Shives Research Articles

Creation of Cellulolytic Communities of Soil Microorganisms—A Search for Optimal Approaches

For the targeted selection of microbial communities that provide cellulose degradation, soil samples containing cellulolytic microorganisms and specific plant residues as a substrate can be used. The details of this process have not been studied: in particular, whether the use of different soils determines the varying efficiency of communities; whether these established cellulolytic communities will have substrate specificity, and other factors. To answer these questions, four soil microbial communities with different cellulolytic activity (Podzol and the soil of Chernevaya taiga) and substrates (oat straw and hemp shives) with different levels of cellulose availability were used, followed by trained communities that were tested on botrooth substrates (in all possible combinations). Based on the analysis of the taxonomic structure of all communities and their efficiency across all substrates (decomposition level, carbon, and nitrogen content), it was shown that the most important taxa of all trained microbial cellulolytic communities are recruited from secondary soil taxa. The original soil does not affect the efficiency of cellulose decomposition: both soils produce equally active communities. Unexpectedly, the resulting communities trained on oats were more effective on hemp than the communities trained on hemp. In general, the usage of pre-trained microbial communities increases the efficiency of decomposition.

Preparation of hemp‐based biocomposites and their potential industrial application

AbstractBiocomposites are an emerging field in plastic industry. The incorporation of agri‐food waste in conventional or biobased polymer matrices allows the industry to lessen its carbon footprint, while producing recyclable plastic products. In this work, hemp hurd, a byproduct of hemp fiber production process, was used as a filler to prepare novel compostable composites in two different loadings (22% and 32% w/w respectively). Waste hemp hurds were selected due to their abundance and the lack of derived high‐value products. Three different polymers were used, namely poly[(tetramethyleneadipate)‐co‐(tetramethyleneterephthalate)] (PBAT) and poly(tetramethylene succinate) (PBS) as compostable polymers and a polyethylene elastomer for comparison. The bare polymers and prepared blends were then characterized for their structure and morphology by XRD and FESEM, as well as for their wettability, thermal and mechanical properties (namely energy absorbed on impact and flexural modulus). Structural and morphological characterization unveiled the different interactions occurring between hemp and the polymer matrices, suggesting the major impact of the type of used polymer when compared with biomass loading percentages. Mechanical tests showed that both PBAT and PBS blends properties are comparable to those of the pure polymers (i.e., in the case of PBAT the flexural modulus of the pure polymer was 82.2 MPa while the hemp‐loaded blends stood at around 50 MPa, whereas all PBS polymers and blends were 220 MPa, with no statistical difference between samples). These biomaterials have also similar thermal properties with respect to the bare polymers, underlining the promising potential as sustainable alternative to pure polymers.Highlights Waste hemp hurds were used to load biodegradable polymers at different percentages. Hemp hurd‐based biomaterials with excellent properties were prepared. Polymer flexural behavior was maintained even after hemp addition. Polymer‐hemp interactions for each polymeric matrix were elucidated. Hemp substitutes up to 32% w/w of polymer without affecting its properties.

StarchCrete: A starch-based biocomposite concrete for lightweight building material applications

StarchCrete is a novel composite material that utilizes starch as a biobased binder, replacing traditional inorganic binders. The composite was prepared using varying hemp shives ratios (from 0−1) at constant sand: corn starch: water ratio (5:1:1). The mixture was manually compacted into a mold and heated under microwave radiation. The effect of different starches on a composite’s compressive strength was investigated. The result reveals that high-viscosity starch leads to strong compressive strength. Increasing the hemp shives ratio significantly reduced thermal conductivity (from 0.52 to 0.15 W/(m·K)) and thermal diffusivity (from 0.85 to 0.35 mm2/s). With its strong compressive strength (2.8 MPa), low density (887 kg/m3), and low thermal conductivity (0.18 W/(m·K)), the hemp shives ratio of 0.5 was deemed appropriate. Furthermore, coating the material with paraffin wax improved its water resistance, extending its durability from 7 to 16 days, making it suitable for industrial applications.

