Search Results (329)

Co-combustion is regarded as an effective means for high-efficiency utilization of low-quality fuels. However, low-quality fuel has problems such as low energy density and high water content. The fuel quality and blending performance can be further optimized by the pretreatment of low-quality fuel, for example, calorific value, hydrophobicity, and NO conversion rate. Based on the idea of co-upgradation, this study systematically investigates the effects of integrated upgrading on fuel quality and hydrophobicity under different conditions. In this study, lignite and wheat straw were selected as research objects. The co-upgrading experiments of wheat straw and lignite were conducted at reaction temperatures of 170 °C, 220 °C, and 270 °C in flue gas and air atmospheres with biomass blending ratios of 0%, 25%, 50%, 75%, and 100%. SEM (scanning electron microscopy) and nitrogen (N₂) adsorption analyses showed that under low-temperature and low-oxygen conditions, organic components from biomass pyrolysis migrated in situ to cover the surface of lignite, resulting in a gradual smoothing of the fuel surface and a decrease in the specific surface area. Meanwhile, water reabsorption experiments and contact angle measurements showed that the equilibrium water holding capacity and water absorption capacity of the lifted fuels was weakened, and hydrophobicity was enhanced. Combustion kinetic parameters and pollutant release characteristics were investigated by thermogravimetric analysis (TGA) and isothermal combustion tests. It was found that co-upgradation could effectively reduce the reaction activation energy and NO conversion rate. Characterized by Raman spectroscopy (Raman) and X-ray photoelectron spectroscopy (XPS), in situ migration of organic components affected combustion reactivity by modulating changes in N-containing product precursors. The results showed that the extracted fuel with a 75% biomass blending ratio in the flue gas atmosphere exhibited the best overall performance at 220 °C, with optimal calorific value, combustion reactivity, and hydrophobicity. These findings may provide important theoretical foundations and practical guidance for the optimization of industrial-scale upgrading processes of low-quality fuels. Full article

In this paper, a combined modification method using thermal modification and wax impregnation was investigated. The advantage of this method is that the two modification steps are completed in one step. Two different wood species, beech (Fagus sylvatica) and Scots pine (Pinus sylvestris), were investigated. The effects of the treatments were tested regarding the wax uptake, mass loss, density, equilibrium moisture content, swelling, water contact angle, strength properties, and durability. Through the synergistic effect of the combined modification, it was possible to significantly improve the dimensional stability and decrease the hygroscopicity and equilibrium moisture content, while swelling anisotropy was not affected. It was proven that the wax uptake during this method is highly dependent on the treatment temperature, resulting in a large density increase. The treatment resulted in an obvious color change as well. Bending strength was not affected by the combined treatment, while impact bending, compression strength, and Brinell hardness were improved. High durability was observed after the combined modification method, indicating that lower treatment temperatures are enough to efficiently protect the wood. Full article

Mixtures containing polyvinyl alcohol (PVA) and methylcellulose (MC) were obtained and used to synthesize hydrogels in various ratios of components. The swelling kinetics of the resulting hydrogels were studied, revealing that the equilibrium swelling degree in artificial saliva is nearly twice as high as in water. It was found that increasing the volumetric content of PVA in the mixture leads to a higher swelling degree. The kinetics of active pharmaceutical ingredient (API) sorption and release from the hydrogels were also investigated. It was demonstrated that hydrogels with a higher PVA content exhibit greater sorption capacity; however, the release of the API from such samples occurs at a slower rate. For the first time, the mucoadhesive properties of PVA-MC-based hydrogels were studied. It was established that the PVA-MC hydrogel with a ratio of 6:4 vol.% remained on the surface of the porcine cheek mucosa for two days, the 5.5:4.5 vol.% sample detached after 24 h, and the 5:5 vol.% sample adhered for approximately 10 h. These findings confirm the mucoadhesive potential of the hydrogels and their suitability for buccal drug delivery forms. The synthesized PVA-MC hydrogels are promising for applications in medicine and pharmacology. Full article

