Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 18 de 18
Filtrar
1.
Int J Biol Macromol ; 259(Pt 1): 128893, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38159693

RESUMO

In this study, a novel mechanical process was used to produce cellulose beads (CB). These beads were then doped with cobalt ferrite nanoparticles (CoFe2O4 NPs) to serve as catalysts for the degradation of rhodamine B (RhB) through peroxymonosulfate (PMS) activation. The physical and chemical properties of CoFe2O4 and CoFe2O4@CB catalysts were characterized using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) combined with energy dispersive X-ray spectrometer (EDX), scanning transmission electron microscopy (STEM) techniques, and thermogravimetric analysis (TGA). To optimize RhB degradation efficiency, Response Surface Methodology (RSM) was employed, utilizing the Box-Behnken design (BBD). Under the optimized conditions of a catalyst dosage of 0.40 g/L, PMS dosage of 0.98 mM, RhB concentration of 40 mg/L, pH of 5.27, and reaction time of 60 min, a remarkable degradation efficiency of 98.51 % was achieved at a temperature of 25 °C. In quenching experiments, 1O2, SO4•-, and HO• species are produced in the CoFe2O4@CB/PMS system, with 1O2, and SO4•- species dominating RhB degradation. Remarkably, the new CoFe2O4@CB catalyst has demonstrated exceptional stability and reusability, validated by recycling tests (up to 78 % of RhB degradation efficiency after a 5-cycle experiment) and subsequent characterizations (FTIR, SEM, and EDX) emphasizing unchanged bands, uniform distribution, and consistent composition after reuse cycles. These results demonstrate the effectiveness of mechanically produced CoFe2O4@CB catalysts for advanced oxidation processes (AOPs), with promising applications in wastewater treatment.


Assuntos
Celulose , Nanopartículas , Peróxidos , Espectroscopia de Infravermelho com Transformada de Fourier , Nanopartículas/química , Rodaminas
2.
Int J Biol Macromol ; 254(Pt 2): 127867, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37935294

RESUMO

In order to enhance the removal of cadmium from phosphoric acid, it is imperative to explore novel resources that may be utilized for the development of highly effective and environmentally sustainable adsorbents. Cellulose beads are composed of naturally occurring polysaccharide fibers and find extensive utilization across several industrial sectors and applications. Within this framework, this research paper presents a green and simple method for producing porous cellulose beads using date palm fibers as the preferred raw material. The innovation lies in immersing the obtained cellulose beads in a Polyvinyl fluoride (PVDF)/N,N-dimethylformamide (DMF) suspension as a coating polymer with different concentrations (2.5, 5, 10 %) to maintain their stability in an acidic environment. The surface of cellulose/PVDF beads were subjected to multiple characterizations like Fourier transform infrared (FTIR) spectroscopy, Scanning electron microscopy (SEM), Thermogravimetric analysis (TGA), size distribution then pH stability confirming that the coating has been perfectly achieved and conserved well the shape of the beads. The coated cellulose/PVDF-2.5 % underwent evaluation by the process of batch adsorption experiments while different parameters were varied including contact time (5, 10, 20, 30, 60, 90 min), temperature (25, 35, 45 and 55 °C), and adsorbent mass (20, 40, 60, 80 and 100 mg). The obtained ICP data showed that the adsorption rate of Cd (II) from phosphoric acid medium decreased while increasing both temperature from 25 to 55 °C and contact time from 5 to 90 min while adding more adsorbent dosage from 20 to 100 mg enhanced the removal percentage. The cellulose/PVDF-2.5 % was more effective with an adsorption capacity equal to 3.4998 mg/g at optimal conditions including 25 °C as the temperature after 5 min as contact time and by adding a mass 100 mg of the biosorbent while the pH = 2 of the solution is maintained the same. The examined material's adsorption processes proved to be exothermic and non-spontaneous, and it proved that the pseudo-second-order model provided the best match for the cellulose/PVDF-2.5 % beads kinetics data. Furthermore, the cellulose beads exhibited exceptional reusability for up to four repeated cycles without undergoing desorption. The present study offers a viable approach for producing environmentally sustainable biomass-derived adsorbents. Additionally, the study validates the potential of cellulose/PVDF beads as an intriguing material for phosphoric acid decadmiation.