Influence of the mass percentage of binders on the properties of LHC

This paper investigates the effects on the physical and mechanical properties and microstructure of lime-hemp concrete (LHC) materials at different binder mass ratios. A mixture of three cementitious materials, slaked lime, cement, and coal gangue powder, was used as binder, and hemp shives were used as concrete aggregate, and five test groups were designed, i.e., binder/hemp shives (B/H) mass ratios of 1.2, 1.4, 1.6, 1.8, and 2.0. The physical properties of LHC, including density, drying rate, water absorption, thermal conductivity coefficients, and mechanical properties (compressive strength and flexural strength) with different binder ratios were investigated. In addition, the microstructural properties of 56d LHC were investigated by SEM, XRD, and TG-DTG micro-scale analysis methods. The results showed that with the increase in binder content, the drying speed of LHC became faster, the thermal conductivity coefficients, compressive strength, and flexural strength increased, and the water absorption was just the opposite. With a fit ratio of 2.0, the strength is the greatest and the toughness is the best; with a fit ratio of 1.2, the thermal conductivity coefficient is the smallest and the insulation effect is the best. In addition, the hydration of the binder produced different forms of hydration products (CaCO3 and C-S-H), and the hydration products increased in quantity with the increase of the binder, resulting in stronger CaCO3 and C-S-H diffraction peaks. The hydration products produce a better bond with the rough cannabis particle surface, filling the internal voids of the LHC, improving the density of the material, and enhancing the mechanical properties of the material.

Development and validation of hydrophobic molded pulp nursery pots made of hemp hurd

Biodegradable nursery pots (BNPs) composed of 50 % hemp hurd and 50 % recycled cardboard fibers (w/w dry basis) were produced using a custom-built handheld molded pulp device. Milling followed by sequential peracetic acid and sodium hydroxide delignification treatment reduced lignin content of hemp hurd from 23.76 % to 2.39 %, liberating cellulose and hemicellulose fibers for enabling the formation of interfiber interactions in molded pulp formulations. Beeswax and precipitated calcium carbonate based hydrophobic coating at ~10 μm thickness significantly enhanced hydrophobicity of the BNPs, as indicated by the surface contact and sliding angle of 116.25° and 34.82°, respectively. Anaerobic biodegradability of BNP was confirmed via carbon dioxide and methane gas accumulation measurements. Developed BNPs were successfully validated through an eleven week greenhouse planting trial. This study introduced a new biodegradable molded pulp formulation made from hemp hurd and validated its application as an alternative to single use plastic nursery pots for growing seedlings.

Congo red Removal using Microwave assisted Pyrolysis derived Magnetic Hemp hurd Biochar

Industrial hemp hurd (HH) are the residue obtained after the decortication of the hemp plant for fibre production, which is seldom explored for biochar potential and as adsorbent for dye removal. The present study focused on the microwave-assisted pyrolysis (MAP) of HH for biochar production, magnetization and application for Congo red (CR) removal from aqueous solutions. Magnetic hemp hurd biochar (MHB) depicted a heterogeneous surface with 4.84µm pore size, 17.64 m2/g surface area, and 10.05wt. % Fe. CR removal of 92% was achieved under optimum conditions i.e., treatment time: 120min, pH: 8, and initial CR concentration: 10mg/L with MHB dosage of 0.6g/L. The CR adsorption on MHB was well-fitted with the Freundlich isotherm (R2 - 0.971), owing to the heterogeneous surface of MHB. A strong match with pseudo-second order model (R2 - 0.973), indicated chemisorption as the likely adsorption mechanism. MHB exhibited 87% CR removal efficiency after three successive reutilization cycles. The outcomes of CR removal efficiency and MHB reusability indicated its potential application for adsorptive removal of CR from aqueous systems.

Evaluation of Mechanical Energy Consumption in WPC Production from Pine (Pinus sylvestris) and Hemp (Cannabis sativa L.) with ABS Thermoplastic Additions.

