Search Results (155)

Hydrothermal co-liquefaction (co-HTL) of biomass and plastic waste represents a promising pathway for sustainable biocrude production and plastic waste valorization. In this study, a coupled CFD–DEM–PBM framework was developed to investigate the co-liquefaction of Miscanthus giganteus with polypropylene (PP), polyethylene terephthalate (PET) and polystyrene (PS) in a 1 L Rushton turbine reactor operated at 400 °C, 200 bar, 60 min and 140 rpm. The model integrates Computational Fluid Dynamics (CFD), the Discrete Element Method (DEM) and Population Balance Modeling (PBM) to predict hydrodynamics, particle agglomeration and biocrude droplet population evolution. The simulations revealed significant spatial variations in temperature, particle concentration and biocrude distribution. The highest biocrude droplet populations were observed for PET, reaching 6.2 × 10⁵ # m⁻³, compared with 4.9 × 10⁵ # m⁻³ for PS and 3.2 × 10⁵ # m⁻³ for PP. PBM analysis predicted characteristic agglomerate sizes of approximately 310 μm, 180 μm and 90 μm for PET, PS and PP, respectively. The agglomeration intensity and droplet population evolution followed the order PET > PS > PP, highlighting the strong influence of polymer type on particle interactions and liquid product formation. The developed CFD–DEM–PBM model provides detailed insight into hydrodynamics, agglomeration kinetics and biocrude evolution, supporting reactor optimization and future scale-up of HTL technologies. Furthermore, hydrothermal co-liquefaction offers a promising route for converting persistent microplastic residues into valuable renewable fuel precursors. Full article

Optimizing nutrient management is essential for improving the productivity and profitability of perennial bioenergy crops on marginal soils. This study evaluated the effects of mineral fertilization, a humic-based biostimulant, and a titanium-containing micronutrient preparation on the growth, biomass yield, and economic performance of Miscanthus × giganteus grown on acidic low-fertility soil in Western Ukraine from 2022 to 2025. A repeated-measures mixed-model analysis showed significant effects of treatment, year, and treatment × year interaction for the main growth and productivity parameters, indicating a year-dependent fertilization response. Integrated fertilization improved plant height, shoot formation, dry biomass yield, and biofuel output compared with the unfertilized control. The highest mean dry biomass yield was obtained with N₃₀P₃₀K₃₀ + Black Jack, reaching 16.43 t ha⁻¹ and exceeding the control by approximately 40%, while N₃₀P₃₀K₃₀ + Intermag Titan also showed high productivity. Dry biomass yield was strongly associated with plant height, confirming the role of structural development in biomass formation. Economic assessment indicated the highest long-term profitability for N₃₀P₃₀K₃₀ + Black Jack. These findings indicate that integrated fertilization is an effective strategy for sustainable miscanthus biomass production on marginal soils. Full article

This paper reports new results on the synthesis and comparative characterization of cellulose nitrates (CNs) derived from Miscanthus × giganteus stems and from commercial microcrystalline cellulose (MCC). Miscanthus CNs synthesized by nitration with mixed sulfuric–nitric acids containing 16–20% water exhibit new functional properties: a high solubility in organic solvents (100% in acetone and 97–99% in alcohol–ether solvent) and a high viscosity (17–51 mPa·s), with a nitrogen content of 10.54–12.08 wt%. CNs from Miscanthus × giganteus are similar in nitrogen content and solubility to those from MCC (11.54% and 99%) but have a significantly greater viscosity (3 mPa·s), which is an undoubted advantage and considerably expands their potential application range. The solubility test of CNs synthesized from both sources demonstrated that Miscanthus CNs have a better film-forming ability. SEM analysis revealed a great difference in fiber length, despite the same cylindrical shape and observed aggregation: 1.0–2.0 mm for CNs from Miscanthus versus 40–60 μm for CNs from MCC. IR spectra of CNs from both sources showed the appearance of five new characteristic frequencies (1632–1633, 1273–1274, 823–826, 748, 677–686 cm^–1 for Miscanthus CNs and 1659, 1277, 832, 747, 691 cm^–1 for CNs from MCC), allowing the obtained compounds to be identified as nitric acid esters of cellulose. According to TGA/DTA analysis, the synthesized polymers have similarly high values of the onset temperature of both intense decomposition (197–198 °C) and narrow exothermic peaks (209–211 °C and 212 °C), respectively, indicating their high thermal stability. The combination of high solubility, viscosity, thermal stability and chemical purity of CNs derived from Miscanthus × giganteus stems suggests that strong thin films can be obtained and recommended for use in the manufacture of nitrocellulose membranes. Full article

