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1.
Small ; 20(26): e2310112, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38221688

RESUMO

The development of effective oxygen evolution reaction (OER) and urea oxidation reaction (UOR) on heterostructure electrocatalysts with specific interfaces and characteristics provides a distinctive character. In this study, heterostructure nanocubes (NCs) comprising inner cobalt oxysulfide (CoOS) NCs and outer CoFe (CF) layered double hydroxide (LDH) are developed using a hydrothermal methodology. During the sulfidation process, the divalent sulfur ions (S2-) are released from the breakdown of the sulfur source and react with the Co-precursors on the surface leading to the transformation of CoOH nanorods into CoOS nanocubes. Further, X-ray photoelectron spectroscopy (XPS) and X-ray absorption spectroscopy (XAS) analyses reveal that the interactions at the interface of the CF@CoOS NCs significantly altered the electronic structure, thus enhancing the electrocatalytic performance. The optimal catalysts exhibited effective OER and UOR activities, the attained potentials are 1.51 and 1.36 V. This remarkable performance is attributable to the induction of electron transfer from the CoFe LDH to CoOS, which reduces the energy barrier of the intermediates for the OER and UOR. Furthermore, an alkaline water and urea two-cell electrolyzer assembled using CF@CoOS-2 NCs and Pt/C as the anode and cathode requires a cell voltage of 1.63 and 1.56 V along with a durability performance.

2.
J Fluoresc ; 2024 Jul 11.
Artigo em Inglês | MEDLINE | ID: mdl-38990455

RESUMO

This review provides a thorough examination of small molecule-based fluorescence chemosensors tailored for bioimaging applications, showcasing their unique ability to visualize biological processes with exceptional sensitivity and selectivity. It explores recent advancements, methodologies, and applications in this domain, focusing on various designs rooted in anthracene, benzothiazole, naphthalene, quinoline, and Schiff base. Structural modifications and molecular engineering strategies are emphasized for enhancing sensor performance, including heightened sensitivity, selectivity, and biocompatibility. Additionally, the review offers valuable insights into the ongoing development and utilization of these chemosensors, addressing current challenges and charting future directions in this rapidly evolving field.

3.
Molecules ; 29(12)2024 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-38930919

RESUMO

The sustainable catalytic efficacy of transition metal oxides (TMO) and rare earth element-based oxides positions them as pivotal materials for effectively treating contaminated wastewater. This study successfully synthesized a series of Ce@MnO2 photocatalysts using a straightforward hydrothermal method. These photocatalysts were thoroughly characterized for their optical properties, structural morphology, and phase purity. Among the synthesized materials, the Ce@MnO2 (40:60) exhibited the highest photocatalytic activity for the degradation of Acebutolol (ACB), achieving a remarkable degradation efficiency of 92.71% within 90 min under visible light irradiation. This superior performance is attributed to the increased presence of active species and the efficient separation of photogenerated carriers. Additionally, the photocatalytic reaction mechanism was elucidated, highlighting the catalyst's surface charge properties which significantly enhanced performance in a solution with pH 8. The outstanding photo-response in the visible spectrum renders this method not only cost-effective but also environmentally benign, presenting a promising approach for large-scale water purification.

4.
Environ Geochem Health ; 46(8): 302, 2024 Jul 11.
Artigo em Inglês | MEDLINE | ID: mdl-38990227

RESUMO

In this study, a highly efficient CoFe2O4-anchored g-C3N4 nanocomposite with Z-scheme photocatalyst was developed by facile calcination and hydrothermal technique. To evaluate the crystalline structure, sample surface morphology, elemental compositions, and charge conductivity of the as-synthesized catalysts by various characterization techniques. The high interfacial contact of CoFe2O4 nanoparticles (NPs) with g-C3N4 nanosheets reduced the optical bandgap from 2.67 to 2.5 eV, which improved the charge carrier separation and transfer. The photo-degradation of methylene blue (MB) and rhodamine B (Rh B) aqueous pollutant suspension under visible-light influence was used to investigate the photocatalytic degradation activity of the efficient CoFe2O4/g-C3N4 composite catalyst. The heterostructured spinel CoFe2O4 anchored g-C3N4 photocatalysts (PCs) with Z-scheme show better photocatalytic degradation performance for both organic dyes. Meanwhile, the efficiency of aqueous MB and Rh B degradation in 120 and 100 min under visible-light could be up to 91.1% and 73.7%, which is greater than pristine g-C3N4 and CoFe2O4 catalysts. The recycling stability test showed no significant changes in the photo-degradation activity after four repeated cycles. Thus, this work provides an efficient tactic for the construction of highly efficient magnetic PCs for the removal of hazardous pollutants in the aquatic environment.