This study investigates lignocellulosic biocomposites' physicochemical properties and strength parameters with varying thermoplastic content. Biocomposites were prepared using wood (Pinus sylvestris) or hemp shives (Cannabis sativa L.) combined with 25% and 50% ABS regranulate. The research focused on evaluating the mechanical energy consumption during the compaction of wood-ABS biocomposites with different pine fractions pretreated with hot water extraction (HWE) and analyzing the relationship between strength and thermoplastic content. Results indicate that the composition of the mixture and the size of the hemp shives fraction did not significantly influence energy consumption during densification. Energy values ranged from 1.234 × 10⁻8 J to 8.296 × 10⁻8 J. While the densification of pine after HWE was unsuccessful without ABS, preheating the mixtures with ABS facilitated the production of a uniform composite. The work required for densification ranged from 1.404 × 10⁻5 J to 2.711 × 10⁻5 J for fractions without ABS. For mixtures with ABS, the work required was 1.954 × 10⁻5 J for fraction 0 ÷ 0.4 (f1) and 0.042 × 10⁻5 J for fraction 0.4 ÷ 0.8.

Preparation and properties of a rigid hemp shiv insulation particle board using citric acid-glycerol mixture as an eco-friendly binder

Particle boards are commonly manufactured from wood-based material bound with a thermosetting adhesive based on the reaction of formaldehyde with phenol, urea, melamine, or co-condensates. The use of formaldehyde is a cause for concern due to its harmful emissions. This study investigates the use of an alternative binder combined with particles derived from a short-cycle crop as an alternative to timber derived particles. A low density particle board was developed using hemp shiv as an aggregate with a binder made with crude glycerol, derived from the waste stream of the bio-diesel industry, esterified with citric acid under heat activation. This board was characterized and found to have good mechanical properties, low thermal conductivity, and good moisture buffering. Dimensional stability was compromised by swelling when exposed to water, but it will be possible to address this shortcoming using hydrophobic additives. The acoustic properties of the board were also found to be excellent, showing potential for use as a thermally insulating acoustic separator for internal walls.

New Refined Experimental Analysis of Fungal Growth in Degraded Bio-Based Materials

When exposed to different building environmental conditions, bio-composite materials, such as hemp mortars, represent a risk of mold proliferation. This later plays a critical role in the biodeterioration of the materials when their physical properties are locally modified by the natural aging process. The primary objectives of the present work are first to assess the evolution of the surface of contaminated mortar; second, to investigate an accurate DNA extraction method that could be used for both bio-composite mortars and their fiber sources collected in situ; then, to understand the process of the proliferation of mold strains on both hemp shives and hemp mortar; and finally, to compare mold strains present in these phases to show their relationship to mold contamination and their impact on human health. In situ hemp mortar contamination behavior was investigated in the region of Pau (France) two months after hemp mortar application in extreme conditions (high humidity, low temperature, no aeration), which did not match the standard conditions under which hemp mortar must be used. The SEM observations and FTIR and pH analyses highlighted the decrease in pH level and the presence of organic matter on the mortar surface. DNA sequencing results showed that hemp shives were the main source of fungal contamination of hemp mortar. A mold population analysis showed that the most dominant phylum was Ophistokonta, which represented 83.6% in hemp shives and 99.97% in hemp mortar. The Acrostalagmus genus representatives were the most abundant, with 42% in hemp shives and 96% in hemp mortar. The interconnection between the mold strain characteristics (particularly the ability to grow in extreme environments) and the presence of hemp mortar was emphasized.