Assuntos
Cádmio , Poluentes Químicos da Água , Celulose , Poluentes Químicos da Água/química , Porosidade , Adsorção , Cinética , Concentração de Íons de Hidrogênio , Espectroscopia de Infravermelho com Transformada de Fourier
3.
Int J Biol Macromol ; 273(Pt 2): 133078, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38942667

RESUMO

This study presents an innovative and environmentally friendly method to produce fibrous cellulose beads by mechanically stirring natural fibers in an aqueous medium. Date palm fibers are transformed into uniform beads with a diameter of 1.5 to 2 mm through chemical treatment and mechanical agitation. These beads are then decorated with silver nanoparticles (Ag0 NPs) in a one-step synthesis, giving them catalytic capabilities for the reduction of 4-nitrophenol (4-NP) and antibacterial activities. Characterization techniques such as FTIR, XRD, SEM, EDX, and TGA confirmed the successful synthesis and deposition of Ag0 NPs on the cellulose beads. Tests showed complete conversion of 4-NP to 4-AP in just 7 min, with pseudo-first-order kinetics and a Kapp of 0.590 min-1. Additionally, Ag0@CB demonstrated exceptional recyclability and stability over five cycles, with minimal silver release. The beads also showed strong antibacterial activity against Escherichia coli and Staphylococcus aureus, effectively eradicating bacterial colonies in 30 min. In summary, Ag0@CB exhibits multifunctional capabilities for degrading organic pollutants and biomedical applications, offering promising potential for large-scale production and practical use in water treatment and antibacterial coatings.


Assuntos
Antibacterianos , Celulose , Escherichia coli , Nanopartículas Metálicas , Nitrofenóis , Prata , Staphylococcus aureus , Prata/química , Prata/farmacologia , Nitrofenóis/química , Antibacterianos/farmacologia , Antibacterianos/química , Nanopartículas Metálicas/química , Celulose/química , Catálise , Staphylococcus aureus/efeitos dos fármacos , Escherichia coli/efeitos dos fármacos , Oxirredução , Testes de Sensibilidade Microbiana , Química Verde , Microesferas
4.
Open Life Sci ; 19(1): 20220895, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38947765

RESUMO

Chenopodium ambrosioides aerial parts have been historically employed in traditional medicine for addressing various ailments such as headaches, abdominal discomfort, joint issues, and respiratory disorders, alongside treatments for lice and warts. This study aimed to conduct a comprehensive phytochemical analysis of C. ambrosioides and assess the acute and subacute toxicity of oral treatments using fractions in preclinical trials. Spectrophotometric analysis via LC-MS/MS was used to characterize the plant's chemical composition. Acute toxicity evaluation followed Organisation for Economic Co-operation and Development code 42 guidelines, conducted on adult male and female Wistar strain mice. Subsequently, Swiss mice were divided into six groups for the subacute toxicity study, receiving oral doses of 200 mg/kg extracts and fractions for 28 days. Daily observations and biochemical analyses were performed, with LC-MS/MS revealing a diverse array of compounds including organic acids, flavonoids, phenolic acids, rutin, hesperidin, nicotiflorine, and fumaric acid. Results indicated no lethality or alterations in body weight in treated groups, though some organ weight changes were noted. Biochemical analyses demonstrated values within the normal range for all groups, suggesting that the treatments did not induce adverse effects. Acute and subacute treatments with fractions did not result in lethality or toxic alterations at therapeutic doses, implying the safety of the product at appropriate levels. This study underscores the potential of C. ambrosioides as a safe therapeutic option warranting further exploration.