The advantages of torrefaction preheating, including the production of a hydrophobic solid product, improved particle size distribution, enhanced fuel properties with fewer environmental issues, decreased moisture content, and reduced volatile content. In order to meet the technical requirements of biomass oriented value-added and energy saving and emission reduction, pine sawdust (PS) was taken as the research object, and the physicochemical properties of the PS samples preheated at a low temperature were analyzed by synchronous thermal analysis (TG-DSC), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM), and organic element analyzer (EA). The effect of preheating at a lower temperature on the physicochemical properties of PS was discussed. The results showed that, under the preheating condition of 200 °C, compared with PS, the water content of PS-200 decreased by 3.23%, the volatile content decreased by 3.69%, the fixed carbon increased by 6.81%, the calorific value increased by 6.90%, the equilibrium water content decreases from 7.06% to 4.46%, and the hydrophobicity increases. This research, based on the improvement of the quality of agricultural and forestry waste and the promotion of the strategy of converting waste into energy, has contributed to the advancement of sustainable energy production. Full article

Antimicrobial resistance in infected chronic wounds present significant risk of complications (e.g., amputations, fatalities). This research aimed to formulate honey-loaded hydrocolloid film comprising gelatin and HPMC, for potential treatment of infected chronic wounds. Honeys from different sources (Cameroonian and Manuka) were used as the bioactive ingredients and their functional characteristics evaluated and compared. The formulated solvent cast films were functionally characterized for tensile, mucoadhesion and moisture handling properties. The morphology and physical characteristics of the films were also analyzed using FTIR, X-ray diffraction and scanning electron microscopy. Antibacterial susceptibility testing was performed to study the inhibition of Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus by honey components released from the films. The % elongation values (8.42–40.47%) increased, elastic modulus (30.74–0.62 Nmm) decreased, the stickiness (mucoadhesion) (0.9–1.9 N) increased, equilibrium water content (32.9–72.0%) and water vapor transmission rate (900–298 gm² day⁻¹) generally decreased, while zones of inhibition (2.4–6.5 mm) increased with increasing honey concentration for 1 and 5% w/v, respectively. The results generally showed similar performance for the different honeys and demonstrate the efficacy of honey-loaded hydrocolloid films as potential wound dressing against bacterial growth and potential treatment of infected chronic wounds. Full article

Carbonaceous sorbents were prepared from Chlorella vulgaris via hydrothermal carbonization (200 °C and 250 °C) and slow pyrolysis (300–500 °C) to assess their effectiveness in removing the herbicide metribuzin from water. The biomass was cultivated under controlled laboratory conditions, allowing for consistent feedstock quality and traceability throughout processing. Using a single microalgal feedstock for both thermal methods enabled a direct comparison of hydrochar and pyrochar properties and performance, eliminating variability associated with different feedstocks and allowing for a clearer assessment of the influence of thermal conversion pathways. While previous studies have examined algae-derived biochars for heavy metal adsorption, comprehensive comparisons targeting organic micropollutants, such as metribuzin, remain scarce. Moreover, few works have combined kinetic and isotherm modeling to evaluate the underlying adsorption mechanisms of both hydrochars and pyrochars produced from the same algal biomass. Therefore, the materials investigated in the present work were characterized using a combination of standard physicochemical and structural techniques (FTIR, SEM, BET, pH, ash content, and TOC). The kinetics of sorption were also studied. The results show better agreement with the pseudo-second-order model, consistent with chemisorption, except for the hydrochar produced at 250 °C, where physisorption provided a more accurate fit. Freundlich isotherms better described the equilibrium data, indicating heterogeneous adsorption. The hydrochar obtained at 200 °C reached the highest adsorption capacity, attributed to its intact cell structure and abundance of surface functional groups. The pyrochar produced at 500 °C exhibited the highest surface area (44.3 m²/g) but a lower affinity for metribuzin due to the loss of polar functionalities during pyrolysis. This study presents a novel use of Chlorella vulgaris-derived carbon materials for metribuzin removal without chemical activation, which offers practical benefits, including simplified production, lower costs, and reduced chemical waste. The findings contribute to expanding the applicability of algae-based sorbents in water treatments, particularly where low-cost, energy-efficient materials are needed. This approach also supports the integration of carbon sequestration and wastewater remediation within a circular resource framework. Full article