The agricultural and environmental application of Miscanthus × giganteus biomass ash (MBA) as a soil amendment requires a thorough assessment of its properties, nutrient potential, and associated risks. This study characterizes the elemental composition, pH, cation exchange capacity (CEC), and polycyclic aromatic hydrocarbons (PAHs) content of MBA in comparison with other common biomass ashes (crops, wood, and sewage sludge) referred to the international regulatory standards. The ash exhibits a strong alkaline pH (11.03), suggesting potential to improve soil pH in acid soils, but requires careful controlled application to prevent excessive alkalization. The main nutrients detected include K (5.54%), Ca (2.07%), Mg (0.37%), and P (0.86%), indicating its potential as a soil amendment, though long-term use may cause nutrient imbalances. Micronutrients such as Zn (240.67 mg·kg⁻¹), Mn (297 mg·kg⁻¹), and Cu (33.5 mg·kg⁻¹) are found in concentrations suitable for agricultural use, while potentially toxic elements (PTEs), including Cd, Cr, Ni, and Pb, are below detection limits, thereby reducing the risk of pollution. As (8.3 mg·kg⁻¹) and ΣPAHs (1.63 mg·kg⁻¹) remain within safety thresholds, suggesting a low environmental toxicity of MBA. The low Na content (0.12%) indicates a minimal risk of salinity accumulation, distinguishing MBA from high-sodium biomass ashes. Soil alkalization, disruptions in nutrient balance, and element leaching are risks to be considered. Despite these concerns, its composition is in agreement with established safety guidelines, supporting its feasibility for valorization as a sustainable soil amendment and remediation material. To maximize agronomic benefits and mitigate environmental risks, it is important to utilize the ash, considering site conditions and carry out regular monitoring of the soil. Full article

Second-generation bioethanol technology is based on renewable raw materials with an unlimited potential for replenishment. However, the production cost of second-generation bioethanol is still higher than that of the first-generation. Biomass pretreatment is a key challenge, and solving it will improve the technology efficiency. In this study, Miscanthus × giganteus from the Russian breeding stock was subjected to pretreatments with dilute HNO₃ under atmospheric pressure. Pretreatments were carried out either as a single stage (HNO₃) or as two stages ((i) HNO₃ followed by NaOH, and (ii) NaOH followed by HNO₃). Classical delignification with NaOH was also performed for comparison. Simultaneous saccharification and fermentation with delayed inoculation (dSSF) was then performed under identical conditions, with Saccharomyces cerevisiae Y-3136 as the microbial producer. Two-stage pretreatments were found to excel in purity, pulp composition, pulp conversion, bioethanol yield during fermentation, and raw bioethanol purity (impurities decreased by a factor of 21 compared to NaOH delignification). However, fermentation indicators are not the only critical aspect in bioethanol production technology. The complete cycle from Miscanthus × giganteus feedstock to the target bioethanol product was evaluated. The single-stage pretreatment with HNO₃ performed best among the tested conditions. The HNO₃ pretreatment achieved a 50% yield of pulps and a maximal bioethanol yield of 267 L/t, which is 44% higher compared to NaOH delignification. Furthermore, the HNO₃ pretreatment enables savings in resources and electric power, as well as full commercial utilization of all polymers of the lignocellulosic matrix of the feedstock. Full article

Environmental contamination by potentially toxic elements (PTEs) originating from industrial activities represents a major global challenge, necessitating the development of sustainable remediation strategies. While remediation of legacy (post-industrial) contamination has been relatively well studied, the remediation of ecosystems surrounding operating facilities subjected to increasing PTE loads remains insufficiently investigated. Therefore, the present study evaluated the efficacy of biochar derived from post-phytoremediation Miscanthus × giganteus (M×g) biomass to optimise the phytoremediation process using soil from an operating facility in a pot system. Valorisation of 29.0 kg of waste biomass yielded 12.8 kg of biochar (44.2%) with a high specific surface area (672 m² g⁻¹). Despite PTE enrichment during pyrolysis, the biochar was classified safe according to IBI thresholds. A pot experiment was conducted using contaminated and local background soils, amended with 3% (w/w) Miscanthus-derived biochar. Biochar application significantly improved plant performance in contaminated soil, increasing plant height, aboveground biomass, and root parameters by up to 208%, while restoring chlorophyll content and reducing stress indicators such as proline. Furthermore, biochar reduced PTE accumulation in plant tissues and supported the production of less contaminated biomass. These findings demonstrate that post-phytoremediation biomass-derived biochar enhances phytomanagement efficiency and supports sustainable biomass valorisation within a circular economy framework. Full article