Assuntos
Cobalto , Compostos Férricos , Azul de Metileno , Nanocompostos , Rodaminas , Poluentes Químicos da Água , Cobalto/química , Compostos Férricos/química , Catálise , Nanocompostos/química , Rodaminas/química , Poluentes Químicos da Água/química , Azul de Metileno/química , Fotólise , Luz , Compostos Inorgânicos de Carbono/química , Nitrilas/química , Processos Fotoquímicos , Compostos de Nitrogênio/química , Grafite
5.
Environ Geochem Health ; 46(10): 376, 2024 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-39167294

RESUMO

Currently, one of the primary challenges that human society must overcome is the task of decreasing the amount of energy used and the adverse effects that it has on the environment. The daily increase in liquid waste (comprising organic pollutants) is a direct result of the creation and expansion of new companies, causing significant environmental disruption. Water contamination is attributed to several industries such as textile, chemical, poultry, dairy, and pharmaceutical. In this study, we present the successful degradation of methylene blue dye using g-C3N4 (GCN) mixed with WO3 and V2O5 composites (GCN/WO3/V2O5 ternary composite) as a photocatalyst, prepared by a simple mechanochemistry method. The GCN/WO3/V2O5 ternary composite revealed a notable enhancement in photocatalytic performance, achieving around 97% degradation of aqueous methylene blue (MB). This performance surpasses that of the individual photocatalysts, namely pure GCN, GCN/WO3, and GCN/V2O5 composites. Furthermore, the GCN/WO3/V2O5 ternary composite exhibited exceptional stability even after undergoing five consecutive cycles. The exceptional photocatalytic activity of the GCN/WO3/V2O5 ternary composite can be ascribed to the synergistic effect of metal-free GCN and metal oxides, resulting in the alteration of the band gap and suppression of charge recombination in the ternary photocatalyst. This study offers a better platform for understanding the characteristics of materials and their photocatalytic performance under visible light conditions.


Assuntos
Azul de Metileno , Óxidos , Tungstênio , Poluentes Químicos da Água , Tungstênio/química , Óxidos/química , Catálise , Poluentes Químicos da Água/química , Concentração de Íons de Hidrogênio , Azul de Metileno/química , Grafite/química , Purificação da Água/métodos , Processos Fotoquímicos , Fotólise , Compostos de Nitrogênio
6.
Environ Res ; 233: 116431, 2023 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-37329946

RESUMO

In this study, we synthesized silver nanoparticle-loaded cashew nut shell activated carbon (Ag/CNSAC). The synthesized samples were characterized by XRD, XPS, SEM with EDS, FT-IR, and BET analysis. The XRD, XPS, and EDS data provided convincing proof that Ag loaded on CNSAC is formed. The energy dispersive spectrum analysis and X-ray diffraction pattern both supported the face-centered cubic and amorphous structures of Ag/CNSAC. The SEM micrographs showed the inner surface development of Ag NPs and many tiny pores in CNSAC. The photodegradation of methylene blue (MB) dye by the Ag/CNSAC photocatalyst was investigated. This effective degradation of MB dye by Ag/CNSAC is attributed to the cooperative action of Ag as a photocatalyst and CNSAC as a catalytic support and adsorbent. In tests with gram-positive and negative bacteria including Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), the as-synthesized Ag/CNSAC showed outstanding antibacterial efficiency. Additionally, this study demonstrates a workable procedure for creating an affordable and efficient Ag/CNSAC for the photocatalytic eradication of organic contaminants.