A Preliminary Experimental Study on Biodegradation of 3D-Printed Samples from Biomass–Fungi Composite Materials

Products made from petroleum-derived plastic materials are linked to many environmental problems, such as greenhouse gas emissions and plastic pollution. It is desirable to manufacture products from environmentally friendly materials instead of petroleum-based plastic materials. Products made from biomass–fungi composite materials are biodegradable and can be utilized for packaging, construction, and furniture. In biomass–fungi composite materials, biomass particles (derived from agricultural wastes) serve as the substrate, and the fungal hyphae network binds the biomass particles together. There are many reported studies on the 3D printing of biomass–fungi composite materials. However, there are no reported studies on the biodegradation of 3D-printed samples from biomass–fungi composite materials. In this study, two types of biomass materials were used to prepare printable mixture hemp hurd and beechwood sawdust. The fungi strain used was Trametes versicolor. Extrusion based 3D printing was used to print samples. 3D-printed samples were left for five days to allow fungi to grow. The samples were then dried in an oven for 4 h at 120 °C to kill all the fungi in the samples. The samples were buried in the soil using a mesh bag and kept in an environmental chamber at 25 °C with a relative humidity of 48%. The weight of these samples was measured every week over a period of three months. During the testing period, the hemp hurd test samples lost about 33% of their original weight, whereas the beechwood sawdust samples lost about 30% of their original weight. The SEM (scanning electron microscope) micrographs showed the presence of zygospores in the test samples, providing evidence of biodegradation of the test samples in the soils. Additionally, the difference in peak intensity between the control samples and test samples (for both hemp hurd and beechwood sawdust) showed additional evidence of biodegradation of the test samples in the soils.

Innovative Hemp Shive-Based Bio-Composites: Part I: Modification of Potato Starch Binder by Sodium Meta-Silicate and Glycerol

The growing demand for sustainable building materials has boosted research on plant-based composite materials, including hemp shives bound with biodegradable binders. This study investigates the enhancement of potato-starch-based binders with sodium metasilicate and glycerol to produce eco-friendly bio-composites incorporating hemp shives. Potato starch, while renewable, often results in suboptimal mechanical properties and durability in its unmodified form. The addition of sodium metasilicate is known to improve the mechanical strength and thermal stability of starch-based materials, while glycerol acts as a plasticizer, potentially enhancing flexibility and workability. Bio-composites were produced with varying concentrations of sodium metasilicate (0–107% by mass of starch) and glycerol (0–133% by mass of starch), and their properties were evaluated through thermal analysis, density measurements, water absorption tests, compressive strength assessments, and thermal conductivity evaluations. The results demonstrate that sodium metasilicate significantly increases the bulk density, water resistance, and compressive strength of the bio-composites, with enhancements up to 19.3% in density and up to 2.3 times in compressive strength. Glycerol further improves flexibility and workability, though excessive amounts can reduce compressive strength. The combination of sodium metasilicate and glycerol provides optimal performance, achieving the best results with an 80% sodium metasilicate and 33% glycerol mixture by weight of starch. These modified bio-composites offer promising alternatives t2 o conventional building materials with improved mechanical properties and environmental benefits, making them suitable for sustainable construction applications.

Investigation of light earth sound transmission loss at the wall scale

A fine understanding of the acoustic dissipation in walls made from biobased concrete is needed to predict and design properly their performances and to create comfortable spaces. This understanding is one of the objective of LOB+HIE (LOW BETON / HIGH EARTH) project, funded by Ademe, and focusing on the use of light earth (a biobased concrete resulting from the mix between clay and hemp shiv) to meet acoustic requirements in a public worksite. Acoustic data are already available in the literature at the material scale for this kind of solution. The aim of the present work is to provide experimental reference data at the wall scale for sound transmission on full-scale vertical walls, and then to extend it to other configurations by numerical simulations. The work is organised in three parts, including the transmission loss measurements on two different walls, the modelling of the walls with numerical simulations using a transfer matrix method approach, and finally the extension by simulation to other wall configurations, with a view to producing design aids for use by building professionals.

Acoustical dissipation in biobased granular packings

Biobased building materials have many advantages, including local availability and functional performance in terms of mechanical, acoustic and hygrothermal properties. Besides, the biobased solutions coming from plants that uptake CO2 during their growth, are good opportunities to reach carbon-neutral building construction. However, mastering their acoustical performance still raises a number of questions directly linked to their microstructure, which is characterised by a high degree of porosity spread over several scales. The work presented here aims to highlight the effect of the porosity distribution in biobased granular packings on their acoustical performances. Several plant aggregates are considered, such as hemp shiv, sunflower pith or reed as a function of their density and water content. Characterizations are performed in normal incidence and compared to fluid equivalent modellings based on various assumptions, to analyze the effective contribution of the various types of pores at the aggregate level, and between the aggregates.

