Search Results (48)

The agri-food supply chain and other industries that convert agricultural raw materials into various consumer goods generate large quantities of by-products, most of which end up in landfills. This waste, rich in cellulose, provides a significant opportunity for the conversion of agricultural residues into valuable products. In this paper, soybean hulls and hemp waste were subjected to chemical treatments with alkaline (NaOH 2% w/v) and acidic solutions (HCl 1 M) to remove non-cellulosic components and isolate cellulose. The biomass was characterized after each chemical process through FTIR, SEM, EDX, elemental analysis, TGA, and XRD. Lignin was determined following two different procedures, a conventional TAPPI protocol and a method recently proposed in the literature (CASA method). The results indicated that the chemical treatments favored the removal of organic compounds and minerals, increasing the cellulose content in biomass after each step. The purified product of soybean hulls consists of fibers 35–50 µm long and 5–11 µm thick, containing nearly pure cellulose arranged in crystalline domains. Fibers of variable sizes, rich in crystalline cellulose, were isolated from hemp waste. These fibers have diameters ranging between 2 and 60 µm and lengths from 40 to 800 µm and contain considerable amounts of lignin (~14%). Full article

In this paper, a composite separator for lithium-ion batteries was successfully prepared by electrostatic spinning, based on polyacrylonitrile (PAN) and 5% cellulose nanocrystals (CNCs) derived from sisal fiber. Its physical and electrochemical properties as well as the enhanced mechanism were investigated. The obtained 5%CNCs/PAN separator offers an excellent thermal stability, ultra-high electrolyte uptake (486 ± 30%), high ionic conductivity (2.82 mS cm⁻¹ at 25 °C) and a wide electrochemical window (5.3 V). In addition, a lithium-ion battery assembled with the 5%CNCs/PAN separator can work stably for 1000 h at 5 mA cm⁻². The CNCs in the electrolyte enable the immobilization of PF₆⁻, thereby inhibiting the migration of anions and increasing its Li⁺ transfer number (t_Li⁺) to 0.75, which is 65.3% higher than that of a pure PAN separator. The battery with the 5%CNCs/PAN separator retains 97.4% of its initial reversible capacity after 100 cycles, which is much higher than that of a pure PAN separator, with a value of 62.9%. These results suggest the potential utility of 5%CNCs/PAN separators as high-performance separators required in lithium-ion batteries. Full article

Cellulose acetate (CA) motion picture films are subjected to degradation, especially due to the “vinegar syndrome”, a de-acetylation process catalyzed by high temperature, humidity, and acidity. Acetic acid is released as a by-product of this reaction and acts as a catalyst that triggers an autocatalytic process. The main aim of this study was to evaluate the use of metal oxide, hydroxide, and carbonate nanoparticles, as well as their composite inorganic–organic systems, for the adsorption of acetic acid and the inhibition of the deacetylation process. Various nanoparticles (Ca(OH)₂, ZnO and CaCO₃) were compared in terms of their ability to adsorb glacial acetic acid vapors through gravimetry analysis, Fourier Transform Infrared (FTIR) Spectroscopy, X-ray diffraction (XRD), and Thermogravimetric Analysis (TGA). The variation in the size and morphology of the nanoparticles was investigated via Scanning Electron Microscopy (SEM), too. Subsequently, the most promising nanoparticles (ZnO) were incorporated into composite organic–inorganic systems, made of Whatman paper (WP) and polyvinyl alcohol formaldehyde (PVF) xerogels, and their ability to adsorb acetic acid vapors was again evaluated. Finally, the performances of both the pure ZnO nanoparticles and the organic–inorganic composite systems as inhibitors of the “vinegar syndrome” were assessed on artificially degraded motion picture films using a specifically developed and validated multi-analytical protocol. Full article

