Search Results (15)

Excessive use of fertilizers will not only cause the enrichment of soil N nutrients, soil secondary salinization, soil acidification, and an imbalance of the soil microbial community structure, but will also lead to the nitrate content of vegetables and the ground water exceeding the standard. The application of bio-organic fertilizer could reduce the amount of mineral fertilizer used. However, the effects of nitrogen reduced with different bio-organic fertilizers on soil chemical properties, microbial community structure, and the yield and quality of radish are not clear. In a field experiment, we designed six fertilization treatments: no fertilization (CK), conventional fertilization (T1), a total nitrogen reduction of 20% (T2), and a total nitrogen reduction of 20% with “No. 1”, “Seek” or “Jiajiapei” bio-organic fertilizers. The results showed that nitrogen reduction of 20% with Bacillus bio-organic fertilizer (N1) significantly increased the organic matter, pH, total nitrogen content, and the relative abundance of Bacillus and Streptomyce in the soil compared with T1. RDA analysis showed that the pH, organic matter content, invertase and fluorescein diacetate enzyme activity of the soil were significantly correlated with the soil microbial community structure. In addition, the yield and Vc content in radish were increased with the application of bio-organic fertilizers, while on the contrary, the nitrate and cellulose content were decreased, and the N1 treatment showed the best effect. Moreover, the yield had a significant positive correlation with Bacillus. Overall, nitrogen reduction with bio-organic fertilizers, especially full-effective “No. 1” enriched with Bacillus, could alter the soil microbial community structure and effectively improve soil fertility, which in turn enhanced the yield and quality of radish. An application of Bacillus bio-organic fertilizer was an effective strategy to improve soil quality and vegetable safety. Full article

Lignin, a significant industrial byproduct from paper manufacturing processes, exhibits ultraviolet (UV) radiation absorption properties. Cellulose nanofibers (CNFs) demonstrate universal ligand characteristics and represent an innovative approach for converting industrial waste into value-added products. Given their potential applications in cosmetic formulations, their efficacy and safety parameters, such as their photoprotection mechanisms and phototoxicity, need to be investigated. Therefore, two kraft lignin fractions, LE and R1, along with a kraft-bleached pulp CNF, were evaluated for their phototoxicity and photoprotection mechanisms, both using the HaCaT cell line (immortalized human keratinocytes) as the in vitro model. Phototoxicity assessment involved exposing cells to UVA radiation (4 J/cm²), with the subsequent comparison of cell viability between irradiated and non-irradiated samples. ROS quantification was performed using a 2′,7′-dichlorofluorescein diacetate (DCF-DA) probe, with fluorescence intensity measurements, and was then used to evaluate the photoprotection effect. The results demonstrated that both LE and R1 exhibited concentration-dependent increases in phototoxicity, whereas CNF showed no phototoxic effects under the conditions tested. For photoprotection, LE, R1, and CNF reduced UV-induced ROS production, a result which could be associated with antioxidant properties in the case of the lignin fractions. These findings suggest that both lignin fractions and CNF hold promise for use in renewable and sustainable cosmetic formulations. Full article

As a renewable and degradable biomass material, cellulose diacetate (CDA) has significant development potential and has gained widespread interest from researchers. However, its poor thermal stability at high temperatures limits its practical use in the extrusion process and restricts its applications in other fields, such as high-heat airflow filters, battery separators and special textile materials. To enhance the thermal stability of CDA, three heat-resistance additives, i.e., polyphenylene sulfide (PPS), polycarbonate (PC) and polyimide (PI), were introduced to synthesize PPS/CDA, PC/CDA and PI/CDA composite materials through melt extrusion. The incorporation of three heat-resistant additives increased the glass transition temperature (T_g), initial melting temperature (T_mⁱ) and final melting temperature (T_m^f) of the composites, and it reduced the heat loss at 195 °C. After conducting the isothermal thermogravimetry test for 3 h at 215 °C in an air atmosphere, the weight loss of PPS/CDA, PC/CDA and PI/CDA composites was 4.6%, 4.1% and 3.7%, respectively, which was 5.1% lower than that of pure CDA. Morphology characterization tests using a 3D digital microscope and a field emission scanning electron microscope (FESEM) revealed the compatibility order with CDA as the following: PC > PPS > PI. Additionally, Fourier transform infrared spectroscopy (FT–IR) disclosed that hydrogen bonds were formed between heat-resistant additives and CDA molecules, and the carbonyl groups in CDA showed conjugation and hyperconjugation effects with the benzene rings in the additives. Therefore, the enhanced thermal stability of CDA composites can be attributed to the molecular entanglement and crosslinking between additives and CDA molecules. Full article