Characterization of 3D printed samples from biomass-fungi composite materials

Biomass-fungi composite materials are derived from sustainable sources and can biodegrade at the end of their service. In these composite materials, the biomass particles (made from agricultural waste such as hemp hurd) act as the substrate, and a network of fungal hyphae grow through and bind the biomass particles together. These composite materials can be used to manufacture products traditionally made from petroleum-based plastics. Potential applications of these products are in the packaging, furniture, and construction industries. Typically, molding-based methods are used to manufacture products using these composite materials. Recently, the authors reported a novel 3D printing-based method using these composite materials. This paper reports a follow-up investigation into the characterization of 3D printed samples from biomass-fungi composite materials. Tensile and compressive testing samples were shaped using molds from a portion of each printed sample. Mechanical properties of these tensile and compressive testing samples and chemical properties of the printed samples were measured. Tensile and compressive testing measurement results showed that, at the significance level of 0.05, effects of 3D printing parameters studied (printing speed and extrusion pressure) were not statistically significant on Young’s modulus and ultimate tensile strength of the tensile testing samples, as well as on compressive strength and compressive modulus of the compressive testing samples. Results obtained from the Fourier transform infrared spectroscopy analysis show that chemical composition of printed samples was consistent with the data in the literature.

Synthesis of Porous Carbon Honeycomb Structures Derived from Hemp for Hybrid Supercapacitors with Improved Electrochemistry.

Energy storage in electrochemical hybrid capacitors involves fast faradaic reactions such as an intercalation, or redox process occurring at a solid electrode surface at an appropriate potential. Hybrid sodium-ion electrochemical capacitors bring the advantages of both the high specific power of capacitors and the high specific energy of batteries, where activated carbon serves as a critical electrode material. Herein, we have demonstrated that a porous honeycomb structure activated carbon derived from Australian hemp hurd (Cannabis sativa L.) in aqueous Na2SO4 electrolyte showed a specific capacitance of 240 F/g at 1 A/g.The hybrid sodium-ion device employing hemp-derived activated carbon (HAC) coupled with electrolytic manganese dioxide (EMD) in an aqueous Na2SO4 electrolyte showed a specific capacitance of 95 F/g at 1 A/g having a capacitance retention of 90%. The hybrid device (HAC||EMD) can possess excellent electrochemical performance metrics, having a high energy density of 38 Wh/kg at a power density of 761 W/kg. Overall, this study provides insights into the influence of the activation temperature and the KOH impregnation ratio on morphology, porosity distribution, and the activated carbon's electrochemical properties with faster kinetics. The high cell voltage for the device is devoted to the EMD electrode.

Biodegradable composite hydromulches for sustainable organic horticulture

Surface-applied mulches help retain soil moisture and optimize soil temperature while preventing weed growth and benefiting many horticultural crops. The most common mulch material is low-density polyethylene (LDPE), is typically landfilled, buried, or burned at the end of growing season causing negative environmental impacts. The goal of this research was to develop soil-biodegradable, liquid-applied (i.e., hydromulch) alternatives to LDPE mulch and optimize formulations that are acceptable for organic horticulture. Hydromulch (HM) treatments contained mixtures of paper pulp, wood fiber, or hemp hurds (Cannabis sativa L.) combined with various tackifiers and water. The tackifiers were guar gum (Cyamopsis tetragonoloba (L.) Taub.), psyllium husk (Plantago ovata L.), and camelina meal (Camelina sativa (L.) Crantz), included at various proportions. Hydromulch samples were tested for physical properties (density, water holding capacity, C:N ratio, soil adhesion) and mechanical properties (tensile strength, puncture resistance). Hydromulches containing no tackifiers were included as controls to determine if the addition of tackifiers resulted in enhanced mechanical properties. The results showed addition of 6 % guar gum tackifier improved the tensile strength and puncture resistance by 182 % and 91 % respectively compared to control sample, and HM formulations containing paper were 200 % or more stronger than those containing wood or hemp hurds. Increased tackifier proportion was found to improve most mechanical properties, with guar gum performing best. Blending of tackifiers resulted in an interaction that decreased strength. Hydromulches containing wood fiber and hemp hurds did not show promising results. Paper in HM formulations helped to reduce mulch porosity and improved adhesion to soil. Results from the study provide a foundation on optimal formulations for expanded trials at field-scale.

