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1.
Int J Biol Macromol ; 269(Pt 2): 132162, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38723825

RESUMO

Polylactic acid (PLA) attains much attention because of its biodegradability, biocompatibility, and high strength, but its further application was remarkably hindered by its brittleness. In order to improve the toughness of PLA, a biodegradable composite was prepared by blending ductile polycaprolactone (PCL), stiff microcrystalline cellulose (MCC), and green plasticizer tributyl citrate (TBC) with PLA by melting extrusion. The physicochemical properties and microstructure of PLA composites were thoroughly investigated using FTIR, TGA, DSC, XRD, melting rheology, optical transmittance, 3d printing, tensile tests, and SEM. The tensile tests results show that introduction of TBC exhibited a remarkable improvement effect in the elongation at break of PLA/PCL/MCC (PPM) composite, increasing from 2.9 % of PPM to up to 30 % of PPM/6TBC and PPM/8TBC. Noticeably, the strength of PPM/TBC composites (at least 33.1 MPa) was enhanced compared with that of PPM (28.2 MPa). The plasticization of TBC, enhancing the compatibility of composites, and reinforcing effect of MCC were identified as pivotal factors in toughening and reinforcing PLA. Furthermore, it is observed that the incorporation of TBC contributed to enhanced thermal stability, crystallinity, and rheology property of composites. This research supplies a novel approach to bolstering the toughness of PLA and broaden its potential applications.


Assuntos
Plastificantes , Poliésteres , Impressão Tridimensional , Poliésteres/química , Plastificantes/química , Celulose/química , Resistência à Tração , Reologia
2.
Int J Biol Macromol ; 270(Pt 1): 132298, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38750863

RESUMO

Microcrystalline cellulose (MCC) is one of the essential functional excipients in the formulation of tablets. The need for cheaper MCC sources has drawn significant attention to exploring renewable sources. In this study, MCC was produced from soybean hull (SBH), the primary by-product of the soy industry, using a novel, simplified, and cost-effective approach. Various characterization techniques were used to study the physicochemical properties and micromeritics of the SBH-based MCC powders and compare them to those of the commercial Avicel PH-101. SBH MCCs had a larger particle size, a broader particle size distribution, a higher degree of polymerization, a higher degree of crystallinity, better thermal stability, and slightly superior flowability and compressibility than Avicel PH-101. The tableting blends (containing 60 % MCC) were prepared, and the post-compression out-of-die Heckel analysis showed that formulations with aggregated SBH MCCs were less ductile than those made with Avicel PH-101, resulting in a lower porosity (better compressibility) of the latter at higher compression pressures. The hardness values for all formulations were above 6 kg, with higher values for those made with Avicel PH-101. The lubricant sensitivity was lower for SBH MCCs. All tablets made using developed formulations showed very low friability (<0.1 %) and short disintegration times (<90 s), making them well-suited candidates for manufacturing orally disintegrating tablets (ODTs).


Assuntos
Celulose , Excipientes , Glycine max , Pós , Comprimidos , Celulose/química , Glycine max/química , Excipientes/química , Tamanho da Partícula , Composição de Medicamentos/métodos
3.
Sci Rep ; 14(1): 10935, 2024 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-38740877

RESUMO

Sustainable cellulose-based hydrogels are used in medicine and environmental science. Hydrogels' porosity makes them excellent adsorbents and stable substrates for immobilizing photocatalysts to remove organic dyes. Despite their potential, the implementation of hydrogels for this purpose is still limited due to their high synthesis temperature and low cellulose content. To overcome these challenges, this study develops cellulose-based hydrogels, which have a high cellulose content and can be easily synthesized under ambient conditions. Containing a higher cellulose concentration than previous hydrogels, the synthesized hydrogels are more stable and can be reused numerous times in treatment operations. The hydrogel properties were investigated using Fourier transform infrared spectroscopy, X-ray diffraction and thermal analysis. Scanning electronic microscopy revealed that TiO2 nanoparticles were homogeneously distributed throughout the hydrogel's matrices. In addition, transparent hydrogels allow light to pass through, making them suitable substrates to remove organic dye. The results showed that the hydrogel with TiO2 was able to degrade nearly 90% of organic dye within 180 min. Furthermore, the hydrogel with the embedded catalyst exhibits the potential for reusability with a regeneration efficiency of 80.01% after five runs. These findings suggest that this novel hydrogel is a promising candidate for water pollution remediation.

