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1.
Environ Res ; 257: 119328, 2024 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-38851369

RESUMO

The growing effects of climate change on Malaysia's coastal ecology heighten worries about air pollution, specifically caused by urbanization and industrial activity in the maritime sector. Trucks and vessels are particularly noteworthy for their substantial contribution to gas emissions, including nitrogen dioxide (NO2), which is the primary gas released in port areas. The application of advanced analysis techniques was spurred by the air pollution resulting from the combustion of fossil fuels such as fuel oil, natural gas and gasoline in vessels. The study utilized satellite photos captured by the Tropospheric Monitoring Instrument (TROPOMI) on the Sentinel-5P satellite to evaluate the levels of NO2 gas pollution in Malaysia's port areas and exclusive economic zone. Before the COVID-19 pandemic, unrestricted gas emissions led to persistently high levels of NO2 in the analyzed areas. The temporary cessation of marine industry operations caused by the pandemic, along with the halting of vessels to prevent the spread of COVID-19, resulted in a noticeable decrease in NO2 gas pollution. In light of these favourable advancements, it is imperative to emphasize the need for continuous investigation and collaborative endeavours to further alleviate air contamination in Malaysian port regions, while simultaneously acknowledging the wider consequences of climate change on the coastal ecology. The study underscores the interdependence of air pollution, maritime activities and climate change. It emphasizes the need for comprehensive strategies that tackle both immediate environmental issues and the long-term sustainability and resilience of coastal ecosystems in the context of global climate challenges.


Assuntos
Poluentes Atmosféricos , Poluição do Ar , Mudança Climática , Monitoramento Ambiental , Dióxido de Nitrogênio , Imagens de Satélites , Malásia , Dióxido de Nitrogênio/análise , Poluentes Atmosféricos/análise , Poluição do Ar/análise , Monitoramento Ambiental/métodos , Navios , COVID-19/epidemiologia , Emissões de Veículos/análise
2.
Environ Res ; 252(Pt 3): 118858, 2024 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-38609066

RESUMO

Crucial to the Earth's oceans, ocean currents dynamically react to various factors, including rotation, wind patterns, temperature fluctuations, alterations in salinity and the gravitational pull of the moon. Climate change impacts coastal ecosystems, emphasizing the need for understanding these currents. This study explores multibeam echosounder (MBES), specifically R2-Sonic 2020 instrument, offering detailed seabed information. Investigating coral reefs, rocky reefs and artificial reefs aimed to map seafloor currents movement and their climate change responses. MBES data viz. Bathymetry and backscatter were classified and acoustic doppler current profiler (ADCP) ground data were validated using random forest regression. Results indicated high precision in currents speed measurement i.e. coral reefs with 0.96, artificial reefs with 0.94 and rocky reefs with 0.97. Currents direction accuracy was notable in coral reefs with 0.85, slightly lower in rocky reefs with 0.72 and artificial reefs with 0.60. Random forest identified sediment and backscatter as key for speed prediction while direction relies on bathymetry, slope and aspect. The study emphasizes integrating sediment size, backscatter, bathymetry and ADCP data for seafloor current analysis. This multibeam data on sediments and currents support better marine spatial planning and determine biodiversity patterns planning in the reef area.


Assuntos
Mudança Climática , Recifes de Corais , Movimentos da Água , Monitoramento Ambiental/métodos , Acústica , Efeito Doppler
3.
Environ Res ; 239(Pt 2): 117314, 2023 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-37805186

RESUMO

Coastal ecosystems are facing heightened risks due to human-induced climate change, including rising water levels and intensified storm events. Accurate bathymetry data is crucial for assessing the impacts of these threats. Traditional data collection methods can be cost-prohibitive. This study investigates the feasibility of using freely accessible Landsat and Sentinel satellite imagery to estimate bathymetry and its correlation with hydrographic chart soundings in Port Klang, Malaysia. Through analysis of the blue and green spectral bands from the Landsat 8 and Sentinel 2 datasets, a bathymetry map of Port Klang's seabed is generated. The precision of this derived bathymetry is evaluated using statistical metrics like Root Mean Square Error (RMSE) and the coefficient of determination. The results reveal a strong statistical connection (R2 = 0.9411) and correlation (R2 = 0.7958) between bathymetry data derived from hydrographic chart soundings and satellite imagery. This research not only advances our understanding of employing Landsat imagery for bathymetry assessment but also underscores the significance of such assessments in the context of climate change's impact on coastal ecosystems. The primary goal of this research is to contribute to the comprehension of Landsat imagery's utility in bathymetry evaluation, with the potential to enhance safety protocols in seaport terminals and provide valuable insights for decision-making concerning the management of coastal ecosystems amidst climate-related challenges. The findings of this research have practical implications for a wide range of stakeholders involved in coastal management, environmental protection, climate adaptation and disaster preparedness.