Assuntos
Nanopartículas Metálicas , Prata , Prata/farmacologia , Prata/química , Nanopartículas Metálicas/química , Carvão Vegetal , Espectroscopia de Infravermelho com Transformada de Fourier , Escherichia coli , Staphylococcus aureus , Antibacterianos/farmacologia , Antibacterianos/química , Difração de Raios X
7.
J Mol Struct ; 1285: 135461, 2023 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-37041803

RESUMO

The respiratory infection tuberculosis is caused by the bacteria Mycobacterium tuberculosis and its unrelenting spread caused millions of deaths around the world. Hence, it is needed to explore potential and less toxic anti-tubercular drugs. In the present work, we report the synthesis and antitubercular activity of four different (hydrazones 7-12, O-ethynyl oximes 19-24, triazoles 25-30, and isoxazoles 31-36) hybrids. Among these hybrids 9, 10, 33, and 34, displayed high antitubercular activity at 3.12 g/mL with >90% of inhibitions. The hybrids also showed good docking energies between -6.8 and -7.8 kcal/mol. Further, most active molecules were assayed for their DNA gyrase reduction ability towards M. tuberculosis and E.coli DNA gyrase by the DNA supercoiling and ATPase gyrase assay methods. All four hybrids showed good IC50 values comparable to that of the reference drug. In addition, the targets were also predicted as a potential binder for papain-like protease (SARS CoV-2 PLpro) by molecular docking and a good interaction result was observed. Besides, all targets were predicted for their absorption, distribution, metabolism, and excretion - toxicity (ADMET) profile and found a significant amount of ADMET and bioavailability.

8.
Int J Mol Sci ; 24(22)2023 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-38003475

RESUMO

A key challenge in the development of sustainable water-splitting (WS) systems is the formulation of electrodes by efficient combinations of electrocatalyst and binder materials. Cellulose, a biopolymer, can be considered an excellent dispersing agent and binder that can replace high-cost synthetic polymers to construct low-cost electrodes. Herein, a novel electrocatalyst was fabricated by combining Fe2O3 and Ni on microcrystalline cellulose (MCC) without the use of any additional binder. Structural characterization techniques confirmed the formation of the Fe2O3-Ni nanocomposite. Microstructural studies confirmed the homogeneity of the ~50 nm-sized Fe2O3-Ni on MCC. The WS performance, which involves the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER), was evaluated using a 1 M KOH electrolyte solution. The Fe2O3-Ni nanocomposite on MCC displayed an efficient performance toward lowering the overpotential in both the HER (163 mV @ 10 mA cm-2) and OER (360 mV @ 10 mA cm-2). These results demonstrate that MCC facilitated the cohesive binding of electrocatalyst materials and attachment to the substrate surface. In the future, modified cellulose-based structures (such as functionalized gels and those dissolved in various media) can be used as efficient binder materials and alternative options for preparing electrodes for WS applications.


Assuntos
Celulose , Nanocompostos , Polímeros , Hidrogênio , Oxigênio , Água
9.
J Environ Manage ; 330: 117134, 2023 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-36584459

RESUMO

Recently, the major environmental pollution produced by the release of wastewater in liquid type is one of the most extensive forms of foremost pollution in water ecosystems. In this article, the Bi2O3/g-C3N4 nanocomposite with a direct Z-scheme was effectively obtained by a facile hydrothermal system. The crystal structures, surface morphology, chemical composition, and the optical belongings of the as-obtained composite catalysts were examined by Power XRD, FT-IR spectra, High-resolution XPS spectra, FE-SEM images with EDX spectra, High-resolution TEM images, UV-Vis DRS, and PL spectra respectively. Furthermore, the photocatalytic performance was assessed by the degradation of aqueous Rhodamine B (Rh B) dye under visible-light exposure. The Bi2O3/g-C3N4 composite photocatalysts (PCs) showed the maximum photo-degradation efficiency through a rate constant value of 0.0149 min-1, which is 4.9 and 5.3 folds superior to Bi2O3, and GCN, respectively. The better GBO2 nanocomposite PCs showed a superior photocatalytic degradation performance (>82%) of aqueous Rh B dye after five successive recycles. Moreover, based on these outcomes of the radical scavenging test, a direct and effective Z-scheme photocatalytic charger transfer mechanism was also projected. Finally, the reusability of the as-obtained Bi2O3/g-C3N4 nanocomposite has better stability and reusability, which was a favourable applicant for wastewater handling.