Abiotic stresses, including heavy metal contamination, can severely impair plant growth and antioxidative defense. However, their adverse effects may be mitigated through sustainable strategies such as biostimulant application. This study investigated the effects of humic substances (HSs), alone or combined with mycorrhizal inoculation (M), on oxidative stress and antioxidative responses in Cannabis sativa, Sorghum sudanense × bicolor, and Miscanthus × giganteus grown under field conditions on metal-contaminated agricultural soil exceeding regulatory thresholds for Zn, Pb, and Cd. Plant growth, lipid peroxidation, stress-related metabolites (proline, sugars), antioxidative enzyme activities (catalase, CAT; ascorbate peroxidase, APX; guaiacol peroxidase, GOPX; glutathione reductase, GR, and superoxide dismutase, SOD), and leaf metal concentrations were analyzed. Biostimulants increased proline and sugars in Sorghum (by up to 55% and 80%, respectively), accompanied by reduced oxidative stress indicators and improved biomass (by 26%). In Cannabis, higher Cd and Pb concentrations following biostimulant treatments were associated with increased SOD, APX, and GR activities (by 33–267%), without affecting growth. In Miscanthus, increased lipid peroxidation (by 37–60%) occurred alongside enhanced GR and APX activities. These results indicate strong species-specific responses and absence of consistent synergistic effects of HSs and M, highlighting distinct physiological strategies of stress adaptation and antioxidative defense on metal-contaminated soils. Future research should address physiological and molecular mechanisms underlying these responses. Full article

In the conducted study, the structure of weed communities and their dynamics were assessed and compared in relation to plantation age and the species of energy crop. Weed diversity within the stands of the investigated energy crops was evaluated in three-year cycles, from 2006 to 2024. The assessment of weed diversity in the stands of the studied energy crops was conducted in three-year cycles, i.e., in the first year of cultivation (2006—the year of plantation establishment), the fourth year of cultivation (2009), the seventh year of cultivation (2012), the tenth year of cultivation (2015), the thirteenth year of cultivation (2018), the sixteenth year of cultivation (2021), and the nineteenth year of cultivation (2024). The species composition of weed communities and the abundance of individual weed species were determined. The diversity and dominance patterns of weed communities occurring in Salix viminalis, Miscanthus × giganteus, and Phalaris arundinacea were described using two indices: the Shannon–Wiener diversity index and the Simpson dominance index. As a result of the conducted observations, it was found that weed abundance, species diversity, and weed infestation dynamics depended on the energy crop species and the age of the plantation. Greater interannual variability was observed in weed abundance, whereas species richness remained relatively more stable between years. The highest species diversity was recorded in the Salix viminalis plantation, where a total of 53 weed species were identified. In contrast, considerably fewer taxa were found in Miscanthus × giganteus (42 species) and Phalaris arundinacea (41 species). Moreover, it was found that regardless of the energy crop species, segetal weeds dominated during the first years of cultivation, i.e., E. crus-galli, A. spica-venti, A. retroflexus, Ch. album, M. inodora, and V. arvensis. In subsequent years of cultivation, however, the dominant species were ruderal weeds, such as A. vulgaris, T. officinale, and U. dioica, as well as invasive species, e.g., S. canadensis and S. gigantea. In subsequent years, ruderal species became dominant. The Shannon–Wiener diversity and Simpson dominance indices indicated differences in species richness and the relative abundance of individual weed species. The highest values of the Shannon–Wiener diversity index and the lowest values of the Simpson dominance index were recorded in weed communities of Salix viminalis plantations aged 7–16 years after establishment. In contrast, the highest Simpson index values, indicating dominance by one or a few weed species, were observed in the first year of cultivation regardless of the energy crop species, as well as in the 19-year-old Miscanthus × giganteus plantation. Full article