Assuntos
Ecossistema , Imagens de Satélites , Humanos , Mudança Climática , Conservação dos Recursos Naturais , Água
4.
Molecules ; 28(3)2023 Jan 27.
Artigo em Inglês | MEDLINE | ID: mdl-36770904

RESUMO

Due to the large versatility in organic semiconductors, selecting a suitable (organic semiconductor) material for photodetectors is a challenging task. Integrating computer science and artificial intelligence with conventional methods in optimization and material synthesis can guide experimental researchers to develop, design, predict and discover high-performance materials for photodetectors. To find high-performance organic semiconductor materials for photodetectors, it is crucial to establish a relationship between photovoltaic properties and chemical structures before performing synthetic procedures in laboratories. Moreover, the fast prediction of energy levels is desirable for designing better organic semiconductor photodetectors. Herein, we first collected large sets of data containing photovoltaic properties of organic semiconductor photodetectors reported in the literature. In addition, molecular descriptors that make it easy and fast to predict the required properties were used to train machine learning models. Power conversion efficiency and energy levels were also predicted. Multiple models were trained using experimental data. The light gradient boosting machine (LGBM) regression model and Hist gradient booting regression model are the best models. The best models were further tuned to achieve better prediction ability. The reliability of our designed approach was further verified by mining the photovoltaic database to search for new building units. The results revealed that good consistency is obtained between experimental outcomes and model predictions, indicating that machine learning is a powerful approach to predict the properties of photodetectors, which can facilitate their rapid development in various fields.

5.
Org Biomol Chem ; 20(16): 3397-3407, 2022 04 20.
Artigo em Inglês | MEDLINE | ID: mdl-35362508

RESUMO

A catalyst-free microwave-assisted annulation protocol for the preparation of biologically interesting pyrido-fused quinazolinones and pyrido[1,2-a]benzimidazoles is developed. This reaction involves the [3 + 3] annulation of various quinazolinones or benzimidazoles with 3-formylchromones to yield functionalized 11H-pyrido[2,1-b]quinazolin-11-one and pyrido[1,2-a] benzimidazole derivatives. This approach is successfully extended to the construction of various pyrazolo[4,3-d]pyrido[1,2-a]pyrimidin-10(1H)-ones. The present approach is complementary to the existing synthetic methodologies and offers a rapid and facile approach with a broad substrate scope, good yields, catalyst-free conditions, and a high functional group tolerance. The optimal synthesized compound is also employed as an "on-off" photoluminescent probe for the selective detection of Fe3+ and Ag+ metal ions.


Assuntos
Benzimidazóis , Micro-Ondas , Benzimidazóis/química , Catálise , Quinazolinonas
6.
Org Biomol Chem ; 20(34): 6776-6783, 2022 08 31.
Artigo em Inglês | MEDLINE | ID: mdl-35959713

RESUMO

The directing group-assisted regioselective C-H activation of carbazoles and indolines is achieved via transition metal-catalyzed reactions. This C-H functionalization protocol provides a rapid approach to install diversely functionalized succinimide groups at the C-1 position of the carbazole moiety. In addition, this protocol demonstrates the intrinsic reactivity of indolines in providing C-2 succinimide-substituted indoles via cascade direct oxidation and C-H functionalization. This protocol also provides C-7 succinimide-substituted indolines under mild reaction conditions. The features of this reaction include a wide substrate scope and excellent regioselectivity for the installation of the succinimide moiety on biologically interesting molecules.