4.
EFSA J ; 22(3): e8625, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38435092

RESUMO

Following a request from the European Commission, the EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) was asked to deliver a scientific opinion on the safety of microcrystalline cellulose and carboxymethyl cellulose as technological feed additives for all animal species. In its previous opinions on the safety and efficacy of the products, the FEEDAP Panel could not conclude on proper identification and characterisation as required for a feed additive. The occurrence of potential toxic impurities could also not be assessed. Based on the new data provided, the feed additives microcrystalline cellulose and carboxymethyl cellulose were properly identified and characterised and were shown to meet the specifications set for their use as food additives. Therefore, the conclusions of the safety reached in the previous opinions for microcrystalline cellulose and carboxymethyl cellulose meeting the food additive specifications apply to the microcrystalline cellulose and carboxymethyl cellulose under assessment as feed additives. The additives are considered safe for all animal species, the consumer and the environment. In the absence of data, the FEEDAP Panel is not in the position to conclude on the safety for the user.

5.
Carbohydr Polym ; 332: 121851, 2024 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-38431425

RESUMO

Cuprous oxide (Cu2O) is proven as an excellent anti-harmful microbial material. However, the liquid and vapor pha5se preparation methods reported so far hardly make pure Cu2O-containing composites and suffer environmental issues caused by chemical reducing agents with multiple processing steps. This work develops a facile one-pot solid-state sintering method to synthesize Cu2O/microcrystalline cellulose (MCC) composite via the thermal decomposition and oxidation-reduction reactions where copper formate was reduced by MCC. The Cu2O/MCC composite exhibits superior purity, dispersibility, stability, high yield, and high efficacy of antibacterial and antiviral properties, e.g., against E. coli, S. aureus, and Equine Arteritis Viral. This work utilizes elegantly the strong reducing capability of cellulose to develop an environmentally benign method to prepare high-purity Cu2O-polymer composites with low cytotoxicity and cost, which can be incorporated readily into other substrate materials to form various forms of anti-harmful microbial materials widely used in public health care products. In addition, the preparation of Cu2O-containing composites based on the reducing capability of cellulose is also expected to be applied to other cellulose-based materials for the loading of Cu2O particles.

6.
Int J Biol Macromol ; 264(Pt 2): 130674, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38458273

RESUMO

Microcrystalline cellulose (MCC) was successfully synthesized from sugarcane bagasse using a rapid, low-temperature hydrochloric acid (HCl) gas treatment. The primary aim was to develop an energy-efficient "green" cellulose extraction process. Response surface methodology optimized the liquid-phase hydrolysis conditions to 3.3 % HCl at 117 °C for 127 min to obtain MCC with 350 degree of polymerization. An alternative gas-phase approach utilizing gaseous HCl diluted in hot 40 °C air was proposed to accelerate MCC production. The cellulose pulp was moistened to 15-18 % moisture content and then exposed to HCl gas, which was absorbed by the moisture in the cellulose fibers to generate a highly concentrated acidic solution that hydrolyzed the cellulose. The cellulose pulp was isolated from depithed bagasse through soda pulping, multistage bleaching and cold alkali purification. Hydrolysis was conducted by saturating the moist cellulose fibers with gaseous HCl mixed with hot air. Extensive analytical characterization using FT-IR, XRD, SEM, TGA, DSC, particle size, and porosity analyses verified comparable physicochemical attributes between MCC samples prepared via liquid and gas phase methods. The gas-produced MCC revealed 85% crystallinity, 71 Å crystallite dimensions, and thermally stable rod-shaped morphology with an average diameter below 200 µm. The similar material properties validate the proposed gas-based technique as an equally effective yet more energy-efficient alternative to conventional aqueous acid hydrolysis for fabricating highly pure MCC powders from lignocellulose. This sustainable approach enables the value-addition of sugarcane bagasse agro-industrial residue into cellulosic nanomaterials for wide-ranging industrial applications. In summary, the key achievements of this work are rapid MCC production under mild temperatures using HCl gas, optimization of liquid phase hydrolysis, successful demonstration of gas phase method, and extensive characterization verifying equivalence between both protocols. The gas methodology offers a greener cellulose extraction process from biomass.