This study is focused on the detailed examination of the combustion properties and kinetic analysis of a cellulose acetate fibrous bundle (CAFB), separated from used cigarette filters. It was shown that the faster rate of CAFB heating allows a large amount of heat to be supplied to a combustion system in the initial stages, where the increase in heating rate has a positive response to ignition behavior. The best combustion stability of CAFB is achieved at the lowest heating rate. Through the use of different kinetic methods, it was shown that combustion takes place through two series of consecutive reaction steps and one independent single-step reaction. By optimizing the kinetic parameters within the proposed reaction models, it was found that the steps related to the generation of levoglucosenone (LGO) (by catalytic dehydration of levoglucosan (LG)) and acrolein (by breakdown of glycerol during CAFB burning—which was carried out through glycerol adsorption on a TiO₂ surface in a the developed dehydration mechanism) represent rate-controlling steps, which are strongly controlled by applied heating rate. Isothermal predictions have shown that CAFB manifests very good long-term stability at 60 °C (which corresponds to storage in a sea shipping container), while at 200 °C, it shows a sudden loss in thermal stability, which is related to the physical properties of the sample. Full article

The inherent characteristics of cellulose-derived aerogels, such as their natural abundance and environmental friendliness, make them highly interesting. However, its significant shrinkage before and after the supercritical drying procedure and low mechanical strength limit its potential application. Here, we propose a strategy to prepare cellulose diacetate aerogels (CDAAs) with low drying shrinkage, exceptional thermal insulation, and superior mechanical strength. The low drying shrinkage (radial drying shrinkage of 1.4%) of CDAAs is attributed to their relative strong networking skeletons, which are greatly formed by tert-butanol solvent exchange in exerting the interaction of reducing the surface tension force. In this case, CDAAs are eventually endowed with the low bulk density of 0.069 g cm⁻³ as well. Additionally, as-prepared CDAAs possess an abundant three-dimensional networking structure whose pore size is concentrated in the diameter range of ~50 nm, and the result above is beneficial for improving the thermal insulation performance (thermal conductivity of 0.021 W m⁻¹ K⁻¹ at ambient environmental and pressure conditions). On the other hand, the optimal compressive stresses of CDAAs at 3% and 5% strain are 0.22 and 0.27 MPa respectively, indicating a mechanically well robustness. The above evidence demonstrates indeed the exceptional thermal insulation and superior compressive properties of CDAAs. This work may provide a new solution for developing a kind of high-performance cellulose-derived aerogel in the future. Full article

To monitor soil biological quality, it is of paramount importance to assess how chemically diverse organic residue amendments reciprocate to organic matter. The present incubation study aimed to evaluate the effect of organic residue amendments varying widely in their biochemical composition on the dynamics of soil enzymatic activity. The changes in the pattern of soil enzymatic activity have been monitored over a period of 63 days using a total of eleven different crop residues. The enzyme activity (dehydrogenase, fluorescein diacetate hydrolysis, acid phosphatase, alkaline phosphatase and phytase) in soils amended with chemically diverse organic residues were significantly higher as compared to the control. It was further observed that the enzymatic activities in Azadirachta indica, Avena sativa and Lens culinaris continued to be higher up to 28 days after their incorporation (DAI). Our study showed that plant residues varying in different cellulose and hemicellulose contents influenced the enzymatic activities as well as functional diversity of soil microbial communities. Full article