Assuntos
Indóis , Elementos de Transição , Carbazóis/química , Catálise , Indóis/química , Maleimidas , Estrutura Molecular , Succinimidas
7.
Langmuir ; 37(46): 13767-13777, 2021 11 23.
Artigo em Inglês | MEDLINE | ID: mdl-34753286

RESUMO

Microemulsified gels (µEGs) with fascinating functions have become indispensable as topical drug delivery systems due to their structural flexibility, high stability, and facile manufacturing process. Topical administration is an attractive alternative to traditional methods because of advantages such as noninvasive administration, bypassing first-pass metabolism, and improving patient compliance. In this article, we report on the new formulations of microemulsion-based gels suitable for topical pharmaceutical applications using biocompatible and ecological ingredients. For this, two biocompatible µE formulations comprising clove oil/Brij-35/water/ethanol (formulation A) and clove oil/Brij-35/water/1-propanol (formulation B) were developed to encapsulate and improve the load of an antimycotic drug, Clotrimazole (CTZ), and further gelatinized to control the release of CTZ through skin barriers. By delimiting the pseudo-ternary phase diagram, optimum µE formulations with clove oil (∼15%) and Brij-35 (∼30%) were developed, keeping constant surfactant/co-surfactant ratio (1:1), to upheld 2.0 wt % CTZ. The as-developed formulations were further converted into smart gels by adding 2.0 wt % carboxymethyl cellulose (CMC) as a cross-linker to adhere to the controlled release of CTZ through complex skin barriers. Electron micrographs show a fine, monodispersed collection of CTZ-µE nanodroplets (∼60 nm), which did not coalesce even after gelation, forming spherical CTZ-µEG (∼90 nm). However, the maturity of CTZ nanodroplets observed by dynamic light scattering suggests the affinity of CTZ for the nonpolar microenvironment, which was further supported by the peak-to-peak correlation of Fourier transform infrared (FTIR) analysis and fluorescence measurement. In addition, HPLC analysis showed that the in vitro permeation release of CTZ-µEG from rabbit skin in the ethanolic phosphate buffer (pH = 7.4) was significantly increased by >98% within 6.0 h. This indicates the sustained release of CTZ in µEBG and the improvement in transdermal therapeutic efficacy of CTZ over its traditional topical formulations.


Assuntos
Clotrimazol , Óleo de Cravo , Administração Cutânea , Animais , Sistemas de Liberação de Medicamentos , Emulsões , Géis , Coelhos
8.
Molecules ; 26(23)2021 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-34885891

RESUMO

Synthesis of 5-aryl-N-(pyrazin-2-yl)thiophene-2-carboxamides (4a-4n) by a Suzuki cross-coupling reaction of 5-bromo-N-(pyrazin-2-yl)thiophene-2-carboxamide (3) with various aryl/heteroaryl boronic acids/pinacol esters was observed in this article. The intermediate compound 3 was prepared by condensation of pyrazin-2-amine (1) with 5-bromothiophene-2-carboxylic acid (2) mediated by TiCl4. The target pyrazine analogs (4a-4n) were confirmed by NMR and mass spectrometry. In DFT calculation of target molecules, several reactivity parameters like FMOs (EHOMO, ELUMO), HOMO-LUMO energy gap, electron affinity (A), ionization energy (I), electrophilicity index (ω), chemical softness (σ) and chemical hardness (η) were considered and discussed. Effect of various substituents was observed on values of the HOMO-LUMO energy gap and hyperpolarizability. The p-electronic delocalization extended over pyrazine, benzene and thiophene was examined in studying the NLO behavior. The chemical shifts of 1H NMR of all the synthesized compounds 4a-4n were calculated and compared with the experimental values.

9.
J Org Chem ; 85(23): 15129-15138, 2020 12 04.
Artigo em Inglês | MEDLINE | ID: mdl-33147948

RESUMO

An efficient and facile protocol for the synthesis of biologically and pharmaceutically important phthalimides is developed by l-proline-catalyzed reaction between two dienophiles of α,ß-unsaturated aldehydes and maleimides. The reaction involves an efficient benzannulation that proceeds via a formal [4 + 2] cycloaddition of azadiene intermediates generated in situ from enals and N-substituted maleimides. This protocol provides a variety of functionalized phthalimide derivatives, including a potent COX-2 enzyme inhibitor.