Assuntos
Ecossistema , Nanopartículas , Espectroscopia de Infravermelho com Transformada de Fourier , Águas Residuárias , Fontes de Energia Elétrica , Água
10.
Int J Mol Sci ; 24(1)2022 Dec 26.
Artigo em Inglês | MEDLINE | ID: mdl-36613798

RESUMO

Dextran sulfate (DXS) is a hydrophilic, non-toxic, biodegradable, biocompatible and safe biopolymer. These biomedically relevant characteristics make DXS a promising building block in the development of nanocarrier systems for several biomedical applications, including imaging and drug delivery. DXS polyanion can bind with metal oxide nanomaterials, biological receptors and therapeutic drug molecules. By taking advantage of these intriguing properties, DXS is used to functionalize or construct nanocarriers for specific applications. In particular, the diagnostic or therapeutic active agent-loaded DXS nanoparticles are prepared by simple coating, formation of polyelectrolyte complexes with other positively charged polymers or through self-assembly of amphiphilic DXS derivatives. These nanoparticles show a potential to localize the active agents at the pathological site and minimize undesired side effects. As DXS can recognize and be taken up by macrophage surface receptors, it is also used as a targeting ligand for drug delivery. Besides as a nanocarrier scaffold material, DXS has intrinsic therapeutic potential. DXS binds to thrombin, acts as an anticoagulant and exhibits an inhibitory effect against coagulation, retrovirus, scrapie virus and human immunodeficiency virus (HIV). Herein, biomedical applications involving the use of DXS as nanocarriers for drugs, biomolecules, and imaging agents have been reviewed. A special focus has been made on strategies used for loading and delivering of drugs and biomolecules meant for treating several diseases, including cancer, inflammatory diseases and ocular disease.


Assuntos
Anticoagulantes , Coagulação Sanguínea , Humanos , Anticoagulantes/farmacologia , Sulfato de Dextrana/farmacologia , Sistemas de Liberação de Medicamentos , Macrófagos/metabolismo
11.
Mar Drugs ; 19(4)2021 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-33921174

RESUMO

Much attention is being devoted to the potential of marine sulfated polysaccharides as antiviral agents in preventing COVID-19. In this study, sulfated fucoidan and crude polysaccharides, extracted from six seaweed species (Undaria pinnatifida sporophyll, Laminaria japonica, Hizikia fusiforme, Sargassum horneri, Codium fragile, Porphyra tenera) and Haliotis discus hannai (abalone viscera), were screened for their inhibitory activity against SARS-CoV-2 virus entry. Most of them showed significant antiviral activities at an IC50 of 12~289 µg/mL against SARS-CoV-2 pseudovirus in HEK293/ACE2, except for P. tenera (IC50 > 1000 µg/mL). The crude polysaccharide of S. horneri showed the strongest antiviral activity, with an IC50 of 12 µg/mL, to prevent COVID-19 entry, and abalone viscera and H. fusiforme could also inhibit SARS-CoV-2 infection with an IC50 of 33 µg/mL and 47 µg/mL, respectively. The common properties of these crude polysaccharides, which have strong antiviral activity, are high molecular weight (>800 kDa), high total carbohydrate (62.7~99.1%), high fucose content (37.3~66.2%), and highly branched polysaccharides. These results indicated that the crude polysaccharides from seaweeds and abalone viscera can effectively inhibit SARS-CoV-2 entry.