This paper presents the preparation and study of the properties of alginate materials, which were obtained on the basis of sodium alginate, activated carbon, cellulose, and calcium chloride. Alginate–carbon (AlgCa + C) and alginate–cellulose (AlgCa + Cel) composites, as well as pure calcium alginate (AlgCa) for comparative purposes, were obtained. Their textural (nitrogen adsorption/desorption isotherms), morphological (scanning electron microscopy), thermal (thermal analysis), and acid–base (pH drift method) properties, as well as the swelling index, were investigated. Additionally, to determine the adsorption properties, comprehensive equilibrium and kinetic studies of the adsorption of sodium salts of ibuprofen (IBP), diclofenac (D), and naproxen (NPX) from aqueous solutions on biocomposities were carried out. Adsorption isotherms were fitted using the Marczewski–Jaroniec isotherm equation (R² = 0.941–0.988). Data on the adsorption rate were analyzed using simple kinetic equations, of which the best quality of fit was obtained using the multi-exponential equation (R² − 1 = (3.9 × 10⁻⁴)–(6.9 × 10⁻⁴)). The highest obtained adsorption values were reached in systems with alginate–carbon composite and were 1.23 mmol/g for NPX, 0.81 mmol/g for D, and 0.43 mmol/g for IBP. The AlgCa + C material was characterized by a large specific surface area (1151 m²/g), a high degree of swelling (300%) and high resistance to high temperatures. Full article

The presence of harmful oxidizing gases accelerates the oxidation of cellulose fibers in paper, resulting in reduced strength and fading ink. Therefore, the development of highly sensitive NO₂ gas sensors for monitoring and protecting books holds significant practical value. In this manuscript, ZnO/MoS₂ composites were synthesized using sodium molybdate and thiourea as raw materials through a hydrothermal method. The morphology and microstructure were characterized by X-ray diffraction analysis (XRD), energy dispersive spectroscopy (EDS), field emission scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The ZnO/MoS₂ composite exhibited a flower-like structure, with ZnO nanoparticles uniformly attached to the surface of MoS₂, demonstrating advantages such as high specific surface area and good uniformity. The gas sensitivity of the ZnO/MoS₂ nanocomposites reached its peak at 260 °C, with a sensitivity value around 3.5, which represents an improvement compared to pure ZnO, while also enhancing sensitivity. The resistance of the ZnO/MoS₂ gas sensor remained relatively stable in air, exhibiting short response times during transitions between air and NO₂ environments while consistently returning to a stable state. In addition to increasing adsorption capacity and improving light utilization efficiency, the formation of hetero-junctions at the ZnO-MoS₂ interface creates an internal electric field that effectively promotes the rapid separation of photo-generated charge carriers within ZnO, thereby extending carrier lifetime. Full article

Suitable fermentation substrates and fermentation modes can effectively improve the fermentation ethanol yield. In this study, we optimised the hydrothermal pretreatment conditions by orthogonal optimisation using waste tissue paper as substrate. These conditions consisted of 50 min duration in a high-pressure reactor with pure water as solvent at a temperature of 160 °C. The biomass to water ratio was maintained at a constant level. The cellulose content of the pretreated TP was 81.19 ± 4.06%, which was an increase of 21.59% compared to the blank control. The 72 h reducing sugar yield of pretreated TP was 0.61 g sugar/g paper, which was 38.64% higher than that of untreated TP. Subsequently, the pretreated TP was fermented under optimal conditions. The mixed group of Saccharomyces cerevisiae and Candida shehatae (SC) showed a distributed saccharification fermentation pattern, with an ethanol yield of 28.11 g/L in 72 h. On the other hand, the single Saccharomyces cerevisiae (S) exhibited a homobloc saccharification fermentation pattern, with an ethanol yield of 35.15 g/L in 72 h. Full article