The objective of this study was to evaluate the impact of seasonal changes in the chemical and structural composition of giant miscanthus (Miscanthus × giganteus) biomass on the performance, kinetics, and efficiency of anaerobic digestion (AD), as well as on the overall energy and techno-economic balance of the conversion chain. The AD performance was assessed using batch biochemical methane potential (BMP) assays conducted for eight harvest dates (June–January). Comprehensive characterization included fundamental physicochemical properties of the biomass, lignocellulosic fraction composition, AD kinetics, and methane production yield. A statistically significant (p < 0.05) increase in structural fiber fractions was observed with advancing plant maturity, accompanied by a progressive decline in specific methane yield from 281 ± 32 mL CH₄/g VS in June to 170 ± 11–172 ± 13 mL CH₄/g VS in winter harvests. Despite a relatively stable theoretical biochemical methane potential (TBMP) ranging from 425 to 443 mL CH₄/g VS, the conversion efficiency (BMP/TBMP) decreased from approximately 66% to below 40%, indicating increasing structural and kinetic limitations to substrate biodegradability. Kinetic parameters deteriorated systematically in late harvests, as reflected by a reduction in the first-order rate constant k_CH₄ from 0.115 to approximately 0.072 1/d and an extension of the lag phase λ from 2.19 to over 4 days. Regression analysis revealed strong negative correlations between lignocellulosic complex content and both BMP and k_CH₄, whereas the C/N ratio exhibited a positive association with process performance under the experimental conditions applied. The highest methane production per hectare (3904 ± 720 m³CH₄/ha) and the most favorable economic outcome (1979 ± 465 EUR/ha) were achieved for the September harvest. The results demonstrate that harvest timing constitutes a critical optimization parameter in lignocellulosic biogas systems, governing not only methane yield and process kinetics but also the overall energy output and economic viability of the bioenergy production chain. Full article

The aim of the experiment was to assess the effects of municipal sewage sludge, mushroom substrate, and hydrogel on the quality of energy grass species and their biomass yield. The experiment was conducted in the climatic conditions of central-eastern Poland between 2020 and 2022. Two perennial grass species were used: Miscanthus giganteus (giant miscanthus) M 19 and Panicum virgatum L. (rod millet) var. Northwind. Sewage sludge and mushroom substrate doses, each corresponding to 170 kg N·ha⁻¹, were applied in the spring of the first year. The experiment was established on microplots with four replications. Each year, biomass was harvested in January, and the yield of fresh and dry matter was determined. Then plant material was adequately prepared, and the total content of P, Ca, and Mg was measured with the ICP-OES method. The application of hydrogel resulted in a significant increase in the yield of each grass species: giant miscanthus by 11.87% and rod millet by 8.28%. Organic waste applied in combination with hydrogel increased the yield of energy plants and improved their chemical composition. Full article

Wastewater generated in municipal rendering facilities requires multi-step treatment, but it may also serve as a source of nutrients and water and thus may be valorized before or instead of the necessary wastewater treatment operations. In this work, wastewaters from a composting plant were utilized to support the growth of Miscanthus x giganteus, known as both a remediation plant and an energy biomass source. A pot experiment was established to compare the effects of different wastewater doses (0, 50, 100, and 200 mL per pot per week) on the miscanthus biomass yield, phytoextraction of heavy metals, biomass heat of combustion, and plant condition. The increase in the wastewater dose resulted in increases in both biomass yield (from about 44 to 139%) and biomass heat of combustion (from 7 to 17%) when compared to the control sample, with no adverse effects on plant physiological parameters. The highest concentrations of metals were found in miscanthus grown with the highest dose of wastewaters. It was found that higher wastewater dose correlates to both higher phytoextraction and phytorecovery of metals from plant substrate and wastewaters. The highest metal uptake was identified for Fe (431 mg·pot⁻¹), followed by Al, Zn, Mn, Cu, Ni, Cr. The lowest metal uptake was noted for Pb, Co and Cd (0.88, 0.11, and 0.95 mg·pot⁻¹, respectively). The results indicate that miscanthus can be recommended for industrial wastewater treatment. In addition, due to high absorption efficiency of the substrate components, miscanthus can be used as a remediation tool, e.g., for the ecological stabilization of remediation of metal-polluted soils, especially in municipal facilities like rendering plants. This presents a circular perspective for the valorization of post-fermentation wastewaters with subsequent growth of energy crops, with other potential benefits for the environment, such as soil treatment, absorption of CO₂, and air purification. Full article

This study evaluated the production potential of M. sacchariflorus and M. giganteus depending on plantation age and soil type. The analyses showed that the leaf area index was dependent on the Miscanthus genotype, soil type, and plantation age. The mean leaf angle, on the other hand, was mainly affected by plantation age. Significant differences in plant height were found, resulting from genotype, soil type, and plantation age. The biomass yield obtained from Miscanthus plantations was also dependent on soil type, plantation age, and genotype. The biomass moisture content was to a lesser extent affected by the interactions between genotype and soil type, and between soil type and plantation age, but it was dependent on the interaction between genotype and plantation age. The calorific value of the tested biomass was mainly influenced by the Miscanthus genotype and, to a lesser extent, by plantation age and soil type. The highest calorific value was found in the biomass of M. sacchariflorus, regardless of soil type and plantation age, while the lowest was recorded for M. giganteus biomass, irrespective of soil type. Full article