Polylactide (PLA) nanofiber membranes with enhanced hydrophilic properties were prepared through electrospinning. As a result of their poor hydrophilic properties, common PLA nanofibers have poor hygroscopicity and separation efficiency when used as oil–water separation materials. In this research, cellulose diacetate (CDA) was used to improve the hydrophilic properties of PLA. The PLA/CDA blends were successfully electrospun to obtain nanofiber membranes with excellent hydrophilic properties and biodegradability. The effects of the additional amount of CDA on the surface morphology, crystalline structure, and hydrophilic properties of the PLA nanofiber membranes were investigated. The water flux of the PLA nanofiber membranes modified with different CDA amounts was also analyzed. The addition of CDA improved the hygroscopicity of the blended PLA membranes; the water contact angle of the PLA/CDA (6/4) fiber membrane was 97.8°, whereas that of the pure PLA fiber membrane was 134.9°. The addition of CDA enhanced hydrophilicity because it tended to decrease the diameter of PLA fibers and thus increased the specific surface area of the membranes. Blending PLA with CDA had no significant effect on the crystalline structure of the PLA fiber membranes. However, the tensile properties of the PLA/CDA nanofiber membranes worsened due to the poor compatibility between PLA and CDA. Interestingly, CDA endowed the nanofiber membranes with improved water flux. The water flux of the PLA/CDA (8/2) nanofiber membrane was 28,540.81 L/m²·h, which was considerably higher than that of the pure PLA fiber membrane (387.47 L/m²·h). The PLA/CDA nanofiber membranes can be feasibly applied as an environmentally friendly oil–water separation material because of their improved hydrophilic properties and excellent biodegradability. Full article

The biofabrication of three-dimensional scaffolds using 3D printers and cell-containing bioinks is very promising. A wide range of materials and bioink compositions are being created and tested for cell viability and printability in order to satisfy the requirements of a bioink. This methodology has not still achieved technological maturity, and the actual costs mean that they are often inaccessible for researchers, consequently lowering the development and extending the required times. This research aims to apply this methodology on a laboratory scale by re-adapting a commercial 3D printer, consequently lowering the costs and energy impacts, and, at the same time, ensuring a level of accuracy extremely close to the currently adopted devices and, more in general, suitable for the scopes of the research. To accomplish this, we assembled a biomimetic scaffold made of human Umbilical Cord Matrix Stem Cells (hUCMS), cellulose, and alginate. Various molds were used to produce 3D scaffolds of different sizes. After bioprinting, cell viability was analyzed using ethidium bromide and fluorescein diacetate, and a histological stain was used to evaluate cell and bioink morphology. All of the examined bioinks had a uniform final 3D structure and were stable, easily printable, and procedure-adapted. Up until 21 days of culture, the bioinks remained unaltered and were simple to manipulate. After 7 and 21 days of cell culture, the hUCMS in the cellulose/alginate-based bioinks exhibited cell viabilities of 95% and 85%, respectively. The cells did not present with a fibroblast-like shape but appeared to be round-shaped and homogeneously distributed in the 3D structure. Biomimetic bioink, which is based on cellulose and alginate, is an appropriate hydrogel for 3D bioprinting. This preliminary work illustrated the potential use of these two biomaterials for the 3D bioprinting of mesenchymal stem cells. Full article