Occupational exposure to commercial formic and acetic acids through dermal contact and inhalation during rubber sheet processing poses significant health risks to workers. Additionally, the use of these acids contributes to environmental pollution by contaminating water sources and soil. This study investigates the potential of three types of wood vinegar—derived from para-rubber wood, bamboo, and eucalyptus—obtained through biomass pyrolysis under anaerobic conditions, as sustainable alternatives to formic and acetic acids in the production of ribbed smoked sheets (RSSs). The organic constituents of each wood vinegar were characterized using gas chromatography and subsequently mixed with fresh natural latex to produce coagulated rubber sheets. The physical and chemical properties, equilibrium moisture content, and drying kinetics of the resulting sheets were then evaluated. The results indicated that wood vinegar derived from para-rubber wood contained a higher concentration of acetic acid compared to that obtained from bamboo and eucalyptus. As a result, rubber sheets coagulated with para-rubber wood and bamboo vinegars exhibited moisture sorption isotherms comparable to those of sheets coagulated with acetic acid, best described by the modified Henderson model. In contrast, sheets coagulated with eucalyptus-derived vinegar and formic acid followed the Oswin model. In terms of physical and chemical properties, extended drying times led to improved tensile strength in all samples. No statistically significant differences in tensile strength were observed between the experimental and reference samples. The concentration of acid was found to influence Mooney viscosity, the plasticity retention index (PRI), the thermogravimetric curve, and the overall coagulation process more significantly than the acid type. The drying kinetics of all five rubber sheet samples displayed similar trends, with the drying time decreasing in response to increases in drying temperature and airflow velocity. Full article

Biochar is a solid product generated through the pyrolysis of biomass materials under anaerobic or hypoxic conditions, and it is characterized by its strong adsorption capacity. To investigate the phosphorus adsorption performance of biochar derived from wheat straw, bamboo, and water hyacinth in wastewater, iron modification treatments were applied to these biochars, and the most effective modified biochar was identified. The physicochemical properties of the modified biochars were characterized using Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), and scanning electron microscopy (SEM). The results showed that optimal modification was achieved with an iron–carbon mass ratio of 0.70 for wheat straw biochar (Fe-WBC) and 0.45 for both bamboo biochar (Fe-BBC) and water hyacinth biochar (Fe-HBC). The maximum phosphorus adsorption capacities of the three modified biochars were as follows: 31.76 mg g⁻¹ (Fe-WBC) > 27.14 mg g⁻¹ (Fe-HBC) > 25.31 mg g⁻¹ (Fe-BBC). It was demonstrated that the adsorption behavior of Fe-BBC was predominantly multi-molecular layer adsorption, whereas the adsorption behavior of Fe-WBC and Fe-HBC was primarily monolayer adsorption. All three types of modified biochars reached adsorption equilibrium within 30 min, with Fe-WBC exhibiting the best adsorption performance. Analysis revealed that the modified biochars contained a large number of unsaturated C bonds and aromatic rings, indicating relatively stable structures. The surfaces of the modified biochars were rich in hydroxyl and carbonyl groups, which contributed to their strong adsorption properties. Post-modification analysis indicated that iron in the biochars predominantly existed in forms such as goethite (FeOOH) and hematite (Fe₂O₃). The iron content in each type of modified biochar constituted approximately 3.08% for Fe-WBC, 5.94% for Fe-BBC, and 5.68% for Fe-HBC relative to their total elemental composition. Overall, the iron-modified biochars employed in this study significantly enhanced the adsorption capacity and efficiency for phosphorus removal in wastewater. Full article

Chitosan–hydroxyapatite (CS-HAp) biocomposites, combining the biocompatibility and bioactivity of chitosan with the osteoconductive properties of hydroxyapatite, are emerging as promising candidates for tissue engineering applications. These materials consistently exhibit excellent cytocompatibility, with cell viability rates greater than 95% in MTT and Neutral Red Uptake assays, and minimal cytotoxicity, as demonstrated by low levels of cell death in DAPI and Trypan blue staining. More importantly, CS-HAp biocomposites modulate the immune environment by enhancing the expression of anti-inflammatory cytokines (IL-10 and IL-4) and the pro-inflammatory cytokine TGF-β, while avoiding significant increases in TNF-α, IL-6, or NF-κB expression in fibroblast cells exposed to HAC and HACF scaffolds. In an in vivo dermatitis model, these biocomposites reduced mast cell counts and plasma histamine levels and significantly decreased pro-inflammatory cytokines (TNF-α, IL-1β, IL-6), JAK1/3, VEGF, and AnxA1 levels. Structurally, HACF scaffolds demonstrated larger average pore sizes (95 µm) compared to HAC scaffolds (74 µm), with porosities of 77.37 ± 2.4% and 65.26 ± 3.1%, respectively. These materials exhibited high swelling ability, equilibrium water content, and controlled degradation over a week in culture media. In addition to their immunomodulatory effects, CS-HAp composites promote essential cellular activities, such as attachment, proliferation, and differentiation, thereby supporting tissue integration and healing. Despite these promising findings, significant gaps remain in understanding the underlying mechanisms of immune modulation by CS-HAp biocomposites, and formulation-dependent variability raises concerns about reproducibility and clinical application. Therefore, a comprehensive review is essential to consolidate existing data, identify key knowledge gaps, and standardize the design of CS/HAp composites for broader clinical use, particularly in immunomodulatory and regenerative medicine contexts. Full article