10.
Pak J Med Sci ; 35(4): 1099-1103, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31372150

RESUMO

OBJECTIVE: To compare the effects of simple saline dressings versus topical vancomycin dressings on Methicillin-resistant Staphylococcus Aureus positive chronic diabetic foot ulcers. METHODS: It was quasi experimental study conducted in Combined Military Hospital Kohat and PNS-Shifa Hospital Karachi from 01 January 2017 to 31 December 2017. A total of 23 patients were included based on non-probability convenient sampling who had diabetes and presented with foot ulcers for more than two weeks showing positive growth of Methicillin-Resistant Staphylococcus Aureus. The patients were treated with simple saline soaked dressings and debridement at first for three weeks followed by three weeks of topical vancomycin dressings with debridement. Thus patients served as their own controls. RESULTS: The average change in surface area with saline dressing was +1.73 ±1.53cm2 per week whereas with vancomycin soaked dressing it was --0.06±1.60 cm2 per week (p <0.05). The average exudate also decreased from 1.78±1.23 to 0.99±0.72 (p<0.05) and same trend was observed in percentage of slough covering the ulcer from 45% ± 22.3% to 24.3% ±12.90% (p<0.05) with vancomycin dressing. Moreover, fifteen patients had negative culture for MRSA within 2 weeks. CONCLUSION: Vancomycin impregnated dressing in MRSA positive Diabetic foot may help achieve early healing as compared to simple conventional dressings with no systemic toxicity.

11.
Pak J Med Sci ; 34(3): 564-567, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30034416

RESUMO

OBJECTIVE: To determine the seasonal variation of acute appendicitis. METHODS: A total of 320 patients fulfilling the inclusion criteria were enrolled in the study after getting the written informed consent. Appendectomies were performed by consultant surgeons and residents. After surgery histopathological examination of specimens was performed by consultant Histopathologists at Armed Forces Institute of Pathology Rawalpindi and CMH Peshawar. The patients presenting in different four seasons September to November as autumn, December to February as winter, March to May as spring, June to August as summer, were compared to determine seasonal variations. RESULTS: In our study out of all 320 patients 188 (58.75%) were males and 132 (41.25%) were females. Sixty patients (18.75 %) presented in autumn season (Sep-Nov), 52 patients (16.25%) in winter season (Dec-Feb), 78 (24.25%) patients in Spring season (Mar-May).130 (40.62%) patients presented in Summer season (Jun-Aug). There was almost 24.37% increased incidence in summer as compared to winter season, 21.87% increased incidence as compared to autumn season, 16.37% increased incidence as compared to spring season. CONCLUSION: Acute appendicitis incidence is increased in summer months in Pakistan. Preventive measures can be taken during summer season (June to Aug) to decrease morbidity and mortality associated with this disease.

12.
Org Biomol Chem ; 14(43): 10285-10297, 2016 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-27752699

RESUMO

A highly efficient and facile thermal multicomponent cascade reaction of readily available 4-oxo-4H-chromene-3-carbaldehydes with cyanoacetates or cyanoamides and anilines or aliphatic amines under solvent and catalyst-free conditions was developed for the synthesis of a range of polysubstituted 2-aminopyridine derivatives in good to excellent yield. This protocol proceeds via a cascade reaction of Knoevenagel condensation, nucleophilic addition, intramolecular Michael addition, and ring opening. As an application of this methodology, the antibacterial activities of some of the synthetic compounds were evaluated.


Assuntos
Aminopiridinas/síntese química , Aminopiridinas/farmacologia , Antibacterianos/síntese química , Antibacterianos/farmacologia , Temperatura , Aminopiridinas/química , Antibacterianos/química , Bactérias/efeitos dos fármacos , Técnicas de Química Sintética
13.
Org Lett ; 26(1): 142-147, 2024 Jan 12.
Artigo em Inglês | MEDLINE | ID: mdl-38109110

RESUMO

An unprecedented strategy for Rh-catalyzed C-H activation/C═C bond cleavage of enaminones is described for the construction of biologically interesting aza-spiro α-tetralones and benzo[e]isoindoles. This protocol provides diversely functionalized aza-spiro α-tetralones and benzo[e]isoindoles in good yields via a [4 + 2] annulation of the exomaleimides and maleimides. This strategy displays a good substrate scope, outstanding functional group tolerance, and excellent regioselectivity.