Assuntos
Celulose , Saccharum , Celulose/química , Hidrólise , Ácido Clorídrico/química , Saccharum/química , Espectroscopia de Infravermelho com Transformada de Fourier
7.
Pharmaceutics ; 16(3)2024 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-38543256

RESUMO

Using microcrystalline cellulose (MCC) with plastic behaviour and calcium phosphate anhydrous (CaHPO4) with brittle behaviour under compaction is very popular in the pharmaceutical industry for achieving desirable structural-mechanical properties of tablet formulations. Thus, mixtures of specific grades of MCC and CaHPO4 were tested in volume proportions of 100-0, 75-25, 50-50, 25-75, and 0-100 at a constant weight-by-weight concentration of sodium stearyl fumarate lubricant, utilizing a state-of-the-art benchtop compaction simulator (STYL'One Nano). Tablet formulations were prepared at 100, 150, 250, 350, 450, and 500 MPa, and characterized by tabletability profile, ejection force profile, proportion-tensile strength relationship, proportion-porosity relationship, pressure-displacement, and elastic recovery profiles, as well as by in-/out-of-die Heckel plots and yield pressures. Interestingly, the 25-75 formulation demonstrated a two-stage out-of-die Heckel plot and was additionally investigated with X-ray micro-computed tomography (µCT). By post-processing the µCT data, the degree of brittle CaHPO4 particles falling apart, along with the increasing compression pressure, was quantified by means of the surface area to volume (S/V) ratio. For the 25-75 formulation, the first stage (up to 150 MPa) and second stage (above the 150 MPa) of the out-of-die Heckel plot could be attributed to predominant MCC and CaHPO4 deformation, respectively.

8.
Polymers (Basel) ; 16(6)2024 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-38543441

RESUMO

This paper describes the use of microcrystalline cellulose (MCC) as an additive in wood-polylactic acid (PLA) filaments suitable for 3D printing. Filaments prepared with PLA, thermally modified (TM) wood, and three different MCC loadings (1, 3, and 5 wt%) by two-step melt blending in the extruder were characterized with respect to their rheological, thermal, and mechanical response. The analyses demonstrate that a low MCC content (1%) improves the mobility of the polymer chains and contributes to a higher elasticity of the matrix chain, a higher crystallinity, a lower glass transition temperature (by 1.66 °C), and a lower melting temperature (by 1.31 °C) and leads to a higher tensile strength (1.2%) and a higher modulus of elasticity (12.1%). Higher MCC loading hinders the mobility of the polymer matrix and leads to a rearrangement of the crystal lattice structure, resulting in a decrease in crystallinity. Scanning electron micrographs show that the cellulose is well distributed and dispersed in the PLA matrix, with some agglomeration occurring at higher MCC levels. The main objective of this study was to develop and evaluate a filament containing an optimal amount of MCC to improve compatibility between wood and PLA, optimize melt processability, and improve mechanical properties. It can be concluded that a 1% addition of MCC favorably changes the properties of the wood-PLA filaments, while a higher MCC content does not have this effect.