Assuntos
COVID-19/virologia , Gastrópodes/química , Polissacarídeos/farmacologia , SARS-CoV-2/fisiologia , Alga Marinha/química , Internalização do Vírus/efeitos dos fármacos , Animais , Antivirais/química , Antivirais/farmacologia , Células HEK293 , Humanos , Concentração Inibidora 50 , Polissacarídeos/química , Vísceras
12.
Polymers (Basel) ; 16(15)2024 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-39125239

RESUMO

The development of environmentally friendly technology is vital to effectively address the issues related to environmental deterioration. This work integrates ZnO-decorated MoS2 (MZ) to create a high-performing PVDF-based PVDF/MoS2-ZnO (PMZ) hybrid polymer composite film for sonocatalytic organic pollutant degradation. An efficient synergistic combination of MZ was identified by altering the ratio, and its influence on PVDF was assessed using diverse structural, morphological, and sonocatalytic performances. The PMZ film demonstrated very effective sonocatalytic characteristics by degrading rhodamine B (RhB) dye with a degradation efficiency of 97.23%, whereas PVDF only degraded 17.7%. Combining MoS2 and ZnO reduces electron-hole recombination and increases the sonocatalytic degradation performance. Moreover, an ideal piezoelectric PVDF polymer with MZ enhances polarization to improve redox processes and dye degradation, ultimately increasing the degradation efficiency. The degradation efficiency of RhB was seen to decrease while employing isopropanol (IPA) and p-benzoquinone (BQ) due to the presence of reactive oxygen species. This suggests that the active species •O2- and •OH are primarily responsible for the degradation of RhB utilizing PMZ2 film. The PMZ film exhibited improved reusability without substantially decreasing its catalytic activity. The superior embellishment of ZnO onto MoS2 and effective integration of MZ into the PVDF polymer film results in improved degrading performance.

13.
Polymers (Basel) ; 16(16)2024 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-39204563

RESUMO

Anodized aluminum oxide (AAO) molds were used for the production of large-area and inexpensive superhydrophobic polymer films. A controlled anodization methodology was developed for the fabrication of hierarchical micro-nanoporous (HMN) AAO imprint molds (HMN-AAO), where phosphoric acid was used as both an electrolyte and a widening agent. Heat generated upon repetitive high-voltage (195 V) anodization steps is effectively dissipated by establishing a cooling channel. On the HMN-AAO, within the hemispherical micropores, arrays of hexagonal nanopores are formed. The diameter and depth of the micro- and nanopores are 18/8 and 0.3/1.25 µm, respectively. The gradual removal of micropatterns during etching in both the vertical and horizontal directions is crucial for fabricating HMN-AAO with a high aspect ratio. HMN-AAO rendered polycarbonate (PC) and polymethyl methacrylate (PMMA) films with respective water contact angles (WCAs) of 153° and 151°, respectively. The increase in the WCA is 80% for PC (85°) and 89% for PMMA (80°). On the PC and PMMA films, mechanically robust arrays of nanopillars are observed within the hemispherical micropillars. The micro-nanopillars on these polymer films are mechanically robust and durable. Regular nanoporous AAO molds resulted in only a hydrophobic polymer film (WCA = 113-118°). Collectively, the phosphoric acid-based controlled anodization strategy can be effectively utilized for the manufacturing of HMN-AAO molds and roll-to-roll production of durable superhydrophobic surfaces.

14.
Gels ; 10(6)2024 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-38920911

RESUMO

This study examined the tensile strength and biocompatibility properties of polyvinyl alcohol (PVA) hydrogel tissue regeneration scaffolds with polylactic acid (PLA) mesh fabric added as reinforcement, with a focus on the impact of heat treatment temperature and the number of layers of the PLA mesh fabric. The hydrogel scaffolds were prepared using a freeze-thaw method to create PVA hydrogel, with the PLA mesh fabric placed inside the hydrogel. The swelling ratio of the PVA/PLA hydrogel scaffolds decreased with increasing layer number and heat treatment temperature of the PLA mesh. The gel strength was highest when five layers of PLA mesh fabric were added, heat-treated at 120 °C, and confirmed to be properly placed inside the hydrogel by SEM images. The MTT assay and DAPI staining using HaCaT cells demonstrated that the cell proliferation was uninterrupted throughout the experimental period, confirming the biocompatibility of the scaffold. Therefore, we confirmed the possibility of using PLA mesh fabric as a reinforcement for PVA hydrogel to improve the strength of scaffolds for tissue regeneration, and we confirmed the potential of PLA mesh fabric as a reinforcement for various biomaterials.