Experimental Assessment of Hemp Shiv and Green Adhesives to Produce a Biocomposite Material.

This study investigated the utilization of innovative green composites made from hemp shiv, a waste by-product of hemp cultivation, with the aim of promoting sustainability within the construction industry. The manufacturing method involved the application of pressure in a mold to create the samples. These materials were produced using an environmentally friendly binder consisting of colophony, arabic gum, and corn starch. Moreover, white glue and bioepoxy were also used to compare with the green resins. Three different binder compositions were used for the specimens. The samples underwent mechanical testing through tensile and bending assessments, and their performance was compared to that of non-green binders to validate the effectiveness of the manufacturing processes. The study revealed that decreasing the moisture content during the curing process was crucial for improving the mechanical properties. The best results were achieved when using arabic gum as a binder, yielding a tensile strength of 2.16 MPa and a bending strength of 5.25 MPa, with a composition of 62.5% hemp shiv and a manufacturing process involving a pressure of 5 MPa.

Degradation kinetics of PLA/hemp biocomposites: Tradeoff between nucleating action and pro-hydrolytic effect of natural fibers

Natural fibers are not only a sustainable alternative to synthetic reinforcement materials, but can also be used to produce truly sustainable biocomposites with fast degradation kinetics. Indeed, due to their hygroscopicity, lignocellulosic fibers allow water and/or degrading organisms from the external environment to penetrate inside the host matrix and trigger its hydrolysis. The latter is the rate-limiting step for the degradation of bio-polyesters, which exhibit unacceptably slow degradation kinetics at ambient temperature and humidity. However, fibers also promote crystallization of the host matrix and thus slow down its degradation kinetics. To better understand and potentially control the degradation kinetics of biocomposites, here we investigate the ability of hemp shives, a hygroscopic by-product of hemp fiber production, to accelerate the hydrolysis of poly (lactic acid) (PLA). The degradation kinetics and degree of crystallinity of PLA are monitored in water and mature compost as a function of fiber content, which was varied across the percolation threshold (Φc) to study the effect of fiber interconnectivity. Above Φc, the fibers accelerate PLA hydrolysis in water despite their nucleating effect. Conversely, in compost the shielding effect of fiber-induced crystallinity prevails, and the fibers eventually slow down the degradation kinetics of PLA.

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.

Enhancing the Properties of Cement Composites Using Granulated Hemp Shive Aggregates

In recent years, civil engineers have been exploring innovative methods of constructing buildings using environmentally friendly materials. The beneficial properties of hemp harl, an agricultural waste that is gaining popularity in construction, prompted the idea of strengthening its properties through the granulation process and using it as an aggregate in cement composites. This work aimed to investigate whether the use of hemp husk in the form of granules would have a positive effect on the properties of cement composites compared to their traditional form (stems). Potato starch was introduced as an additional factor in the granulation process to improve the material. Experimental tests were carried out on organic fillers, fresh mixtures, and hardened composites. Physical, mechanical, and structural tests (SEM imaging) were carried out. The highest strength was demonstrated by samples containing hemp shive aggregate (1.186 MPa), while the use of hemp shives in the form of granules had a positive effect on the consistency and density, and it also reduced water absorption by 30% during the production of the composite. The apparent density of composites with hemp shives in the form of hemp pellets was higher (1042 ÷ 1506 kg/m3) than in the case of composites with shives in the form of harl (727 ÷ 1160 kg/m3). Nevertheless, hemp shive in both forms can be used as a natural aggregate in cement composites.