5.
J Tradit Complement Med ; 14(4): 355-380, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-39035692

RESUMO

Dittrichia viscosa is a perennial herb that has been used for generations in traditional medicine to address a variety of diseases, including diabetes, hypertension, cancer, microbial disorders, inflammatory conditions, and wound healing. The objective of this review is to provide an overview of existing knowledge on D. viscosa with regards to its botanical description, ethnomedicinal uses, and pharmacological properties. Databases such as Scopus, Wiley-Online, PubMed, Springer, Google Scholar, and ScienceDirect were used to select relevant articles based on their title and abstract. The reviewed studies found a strong correlation between D. viscosa's traditional uses and its observed biological effects. Pharmacological research has shown that the essential oils and extracts from D. viscosa possess a variety of biological activities, such as anti-inflammatory, anticancer, antibacterial, antifungal, analgesic, and antioxidant properties. The chemical compounds found in D. viscosa include sesquiterpenes, monoterpenes, flavonoids, and phenolic acids; some of these compounds, such as tometosin and inuviscolide, have been isolated and displayed promising cytotoxic and anti-inflammatory activity. The present review suggests that the pharmacological properties of D. viscosa align well with its ethnomedicinal uses. These findings support the traditional use of D. viscosa in treating various illnesses. Additionally, toxicological examinations of D. viscosa extracts and essential oil have demonstrated the plant's safety, which supports the need for comprehensive pharmacological studies, in vivo studies, and clinical trials to evaluate the best doses for optimal medicinal effects. This work underscores the medicinal value of D. viscosa and its potential in developing new pharmacological agents to address major health challenges like antibiotic resistance and cancers.

6.
Environ Sci Pollut Res Int ; 30(25): 67720-67729, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-37115451

RESUMO

To selectively remove Cr (III) from synthetic phosphoric acid solution, a chelating ion exchanger was developed through Merrifield resin (MHL) functionalization with diethylenetriamine (DETA). The functional moieties of the grafted Merrifield resin were characterized and confirmed by means of Fourier-transform infrared spectroscopy. The morphological changes before and right after functionalization were visualized with Scanning electron microscopy and enhanced amine content was confirmed via energy dispersive X-ray. To assess the effectiveness of the MHL-DETA in the extraction of Cr (III) from a synthetic phosphoric acid solution, batch shaking adsorption tests were conducted through optimizing different factors such as contact time, metal ion concentration and temperature. According to our findings, higher adsorption was achieved when increasing contact time and decreasing metal ion concentration, while temperature variation doesn't affect much the process. The higher sorption yield was found to be 95.88% attained within 120 min at room temperature without varying the solution's pH. Under optimum conditions (120 min, 25 °C and 300 mg. L-1), the total sorption capacity was reported to be 38.35 mg. g-1. The system's adsorption behavior was found to be consistent with the Langmuir isotherm and the pseudo second-order model accurately described the kinetic data. In this view, Merrifield resin functionalized with DETA could be used as a promising adsorbent material for Cr (III) adsorption from synthetic phosphoric acid medium.


Assuntos
Cromo , Poluentes Químicos da Água , Cromo/química , DEET , Adsorção , Espectroscopia de Infravermelho com Transformada de Fourier , Cinética , Concentração de Íons de Hidrogênio , Poluentes Químicos da Água/química
7.
J Taibah Univ Med Sci ; 18(6): 1557-1566, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37693822

RESUMO

Objective: The main purpose of the present work was to determine the chemical composition, safety, and antioxidant and antihyperlipidemic activities of an aqueous extract of Teucrium takoumitense. Methods: Phytochemical analysis (total phenolic, total flavonoid, and total hydroxycinnamic acid contents), antioxidant activity (ferric-reducing antioxidant power, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid, 2,2-diphenyl-1-picrylhydrazil, and total antioxidant capacity tests), acute toxicity, and antihyperlipidemic activity were evaluated according to established models. In addition, the phytochemical profile was determined by methylation followed by gas chromatography-mass spectrometry (GC/MS). Results: The aqueous extract of T. takoumitense had a high content of total polyphenols (87.01 ± 0.31 mg gallic acid equivalent (GAE)/g extract) and hydroxycinnamic acid (2.28 ± 0.1 g/100 g Powdered Material) and a low content of total flavonoids (2.99 ± 0.16 mg GAE/g extract). In addition, the extract demonstrated remarkable antioxidant activity (DPPH IC50 = 76.67 ± 0.56 µg/mL, ABTS IC50 = 89.65 ± 0.27 µg/mL, FRAP EC50 = 296.32 ± 0.86 µg/mL, TAC value = 43 ± 0.27 mg EAA/g extract). The main compounds were identified as benzene, (hexyloxy)- (19.32%), 2,6a-methano-6aH-indeno[4,5-b]oxirene, octahedro-(1a.alpha., 2.beta., 3a.alpha., 6a.beta., 6b.alpha.)- (32.42%), d-fucose (5.47%), 5-hydroxymethylfurfural (5.47%) and guaiacol (3.19%). The LD50 was estimated to be between 500 and 2000 mg/kg. Furthermore, at 500 and 250 mg/kg, the aqueous extract of T. takoumitense exhibited good antihyperlipidemic activity in vivo. Conclusion: T. takoumitense extract has significant pharmacological potential and a varied chemical composition.