14.
Front Plant Sci ; 15: 1396594, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39166242

RESUMO

Background: Zea mays (maize) is a globally significant cereal crop with diverse applications in food, feed, and industrial products. However, maize cultivation is often challenged by environmental stressors such as heavy metal toxicity and drought stress (DS). Heavy metals like cadmium (Cd) and lead (Pb) can accumulate in soil through industrial activities and improper waste disposal, posing significant threats to plant growth and development. Drought stress further exacerbates these challenges by limiting water availability and affecting physiological processes in plants. This study explores the impact of Cd and Pb toxicity, as well as DS, on maize growth and development, and investigates the potential mitigating effects of various treatments, including gibberellic acid (GA3), biochar (BC), rhizobacteria (RB), and their combinations. Methods: The experiment involved maize plants subjected to different stress conditions: cadmium (Cd) at concentrations of 0, 6, and 12 ppm, lead (Pb) at 0 and 400 ppm, and drought stress (DS). Treatments included the application of 10 ppm GA3, 0.75% BC, a combined treatment of 10 ppm GA3 and 0.75% BC, rhizobacteria (RB), and a combined treatment of 0.5% BC and RB. The study measured germination rates, shoot and root lengths, and biochemical parameters such as shoot and root protein, phenolics, and chlorophyll contents under these conditions. Results: In the absence of Cd stress (0 Cd), the application of 10 ppm GA3 and 0.75% BC significantly enhanced germination rates by 72% and 76%, respectively, compared to the control, with the combined treatment exhibiting the highest enhancement of 86%. Under Cd stress (6 ppm Cd), GA3 and BC individually improved germination by 54% and 57%, respectively, with the combined treatment showing the largest increase of 63%. Drought stress influenced germination, with notable improvements observed with the application of 0.5% BC (50% increase) and RB (49% increase). Similar trends were observed in shoot and root lengths, where the combined treatment of GA3 and BC resulted in the most significant improvements. The treatments positively influenced shoot and root protein, phenolics, and chlorophyll contents, particularly under stress conditions. Conclusion: These findings highlight the potential of combined treatments, such as the application of GA3 and BC or BC with RB, in alleviating the adverse effects of heavy metals (Cd and Pb) and drought stress in maize cultivation. The combined treatments not only improved germination rates but also significantly enhanced shoot and root growth, as well as important biochemical parameters under stress conditions. This suggests that GA3 and BC, alone or in combination with RB, can play a crucial role in enhancing maize resilience to environmental stressors. The study highlights the importance of exploring sustainable agricultural practices to mitigate the impacts of heavy metal toxicity and drought stress. Future research should focus on long-term field trials to validate these findings and further investigate the mechanistic pathways involved in stress mitigation by these amendments, as well as their economic feasibility and environmental impact on a larger scale to ensure their practical applicability in real-world agricultural settings.

15.
Polymers (Basel) ; 16(11)2024 May 27.
Artigo em Inglês | MEDLINE | ID: mdl-38891459

RESUMO

In this study, nanocomposites of AgNPs encapsulated in carboxymethyl chitosan (CMCS) with sulfobetaine methacrylate (SB) hydrogel (AgNPs/CMCS-SB) were synthesized. The UV-Vis spectra indicated the presence of AgNPs, with a broad peak at around 424 nm, while the AgNPs-loaded CMCS-SB nanocomposite exhibited absorption peaks at 445 nm. The size and dispersion of AgNPs varied with the concentration of the AgNO3 solution, affecting swelling rates: 148.37 ± 15.63%, 172.26 ± 18.14%, and 159.17 ± 16.59% for 1.0 mM, 3.0 mM, and 5.0 mM AgNPs/CMCS-SB, respectively. Additionally, water absorption capacity increased with AgNPs content, peaking at 11.04 ± 0.54% for the 3.0 mM AgNPs/CMCS-SB nanocomposite. Silver release from the nanocomposite was influenced by AgNO3 concentration, showing rapid initial release followed by a slower rate over time for the 3.0 mM AgNPs/CMCS-SB. XRD patterns affirmed the presence of AgNPs, showcasing characteristic peaks indicative of a face-centered cubic (fcc) structure. The FTIR spectra highlighted interactions between AgNPs and CMCS-SB, with noticeable shifts in characteristic bands. In addition, SEM and TEM images validated spherical AgNPs within the CMCS-SB hydrogel network, averaging approximately 70 and 30 nm in diameter, respectively. The nanocomposite exhibited significant antibacterial activity against S. aureus and E. coli, with inhibition rates of 98.9 ± 0.21% and 99.2 ± 0.14%, respectively, for the 3.0 mM AgNPs/CMCS-SB nanocomposite. Moreover, cytotoxicity assays showcased the efficacy of AgNPs/CMCS-SB against human colorectal cancer cells (HCT-116 cells), with the strongest cytotoxicity (61.7 ± 4.3%) at 100 µg/mL. These results suggest the synthesized AgNPs/CMCS-SB nanocomposites possess promising attributes for various biomedical applications, including antimicrobial and anticancer activities, positioning them as compelling candidates for further advancement in biomedicine.