15.
Chemosphere ; 338: 139513, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37454984

RESUMO

An effective catalyst for the removal of antibiotic pollutants which severely impact water bodies and the environment is most favorable. In this study, g-C3N4 (gCN) and nitrogen-doped Bi2MoO6 (gCN-NBM) heterostructures are developed using a solvothermal process with enhanced photocatalytic degradation of tetracycline (TC) pollutants under visible-light irradiation. The experimental results confirm that nitrogen-doped Bi2MoO6 (NBM) nanomaterials were dispersed on the gCN surface, and a close combination of NBM and gCN leads to the efficient photocatalytic performance of TC. The photocatalytic efficiency of the heterostructure catalysts is four-fold higher than those of the pristine Bi2MoO6 catalysts owing to the excellent photogenerated charge separation and reduced recombination rate. Photocurrent measurements and electrochemical impedance spectra results disclose that the prepared heterostructure catalysts exhibit efficient photo-induced charge transfer. The electron spin resonance spectra and quenching experiments results reveal that superoxide radicals (.O2-) play a major role in TC degradation. This study presents a promising approach for designing efficient visible-light photocatalysts for environmental remediation applications.


Assuntos
Poluentes Ambientais , Compostos Heterocíclicos , Tetraciclina , Antibacterianos , Bismuto , Luz , Catálise
16.
Int J Biol Macromol ; 253(Pt 7): 127471, 2023 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-37863142

RESUMO

As an excellent alternative to petroleum-based food packaging materials, a novel green hybrid composite film with an excellent interconnected network structure was successfully fabricated by integrating chitosan (chi), microcrystalline cellulose (MCC), and lignin nanoparticles (LNP), including the desired amount of plasticizer glycerol (gly). Overall, 36 combinations were developed and investigated for superior biocomposite film formation. Among the various concentration ratios, the 40:35:25 chi-MCC-gly film provided well-organized film formation, good physicochemical properties, mechanical stability, efficient water contact angle, reduced water solubility, and lower water vapor permeability (11.43 ± 0.55 × 10-11 g.m-1.s-1.Pa-1). The performance of the chi-MCC-gly film further enhanced by the homogeneous incorporation of ∼100 nm LNP. With 1 % LNP addition, the tensile strength of the film increased (28.09 MPa, 47.10 % increase) and the water vapor permeability reached a minimum of 11.43 × 10-11 g.m-1.s-1.Pa-1, which proved the impact of LNP in composite films. Moreover, the films showed excellent resistance to thermal shrinkage even at 100 °C and exhibited nearly 100 % UV blocking efficiency at higher LNP concentrations. Interestingly, the green composite films extended the shelf life of freshly cut cherry tomatoes to seven days without spoilage. Overall, the facile synthesis of strong, insoluble, UV-blocking, and thermally stable green composite films realized for food packaging applications.


Assuntos
Quitosana , Lignina , Quitosana/química , Vapor , Biopolímeros/química , Embalagem de Alimentos
17.
Polymers (Basel) ; 15(5)2023 Mar 03.
Artigo em Inglês | MEDLINE | ID: mdl-36904534

RESUMO

Microbial fuel cells (MFCs) provide considerable benefits in the energy and environmental sectors for producing bioenergy during bioremediation. Recently, new hybrid composite membranes with inorganic additives have been considered for MFC application to replace the high cost of commercial membranes and improve the performances of cost-effective polymers, such as MFC membranes. The homogeneous impregnation of inorganic additives in the polymer matrix effectively enhances the physicochemical, thermal, and mechanical stabilities and prevents the crossover of substrate and oxygen through polymer membranes. However, the typical incorporation of inorganic additives in the membrane decreases the proton conductivity and ion exchange capacity. In this critical review, we systematically explained the impact of sulfonated inorganic additives (such as (sulfonated) sSiO2, sTiO2, sFe3O4, and s-graphene oxide) on different kinds of hybrid polymers (such as PFSA, PVDF, SPEEK, SPAEK, SSEBS, and PBI) membrane for MFC applications. The membrane mechanism and interaction between the polymers and sulfonated inorganic additives are explained. The impact of sulfonated inorganic additives on polymer membranes is highlighted based on the physicochemical, mechanical, and MFC performances. The core understandings in this review can provide vital direction for future development.

