface coating, and for MВ, the character of the adsorbent surface coating depends on the pyrolysis temperature. It is established that the physical adsorption of dyes is due to the interaction between delocalized graphite π-electrons and free electrons in the aromatic rings of dye molecules, electrostatic and adsorption interactions. The resulting composites may be potential candidates as dye adsorbents for wastewater treatment.

Heating value of agricultural biomass: the basic value and intervals for certain types

Higher heating value (HHV) on a dry and ash free basis (daf) is a convenient platform for comparing the energy content in various types of agricultural biomass. HHV and ash content for 90 samples of straw, seed, husk, meal, its waste, etc. were experimentally determined. HHVdaf for 80 samples from different regions were calculated by the literature data. The basic value of HHVdaf agricultural biomass at 19.6 MJ kg–1 was recommended for verifying data on solid biofuels. The intervals of variation of HHVdaf for sugar beet pulp, straw, meal, flax shives and sunflower husk are established. The deviations from the base value of HHVdaf and from intervals of variation of HHVdaf for certain types of agricultural biomass are discussed.