16.
Chemosphere ; 314: 137604, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36574789

RESUMO

Depletion of non-renewable fuel has obliged researchers to seek out sustainable and environmentally friendly alternatives. Membranes have proven to be an effective technique in biofuel production for reaction, purification, and separation, with the ability to use both porous and non-porous membranes. It is demonstrated that a membrane-based sustainable and green production can result in a high degree of process intensification, whereas the recovery and repurposing of catalysts and alcohol are anticipated to increase the process economics. Therefore, in this study sustainable biodiesel was synthesized from inedible seed oil (37 wt%) of Cordia myxa using a membrane reactor. Transesterification was catalyzed by heterogenous nano-catalyst of indium oxide prepared with leaf extract of Boerhavia diffusa. Highest biodiesel yield of 95 wt% was achieved at methanol to oil molar ratio of 7:1, catalyst load 0.8 wt%, temperature 82.5 °C and time 180 min In2O3 nanoparticles exhibited reusability up to five successive transesterification rounds. The production of methyl esters was confirmed using Fourier-transform infrared spectroscopy and Nuclear Magnetic Resonance. The predominant fatty acid methyl ester detected in the biodiesel was 5, 8-octadecenoic acid. Biodiesel fuel qualities were determined to be comparable to worldwide ASTM D-6571 and EN-14214 standards. Finally, it was concluded that membrane technology can result in a highly intensified reaction process while efficient recovery of both nano catalysts and methanol increases the economics of transesterification and lead to sustainable production.


Assuntos
Cordia , Nanopartículas , Óleos de Plantas/química , Metanol , Biocombustíveis , Biomassa , Esterificação , Catálise , Etanol , Ácidos Graxos/química
17.
Chemosphere ; 322: 138080, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-36781001

RESUMO

Research on ionic liquids (ILs) and biochars (BCs) is a novel site of scientific interest. An experiment was designed to assess the effect of 1-propanenitrile imidazolium trifluoro methane sulfonate ([C2NIM][CF3SO3]) ionic liquid (IL) and IL-BC combination on the wheat plant. Three working standards of the IL; 50, 250, 500 and 1000 mg/L, prepared in deionized water, were tested in the absence and presence of BC on wheat seedling. Results indicated significant decrease in seed germination (%), length, fresh weight, chlorophyll a, b and carotenoid contents of wheat seedlings at 250, 500 and 1000 mg/L of the IL. An admirable increase in phenolic and 2,2-diphenyl-1-picrylhydrazyl (DPPH) contents of wheat seedlings was noted at 250, 500 and 1000 mg/L of the IL. The application of BC significantly ameliorated the negative effects of IL on the selected parameters of wheat. It is inferred that the undesirable effects of the IL on wheat growth can be positively restored by addition of BC.


Assuntos
Líquidos Iônicos , Líquidos Iônicos/química , Clorofila A , Triticum , Plântula
18.
Chemosphere ; 322: 138078, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-36754302

RESUMO

Conventional homogeneous-based catalyzed transesterification for the production of biodiesel can be replaced with a membrane reactor that has an immobilized heterogeneous catalyst. Combining reaction with separation while utilizing membranes with a certain pore size might boost conversion process. this investigation to study the effectiveness of membrane reactor in combination with heterogeneous green nano catalysis of MnO2. Techniques such as XRD, EDX, FTIR, SEM, and TGA were used to characterize the synthesized MnO2 nano catalyst. The highest conversion of around 94% Trachyspermum ammi oil was obtained by MnO2. The optimum process variables for maximum conversion were catalyst loading of 0.26 (wt.%), 8:1 M ratio, 90 °C reaction temperature, and time 120 min. The green nano catalyst of MnO2 was reusable up to five cycles with minimum loss in conversion rate of about 75% in the fifth cycle. Nuclear magnetic resonance validated the synthesis of methyl esters. It was concluded that membrane reactor a promising technique to efficiently transesterify triglycerides into methyl esters and enable process intensification uses MnO2 as a catalyst.