8.
RSC Adv ; 13(47): 33294-33304, 2023 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-37964908

RESUMO

Hemp is known for its swift growth and remarkable sustainability, requiring significantly less water, an adaptable cultivation to a wide range of climates when compared to other fibers sources, making it a practical and environmentally friendly choice for packaging materials. The current research seeks to extract cellulose nanocrystals (CNCs) from hemp fibers using alkali treatment followed by acid hydrolysis and assess their reinforcing capacity in polyvinyl alcohol (PVA) and chitosan (CS) films. AFM analysis confirmed the existence of elongated, uniquely nanosized CNC fibers. The length of the isolated CNCs was approximately 277.76 ± 61 nm, diameter was 6.38 ± 1.27 nm and its aspect ratio was 44.69 ± 11.08. The FTIR and SEM analysis indicated the successful removal of non-cellulosic compounds. Furthermore, the study explored the impact of adding CNCs at varying weight percentages (0, 0.5, 1, 2.5, and 5 wt%) as a strengthening agent on the chemical composition, structure, tensile characteristics, transparency, and water solubility of the bionanocomposite films. Adding CNCs to the CS/PVA film, up to 5 wt%, resulted in an improvement in both the Young's modulus and tensile strength of the bionanocomposite film, which are measured at (412.46 ± 10.49 MPa) and (18.60 ± 3.42 MPa), respectively, in contrast to the control films with values of (202.32 ± 22.50 MPa) and (13.72 ± 2.61 MPa), respectively. The scanning electron microscopy (SEM) images reveal the creation of a CS/PVA/CNC film that appears smooth, with no signs of clumping or clustering. The blending and introduction of CNCs have yielded transparent and biodegradable CS/PVA films. This incorporation has led to a reduction in the gas transmission rate (from 7.013 to 4.159 cm3 (m2 day·0.1 MPa))-1, a decrease in transparency (from 90.23% to 82.47%), and a lowered water solubility (from 48% to 33%). This study is the inaugural effort to propose the utilization of hemp-derived CNC as a strengthening component in the development of mechanically robust and transparent CS/PVA-CNC bio-nanocomposite films, holding substantial potential for application in the field of food packaging.

9.
Acta Crystallogr Sect E Struct Rep Online ; 67(Pt 11): o2990, 2011 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-22220010

RESUMO

The title compound, C(17)H(14)N(2)O, crystallizes with two mol-ecules in the asymmetric unit. The dihedral angles between the mean planes of the quinoxaline ring system and the phenyl ring in the two mol-ecules are 38.27 (10) and 37.14 (8)°. In the crystal, π-stacking along the b axis contributes to the crystal cohesion with an average distance between quinoxaline units of 3.397 (3) Å. Weak C-H⋯O interactions also occur.

10.
Environ Sci Pollut Res Int ; 28(33): 44638-44666, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34212334

RESUMO

For many decades, titanium dioxide (TiO2) semiconductor has been extensively applied in several environmental applications due to its higher photocatalytic performances toward different organic pollutants, pharmaceutical compounds, and bacteria. However, its shortfall response to visible light, and the expeditious recombination rate of the photogenerated electron-hole pairs, hampers its utilization. Doping TiO2 semiconductor with silver nanoparticles is a sound strategy to (1) extend its photocatalytic activity to visible light, (2) prevent the electron/holes pairs recombination due to the formation of the Schottky barrier at the interfaces with TiO2 that act as an electron-trapping center, and (3) enhance its bactericide performances. This review focuses on the recent progress on silver-doped titanium dioxide (Ag/TiO2)-based photocatalysts. It addresses a wide range of Ag/TiO2 synthesis techniques, their physicochemical properties and discusses thoroughly the important role of silver (Ag) nanoparticles in enhancing the removal capacity and antibacterial performances of the Ag/TiO2 photocatalysts.