This paper presents a study of the characteristic effects of the physicochemical properties of microcrystalline cellulose and a series of biocarbon samples produced from this raw material through thermal conversion at temperatures ranging from 200 °C to 850 °C. Structural studies revealed that the biocarbon samples produced from cellulose had a relatively low degree of graphitization of the carbon and an isometric shape of the carbon particles. Based on thermal investigations using the differential thermal analysis/differential scanning calorimeter method, obtaining fully formed biocarbon samples from cellulose feedstock was possible at about 400 °C. The highest direct carbon solid oxide fuel cell (DC-SOFC) performance was found for biochar samples obtained via thermal treatment at 400–600 °C. The pyrolytic gases from cellulose decomposition had a considerable impact on the achieved current density and power density of the DC-SOFCs supplied by pure cellulose samples or biochars derived from cellulose feedstock at a lower temperature range of 200–400 °C. For the DC-SOFCs supplied by biochars synthesised at higher temperatures of 600–850 °C, the “shuttle delivery mechanism” had a substantial effect. The impact of the carbon oxide concentration in the anode or carbon bed was important for the performance of the DC-SOFCs. Carbon oxide oxidised at the anode to form carbon dioxide, which interacted with the carbon bed to form more carbon oxide. The application of biochar obtained from cellulose alone without an additional catalyst led to moderate electrochemical power output from the DC-SOFCs. The results show that catalysts for the reverse Boudouard reactions occurring in a biocarbon bed are critical to ensuring high performance and stable operation under electrical load, which is crucial for DC-SOFC development. Full article

Nanocellulose is a nanostructured form of cellulose, which retains valuable properties of cellulose such as renewability, biodegradability, biocompatibility, nontoxicity, and sustainability and, due to its nano-sizes, acquires several useful features, such as low density, high aspect ratio and stiffness, a high specific surface area, easy processing and functionalisation, and good thermal stability. All these make it a highly versatile green nanomaterial for multiple applications, including the conservation of cultural heritage. This review provides the basic characteristics of all nanocellulose forms and their properties and presents the results of recent research on nanocellulose formulations applied for conserving historical artefacts made of wood and paper, discussing their effectiveness, advantages, and disadvantages. Pure nanocellulose proves particularly useful for conserving historical paper since it can form a durable, stable coating that consolidates the surface of a degraded object. However, it is not as effective for wood consolidation treatment due to its poor penetration into the wood structure. The research shows that this disadvantage can be overcome by various chemical modifications of the nanocellulose surface; owing to its specific chemistry, nanocellulose can be easily functionalised and, thus, enriched with the properties required for an effective wood consolidant. Moreover, combining nanocellulose with other agents can also improve its properties, adding new functionalities to the developed supramolecular systems that would address multiple needs of degraded artefacts. Since the broad use of nanocellulose in conservation practice depends on its properties, price, and availability, the development of new, effective, green, and industrial-scale production methods ensuring the manufacture of nanocellulose particles with standardised properties is necessary. Nanocellulose is an interesting and very promising solution for the conservation of cultural heritage artefacts made of paper and wood; however, further thorough interdisciplinary research is still necessary to devise new green methods of its production as well as develop new effective and sustainable nanocellulose-based conservation agents, which would replace synthetic, non-sustainable consolidants and enable proper conservation of historical objects of our cultural heritage. Full article

Buildings utilize both inorganic and organic insulation materials to conserve energy and prevent heat loss. However, while exhibiting excellent thermal insulation performance, organic insulation materials increase the risk of fire due to the emission of intense heat and toxic smoke in the event of a fire. Conversely, inorganic insulation materials are characterized by a lower thermal insulation performance, leading to an increase in the weight of the building with extensive use. Therefore, the necessity for research into new insulation materials that address the drawbacks of existing ones, including reducing weight, enhancing fire resistance, and improving thermal insulation performance, has been recognized. This study focuses on evaluating the enhancement of the thermal insulation performance using novel building materials compared to conventional ones. The research methodology involved the incorporation of porous aerogel powders into paper-based cellulose insulation to improve its insulating properties. Samples were prepared in standard 100 × 100 mm² panel forms. Two control groups were utilized: a pure control group, where specimens were fabricated using 100% recycled cardboard for packaging, and a mixed control group, where specimens were produced using a mixture ratio of 30 wt% ceramic binder and 40 wt% expandable graphite. Experimental group specimens were prepared by increasing the aerogel content from 200 to 1000 mL under each condition of the control groups (pure and mixed) after mixing. The thermal insulation performance of the specimens was evaluated in terms of thermal conductivity and thermal diffusivity according to ISO 22007-2 (for solids, paste, and powders). Through this study, it was found that the thermal insulation performances of the pure control and experimental groups improved by 16.66%, while the mixed control and experimental groups demonstrated a 17.06% enhancement in thermal insulation performance with the addition of aerogel. Full article