Assuntos
Ammi , Óxidos , Compostos de Manganês , Biocombustíveis , Esterificação , Ésteres , Óleos de Plantas
19.
Chemosphere ; 321: 137999, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-36724850

RESUMO

Green and efficient removal of polluted materials are essential for the sustainability of a clean and green environment. Nanomaterials, particularly cellulose nanocrystals (CNCs), are abundant in nature and can be extracted from various sources, including cotton, rice, wheat, and plants. CNCs are renewable biomass materials with a high concentration of polar functional groups. This study used succinic anhydride to modify the surface of native cellulose nanocrystals (NCNCs). Succinic anhydride has been frequently used in adhesives and sealant chemicals for a long time, and here, it is evaluated for dye removal performance. The morphology and modification of CNCs studied using FTIR, TGA & DTG, XRD, SEM, AFM, and TEM. The ability of modified cellulose nanocrystals (MCNCs) to adsorb cationic golden yellow dye and methylene blue dye was investigated. The MCNCs exhibited high adsorption affinity for the two different cationic dyes. The maximum adsorption efficiency of NCNCs and MCNCs towards the cationic dye was 0.009 and 0.156 wt%. The investigation for adhesive properties is based on the strength and toughness of MCNCs. MCNCs demonstrated improved tensile strength (2350 MPa) and modulus (13.9 MPa) using E-51 epoxy system and a curing agent compared to 3 wt% composites. This research lays the groundwork for environmentally friendly fabrication and consumption in the industrial sector.


Assuntos
Corantes , Nanopartículas , Corantes/química , Anidridos Succínicos , Adsorção , Celulose/química , Nanopartículas/química , Cátions
20.
Chemosphere ; 319: 137994, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-36720415

RESUMO

Better processing techniques must be utilized widely due to the rising demand for honey. The most common honey processing techniques are applied to melissopalynomorphs to check the quality and quantity of valuable honey using microporous ultrafiltration membranes. It is essential to have the ability to selectively filter out sugars from honey using ultrafiltration. This study authenticated 24 honey samples using membrane reactors ultrafiltration protocol to describe the pollen spectrum of dominant vegetation. The purpose of this study was also to explore nutritional benefits as well as the active phytochemical constituents of honey samples. Honey samples were collected and labeled Acacia, Eucalyptus, and Ziziphus species based on plant resources provided by local beekeepers. A variety of honeybee flora was collected around the apiaries between 2020 and 2021. Honey analysis revealed that the pollen extraction of 24 bee foraging species belonging to 14 families. The honey membrane technology verified the identities of honey and nectar sources. Also, pollen identified using honey ultrafiltration membranes revealed dominant resources: Acacia spp. (69%), Eucalyptus spp. (52%) and Ziziphus spp. Honey filtration using a membrane technology classified 14 samples as unifloral, represented by six dominant pollen types. The absolute pollen count in the honey sample revealed that 58.33% (n = 14) belong to Maurizio's class I. Scanning ultrasculpturing showed diverse exine patterns: reticulate, psilate, scabrate-verrucate, scabrate-gemmate, granulate, perforate, microechinate, microreticulate, and regulate to fossulate for correct identification of honey pollen types. Honey ultrafiltration should be utilized to validate the botanical sources of honey and trace their biogeographic authenticity. Thus, it is imperative to look at the alternative useful method to identify the botanical origin of filtered honey. It is critical to separate honey from adulteration by a standardized protocol. Membrane technology has yielded significant outcomes in the purification of honey.


Assuntos
Eucalyptus , Mel , Abelhas , Animais , Mel/análise , Pólen/química , Plantas , Néctar de Plantas , Eucalyptus/química
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