Cellulose diacetate (CDA) and L-lactide (L-LA) were used to prepare CDA−g−PLLA with a low glass transition temperature under different process conditions. Given the high glass transition temperature (T_g) of CDA, the thermal processing performance of CDA is poor, which greatly limits its application fields. To decrease the T_g of CDA, graft copolymerization was used in this research. A CDA−g−PLLA graft copolymer was synthesized by grafting CDA with L-LA under different reaction conditions using stannous octanoate as the catalyst and variations in the grafting rate under different reaction conditions were compared. The chemical structure and crystal structure of the CDA−g−PLLA were investigated, and thermal properties were also studied. The results showed that the grafting rate was the highest at the L-LA/CDA mass ratio of 4:1 under a reaction temperature of 150 °C for 90 min, and no poly-L-lactide (PLLA) homopolymer was found among the CDA−g−PLLA graft copolymers after purification. The T_g of CDA−g−PLLA was 54.2 °C, and the initial temperature of weightlessness of CDA−g−PLLA was 218.7 °C. The regularity of the original CDA molecular chains was destroyed after grafting PLLA molecular chains. In this research, we investigated the optimal grafting conditions for CDA−g−PLLA and the CDA−g−PLLA had a low T_g, which improves the thermal processing performance of CDA and broadens its application prospects in the industry. Full article

Cellulose and its derivative aerogels have attracted much attention due to their renewable and biodegradable properties. However, the significant shrinkage in the supercritical drying process causes the relatively high thermal conductivity and low mechanical property of cellulose and its derivatives aerogels. Considering the pearl-necklace-like skeleton network of silica aerogels, which can improve thermal insulation property and mechanical property. Herein, we propose a new strategy for fabricating cellulose diacetate aerogels (CDAAs) with pearl-necklace-like skeletons by using tert-butanol (TBA) as exchange solvent after experiencing the freezing-drying course. CDAAs obtained have the low density of 0.09 g cm⁻³, the nanopore size in the range of 10–40 nm, the low thermal conductivity of 0.024 W m⁻¹ K⁻¹ at ambient conditions, and the excellent mechanical properties (0.18 MPa at 3% strain, 0.38 MPa at 5% strain). Ultimately, CDAAs with moderate mechanical property paralleled to cellulose-derived aerogels obtained from supercritical drying process are produced, only simultaneously owning the radial shrinkage of 6.2%. The facile method for fabricating CDAAs could provide a new reference for constructing cellulose/cellulose-derived aerogels and other biomass aerogels. Full article

Currently, cellulose acetate (CA) membranes dominate membrane-based CO₂ separation for natural gas purification due to their economical and green nature. However, their lower CO₂ permeability and ease of plasticization are the drawbacks. To overcome these weaknesses, we have developed high-performance mixed matrix membranes (MMMs) consisting of cellulose triacetate (CTA), cellulose diacetate (CDA), and amine functionalized zeolitic imidazolate frameworks (NH₂-ZIF-8) for CO₂ separation. The NH₂-ZIF-8 was chosen as a filler because (1) its pore size is between the kinetic diameters of CO₂ and CH₄ and (2) the NH₂ groups attached on the surface of NH₂-ZIF-8 have good affinity with CO₂ molecules. The incorporation of NH₂-ZIF-8 in the CTA/CDA blend matrix improved both the gas separation performance and plasticization resistance. The optimized membrane containing 15 wt.% of NH₂-ZIF-8 had a CO₂ permeability of 11.33 Barrer at 35 °C under the trans-membrane pressure of 5 bar. This is 2-fold higher than the pristine membrane, while showing a superior CO₂/CH₄ selectivity of 33. In addition, the former had 106% higher CO₂ plasticization resistance of up to about 21 bar and an impressive mixed gas CO₂/CH₄ selectivity of about 40. Therefore, the newly fabricated MMMs based on the CTA/CDA blend may have great potential for CO₂ separation in the natural gas industry. Full article

