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1.
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.

2.
Environ Res ; 257: 119328, 2024 Jun 06.
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.

3.
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
4.
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.

5.
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
6.
Chemosphere ; 338: 139621, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37487973

RESUMO

The earth's nitrogen cycle relies on the effective conversion of nitrogen (N2) to ammonia (NH3). As a result, the research and development of catalysts that are earth-abundant, inexpensive, and highly efficient but do not need precious metals is of the utmost significance. In this investigation, we present a controlled synthesis technique to the fabrication of an iron oxide (Fe2O3) nanosheet array by annealing at temperatures ranging from 350 to 550 °C. This array will be used for the electrochemical reduction of atmospheric N2 to NH3 in electrolytes. The Fe2O3 nanosheet array that was produced as a result displays outstanding electrochemical performance as well as remarkable stability. When compared to a hydrogen electrode working under normal temperature and pressure conditions, the Fe2O3 nanosheet array produces an impressive NH3 production rate of 18.04 g per hour per mg of catalytically active material in 0.1 M KOH electrolyte, exhibiting an enhanced Faradaic efficiency (FE) of 13.5% at -0.35 V. This is accomplished by exhibiting an enhanced Faradaic efficiency (FE) of 0.1 M KOH electrolyte. The results of experiments and electrochemical studies reveal that the existence of cation defects in the Fe2O3 nanosheets plays an essential part in the enhancement of the electrocatalytic activity that takes place during nitrogen reduction reactions (NRR). This study not only contributes to the expanding family of transition-metal-based catalysts with increased electrocatalytic activity for NRR, but it also represents a substantial breakthrough in the design of catalysts that are based on transition metals, so it's a win-win. In addition, the use of Fe2O3 nanosheets as electrocatalysts has a lot of potential in algal membrane bioreactors because it makes nitrogen fixation easier, it encourages algae growth, and it makes nitrogen cycling more resource-efficient.


Assuntos
Amônia , Reatores Biológicos , Estudos Prospectivos , Nitrogênio
7.
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
8.
Chemosphere ; 322: 138079, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-36775030

RESUMO

Oryza sativa is grown worldwide and exhibit sensitivity to different stresses. Exponential increase in microplastics in agroecosystems is damaging and demand pragmatic strategies to protect growth and yield losses. We evaluated exogenous application of different doses of glutathione (GSH) for mediation of physiological traits of rice plants experiencing two different MPs i.e. PET and HDPE in root zone. All the rice seedlings exhibited MP-induced significant (P ≤ 0.001) growth inhibition compared to the control plants. GSH application (T3) significantly increased the shoot fresh weight (8.80%), root fresh weight (19.22%), shoot dry weight (13.705%), root dry weight (25.52%), plant height (5.75%) and 100-grain weight (9.36%), compared to control plants. GSH treated plants (T4) showed a recovery mechanism by managing the marginal rate of reduction of all photosynthetic and gas exchange attributes by showing 34.44, 20.98, 34.83, 42.16, 39.70, and 51.38% reduction for Chl-a, Chl-b, total cholophyll, photosynthetic rate (A), transpiration rate (E), and stomatal conductance (Gs), respectively, compared to control plants. Under 5 mg L-1 HDPE and PET, rice seedlings without GSH treatment responded in terms of increase in total soluble sugar, total free amino acid, glutathione, glutathione disulfide contents, while total soluble protein and ascorbic acid contents decreased significantly, compared with control plants. Corrleation matrix revealed positive relationship between GSH and improvement in studied attributes. Moreover, exogenous GSH improved rice growth and productivity to counter the negative role of MPs. This unique study examined the effects of GSH on rice plants growing in MP-contaminated media and revealed how exogenous GSH helps plants survive MP-stress.


Assuntos
Antioxidantes , Oryza , Antioxidantes/metabolismo , Oryza/metabolismo , Microplásticos/metabolismo , Plásticos/metabolismo , Polietileno/metabolismo , Glutationa/metabolismo , Plântula , Raízes de Plantas/metabolismo
9.
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.

10.
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
11.
Chemosphere ; 322: 138151, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-36804633

RESUMO

Dyes contaminated water has caused various environmental and health impacts in developing countries especially Pakistan due to different industrial activities. This issue has been addressed in present study by fabricating biocompatible ionic liquid (IL) membranes for the remediation of Crystal violet (CV) dye from contaminated water. Novel ammonium-based IL such as Triethyl dimethyl ammonium sulfate ([C3A][C2H6]SO4); (A2) was synthesized and further functionalized with hydroxyapatite (HAp; extracted from refused fish scales) resulting in the formation of HA2. Furthermore, A2 and HA2 were then used to fabricate the cellulose acetate (CA) based membranes with different volume ratios. The physicochemical properties of membranes-based composite materials were investigated using FTIR, XRD, and TGA and used for the adsorption of CV in the closed batch study. In results, CA-HA2 (1:2) showed higher efficiency of 98% for CV reduction, after the contact time of 90 min. Kinetic studies showed that the adsorption of CV followed the pseudo-second-order kinetic model for all adsorbents. The antibacterial properties of the synthesized membrane were investigated against gram-positive strain, S. aureus and CA-A2 (1:1) showed better antibacterial properties against S. aureus. The developed membrane is sustainable to be used for the adsorption of CV and against bacteria.


Assuntos
Compostos de Amônio , Líquidos Iônicos , Poluentes Químicos da Água , Líquidos Iônicos/química , Cinética , Staphylococcus aureus , Corantes/química , Violeta Genciana , Água , Antibacterianos/farmacologia , Poluição da Água , Adsorção , Poluentes Químicos da Água/química
12.
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
13.
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
14.
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
15.
Chemosphere ; 309(Pt 1): 136613, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36183888

RESUMO

Pollution harms ecosystems and poses a serious threat to human health around the world through direct or indirect effects on air, water, and land. The importance of remediating effluents is paramount to reducing environmental concerns. CO2 emissions are removed efficiently and efficaciously with mixed matrix membranes (MMMs), which are viable replacements for less efficient and costly membranes. In the field of membrane technology, MMMs are advancing rapidly due to their good separation properties. The selection of filler to be incorporated in mixed matrix membranes is very considered very important. There has been considerable interest in MOFs, carbon nanotubes (CNTs), ionic liquids (ILs), carbon molecular sieves (CMSs), sulfonated fillers (SFs), and layered silicates (LSs) as inorganic fillers for improving the properties of mixed matrix membranes. These fillers promise superb results and long durability for mixed matrix membranes based on them. The purpose of this review is to review different fillers used in MMMs for improving separation properties, limitations, and thermomechanical properties for environmental control and remediation.


Assuntos
Recuperação e Remediação Ambiental , Líquidos Iônicos , Nanotubos de Carbono , Humanos , Dióxido de Carbono , Ecossistema , Água
16.
Polymers (Basel) ; 14(17)2022 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-36080776

RESUMO

The search for renewable resources that can replace petroleum products is not only nerve-wracking, but also perplexing, as there is an abundance of plants that have yet to be explored. In this project, virgin castor oil was converted to polyol in two steps: epoxidation and hydroxylation. The resulting polyol was used to synthesize two series of water-borne polyurethane dispersions (WPUDs). The effects of the diisocyanates on the final product were evaluated. Isophorone diisocyanate (IPDI) and dicyclohexylmethane-4,4'-diisocyanate (H12MDI) were used as the hard segment (HS) up to 72 wt%, along with 1-4 butanediol (BD) as the chain extender, for the dispersions. Fourier transform infrared spectroscopy (FTIR) confirmed the bonds required for the synthesis of the dispersions. Thermogravimetric analysis (TGA) showed the multistep degradation for both series: maximum degradation took place at 500 °C for IPDI and 600 °C for H12MDI-based series. Scanning electron microscopy (SEM) showed phase-segmented morphology. Hemolytic activity was observed at biologically safe levels of up to 7.5% for H12MDI-based series. Inhibition of biofilm formation showed comparable results against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus): up to 46%. The results were also confirmed by phase contrast microscopy.

17.
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
18.
Chemosphere ; 306: 135580, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-35810864

RESUMO

The presence of 1,4 dioxane in wastewater is associated with severe health and environmental issues. The removal of this toxic contaminant from the industrial effluents prior to final disposal is necessary. The study comprehensively evaluates the performance of sequential batch membrane bioreactor (MBR) for treating wastewater laden with 1,4 dioxane. Acetate was supplemented to the wastewater feed as an electron donor for enhancing and stimulating the microbial growing activities towards the degradation of 1,4 dioxane. The removal efficiency of 1,4 dioxane was maximized to 87.5 ± 6.8% using an acetate to dioxane (A/D) ratio of 4.0, which was substantially dropped to 31.06 ± 3.7% without acetate addition. Ethylene glycol, glyoxylic acid, glycolic acid, and oxalic acid were the main metabolites of 1,4 dioxane biodegradation using mixed culture bacteria. The 1,4 dioxane degrading bacteria, particularly the genus of Acinetobacter, were promoted to 92% at the A/D ratio of 4.0. This condition encouraged as well the increase of the main 1,4 dioxane degraders, i.e., Xanthomonadales (12.5%) and Pseudomonadales (9.1%). However, 50% of the Sphingobacteriales and 82.5% of Planctomycetes were reduced due to the inhibition effect of the 1,4 dioxane contaminate. Similarly, the relative abundance of Firmicutes, Verrucomicrobia, Chlamydiae, Actinobacteria, Chloroflexi, and Nitrospirae was reduced in the MBR at the A/D ratio of 4.0. The results derived from the microbial analysis and metabolites detection at different A/D ratios indicated that acetate supplementation (as an electron donor) maintained an essential role in encouraging the microorganisms to produce the monooxygenase enzymes responsible for the biodegradation process. Economic feasibility of such a MBR system showed that for a designed flow rate of 30 m3∙d-1, the payback period from reusing the treated wastewater would reach 6.6 yr. The results strongly recommend the utilization of mixed culture bacteria growing on acetate for removing 1,4 dioxane from the wastewater industry, achieving dual environmental and economic benefits.