Cellulose-based carbon (CBC) is widely known for its porous structure and high specific surface area and is liable to adsorb gas molecules and macromolecular pollutants. However, the application of CBC in gas sensing has been little studied. In this paper, a ZnO/CBC heterojunction was formed by means of simple co-precipitation and high-temperature carbonization. As a new ammonia sensor, the prepared ZnO/CBC sensor can detect ammonia that the previous pure ZnO ammonia sensor cannot at room temperature. It has a great gas sensing response, stability, and selectivity to an ammonia concentration of 200 ppm. This study provides a new idea for the design and synthesis of biomass carbon–metal oxide composites. Full article

Previous works of the authors have presented the changes in the optical, mechanical, and chemical properties of the oiled areas of the supports that occur upon ageing due to oil-binder absorption in works of art on paper and printed material. In this framework, transmittance FTIR analysis has indicated that the presence of linseed oil induces the conditions to promote the deterioration of the oil-impregnated areas of the paper supports. However, the analysis of oil-impregnated mock-ups did not provide detailed information about the input of linseed oil formulations and the different types of paper support on the chemical changes that occur upon ageing. This work presents the results of ATR-FTIR and reflectance FTIR, which were used for compensating the previous results, proving indications on the effect of different materials (linseed oil formulations, and cellulosic and lignocellulosic papers) on the development of chemical changes, thus, on the condition of the oiled areas upon ageing. Although linseed oil formulations have a determining effect on the condition of the oiled areas of the support, the paper pulp content appears to have an input to the chemical changes that occur in the system of paper–linseed oil upon ageing. The results presented are more focused on the oil-impregnated mock-ups with cold-pressed linseed oil since results have indicated that this causes more extended changes upon ageing. Full article

In this paper, we propose an optimized protocol to synthesize reproducible, accurate, sustainable integrally skinned monophasic hybrid cellulose acetate/silica membranes for ultrafiltration. Eight different membrane compositions were studied, divided into two series, one and two, each composed of four membranes. The amount of silica increased from 0 wt.% up to 30 wt.% (with increments of 10 wt.%) in each series, while the solvent composition was kept constant within each series (formamide/acetone ratio equals 0.57 wt.% in series one and 0.73 wt.% in series two). The morphology of the membranes was analyzed by scanning electron microscopy and the chemical composition by Fourier transform infrared spectroscopy, in attenuated total reflection mode (FTIR-ATR). Mechanical tensile properties were determined using tensile tests, and a retest trial was performed to assess mechanical properties variability over different membrane batches. The hydraulic permeability of the membranes was evaluated by measuring pure water fluxes following membrane compaction. The membranes in series two produced with a higher formamide/acetone solvent ratio led to thicker membranes with higher hydraulic permeability values (47.2–26.39 kg·h⁻¹·m⁻²·bar⁻¹) than for the membranes in series one (40.01–19.4 kg·h⁻¹·m⁻²·bar⁻¹). Results obtained from the FTIR-ATR spectra suggest the presence of micro/nano-silica clusters in the hybrid membranes of series one, also exhibiting higher Young’s modulus values than the hybrid membranes in series two. Full article