The separation and capture of CO₂ have become an urgent and important agenda because of the CO₂-induced global warming and the requirement of industrial products. Membrane-based technologies have proven to be a promising alternative for CO₂ separations. To make the gas-separation membrane process more competitive, productive membrane with high gas permeability and high selectivity is crucial. Herein, we developed new cellulose triacetate (CTA) and cellulose diacetate (CDA) blended membranes for CO₂ separations. The CTA and CDA blends were chosen because they have similar chemical structures, good separation performance, and its economical and green nature. The best position in Robeson’s upper bound curve at 5 bar was obtained with the membrane containing 80 wt.% CTA and 20 wt.% CDA, which shows the CO₂ permeability of 17.32 barrer and CO₂/CH₄ selectivity of 18.55. The membrane exhibits 98% enhancement in CO₂/CH₄ selectivity compared to neat membrane with only a slight reduction in CO₂ permeability. The optimal membrane displays a plasticization pressure of 10.48 bar. The newly developed blended membranes show great potential for CO₂ separations in the natural gas industry. Full article

Wood-derived nanofibrillated cellulose (NFC) has emerged as a sustainable material with a wide range of applications and increasing presence in the market. Surface charges are introduced during the preparation of NFC to facilitate the defibrillation process, which may also alter the toxicological properties of NFC. In the present study, we examined the in vitro toxicity of NFCs with five surface chemistries: nonfunctionalized, carboxymethylated, phosphorylated, sulfoethylated, and hydroxypropyltrimethylammonium-substituted. The NFC samples were characterized for surface functional group density, surface charge, and fiber morphology. Fibril aggregates predominated in the nonfunctionalized NFC, while individual nanofibrils were observed in the functionalized NFCs. Differences in surface group density among the functionalized NFCs were reflected in the fiber thickness of these samples. In human bronchial epithelial (BEAS-2B) cells, all NFCs showed low cytotoxicity (CellTiter-GloVR luminescent cell viability assay) which never exceeded 10% at any exposure time. None of the NFCs induced genotoxic effects, as evaluated by the alkaline comet assay and the cytokinesis-block micronucleus assay. The nonfunctionalized and carboxymethylated NFCs were able to increase intracellular reactive oxygen species (ROS) formation (chloromethyl derivative of 2′,7′-dichlorodihydrofluorescein diacetate assay). However, ROS induction did not result in increased DNA or chromosome damage. Full article

Cellulose diacetate fibers were prepared from cellulosic biomass with high α-cellulose contents such as purified cotton linters and wood pulps. Cellulose diacetate fibers are sensitive to alkaline solution, which causes hydrolysis of the acetate ester to hydroxyl groups, especially at high temperatures. Thus, the low alkali-resistance of cellulose acetate fibers makes it difficult to achieve high wash fastness by restricting the application of intense after-treatment, such as reduction clearing. A series of N-methylphthalimide-based high-washable azo disperse dyes were synthesized and their dyeing and fastness properties on cellulose diacetate fabrics were investigated. From the overall results obtained in this study, N-methylphthalimidylazo disperse dyes are expected to be a desirable alternative to high value-added dyes that can be used for high color fastness dyeing of cellulose diacetate with a minimal discharge of wastewater during washing process. Full article

Orientation birefringence and its wavelength dispersion are studied for hot-drawn films of cellulose esters such as cellulose triacetate (CTA), cellulose diacetate (CDA), and cellulose acetate propionate (CAP) exposed to three different humidities of environments. Hot-drawn CTA films show negative birefringence that decreases with increasing wavelength. On the other hand, CDA and CAP films show positive birefringence that increases with increasing wavelength, i.e., the so-called extraordinary wavelength dispersion of birefringence. Upon exposure to high humidity environment, the orientation birefringence of CDA and CAP decreases. The decrease is prominent for the samples containing a large amount of water. CTA, however, shows an increase in magnitude of its negative orientation birefringence with increasing moisture content. The results can be explained by the increase of the polarizability anisotropy perpendicular to the stretching direction in the cellulose esters. It is found from ATR-FTIR measurements that hydrogen bonds are formed between carbonyl groups of cellulose esters and water molecules. Considering that orientation birefringence of cellulose esters is determined mainly by ester groups, the formation of hydrogen bonds contributes to the polarizability anisotropy, thus affecting the orientation birefringence. Full article