The protective materials for cultural relic buildings generally have a deficiency of relatively shallow penetration depth. Based on the principle of changing the permeability coefficient of cultural relic buildings by “water blocking water” and considering the characteristics of magnesium acrylate polymer and the requirement of extending the curing time, a method of modifying magnesium acrylate polymer with glycerol and sodium methyl silicate is proposed. Experimental studies on magnesium acrylate, glycerol–magnesium acrylate, and sodium methyl silicate—glycerol–magnesium acrylate polymers were carried out, and tests and analyses on curing time, swelling performance, water loss rate, and soil sample protection were conducted. The results show that the initiator concentration is a key factor affecting the curing rate of magnesium acrylate polymers. When the initiator content is ≥4%, the curing time is significantly shortened to 20–67 min, and the incorporation of glycerol prolongs the curing time by more than 100 min through the dilution reaction system. Glycerol modification significantly enhanced the swelling capacity of the polymer, with the swelling rate increasing by approximately 15–20% compared to the unmodified system. Sodium methyl silicate effectively improved the construction performance of magnesium acrylate and prevented the occurrence of bubbles. The optimal formula of magnesium acrylate polymer is 25% magnesium acrylate, 40% glycerol, and 2% sodium methyl silicate. While maintaining curing for 120 min, it features a high swelling rate (equilibrium swelling ratio Ew ≈ 0.32) and a low dehydration rate (dehydration rate ≤ 35% after 48 h), and has volume stability after interaction with soil samples. Full article

Fly ash aggregates (FAAs) were synthesized via a hydrothermal process, involving the reaction of fly ash and cement at 180 °C under saturated steam conditions. A thorough examination was carried out to evaluate the impact of cement content on the physico-mechanical properties of the resulting FAAs. A comprehensive exploration was undertaken to decipher the mechanisms by which cement modulates the cylinder compressive strength of FAAs, encompassing mineralogical composition, microstructure, insoluble residue content, and loss on ignition. As the cement proportion increased, a concomitant rise in the amount of hydration products was observed, leading to an enhanced filling effect. This, subsequently, resulted in reduced water absorption and increased apparent density of the FAAs. The augmented filling effect of hydration products contributed to a gradual elevation in the cylinder compressive strength of FAAs as cement content escalated from 5 to 35 wt%. However, a significant transition occurred when cement content surpassed 35%, reaching 35–45 wt%. Within this range, the micro-aggregate effect was diminished, causing a decrease in cylinder compressive strength. The optimal equilibrium between the filling effect and micro-aggregate effect was attained at 35 wt% cement content, where the cylinder compressive strength of FAAs reached its peak value of 18.5 MPa. This research is expected to provide a feasible approach for solid waste reduction, with a particular emphasis on the utilization of fly ash. Full article

In water-limited regions, plant–water interactions significantly affect the hydrological cycle and vegetation dynamics, particularly in deep-rooted plantations where deep water uptake mitigates water stress during seasonal and interannual droughts. In this study, we improved the University of Arizona version of the Noah-MP model by incorporating actual soil thickness, along with new subsurface and water table schemes, to evaluate the long-term influence of plant–water interactions in Robinia pseudoacacia L. plantations. We found that soil water content was sensitive to both soil stratification and vertical root distribution, with Nash–Sutcliffe efficiency increasing from less than 0.20 to 0.63 in sensitivity experiments. Plant–water interactions resulted in persistent low soil water content within the root zone, whereas the static vegetation experiment overestimated soil moisture because of unrealistic infiltration. Transpiration and water uptake remained in dynamic equilibrium, and vegetation growth was not limited by water availability. Deep water uptake (>2 m) contributed 0.3–20.5% of transpiration during the growing season, with higher contributions observed in drier years. Compared to precipitation, evapotranspiration was more sensitive to soil water storage in the upper 0–2 m of soil. Our results emphasize the critical role of plant–water interactions in regulating water availability for deep-rooted plantations on the Loess Plateau under changing environmental conditions. Full article