The concept of bacterial nanocellulose (BNC) production from low-cost cellulosic raw materials is evolving across the world, as it reduces the production cost of this valuable polymer and expands its technical applications. Miscanthus × giganteus is a widely recognized energy crop with high cellulose content, but its potential as a feedstock for BNC production is underexplored. The cellulose content in the biomass of Miscanthus × giganteus from the Russian breeding stock was 54% in the present study. The Miscanthus × giganteus biomass was subjected to chemical pretreatment by four different techniques: classical alkaline delignification and three authors’ own methods using diluted nitric acid solutions at atmospheric pressure. The resultant substrates were then enzymatically hydrolyzed under identical conditions, yielding carbohydrate-based culture media on which bacterial nanocellulose biosynthesis was carried out using a SCOBY symbiotic culture. All the four chemical pretreatment methods were found to be extremely efficient because they provide a 28–31-fold increase in the biomass reactivity to enzymatic hydrolysis compared to untreated Miscanthus × giganteus. This study clearly demonstrates that it is most expedient to carry out the biomass pretreatment in a single stage using a dilute nitric acid solution in the BNC production technology from Miscanthus × giganteus. In this case, the substrate yield from the feedstock for subsequent hydrolysis was 50%, the recovery of reducing sugars from the Miscanthus × giganteus biomass reached its maximal value (65.2%), and the yield of BNC was 1.1–1.3 times higher compared to the other three methods of biomass pretreatment. Full article

Soil contamination in industrial areas often involves complex mixtures of contaminants, making remediation a significant challenge. Microbe-assisted phytoremediation offers a promising solution, yet its success depends on understanding interaction between plants, microorganisms, and contaminants in rhizosphere. This study examined the effects of organic (oil sludge) and inorganic (Zn) contaminants, applied individually and in combination, on the rhizosphere bacterial community of Miscanthus × giganteus Greef et Deu (M×g), with emphasis on strains exhibiting plant growth-promoting, hydrocarbon-degrading, and metal-tolerant traits. A one-season greenhouse experiment included soils spiked with Zn (1650 mg kg⁻¹) and/or oil sludge (15 mL kg⁻¹). Oil sludge exerted a stronger influence on the taxonomic structure of rhizobacterial communities than Zn, largely shaping the patterns observed under co-contamination. Zn exposure increased the relative abundance of Actinobacteriota, whereas oil sludge favoured Proteobacteriota. Both contaminants, individually and together, enhanced the proportion of Sphingomonadaceae. Across all treatments, taxa with potential plant-growth-promoting traits were present, while co-contaminated soil harboured microorganisms capable of hydrocarbon degradation, heavy metal tolerance, and plant growth promotion. These findings highlight the adaptive capacity of the M×g rhizobiome and support its application in phytoremediation. The isolation and characterisation of rhizosphere-associated strains provide basis for developing microbial bioagents to enhance biomass production and remediation efficiency in multi-contaminated environments. Full article

Miscanthus × giganteus particles possess excellent advantages in biodegradability and sustainability. However, their susceptibility to ultraviolet (UV) degradation limits wider outdoor applications. In the present work, electron beam (e-beam) radiation-induced grafting was used for the first time to attempt covalent grafting of UV absorbers onto miscanthus particles to address a major challenge in natural fiber stabilization. Two UV absorbers, 2-hydroxy-4-(methacryloyloxy) benzophenone (HMB) and 2-(4-benzoyl-3-hydroxyphenoxy) ethyl acrylate (BHEA), were explored using both pre-irradiation and simultaneous approaches. Pre-irradiation grafting did not achieve useful covalent fixation of HMB or BHEA, due in part to the premature decay of radicals at elevated temperatures and with solvent use, and the lignin-based quenching of radicals. Solvent-free mutual irradiation grafting failed due to immobility of the UV absorbers, while grafting of HMB in solvent failed due to radical-scavenging behavior. Grafting of BHEA was successfully achieved under solvent-based simultaneous irradiation, reaching up to 38 wt % DG in a butanone/2.5% H₂SO₄ system. This condition led to the improved UV stability of miscanthus particles, in which color change was reduced significantly after 1000 h of accelerated weathering; this was mainly linked to a beneficial pre-darkening effect which was induced by the presence of the acid. This work proposes a route of grafting strategy that aims to improve the photostability of miscanthus particles, paving the way for durable bio-based materials in outdoor composite applications. Full article