9.
Polymers (Basel) ; 16(5)2024 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-38475252

RESUMO

The transition to a more sustainable lifestyle requires a move away from petroleum-based sources and the investigation and funding of renewable and waste feedstocks to provide biobased sustainable materials. The formulation of films based on chitosan and microcrystalline cellulose with potential applications in the packaging sector has been demonstrated. Glycerol is also used as a plasticizer in the formulation of flexible films, while mucic acid is used as a valid alternative to acetic acid in such films. The film based on chitosan, microcrystalline cellulose, glycerol, and mucic acid shows properties and a performance similar to those of the film formulated with acetic acid, and, in addition, it seems that the photo-oxidation resistance of the film based on mucic acid is better than that of the material containing acetic acid. The films were characterized using spectroscopy (FTIR and UV-vis), tensile testing, water contact angle measurements, surface observations, and photo-oxidation resistance measurements. The presence of microcrystalline cellulose enhances the mechanical behavior, UV barrier properties, and surface hydrophobicity of the film. The feasibility of formulating chitosan-based films, with or without microcrystalline cellulose, which exhibit good properties and performances is demonstrated. Mucic acid instead of acetic acid is used in the formulation of these film.

10.
Int J Biol Macromol ; 265(Pt 1): 130532, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38431009

RESUMO

As a bio-based material, microcrystalline cellulose (MCC) has been applied in many fields including pharmaceuticals, foods, and cosmetics in recent years. However, traditional preparation methods of MCC are facing many challenges due to economic and eco-environmental issues. In this study, softwood dissolved pulp was sieved to long fiber (LF) and short fiber (SF), and subsequently to prepare LF-MCC and SF-MCC by hydrochloric acid hydrolysis at different acid dosages (3-7 wt%), reaction times (30-90 min), and temperatures (75-95 °C). The as-obtained MCC products were compared in terms of morphology, size, crystallinity, and chemical structure. The results indicated that the crystallinity and yield of LF-MCC were high, with maximum values of 78.41 % and 98.68 %, respectively. The particle size distribution of SF-MCC was more uniform in the range of 20-80 µm, with a maximum of 59.44 % at 20-80 µm occupancy proportion. Moreover, SF-MCC had a typical rod-like shape and larger surface area as well as better thermal behavior than LF-MCC. When LF-MCC and SF-MCC were used as fillers in the production of ibuprofen tablets, the tablets added with LF-MCC exhibited higher hardness, friability, dissolution rate, and shorter disintegration time. Therefore, this work is very beneficial for the preparation and application of MCC.


Assuntos
Celulose , Ibuprofeno , Celulose/química , Dureza , Comprimidos
11.
Colloids Surf B Biointerfaces ; 235: 113764, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38301428

RESUMO

Development of immobilized lipase with excellent catalytic performance and low cost is the major challenge for large-scale industrial applications. In this study, green renewable microcrystalline cellulose (MCC) that was hydrophobically modified with D-alanine (Ala) or L-lysine (Lys) was used for immobilizing Candida antarctica lipase B (CALB). The improved catalytic properties were investigated by experimental and computational methods. CALB immobilized on MCC-Ala with higher hydrophobicity showed better catalytic activity than CALB@MCC-Lys because the increased flexibility of the lid region of CALB@MCC-Ala favored the formation of open conformation. Additionally, the low root mean square deviation and the high ß-sheet and α-helix contents of CALB@MCC-Ala indicated that the structure became more stable, leading to a significantly enhanced stability (54.80% and 90.90% relative activity at 70 °C and pH 9.0, respectively) and good reusability (48.92% activity after 5 cycles). This study provides a promising avenue to develop immobilized lipase with high catalytic properties for industry applications.


Assuntos
Aminoácidos , Celulose , Enzimas Imobilizadas , Enzimas Imobilizadas/química , Candida/metabolismo , Lipase/química , Proteínas Fúngicas/química , Alanina , Lisina
12.
Drug Dev Ind Pharm ; 50(4): 297-305, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38385210