Biocomposites are defined as eco-friendly materials from an environmental point of view. Because of the importance of this class of materials, their study is important, especially in moist and heated conditions. In this sense, this work aims to evaluate the transient behavior of moisture absorption and mechanical performance of biocomposites composed of a matrix of high-density biopolyethylene (originated from ethanol produced from sugarcane) filled with curauá vegetable fiber and organophilic montmorillonite clay. For this purpose, dry biocomposites filled with organophilic montmorillonite clay and curauá fiber (1, 3, and 5 wt.%) were prepared using a hand lay-up technique and subjected to moisture absorption and mechanical (flexural and impact tests) characterizations at different times. The experiments were carried out at water bath temperatures of 30 °C and 70 °C. The results have proven the strong influence of chemical composition and temperature on the moisture absorption behavior of biocomposites across time. For a higher percentage of reinforcement on the polymeric matrix, a higher moisture migration rate was verified, reaching a higher hygroscopic equilibrium condition at 16.9% for 5 wt.% of curauá fiber and 10.25% for 5 wt.% of montmorillonite clay particles. In contrast, the mechanical properties of all of the biocomposites were strongly reduced with an increasing moisture content, especially at higher fiber content and water bath temperature conditions. The innovative aspects of this research are related to the study of a new material and its transient mechanical behavior in dry and wet conditions. Full article

Moisture phase change (MPC), a key process in bread baking, significantly impacts heat and mass transfer, as confirmed by experiments. However, existing models poorly characterize this phenomenon, and its quantitative impact on baking needs systematic study. This research develops a coupled multiphase model for heat and mass transfer with large deformation, employing both equilibrium and nonequilibrium approaches to describe MPC in closed and open pores, respectively. Experimentally calibrated pore-opening functions and viscosity variations revealed that pore-opening primarily occurs at 71–81 °C, whereas dough solidification occurs at 50–110 °C. Model-based analysis indicates that in closed pores, evaporation–diffusion–condensation is the primary mode of moisture transport and heat transfer with contributing approximately 60% of the total effective thermal conductivity, and when pores open, water vapor evaporates or condenses on pore walls, forming an ‘evaporation front’ and ‘condensation front’. The content of liquid water increases at the ‘condensation front’ and decreases at the ‘evaporation front’. Bread deformation is predominantly governed by pressure differentials between closed pores and the ambient environment, with the partial pressure of water vapor emerging as the principal driver because its average content exceeds 70% within closed pores. These findings demonstrate that MPC governs heat and mass transfer and deformation during bread baking. Full article

Background: Hydrophobic ion pairing is a technique for reducing the hydrophilicity of charged molecules (drugs) by pairing them with oppositely charged hydrophobic counterions. This method is used to control the solubility of charged molecules in a solvent and is of particular importance in drug delivery. Methods: Dissipative particle dynamics simulations were performed to provide a microscopic understanding of hydrophobic ion pairing in polymyxin B (PMB) and oleate (OA) ions. Solvents and ions were explicitly included in the simulations. Results: We investigated the effects of relative concentrations of PMB and OA (the charge ratio), solvent philicity, and the concentrations of PMB and OA at a fixed composition on the structural stability and the hydrophobicity of the ion paired cluster, as well as the kinetics of assembly. The maximum hydrophobicity belongs to PMB:OA charge ratio 1:1. The clustering efficiency in mixed ethanol–water solutions decreases with the increasing ethanol content of water. The dynamics of PMB/OA exchange between hydrophobic cluster and the surrounding solution reveal two distinct relaxation processes, whose relaxation times differ by two orders of magnitude. Conclusions: The hydrophobicity of the cluster is controlled by the charge ratio. The core of the ion paired cluster acts as the primary barrier and its surface layer acts as the secondary barrier against alcohol permeation into it. The exchange of surface PMB/OA ions with the surrounding is a much faster dynamic process than the establishment of equilibrium between the PMB/OA ions in the cluster and the solution. The time scale for the slower process provides useful information on the rate of drug release from the hydrophobic ion paired complex. Full article