Assuntos
Nanopartículas Metálicas , Prata , Antibacterianos/farmacologia , Catálise , Luz , Titânio
11.
Acta Crystallogr Sect E Struct Rep Online ; 65(Pt 9): o2196, 2009 Aug 22.
Artigo em Inglês | MEDLINE | ID: mdl-21577599

RESUMO

The ten-membered fused ring of the title compound, C(12)H(10)N(2)O, is essentially planar in the two independent mol-ecules of the asymmetric unit (r.m.s. deviations = 0.012 and 0.015 Å).

12.
Acta Crystallogr Sect E Struct Rep Online ; 65(Pt 10): o2322, 2009 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-21577793

RESUMO

The compound, C(15)H(16)N(2)O(2), features a pyrroline ring fused with a seven-membered diazepine ring; the latter system adopts a boat conformation (with the methine C atom as the prow and the two C atoms of the aromatic ring as the stern). A CH(2)-CH(2) segment of the pyrroline ring is disordered over two positions in a 1:1 ratio.

13.
Acta Crystallogr Sect E Struct Rep Online ; 65(Pt 10): o2323, 2009 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-21577794

RESUMO

The phenyl substituents in both independent mol-ecules of the title compound, C(15)H(12)N(2)O, are twisted with respect to the quinoxaline system [dihedral angles = 19.3 (1) and 30.4 (1)°].

14.
Acta Crystallogr Sect E Struct Rep Online ; 65(Pt 11): o2657, 2009 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-21578269

RESUMO

The seven-membered ring of the title compound, C(17)H(20)N(2)O(2), adopts an approximate boat conformation while the cyclo-hexyl ring adopts a chair conformation. In the crystal, adjacent mol-ecules are linked by N-H⋯O hydrogen bonds into a zigzag chain running along the c axis of the monoclinic unit cell.

15.
Acta Crystallogr Sect E Struct Rep Online ; 65(Pt 11): o2684, 2009 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-21578290

RESUMO

The organic mol-ecule and uncoordinated water mol-ecule in the crystal of the title compound, C(25)H(24)N(4)O(4)·2H(2)O, both lie on special positions of twofold symmetry. A twofold rotation axis passes through the methyl-ene C atom connecting the two dihydro-benzopyrrolodiazepindionyl parts. The seven-membered C(5)N(2) ring adopts a boat conformation.

16.
Acta Crystallogr Sect E Struct Rep Online ; 65(Pt 11): o2685, 2009 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-21578291

RESUMO

The ten-membered fused ring system in the title compound, C(21)H(16)N(2)O(2), is planar (r.m.s. deviation = 0.03 Å). The phenyl substituent is aligned at 15.1 (1)° with respect to the mean plane through this system, whereas the phenyl ring of the benzyl substitutent is aligned at 84.4 (1)°.

17.
Acta Crystallogr Sect E Struct Rep Online ; 64(Pt 11): o2234, 2008 Oct 31.
Artigo em Inglês | MEDLINE | ID: mdl-21581088

RESUMO

The asymmetric unit of the title compound, C(11)H(12)N(2)O, contains two independent mol-ecules. In the crystal structure, inter-molecular C-H⋯O hydrogen bonds link the mol-ecules. There are π-π contacts between the quinoxaline rings [centroid-centroid distances = 3.446 (2), 3.665 (2), 3.645 (3) and 3.815 (3) Å]. There also exist C-H⋯π contacts between the methyl groups and the quinoxaline rings.

18.
J Toxicol ; 2018: 4563735, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29853874

RESUMO

Since they are natural, plants are wrongly considered nondangerous; therefore people used them in various contexts. Each plant is used alone or in mixture with others, where knowledge and the requirements of preparation and consumption are not mastered. Thus, intoxications due to the use of plants have become more and more frequent. The reports of intoxications made at the Antipoison Center and Pharmacovigilance of Morocco (ACPM) support this finding, since the interrogations suffered by the victims show that the use of plants is practiced irrationally, anarchically, and uncontrollably. Faced by the increase of these cases of poisoning in Morocco, it seemed necessary to investigate the nature of poisonous plants, their monographs, and the chemicals responsible for this toxicity.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA