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1.
ACS Omega ; 9(13): 15052-15064, 2024 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-38585093

RESUMO

Drilling fluids are an essential component of drilling operations in the oil and gas industry. Nanotechnology is being used to develop advanced drilling fluid additives. This study looked at the viability of synthesizing SiO2/g-C3N4 hybrid extending the Stober process followed by its addition in different concentrations to water-based drilling fluids and studying impact on the rheological and fluid loss properties of the fluids. The synthesized hybrid was analyzed using XRD, SEM, TGA, and FTIR. Subsequently, it was used to develop the water-based drilling mud formulations and subjected to measurements in accordance with API standard practices. The studies were carried out at various SiO2/g-C3N4 nanoparticle concentrations under before hot rolling (BHR) and after hot rolling (AHR) conditions. The outcomes demonstrated that the rheological and fluid loss properties were enhanced by the addition of SiO2/g-C3N4 nanoparticles, as it worked in synergy with other additives. Additionally, it was discovered that the nanoparticles improved the drilling fluid thermal stability. The experimental findings indicate a significant influence of SiO2/g-C3N4 nanoparticles on base fluid properties including rheology and fluid loss as the most remarkable, especially at higher temperatures. The significant improvements in yield point and 10 s gel strength were 55 and 42.8% under BHR and 216 and 140% under AHR conditions, respectively. Permeability plugging test (PPT) fluid loss was reduced by 69.6 and 87.2% under BHR and AHR conditions, respectively, when 0.5 lb/bbl nanoparticles were used in formulations. As a result, SiO2/g-C3N4 nanomaterial has the potential to be used as drilling fluid additive in water-based drilling fluids.

2.
RSC Adv ; 14(18): 12742-12753, 2024 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-38645523

RESUMO

Environmental degradation and energy constraint are important risks to long-term sustainability in the modern world. Water splitting is a vital approach for environmentally friendly and sustainable energy storage, providing a clean way to produce hydrogen without pollutants. Preparing a catalyst that is active, bifunctional, and durable for water splitting is a difficult task. We addressed the difficulty by creating a bifunctional heterogeneous catalyst, MoS2/rGO, with an ideal weight percentage of 5 wt% by a hydrothermal process. The optimized sample showed exceptional electrocatalytic activity, requiring an overpotential of 242 mV and 120 mV to achieve a current density of 10 mA cm-2 in the Hydrogen Evolution Reaction (HER) and Oxygen Evolution Reaction (OER). Furthermore, our synthesized catalyst was validated for its exceptional water-splitting capacity, with the optimized sample showing low Tafel slope values of 59 mV dec-1 for HER and 171 mV dec-1 for OER. The significant OER and HER activity seen in the 5 wt% MoS2/rGO hybrid, compared to other hybrids, is due to the many catalytic active sites that aid in charge and electron transport, as well as the synergistic interaction between MoS2 and rGO.

3.
Chemosphere ; 355: 141775, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38522676

RESUMO

The catalyst's composition and rationally designed structure is significantly interlinked with its performance for wastewater remediation. Here, a novel hollow cobalt phosphides/carbon (HCoP/C) as an efficient catalyst for activating peroxymonosulfate (PMS) was prepared. The ZIF-67 was synthesized first, followed by phytic acid (PA) etching and then heat treatment was used to get HCoP/C. The PA was used as an etching agent and a source of phosphorus to prepare HCoP/C. To analyze catalytic performance, another solid cobalt phosphides/carbon (SCoP/C) catalyst was prepared for comparison. In contrast to SCoP/C, the HCoP/C exhibited higher catalytic efficiency when used to activate PMS to degrade Bisphenol A (BPA). The results showed that about 98 % of targeted pollutant BPA was removed from the system in 6 min with a rate constant of 0.78 min-1, which was 4 times higher than the solid structure catalyst. The higher catalytic performance of HCoP/C is attributed to its hollow structure. In the study, other parameters such as BPA concentration, temperature, pH, and different catalyst amount were also tested. Moreover, the electron paramagnetic resonance (EPR) and radical quenching analysis confirmed that sulfate radicals were dominant in the HCoP/C/PMS system.


Assuntos
Compostos Benzidrílicos , Carbono , Estruturas Metalorgânicas , Fenóis , Carbono/química , Ácido Fítico , Peróxidos/química , Cobalto/química
4.
PLoS One ; 19(3): e0300757, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38530820

RESUMO

The versatile uses of Copper(II) Fluoride (CuF2) are well known; these include its usage as a precursor in chemical synthesis as well as its contribution to the creation of sophisticated materials and electronics. There are interesting opportunities to study the interactions between these elements because of their unique crystal structure, which contains copper ions and fluoride anions. Its potential in optoelectronic devices and conductive qualities also make it a viable material for next-generation technologies. To better understand the structural properties of CuF2 and how they affect its entropy, we present new Zagreb indices in this study and use them to calculate entropy measures. We also build a regression model to clarify the relationship between the calculated indices and entropy levels. The findings of our investigation offer significant understanding regarding the ability of the suggested Zagreb indices to extract meaningful content and their correlation with entropy in the context of CuF2. This information is important for understanding CuF2 alloys and for exploring related complex materials.


Assuntos
Cobre , Fluoretos , Cobre/química , Entropia
5.
Chem Rec ; 24(3): e202300330, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38372409

RESUMO

Electrochemical water splitting for sustainable hydrogen and oxygen production have shown enormous potentials. However, this method needs low-cost and highly active catalysts. Traditional nano catalysts, while effective, have limits since their active sites are mostly restricted to the surface and edges, leaving interior surfaces unexposed in redox reactions. Single atom catalysts (SACs), which take advantage of high atom utilization and quantum size effects, have recently become appealing electrocatalysts. Strong interaction between active sites and support in SACs have considerably improved the catalytic efficiency and long-term stability, outperforming their nano-counterparts. This review's first section examines the Hydrogen Evolution Reaction (HER) and the Oxygen Evolution Reaction (OER). In the next section, SACs are categorized as noble metal, non-noble metal, and bimetallic synergistic SACs. In addition, this review emphasizes developing methodologies for effective SAC design, such as mass loading optimization, electrical structure modulation, and the critical role of support materials. Finally, Carbon-based materials and metal oxides are being explored as possible supports for SACs. Importantly, for the first time, this review opens a discussion on waste-derived supports for single atom catalysts used in electrochemical reactions, providing a cost-effective dimension to this vibrant research field. The well-known design techniques discussed here may help in development of electrocatalysts for effective water splitting.

6.
Environ Sci Pollut Res Int ; 30(50): 109453-109468, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37924166

RESUMO

Mixed matrix membranes (MMMs) containing metal-organic frameworks (MOFs) have been an emerging and promising membrane technology to contribute to different gas separation applications including carbon dioxide (CO2) and oxygen (O2) separation, because of their large surface areas and distinctive gas adsorption features. In this work, the fabrication process of Polydimethylsiloxane (PDMS)-based MMMs was reported, in which 0.5 to 2 wt.% of each type of (Cu, Ni)-based MOF-74 variants were incorporated into a PDMS matrix in order to achieve high CO2/N2, O2/N2, and CO2/O2 separation efficiency. These MMMs and their nanofillers (MOF-74) were extensively characterized using scanning electron microscopy (SEM) along with Energy Dispersive X-Ray (EDX) mapping, X-ray Diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), a single gas permeation testing system, and an ultimate tensile strength testing (UTS) unit in order to gain insight into their properties in relation to their gas separation performance. The 1 wt.% of both (Cu and Ni)-MOF-74@PDMS were selected as the most optimum MMMs due to their uniform morphology and enhanced tensile strength, which exhibited high CO2 permeabilities of 4432 Barrer (37.9% increase) and 4288 Barrer (33.5% increase), respectively. Furthermore, in the case of 1 wt.% Ni-MOF-74@PDMS, the CO2/N2, O2/N2, and CO2/O2 selectivities were also enhanced to 36.2 (141.6% increase), 3.2 (21.9% increase), and 11.25 (98.1% increase), respectively. While, in the case of 1 wt.% Cu-MOF-74@PDMS the CO2/N2 and O2/N2 selectivities showed an increment up-to 94.7 (531.5% increase) and 6.47 (145% increase), respectively, Whereas, at 0.5 wt.%, Cu-MOF-74@PDMS showed the best CO2/O2 selectivity of 25.26 (344.7% increase).


Assuntos
Dióxido de Carbono , Dimetilpolisiloxanos , Espectroscopia de Infravermelho com Transformada de Fourier , Adsorção , Oxigênio
7.
RSC Adv ; 13(36): 24973-24987, 2023 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-37614795

RESUMO

Designing of non-noble, cost-effective, sustainable catalysts for water splitting is essential for hydrogen production. In this research work, ZIF-67, g-C3N4, and their composite (1, 3, 5, 6, 8 wt% g-C3N4@ZIF-67) are synthesized, and various techniques, XRD, FTIR, SEM, EDX and BET are used to examine their morphological properties for electrochemical water-splitting. The linkage of ZIF-67 with g-C3N4 synergistically improves the electrochemical kinetics. An appropriate integration of g-C3N4 in ZIF-67 MOF improves the charge transfer between the electrode and electrolyte and makes it a suitable option for electrochemical applications. In alkaline media, the composite of ZIF-67 MOF with g-C3N4 over a Ni-foam exhibits a superior catalyst activity for water splitting application. Significantly, the 3 wt% g-C3N4@ZIF67 composite material reveals remarkable results with low overpotential values of -176 mV@10 mA cm-2, 152 mV@10 mA cm-2 for HER and OER. The catalyst remained stable for 24 h without distortion. The 3 wt% composite also shows a commendable performance for overall water-splitting with a voltage yield of 1.34 v@10 mA cm-2. The low contact angle (54.4°) proves the electrocatalyst's hydrophilic nature. The results of electrochemical water splitting illustrated that 3 wt% g-C3N4@ZIF-67 is an electrically conductive, stable, and hydrophilic-nature catalyst and is suggested to be a promising candidate for electrochemical water-splitting application.

8.
Chemosphere ; 340: 139721, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37541443

RESUMO

Development of membrane with improved carbon dioxide (CO2) gas separation capability is a significant challenge. However, the fabrication of membrane that efficiently separate and purification CO2-containing gases has been the focus of global attention. Cellulose Acetate (CA) has robust reinforcing characteristics when incorporated within a suitable polymer matrix. This work focus on the synthesis of novel mixed matrix membranes (MMMs) by introducing Graphene-grafted bimetallic MOFs in Cellulose Acetate polymer. The graphene-grafted bimetallic MOF (GG-BM MOFs) was prepared by a hydrothermal technique. Whereas, the solution casting approach used to fabricate membranes. The 1-5 wt% of GG-BM MOFs incorporated into the CA matrix. The mechanical, hydrophilicity and adsorption characteristics of fabricated MMMs were investigated. The crystallinity of MMM enhanced after the addition of GG-BM MOFs. In addition, the mechanical characteristics of MMMs were improved with the incorporation of GG-BM MOFs inside the polymer matrix. Maximum stress and strain was obtained for 2 wt% MMM (36.4 N/mm2 and 11% respectively). The CO2 adsorption performance was evaluated at 10 bar and 45 °C. The FTIR results represent insignificant bond shifting with the addition GG-BM MOFs at these conditions. The overall results showed that MMMs containing 2 wt% GG-BM MOFs have good adsorption properties for CO2 i.e 3.15 wt% of CO2. The MMMs have shown a decrease in the mechanical properties and CO2 adsorption at the higher GG-BM MOFs loading due to the presence of agglomeration which was confirmed through SEM. Thus, the addition of GG-BM MOFs in the CA matrix positively altered the physicochemical characteristics of the resulting MMMs, which could assist them in achieving remarkable CO2 adsorption at 2 wt%.


Assuntos
Dióxido de Carbono , Grafite , Adsorção , Gases , Polímeros
9.
Micromachines (Basel) ; 14(8)2023 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-37630069

RESUMO

The zeolitic imidazolate framework-67 (ZIF-67) adsorbent and its composites are known to effectively remove organic dyes from aqueous environments. Here, we report a unique crystalline MoS2@ZIF-67 nanocomposite adsorbent for the efficient removal of methyl orange (MO) dye from an aqueous medium. In situ synthetic techniques were used to fabricate a well-crystalline MoS2@ZIF-67 nanocomposite, which was then discovered to be a superior adsorbent to its constituents. The successful synthesis of the nanocomposite was confirmed using XRD, EDX, FTIR, and SEM. The MoS2@ZIF-67 nanocomposite exhibited faster adsorption kinetics and higher dye removal efficiency compared with its constituents. The adsorption kinetic data matched well with the pseudo-second-order model, which signifies that the MO adsorption on the nanocomposite is a chemically driven process. The Langmuir model successfully illustrated the MO dye adsorption on the nanocomposite through comparing the real data with adsorption isotherm models. However, it appears that the Freundlich adsorption isotherm model was also in competition with the Langmuir model. According to the acquired thermodynamics parameters, the adsorption of MO on the MoS2@ZIF-67 nanocomposite surface was determined to be spontaneous and exothermic. The findings of this research open an avenue for using the MoS2@ZIF-67 nanocomposite to efficiently remove organic dyes from wastewater efflux.

10.
Food Chem ; 429: 136841, 2023 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-37459709

RESUMO

Proteosomes (P) based on milk fat globule membrane's phospholipids (MPs), whey protein isolate (WPI) and sodium caseinate (CasNa) were developed by ultrasonication to encapsulate ß-carotene. Entirely milk-ingredients based proteosomes (WPI-MPs-P and CasNa-MPs-P) revealed homogenous distribution with size diameters < 250 nm. WPI-MPs-P depicted positive ζ-potential values (+15.7 ± 0.5 mV), while CasNa-MPs-P demonstrated negative (-32.5 ± 3.4 mV) values of surface charge, respectively and hydrophilic nature of proteosomes was observed by measuring contact-angle (θ). AFM and SEM exhibited spherical to oval and slightly irregular morphology of nanocarriers. For various concentrations of ß-carotene, the highest encapsulation efficiency of ß-carotene was 90 ± 0.2% and 92 ± 0.8% in WPI-MPs-P and CasNa-MPs-P respectively. FTIR analyses confirmed the hydrophobic and electrostatic interactions-based encapsulation of ß-carotene. Beneficial antioxidant-potential of ß-carotene was retained after its encapsulation in the proteosomes. Proteosomes increased the digestive-stability (>50%) and bioaccessibility (>85%) of ß-carotene. Thus, milk-ingredients based proteosomes offer a novel-strategy to develop functional dairy products to overcome widespread vitamin-A-deficiency.


Assuntos
Fosfolipídeos , beta Caroteno , beta Caroteno/química , Emulsões/química , Proteínas do Soro do Leite/química , Caseínas/química , Proteínas do Leite/química
11.
Int J Biol Macromol ; 242(Pt 2): 124777, 2023 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-37169055

RESUMO

Surface attributes of nanocarriers are crucial to determine their fate in the gastrointestinal (GI) tract. Herein, we have functionalized chitosan with biochemical moieties including rhamnolipid (RL), curcumin (Cur) and mannose (M). FTIR spectra of functionalized chitosan nanocarriers (FCNCs) demonstrated successful conjugation of M, Cur and RL. The functional moieties influenced the entrapment of model drug i.e., coumarin-6 (C6) in FCNCs with payload-hosting and non-leaching behavior i.e., >91 ± 2.5 % with negligible cumulative release of <2 % for 5 h in KREB, which was further verified in the simulated gastric and intestinal fluids. Consequently, substantial difference in the size and zeta potential was observed for FCNCs with different biochemical moieties. Scanning electron microscopy and atomic force microscopy of FCNCs displayed well-dispersed and spherical morphology. In addition, in vitro cytotoxicity results of FCNCs confirmed their hemocompatibility. In the ex-vivo rat intestinal models, FCNCs displayed a time-dependent-phenomenon in cellular-uptake and adherence. However, apparent-permeability-coefficient and flux values were in the order of C6-RL-FCNCs > C6-M-FCNCs > C6-Cur-FCNCs = C6-CNCs > Free-C6. Furthermore, the transepithelial electrical resistance revealed the FCNCs mediated recovery of membrane-integrity with reversible tight junctions opening. Thus, FCNCs have the potential to overcome the poor solubility and/or permeability issues of active pharmaceutical ingredients and transform the impact of functionalized-nanomedicines in the biomedical industry.


Assuntos
Quitosana , Curcumina , Nanopartículas , Ratos , Animais , Portadores de Fármacos , Curcumina/farmacologia , Solubilidade , Permeabilidade , Tamanho da Partícula
12.
Cureus ; 15(2): e35187, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36960250

RESUMO

Moebius syndrome (MBS) is a rare congenital cranial nerve disorder characterized by unilateral, bilateral symmetrical, or asymmetrical facial (VII) and abducens (VI) nerve palsies. Genetics and rhombencephalon vascular disturbances from intrauterine environmental exposures have been attributed to its development. It can present with various orofacial abnormalities. Although the diagnosis is purely clinical, certain characteristic features are present in the brain's images. With no cure, it is essential to devise management on a personalized basis. We discuss etiology, presentation, diagnostic approaches, and effective management in the existing literature. This comprehensive review examines the clinic-pathological aspects of Moebius syndrome. The authors employed the PUBMED base index to identify pertinent literature and reference it according to research keywords. Findings suggest the most popular etiology is the theory of intrauterine vascular disruption to the brainstem during embryogenesis, followed by the genetic hypothesis. Intrauterine environmental exposures have been implicated as potential risk factors. Facial and abducens nerve palsies are the most common presenting features. However, clinical manifestations of lower cranial nerves (IX, X, XI, XII) may be present with orthopedic anomalies and intellectual deficiencies. The diagnosis is clinical with minimal defined diagnostic criteria. Characteristic radiological manifestations involving the brainstem and cerebellum can be observed in imaging studies. With no definitive treatment options, a multidisciplinary approach is employed to provide supportive care. Despite radiological manifestations, Moebius syndrome is diagnosed clinically. Although incurable, a multidisciplinary approach, with personalized rehabilitative measures, can manage physical and psychological deficits; however, standard guidelines need to be established.

13.
Chemosphere ; 326: 138448, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-36940825

RESUMO

The substantial quantity of Cr(VI) contaminants in the aqueous atmosphere is a major environmental fear that cannot be overlooked. For the first time, MXene and chitosan-coated polyurethane foam have been employed for wastewater treatment, including heavy metal ions (Cr (VI)) through a fixed-bed column study. It is also the most inexpensive, lightweight, and globally friendly material tested. The Mxene and chitosan-coated polyurethane foam hybrid materials were thoroughly investigated using FTIR (Fourier transform infrared), SEM (scanning electron microscope), XPS (X-ray photoelectron spectroscopy) and XRD (X-ray diffraction). The presence of the rough surface and the pore creation in the Mxene- MX3@CS3@PUF should rise its surface area, which is useful to interact the surface-active assembly of MX3@CS3@PUF and the Cr(VI) contaminations in the aqueous solution. With the help of the ion exchange mechanism and electrostatic contact, negatively charged MXene hexavalent ions were being adsorbed on the surface. MXene and chitosan have been coated on PUF foam in the form of three different layers, which shows the highest adsorption capacity, where up to ∼70% Cr (VI) was removed in the first 10 min and more than 60% elimination after 3 h when the metal ion concentration was 20 ppm. The electrostatic interaction between the negative charge MXene and the positive charge chitosan on the surface of PUF, which was absent in MX@PUF, is accountable for the high removal efficiency. This was done through a sequence of fixed-bed column studies, which took place in the continuous flowing of wastewater.


Assuntos
Quitosana , Poluentes Químicos da Água , Águas Residuárias , Quitosana/química , Poluentes Químicos da Água/análise , Cromo/química , Água/química , Íons , Adsorção , Concentração de Íons de Hidrogênio , Cinética , Espectroscopia de Infravermelho com Transformada de Fourier
14.
RSC Adv ; 13(2): 1137-1161, 2023 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-36686941

RESUMO

Worldwide demand for oil, coal, and natural gas has increased recently because of odd weather patterns and economies recovering from the pandemic. By using these fuels at an astonishing rate, their reserves are running low with each passing decade. Increased reliance on these sources is contributing significantly to both global warming and power shortage problems. It is vital to highlight and focus on using renewable energy sources for power production and storage. This review aims to discuss one of the cutting-edge technologies, metal-air batteries, which are currently being researched for energy storage applications. A battery that employs an external cathode of ambient air and an anode constructed of pure metal in which an electrolyte can be aqueous or aprotic electrolyte is termed as a metal-air battery (MAB). Due to their reportedly higher energy density, MABs are frequently hailed as the electrochemical energy storage of the future for applications like grid storage or electric car energy storage. The demand of the upcoming energy storage technologies can be satisfied by these MABs. The usage of metal-organic frameworks (MOFs) in metal-air batteries as a bi-functional electrocatalyst has been widely studied in the last decade. Metal ions or arrays bound to organic ligands to create one, two, or three-dimensional structures make up the family of molecules known as MOFs. They are a subclass of coordination polymers; metal nodes and organic linkers form different classes of these porous materials. Because of their modular design, they offer excellent synthetic tunability, enabling precise chemical and structural control that is highly desirable in electrode materials of MABs.

15.
Environ Res ; 214(Pt 1): 113793, 2022 11.
Artigo em Inglês | MEDLINE | ID: mdl-35780854

RESUMO

Biogas up-gradation is a useful method to control CO2 emission and enhance the green process. The demand for renewable sources is increasing due to the depletion of fossil fuels. Thin-film nanocomposites functionalized with tunable molecular-sieving nanomaterials have been employed to tailor membranes with enhanced permeability and selectivity. In this work, the cellulose nanocrystals as a filler in the polyvinyl alcohol matrix are prepared to achieve high-performance facilitated transport membranes for CO2 capture. Considering the mechanical stability, interfacial compatibility and high moisture uptake of the filler, the main objective of this work was to develop a novel aminated CNC (Am-CNC)/polyvinyl alcohol nanocomposite membrane for biogas upgrading. The hydroxyl groups (O-H) on the reducing end of the cellulose nanocrystals were replaced by amino groups (N-H2). It was discovered through Scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) that adding Am-CNCs in PVA membranes shows an increment in the CO2 removal and effectively upgrades the biogas. The effect of change in concentration of Am-CNC and feed pressure was investigated. The results showed that with increasing Am-CNC concentration up to 1.5 wt%, the thickness of the selective membrane layer increased from 0.95 to 1.9 µm with a decrease in the moisture uptake from 85.04 to 58.84%. However, the best CO2 permeance and selectivity were achieved at 0.306 m3/m2.bar.h (STP) and 33.55, respectively. Furthermore, there was a more than two-fold decrease in CO2 permeance and a 27% decrease in the CO2/CH4 selectivity when the feed pressure increased from 5 to 15 bar. It was revealed that PVA/Am-CNC membrane is high performing for the biogas upgradation.


Assuntos
Nanocompostos , Nanopartículas , Biocombustíveis , Dióxido de Carbono , Celulose , Álcool de Polivinil
16.
Chemosphere ; 307(Pt 1): 135736, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-35850224

RESUMO

Membrane-based gas separation has a great potential for reducing environmentally hazardous carbon dioxide (CO2) gas. The polymeric membranes developed for CO2 capturing have some limitations in their selectivity and permeability. There is a need to overcome these issues and developed such membranes having high-performance CO2 capture with cost-effectiveness. The present study aimed to synthesize mixed matrix membranes (MMMs) having improved properties CO2 adsorption performance and stability than that of pure polymer. Further, the effect on CO2 adsorption by increasing the filler concentration in MMMs was investigated. The MMMs were synthesized by incorporating (1-5 wt%) Cu-MOF-GO composites as filler into cellulose-acetate (CA) polymer matrix by adopting the solution casting method. The performance of MMMs was studied by changing the Cu-MOF-GO composite concentration (1-5 wt%) in the polymer matrix at 45 °C up to 15 bar. Morphological analysis by using SEM confirms that by increasing the concentration of Cu-MOF-GO more than 3% will result in their agglomeration in MMM. The successful incorporation of MOF within the polymer matrix of MMMs was confirmed through the presence of functional groups using FTIR and Raman spectroscopy. XRD analysis revealed that pure CA changes its semi-crystalline behaviour into crystalline by the addition of Cu-MOF-GO. The maximum tensile stress and strain rate of MMMs was 45.1 N/mm2 and 12.8%. In addition, with an increase in (4-5 wt%) Cu-MOF-GO concentration the hydrophilicity of MMMs decreases. The maximum uptake rate of CO2 was 1.79 mmol/g and 7.98 wt% at 15 bar. The adsorption results conclude that Cu-MOF-GO composite and CA-based MMM can be effective for CO2 capture.


Assuntos
Dióxido de Carbono , Recuperação e Remediação Ambiental , Acetatos , Dióxido de Carbono/química , Celulose/análogos & derivados , Polímeros/química
17.
Food Bioproc Tech ; 15(6): 1284-1298, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35495090

RESUMO

To meet the demands for more effective and ecofriendly food packaging strategies, the potential of nisin-loaded rhamnolipid functionalized nanofillers (rhamnosomes) has been explored after embedding in hydroxypropyl-methylcellulose (HPMC) and κ-carrageenan (κ-CR)-based packaging films. It was observed that intrinsically active rhamnosomes based nanofillers greatly improved the mechanical and optical properties of nano-active packaging (NAP) films. Incorporation of rhamnosomes resulted in higher tensile strength (5.16 ± 0.06 MPa), Young's modulus (2777 ± 0.77 MPa), and elongation (2.58 ± 0.03%) for NAP than active packaging containing free nisin (2.96 ± 0.03 MPa, 1107 ± 0.67 MPa, 1.48 ± 0.06%, respectively). NAP demonstrated a homogenous distribution of nanofillers in the biopolymer matrix as elucidated by scanning electron microscopy (SEM). Thermogravimetric analysis (TGA) confirmed that NAP prepared with nisin-loaded rhamnosomes was thermally stable even above 200 °C. Differential scanning calorimetry (DSC) analyses revealed that addition of nisin in nanofillers resulted in a slight increase in Tg (108.40 °C), indicating thermal stability of NAP. Fourier transform infrared spectroscopy (FTIR) revealed slight shift in all characteristic bands of nano-active packaging, which indicated the embedding of rhamnosomes inside the polymer network without any chemical interaction. Finally, when tested on chicken breast filets and cheese slices under refrigerated storage conditions, NAP demonstrated broad-spectrum antimicrobial activity (up to 4.5 log unit reduction) and inhibited the growth of Listeria monocytogenes, Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli. These results suggest that HPMC and κ-CR-based NAP containing functionalized nanofillers can serve as an innovative packaging material for the food industry to improve the safety, quality, and shelf-life of dairy and meat products. Supplementary Information: The online version contains supplementary material available at 10.1007/s11947-022-02815-2.

18.
ACS Omega ; 7(16): 13403-13435, 2022 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-35559169

RESUMO

At present, plastic waste accumulation has been observed as one of the most alarming environmental challenges, affecting all forms of life, economy, and natural ecosystems, worldwide. The overproduction of plastic materials is mainly due to human population explosion as well as extraordinary proliferation in the global economy accompanied by global productivity. Under this threat, the development of benign and green alternative solutions instead of traditional disposal methods such as conversion of plastic waste materials into cherished carbonaceous nanomaterials such as carbon nanotubes (CNTs), carbon quantum dots (CQDs), graphene, activated carbon, and porous carbon is of utmost importance. This critical review thoroughly summarizes the different types of daily used plastics, their types, properties, ways of accumulation and their effect on the environment and human health, treatment of waste materials, conversion of waste materials into carbon-based compounds through different synthetic schemes, and their utilization in energy storage devices particularly in supercapacitors, as well as future perspectives. The main purpose of this review is to help the targeted audience to design their futuristic study in this desired field by providing information about the work done in the past few years.

19.
Int J Biol Macromol ; 204: 540-554, 2022 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-35157901

RESUMO

With the apparent stagnation in the antibiotic discovery and the propagation of multidrug resistance, Helicobacter pylori associated gastric infections are hard to eradicate. In pursuance of alternative medicines, in this study, covalent modification of chitosan (CS) polymer with curcumin (Cur) was accomplished. Proton Nuclear Magnetic Resonance and Fourier Transform Infrared spectroscopy elucidated the covalent interaction between Cur and CS with characteristic peak of imine functional group (C=N). Scanning Electron Microscopy provided visual proof for surface topology, while size and zeta potential values further affirmed the development of curcumin functionalized chitosan nanosystems (Cur-FCNS). The complexation efficiency of CS with Cur was found as 70 ± 3% at an optimal ratio of 5:1 for CS and Cur, respectively. Cur-FCNS developed with ionic gelation and ultrasonication method demonstrated synergistic anti-H. pylori activity in growth-kinetics and anti-biofilm assays, which was superior to free Cur and even chitosan nanosystems. Under simulated gastric conditions, Cur-FCNS revealed cumulative-release of only 16 ± 0.8% till 40 h, which indicated its improved stability to interact with H. pylori. In silico findings affirmed high binding affinity of Cur-FCNS with multiple bacterial virulence factors. Thus, our results affirmed the exceptional potential of Cur-FCNS as next-generation alternative-medicine to treat resistant H. pylori.


Assuntos
Quitosana , Curcumina , Nanopartículas , Antibacterianos/farmacologia , Quitosana/química , Curcumina/química , Curcumina/farmacologia , Nanopartículas/química , Espectroscopia de Infravermelho com Transformada de Fourier
20.
RSC Adv ; 13(1): 652-664, 2022 Dec 19.
Artigo em Inglês | MEDLINE | ID: mdl-36605659

RESUMO

High-efficiency, sustainable, non-precious metal-based electrocatalysts with bifunctional catalytic activity for the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER) are essential for metal-air batteries. In this research, a bifunctional electrocatalyst is developed by synthesizing a novel nanoporous vanadium oxide/carbon composite (NVC-900) through pyrolysis of a highly efficient vanadium metal-organic framework, MIL-101 (V). The fabrication process was conveniently carried out by pyrolyzing the synthesized MIL-101 (V) at 900 °C, producing vanadium oxide nanoparticles embedded in the extensively distributed pores of the carbon network. The evenly distributed nanopores substantially improve the performance of the efficient electrocatalyst for both the oxygen reduction reaction and oxygen evolution reactions (ORR/OER) by increasing surface area and facilitating access to stable catalytic active sites. The unique structure was characterized by powder X-ray diffraction (XRD) and scanning electron microscopy (SEM). For oxygen reduction reaction (ORR), the electrocatalyst established a promising limiting current density (J L) of 5.2 mA cm-2 at 1600 rpm at an onset potential of 1.18 V and a half-wave potential of 0.82 V, and for OER, a current density of 10 mA cm-2 was delivered at a potential of 1.48 V. In comparison to 10% Pt/C, the synthesized bifunctional electrocatalyst being almost equally active towards bifunctional activity, showed much better long-term cyclic stability. The one-step thermal pyrolysis strategy to synthesize the nanoporous functional material and the proposed electrocatalytic material's long-term bifunctional activity and durability make it an ideal fit for next-generation portable green metal-air batteries.

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