18.
Polymers (Basel) ; 15(3)2023 Jan 27.
Artigo em Inglês | MEDLINE | ID: mdl-36771960

RESUMO

A direct methanol fuel cell (DMFC) is an excellent energy device in which direct conversion of methanol to energy occurs, resulting in a high energy conversion rate. For DMFCs, fluoropolymer copolymers are considered excellent proton-exchange membranes (PEMs). However, the high cost and high methanol permeability of commercial membranes are major obstacles to overcome in achieving higher performance in DMFCs. Novel developments have focused on various reliable materials to decrease costs and enhance DMFC performance. From this perspective, cellulose-based materials have been effectively considered as polymers and additives with multiple concepts to develop PEMs for DMFCs. In this review, we have extensively discussed the advances and utilization of cost-effective cellulose materials (microcrystalline cellulose, nanocrystalline cellulose, cellulose whiskers, cellulose nanofibers, and cellulose acetate) as PEMs for DMFCs. By adding cellulose or cellulose derivatives alone or into the PEM matrix, the performance of DMFCs is attained progressively. To understand the impact of different structures and compositions of cellulose-containing PEMs, they have been classified as functionalized cellulose, grafted cellulose, acid-doped cellulose, cellulose blended with different polymers, and composites with inorganic additives.

19.
Membranes (Basel) ; 13(9)2023 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-37755180

RESUMO

Chitosan (CS), a promising potential biopolymer with exquisite biocompatibility, economic viability, hydrophilicity, and chemical modifications, has drawn interest as an alternative material for proton exchange membrane (PEM) fabrication. However, CS in its original form exhibited low proton conductivity and mechanical stability, restricting its usage in PEM development. In this work, chitosan was functionalized (sulfonic acid (-SO3H) groups)) to enhance proton conductivity. The sulfonated chitosan (sCS) was blended with polyvinylidene fluoride (PVDF) polymer, along with the incorporation of functionalized SiO2 (-OH groups), for fabricating chitosan-based composite proton exchange membranes to enhance microbial fuel cell (MFC) performances. The results show that adding functionalized inorganic fillers (fSiO2) into the membrane enhances the mechanical, thermal, and anti-biofouling behavior. From the results, the PVDF/sCS/fSiO2 composite membrane exhibited enhanced proton conductivity 1.0644 × 10-2 S cm-1 at room temperature and increased IEC and mechanical and chemical stability. Furthermore, this study presents a revolutionary way to generate environmentally friendly natural polymer-based membrane materials for developing PEM candidates for enhanced MFC performances in generating bioelectricity and wastewater treatment.

20.
Chemosphere ; 314: 137694, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36587915

RESUMO

Intense studies are being carried out on single atom catalysts that exhibit remarkable activity and selectivity. To enhance their catalytic abilities, one must have a thorough understanding of the properties of the single metal atom active site and its dynamics in the working state. Herein, we report single metal atom oxide (SMAO) (metal: W/Cu) anchored on TiO2-rGO nanomaterials (SMAO-ED-TiO2-rGO) by simple sonication process. It is efficient for the electrocatalytic hydrogen evolution reaction (HER), oxygen evolution reaction (OER) and photocatalytic degradation of pharmaceutical pollutant. The uniform dispersion of the tungsten/copper metal atom oxide over a TiO2-rGO materials is detected by high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM). The SMAO-ED-TiO2-rGO nanocatalyst has shown impressive HER/OER activity with an overpotential of 121/295 mV at (-)10 mA cm-2 current density and the low Tafel slope of 96/60.3 mV dec-1 in 1 M KOH solution. Further, SMAO-ED-TiO2-rGO nanocatalyst was used for the photocatalytic degradation of ciprofloxacin (CF). After 60 min of UV light irradiation, the SMAO-ED-TiO2-rGO nanocatalyst efficiently photodegraded 98.5% of CF while retaining its activity for five cycles. Superoxide radicals (O2•-) are found to be the main reactive species required in the photodegradation of CF, according to scavenger study of the SMAO-ED-TiO2-rGO nanocatalyst for CF degradation.


Assuntos
Cobre , Água , Fotólise , Tungstênio , Óxidos/química
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