RESUMO

OBJECTIVE: This study aimed to investigate the impact of physical solid dispersions of spray-dried glibenclamide (SG) on the surface of microcrystalline cellulose (MC) and mannitol (M) surfaces, as well as their combination with phosphatidylcholine (P), on enhancing the dissolution rate of glibenclamide (G). METHODS: Solid dispersions were prepared using varying proportions of 1:1, 1:4, and 1:10 for SG on the surface of MC (SGA) and M (SGM), and then combined with P, in a proportion of 1:4:0.02 using spray drying. The particle size, specific surface area, scanning electron microscopy (SEM), X-ray diffraction (XRD), and dissolution rate of SGA and SGM were characterized. RESULTS: SEM analysis revealed successful adhesion of SG onto the surface of the carrier surfaces. XRD showed reduced crystalline characteristic peaks for SGA, while SGM exhibited a sharp peaks pattern. Both SGA and SGM demonstrated higher dissolution rates compared to SG and G alone. Furthermore, the dissolution rates of the solid dispersions of SG, MC and P (SGAP), and SG, M, and P (SGMP) were sequentially higher than that of SGA and SGM. CONCLUSIONS: The study suggests that physical solid dispersions of SG on MC and M, along with their combination with P, can effectively enhance the dissolution rate of G. These findings may be valuable in developing of oral solid drug dosage forms utilizing SGA, SGM, SGAP, and SGMP.


Assuntos
Celulose , Glibureto , Manitol , Fosfatidilcolinas , Solubilidade , Difração de Raios X , Varredura Diferencial de Calorimetria
13.
Mater Today Bio ; 24: 100878, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38188645

RESUMO

Excessive bleeding is associated with a high mortality risk. In this study, citric acid and ascorbic acid were sequentially modified on the surface of microcrystalline cellulose (MCAA) to increase its carboxyl content, and their potential as hemostatic materials was investigated. The MCAA exhibited a carboxylic group content of 9.52 %, higher than that of citric acid grafted microcrystalline cellulose (MCA) at 4.6 %. Carboxyl functionalization of microcrystalline cellulose surfaces not only plays a fundamental role in the structure of composite materials but also aids in the absorption of plasma and stimulation of platelets. Fourier -transform infrared (FT-IR), thermogravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS) spectra confirmed that carboxyl groups were successfully introduced onto the cellulose surface. Physical properties tests indicated that the MCAA possessed higher thermal stability (Tmax = 472.2 °C) compared to microcrystalline cellulose (MCC). Additionally, in vitro hemocompatibility, cytotoxicity and hemostatic property results demonstrated that MCAA displayed good biocompatibility (hemolysis ratio <1 %), optimal cell compatibility (cell viability exceeded 100 % after 72 h incubation), and impressive hemostatic effect (BCIMCAA = 31.3 %). Based on these findings, the hemostatic effect of covering a wound with MCAA was assessed, revealing enhanced hemostatic properties using MCAA in tail-amputation and liver-injury hemorrhage models. Furthermore, exploration into hemostatic mechanisms revealed that MCAA can significantly accelerate coagulation through rapid platelet aggregation and activation of the clotting cascade. Notably, MCAA showed remarkable biocompatibility and induced minimal skin irritation. In conclusion, the results affirmed that MCAA is a safe and potentially effective hemostatic agent for hemorrhage control.

14.
Carbohydr Polym ; 327: 121660, 2024 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-38171679

RESUMO

Fibrillated celluloses have gained significant attention due to their exceptional mechanical properties and eco-friendly characteristics, which make them suitable for various applications. In this study, we designed a precise approach for producing highly fibrillated microcrystalline cellulose (MCC) via ball-milling treatment using four typical silane coupling agents. The empirical data demonstrate that the fibrillization of MCC and the properties of fibrillated MCC are largely affected by the size and geometry of the functional groups of the silanes. After ball-milling, most MCC displayed enhanced e-beam tolerance and thermal stability, whereas the silane loading amount, surface area, and morphology of fibrillated MCC appeared to be random, which was exemplified by the proportional and non-proportional relationship between the loading amount and surface area of methyl silane- and phenyl silane-treated MCC, respectively. Density functional theory calculations and molecular dynamics simulations were employed to obtain the intricate details. The simulation results were in agreement with the experimental results. Finally, fibrillated MCC was incorporated into silicone foams as an additive. The thermal stability of fibrillated MCC with added silicone was greatly improved, and the tensile strength of fibrillated MCC-containing silicone foam was 44.1 and 5.4 times higher than that of the neat and MCC-containing silicone foams, respectively.