This paper presents the results of research on the preparation and properties of GO/BC nanocomposite from bacterial cellulose (BC) modified with graphene oxide (GO) using the in situ method. Two bacterial strains were used for the biosynthesis of the BC: Komagataeibacter intermedius LMG 18909 and Komagataeibacter sucrofermentans LMG 18788. A simple biosynthesis method was developed, where GO water dispersion was added to reinforced acetic acid-ethanol (RAE) medium at concentrations of 10 ppm, 25 ppm, and 50 ppm at 24 h and 48 h intervals. As a result, a GO/BC nanocomposite membrane was obtained, characterized by tensile strength greater by 150% as compared with the pure BC (̴ 50 MPa) and lower volume resistivity of ~4 ∙ 10⁹ Ω × cm. Moreover, GO addition increases membrane thickness up to ~10% and affects higher mass production, especially with low GO concentration. All of this may indicate the possibility of using GO/BC membranes in fuel cell applications. Full article

This work evaluates the effect of using selected inorganic chemicals as the main components of waterborne wood preservative systems on the degradation of the cellulose constituent in wood from model samples. The polymeric properties of cellulose and the homogeneity of the degradation process primarily reflect very well the degree of cellulose deterioration. Whatman papers, as pure cellulose model samples, were impregnated with 10 different 5 wt% solutions of inorganic salts and distilled water and consequently subjected to wet-thermal accelerated aging (T = 85 °C, RH = 65%, for 30 days). The samples were then derivatized to cellulose tricarbanilates (CTCs) through two different procedures (by precipitation in a methanol–water mixture/by evaporation of pyridine from the reaction mixture) and finally analyzed using size exclusion chromatography (SEC). Chemically treated and aged cellulose samples showed different changes in the degree of polymerization (DP) and polydispersity (PD) in terms of untreated non-aged standard caused by different ongoing degradation reactions, such as dehydration, hydrolysis, oxidation, and crosslinking. In general, the lowest degradation rate after treatment by chemicals and after accelerated aging was observed in samples treated by borates, NaCl, and ZnSO₄·7H₂O. The greatest depolymerization after treatment and after accelerated aging was caused by sulphates containing NH⁴⁺, Cu²⁺, and Fe³⁺ cations, with aging by NH₄Cl and (NH₄)₂HPO₄-treated samples also leading to significant depolymerization. The higher DP values are linked to the precipitated method of CTC preparation, though not for chlorides and phosphates. PD is also generally higher in precipitated and aged samples and is heavily influenced by the presence of low molecular weight products. This paper brings new insights regarding the complex evaluation of the polymeric properties of degraded cellulose by considering all important factors affecting the sample and the analysis itself through the use of statistics. From the statistical point of view, the influences of all factors (solution, aging, method) and their interactions (except aging*method) on DP are statistically significant. The influence of the sample processing method used for analysis of the desired results becomes important mainly in practice. This work recommends the evaporation method for more accurate description of more degraded cellulose. Full article

The consumption of fossil fuels is one of the main drivers of climate change. Lignin derived from biomass is a carbon-neutral raw feedstock, and its conversion into fuels is gaining much attention. The gasification of biomass aims to transform heterogeneous feedstocks into syngas and heat that could be used for various purposes. Lignin is a biomass feedstock of special interest due to its particular properties and its ability to be obtained in abundant quantities as a side product from the paper pulp industry as well as the growing cellulosic ethanol industry. This review explores the existing works regarding lignin gasification from different perspectives and compares the results obtained with other existing thermochemical processes, in addition to providing a perspective on the long-term fate of gasification as a technology compared to other emerging technologies. The analysis indicates that while lignin gasification may grow in importance in the near future due to increased interest in hydrogen production, its potential in emerging applications indicates that lignin may be too valuable to be used purely for energy generation purposes, and applications that take advantage of its inherent chemical compounds are expected to take priority in the long-term. Full article