Assuntos
Elétrons , Águas Residuárias , Bactérias/metabolismo , Biodegradação Ambiental , Reatores Biológicos , Dioxanos/metabolismo
19.
Chemosphere ; 307(Pt 1): 135633, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-35810866

RESUMO

Cadmium (Cd) and Lead (Pb) from industrial wastewater can bioaccumulate in the living organisms of water bodies, posing serious threats to human health. Therefore, efficient remediation of heavy metal ions of Cd (II) and Pb (II) in aqueous media is necessary for public health and environmental sustainability. In the present study, water stable Zirconium (Zr) based metal organic frameworks (MOFs) with SO3H functionalization were synthesized by solvothermal method and used first time for the adsorption of Cd (II) and Pb (II). Synthesis of UiO-66-SO3H, nano-sized (<100 nm) MOFs, was confirmed by FTIR, XRD, FESEM and BET. Effects of contact time, pH and temperature were investigated for adsorption of Cd (II) and Pb (II) onto SO3H-functionalized Zr-MOFs. The UiO-66-SO3H displayed notable rejections of 97% and 88% towards Cd (II) and Pb (II), respectively, after 160 min at 25 °C and pH (6) with an initial concentration of 1000 mg/L. Adsorption capacities of Cd (II) and Pb (II) were achieved as 194.9154 (mg/g) and 176.6879 (mg/g), respectively, at an initial concentration of 1000 mg/L. The Pseudo second-order kinetic model fitted well with linear regression (R2) of value 1. The mechanism was confirmed mainly as a chemisorption and coordination interaction between sulfone group (-SO3H) and metal ions Cd (IIa) and Pb (II). These results may support effective adsorption and can be studied further to enrich and recycle other heavy metals from wastewater.


Assuntos
Estruturas Metalorgânicas , Metais Pesados , Poluentes Químicos da Água , Adsorção , Cádmio/análise , Humanos , Concentração de Íons de Hidrogênio , Íons , Cinética , Chumbo , Metais Pesados/análise , Ácidos Ftálicos , Sulfonas , Águas Residuárias/química , Água , Poluentes Químicos da Água/análise , Zircônio
20.
Chemosphere ; 304: 135236, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-35688204

RESUMO

The development of polymeric membranes from polymers such as polystyrene (PS), polyvinylchloride (PVC), and their associated family has brought great momentum to the environmental remediation universe, mainly due to their surprisingly diverse and multi-purpose nature. Their usage has surged 20 times in the last half-century and is likely to double again in the coming 20 years. As a result, the polymeric materials economy and commercialization of research become increasingly important as a possible option for a country to boost prosperity while decreasing its reliance on limited raw resources and mitigating negative externalities. This transformation demands a systematic strategy, which involves progress beyond improving the existing models and building new avenues for collaboration. In this work, a sophisticated system, i.e., product space model (PSM), has been presented, explicitly appraising the opportunity space for United Kingdom, Italy, Poland, India, Canada, Indonesia, Brazil, Saudi Arabia, Russia and Colombia for their potential future industrialization and commercialization of polymeric membranes for environmental remediation. The results revealed that UK, Italy, Poland and India are at advantageous positions owing to their close proximity of (distance<2) and their placement in Parsimonious policy, which is the most desired quadrant of Policy Map of PSM, Canada and Indonesia have medium level opportunities, while Russia and Saudi Arabia have opportunities with more challenges to fully exploit the unexploited polymers products in terms of membranes for environmental remediation and prove favorable for export diversification, sustainable economic growth, and commercialization.


Assuntos
Recuperação e Remediação Ambiental , Canadá , Desenvolvimento Econômico , Polímeros , Simulação de Ambiente Espacial
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