15.
Int J Pharm ; 652: 123806, 2024 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-38220119

RESUMO

Minitablets are prepared using multiple die openings and multi-tip punches for greater productivity. With multiple tips on the punch barrel, the overall compaction force to be applied is commonly estimated by multiplying the desired compaction force per tip by the number of punch tips. Few researchers have however examined this proportionality and the effects of the number of punch tips and punch face geometry on the critical quality attributes (CQAs) of high drug load minitablets. In this study, the minitablets prepared by multi-tip tools exhibited greater weight variation than those prepared by single-tip tools. Their compaction was accompanied by a longer dwell time that led to a higher minitablet tensile strength and consequently a longer disintegration time. The compaction forces required to achieve a consistent set of minitablet CQAs were not directly proportional to the number of punch tips used. In comparison, the effect of punch face geometry was negligible. Increasing concentration of magnesium stearate (as lubricant) from 0.75 to 1.25 %, w/w reduced weight variation, especially of minitablets prepared by the multi-tip tools. It also increased the disintegration time but had no significant effect on the tensile strength of the minitablets regardless of type of tools used. The adjustment of compaction speed was an effective compensatory method to mitigate the differences in dwell time and tensile strength between minitablets prepared by single-tip and multi-tip standard concave tools. A larger reduction in compaction speed of the single-tip tools was required at higher compaction pressures.


Assuntos
Excipientes , Comprimidos , Resistência à Tração , Pressão , Composição de Medicamentos/métodos
16.
Int J Biol Macromol ; 260(Pt 1): 129404, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38224807

RESUMO

The widespread use of starch-based films is hindered by inadequate tensile strength and high water sensitivity. To address these limitations, a novel starch film with a dynamic network structure was produced via the dehydration-condensation reaction of N, N'-methylene diacrylamide (MBA) and microcrystalline cellulose (MCC). The improvement in mechanical properties was enhanced by the incorporation of MCC, which was achieved through intermolecular hydrogen bonding and chemical crosslinking. To verify the interactions among MCC, MBA, and starch, x-ray photoelectron spectroscopy (XPS), fourier transform infrared spectroscopy (FTIR), and x-ray diffraction (XRD) were conducted. The results established the predicted interactions. The dynamic network structure of the film reduced the water absorption capacity (WAC) of starch and MCC hydroxyl groups, as confirmed by differential scanning calorimeter (DSC) and dynamic mechanical thermal analysis (DMTA). These analyses showed a restriction in the mobility of starch chains, resulting in a higher glass transition temperature (Tg) of 69.26 °C. The modified starch films exhibited excellent potential for packaging applications, demonstrating a higher contact angle (CA) of 89.63°, the lowest WAC of 4.73 g/g, and the lowest water vapor transmission rate (WVTR) of 13.13 g/m2/d, along with improved mechanical properties and identical light transmittance compared to pure starch films.


Assuntos
Celulose , Embalagem de Produtos , Amido , Amido/química , Fenômenos Químicos , Resistência à Tração , Espectroscopia de Infravermelho com Transformada de Fourier
17.
Int J Biol Macromol ; 260(Pt 1): 129477, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38232894

RESUMO

It reported a porous material prepared from microcrystalline cellulose (MCC), to achieve rapid preparation of adsorbents. The porous material was characterized by several tools including 1H NMR, FTIR, XPS, and SEM. Two adsorbents were prepared and subjected to adsorption experiments. Dye adsorption experiments show that the adsorption driving is electrostatic interactions and the process is chemisorption. The maximum capacity of Microcrystalline cellulose-g-Poly (glycidyl methacrylate)-Tannins (MPT) reached 191.3 (Methylene blue), 123.7 mg g-1 (Rhodamine B), and Microcrystalline cellulose-g-Poly (glycidyl methacrylate)-Lysine (MPL) attained 425.8 (Methylene blue), 480.7 mg g-1 (Methyl orange). The results were followed the pseudo-second-order (PSO) and agreed with the Langmuir fit model. Adsorption-desorption cycling experiments further indicate that the adsorbent possesses outstanding reproducibility. At last, epoxidized bio-porous materials are positive in the preparation of dye adsorbents with critical adsorption properties.


Assuntos
Celulose , Corantes , Compostos de Epóxi , Metacrilatos , Poluentes Químicos da Água , Corantes/química , Adsorção , Porosidade , Azul de Metileno/química , Reprodutibilidade dos Testes , Cátions , Poluentes Químicos da Água/química , Cinética
18.
Int J Mol Sci ; 25(2)2024 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-38255761

RESUMO

This work reports the use of cellulose as a template to prepare nanosized WO3 or NiWO4 and its application as a co-catalyst in the electro-oxidation of ethanol and glycerol. Microcrystalline cellulose was hydrolyzed with phosphotungstic acid (H3PW12O40) to prepare the nanocrystalline cellulose template. The latter was air-calcinated to remove the template and obtain nanometric WO3. Tungsten oxide was impregnated with Ni(NO3)2, which was subsequently air-calcinated to obtain the nanometric NiWO4. Elemental analysis confirmed the coexistence of nickel and tungsten, whereas thermal analysis evidenced a high thermal stability for these materials. The X-ray diffractograms displayed crystal facets of WO3 and, when Ni(II) was added, NiWO4. The transmission electron micrographs corroborated the formation of nanosized particles with average particle sizes in the range of 30 to 50 nm. Finally, to apply this material, Pt/WO3-C and Pt/WO3-NiWO4-C were prepared and used in ethanol and glycerol electro-oxidation in an alkaline medium, observing a promotional effect of the oxide and tungstate by reducing the onset potential and increasing the current density. These materials show great potential to produce clean electricity or green hydrogen, contributing to energetic transition.


Assuntos
Etanol , Glicerol , Oxirredução , Celulose , Eletricidade
19.
Int J Biol Macromol ; 256(Pt 1): 128432, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38013070

RESUMO

Sustainable management of walnut shell (WS) for the extraction of cellulose and preparation of cellulose-based biosorbents of iodine was carried out as a new approach to simultaneously solve the environmental challenge of agricultural solid waste and iodine-contaminated water. A rapid recyclable nitric acid treatment and NaOH-H2O2 alkaline-peroxide treatment of WS (33 % cellulose) extracted pure microcrystalline (Cac) and impure cellulose (Cal) with a 21.70 % and 47.37 % isolation yield, respectively. The techno-economic assessment of cellulose production showed a net profit of 9.02 $/kg for Cac, whereas it was estimated as negative for Cal. The simultaneous carbonization and magnetization of Cac at 550 °C resulted in an amorphous, magnetic cellulose-derived biochar (MB550Cac) with a BET specific surface area of 12.64 m2/g, decorated with scattered irregular Fe3O4 microparticles. The adsorption capacity of MB550Cac for iodine was 555.63 mg/g, which was lost only 17.45 % after six successful cycles of regeneration. Freundlich isotherm model sufficiently described the reversible iodine adsorption on the heterogenous surface. The adsorption kinetics followed the pseudo-second-order model. Further, the adsorption thermodynamics demonstrated spontaneous and favorable adsorption. These findings suggest the valorization of WS to commercially produce cellulose and MB550Cac as a sustainable, efficient biosorbent with a good application prospect in wastewater treatment.


Assuntos
Juglans , Poluentes Químicos da Água , Poluentes Químicos da Água/química , Adsorção , Peróxido de Hidrogênio , Celulose/química , Termodinâmica , Cinética , Concentração de Íons de Hidrogênio
20.
Nanomaterials (Basel) ; 13(24)2023 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-38133048

RESUMO

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.

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