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1.
Environ Geochem Health ; 46(5): 172, 2024 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-38592578

RESUMO

Advancement in bioinspired alloy nanomaterials has a crucial impact on fuel cell applications. Here, we report the synthesis of PtPd alloy nanoclusters via the hydrothermal method using Piper longum extract, representing a novel and environmentally friendly approach. Physicochemical characteristics of the synthesized nanoclusters were investigated using various instrumentation techniques, including X-ray photoelectron spectroscopy, X-ray diffraction, and High-Resolution Transmission electron microscopy. The electrocatalytic activity of the biogenic PtPd nanoclusters towards the oxidation of formic acid and methanol was evaluated chronoamperometry and cyclic voltammetry studies. The surface area of the electrocatalyst was determined to be 36.6 m2g-1 by Electrochemical Surface Area (ECSA) analysis. The biologically inspired PtPd alloy nanoclusters exhibited significantly higher electrocatalytic activity compared to commercial Pt/C, with specific current responses of 0.24 mA cm - 2 and 0.17 mA cm - 2 at synthesis temperatures of 180 °C and 200 °C, respectively, representing approximately four times higher oxidation current after 120 min. This innovative synthesis approach offers a promising pathway for the development of PtPd alloy nanoclusters with enhanced electrocatalytic activity, thereby advancing fuel cell technology towards a sustainable energy solution.


Assuntos
Formiatos , Metanol , Piper , Ligas , Extratos Vegetais
2.
Int J Biol Macromol ; 252: 126381, 2023 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-37595723

RESUMO

In food production sectors, food spoilage and contamination are major issues that threaten and negatively influence food standards and safety. Several physical, chemical, and biological methods are used to extend the shelf-life of food products, but they have their limitations. Henceforth, researchers and scientists resort to novel methods to resolve these existing issues. Nanomaterials-based extension of food shelf life has broad scope rendering a broad spectrum of activity including high antioxidant and antimicrobial activity. Numerous research investigations have been made to identify the possible roles of nanoparticles in food preservation. A wide range of nanomaterials via different approaches is ultimately applied for food preservation. Among them, chemically synthesized methods have several limitations, unlike biological synthesis. However, biological synthesis protocols are quite expensive and laborious. Predominant studies demonstrated that nanoparticles can protect fruits and vegetables by preventing microbial contamination. Though several nanomaterials designated for food preservation are available, detailed knowledge of the mechanism remains unclear. Hence, this review aims to highlight the various nanomaterials and their roles in increasing the shelf life of food products. Adding to the novel market trends, nano-packaging will open new frontiers and prospects for ensuring food safety and quality.


Assuntos
Embalagem de Alimentos , Nanoestruturas , Embalagem de Alimentos/métodos , Conservação de Alimentos/métodos , Armazenamento de Alimentos , Polissacarídeos
3.
Chemosphere ; 340: 139986, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37640213

RESUMO

In this study, we investigated the deactivation kinetics and mechanism of N-F-TiO2/SiO2 nanopowder as a model photocatalyst for the purpose of facilitating the photocatalytic degradation of acrylonitrile (AN) in aqueous environment. Prior research has already displayed the proficient degradation of AN through the utilization of N-F-TiO2/SiO2 catalysts, revealing a degradation efficiency of 81.2% within a span of 6 min at an initial AN concentration of 10 mg/L. Multiple variables including the initial AN concentration, illumination intensity, and initial pH value were extensively analyzed during the degradation process. The kinetics of photocatalytic degradation of AN, facilitated by the N-F-TiO2/SiO2 photocatalyst, were modeled by fitting the pseudo first-order reaction kinetics to each individual factor. Furthermore, the adverse effect of catalyst poisoning during the photocatalytic breakdown of AN using the N-F-TiO2/SiO2 photocatalyst was analyzed through a range of different techniques including SEM, XPS, BET, XRD, TG, and NH3-TPD. The incorporation of findings from these diverse techniques revealed that, the primary factors contributing to the photocatalyst's poisoning were as follows: (i) During the degradation process, the build-up of intermediate molecules on active sites hindered their functionality, leading to a decrease in the efficiency of the photocatalytic reaction, (ii) Carbonaceous deposits formed when the catalyst's pore structure was obstructed by pollutants or intermediate products that had not undergone timely photocatalytic breakdown and (iii) The persistent erosion of active sites due to hydraulic forces resulted in inadequate performance of the N-F-TiO2/SiO2 photocatalyst in aqueous solutions. A comprehensive analysis of the deactivation kinetics was conducted, deciding in the formulation of a detailed poisoning mechanism for the N-F-TiO2/SiO2 photocatalyst. Additionally, we explored the catalysts regeneration, involving thermal treatment, ultrasonic irradiation, and catalyst reloading. This study not only advances our insight into the waning performance of catalysts in aqueous media but also establishes a conceptual framework for extrapolating analogous deactivation dynamics in other catalysts, grounded in precedent experimental knowledge. This research contributes to the development of a deactivation model for catalysts in the aqueous environment, based on existing experimental research, providing a theoretical framework for understanding the deactivation process of photocatalysts.


Assuntos
Acrilonitrila , Nanopartículas , Flúor , Dióxido de Silício , Nitrogênio
4.
Chemosphere ; 336: 139227, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37327825

RESUMO

We report on the synthesis of silver oxide/reduced graphene oxide nanocomposites (Ag/rGO NCs) using a hydrothermal technique. This paper presents a simple method for synthesizing Ag/rGO hybrid nanocomposites, which can be used for environmentally treating hazardous organic pollutants. The photocatalytic degradation of model artificial Rhodamine B dye and bisphenol A was assessed under visible light illumination. The crystallinity, binding energy, and surface morphologies of the synthesized samples were determined. The silver oxide loading sample resulted in a decrease in the rGO crystallite size. SEM and TEM images demonstrate strong adhesion of the Ag NPs to the rGO sheets. XPS analysis validated the binding energy and elemental composition of the Ag/rGO hybrid nanocomposites. The objective of the experiment was to enhance the photocatalytic efficiency of rGO in the visible region using Ag nanoparticles. The synthesized nanocomposites in the visible region exhibited good photodegradation percentages of approximately 97.5% and 98.6% after 120 min of irradiation for pure rGO, Ag NPs, and Ag/rGO nanohybrid, respectively. Furthermore, the Ag/rGO nanohybrid maintained their degradation ability for up to three cycles. The synthesized Ag/rGO nanohybrid demonstrated enhanced photocatalytic activity, expanding their potential for environmental remediation. Based on the investigations, Ag/rGO nanohybrid proved to be an effective photocatalyst and holds promise as an ideal material for future applications in preventing water pollution.


Assuntos
Nanopartículas Metálicas , Nanopartículas Metálicas/química , Prata , Luz , Água
5.
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
6.
Food Sci Biotechnol ; 32(9): 1159-1171, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37362813

RESUMO

Carbon quantum dots (CQDs) are an emerging class of novel carbon nanomaterials (< 10 nm). These zero-dimensional CQDs have recently invoked significant interest due to their high fluorescence ability, strong electronic conductivity, biocompatibility, excellent chemical stability, non-toxicity, and environmental safety. Bio-fabrication of CQDs from organic resources remains attractive owing to their excellent functional properties. An emerging class of CQDs is fabricated by various conventional methods. However, these methods need many chemical agents and instrument facilities. Bio-fabrication of CQDs has a lot of benefits because of its simple fabrication and eco-friendly. Therefore, the green synthesized CQDs are considered optimistic candidates for developing novel functional materials for food packaging applications. Thus, it is important to investigate the latest update on green-based CQDs for food packaging applications. This current review paper discusses the physicochemical properties of CQDs, the bio-fabrication of CQDs, and the fluorescent properties of CQDs along with their food packaging applications.

7.
Chemosphere ; 337: 139255, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37356589

RESUMO

Hydrothermal and wet impregnation methods are presented in this study for synthesizing CoOx(1 wt%)/Sn/Zr-codoped Fe2O3 nanorod photocatalysts for the degradation of organic pollutants and deactivation of bacteria. A hydrothermal route was used to synthesize self-assembled rod-like hierarchical structures of Sn(0-6%) doped Zr-Fe2O3 NRs. Additionally, a wet impregnation method was used to load CoOx onto the surface of photocatalysts (Sn(0-6%)-doped Zr-Fe2O3 NRs). A series of 1 wt% CoOx modified Sn(0-6%)-doped Zr-Fe2O3 NRs were synthesized, characterized, and utilized for the photocatalytic decomposition of organic contaminants, along with the killing of E. coli and S. aureus. In comparison with 0, 2, and 6% Sn co-doped Zr-Fe2O3 NRs, the CoOx(1 wt%)/4%Sn/Zr-Fe2O3 NRs photocatalyst exhibited an E. coli and S. aureus inactivation efficiencies (90 and 98%). A bio-TEM study of treated and untreated bacterial cells revealed that the CoOx(1 wt%)/4%Sn/Zr-Fe2O3 NRs photocatalyst led to considerable changes in the bacterial cell membranes' morphology. The optimal CoOx(1 wt%)/Sn(4%) co-doped Zr-Fe2O3 NRs photocatalyst achieved degradation efficiencies of 98.5% and 94.6% for BPA and orange II dye, respectively. As a result, this work will provide a facile and effective method for developing visible light-active photocatalysts for bacterial inactivation and organic pollutants degradation.


Assuntos
Escherichia coli , Nanotubos , Staphylococcus aureus , Catálise , Luz
8.
Environ Res ; 227: 115723, 2023 06 15.
Artigo em Inglês | MEDLINE | ID: mdl-37003548

RESUMO

Three-dimensional multi-porous Iron Oxide/carbon (Fe2O3/C) composites derived from tamarind shell biomass were synthesized by a single-step co-pyrolysis technique and utilized for Paracetamol (PAC) dismissal in the combined adsorption, and advanced oxidation such as electrochemical regeneration techniques. The Fe2O3/C composites were prepared by different pyrolysis temperatures, and named as TS750 (without Fe2O3at 750 °C), MTS450 BCs (Low-450 °C), MTS600 BCs (Moderate-600 °C) and MTS750 BCs (high-750 °C), respectively. As-prepared Fe2O3/C composite was characterized by FE-SEM, XRD, BET, and XPS analysis. The specific surface area and the spatial interaction between the interlayers of Fe2O3 and C were significantly improved by increasing the pyrolysis temperatures from 450 to 750 °C, which improved the adsorption capacity of Fe2O3/C composites in terms of higher rate constants and chemisorption kinetics. The Pseudo-second-order kinetics model fitted in the adsorption test results of Fe2O3/C composites with the highest correlation co-efficiency. The Langmuir-isotherms model fitted in the adsorption test of the TS750 and MTS450 BCs. The Freundlich isotherms model is more fit with MTS600 and MTS750 BCs. Based on the isotherm results, the MTS750 BCs achieved 46.9 mg/g of maximum PAC adsorption capacity. The optimized MTS750 composites could be completely recovered by using an advanced electrochemical oxidation regeneration approach within 180 min. Also, with the adsorption and recovery process, the TOC removal rate improved to ∼79.4%. After the 6th cycle electrochemical oxidation process, the obtained results of the re-adsorption test showed the stabile adsorption activity of the sorbent material. The data outcomes herein propose that this type of combined adsorption and electrochemical approach will be useful in commercial water treatment plants.


Assuntos
Poluentes Químicos da Água , Purificação da Água , Ferro/química , Acetaminofen , Adsorção , Poluentes Químicos da Água/análise , Carbono , Cinética , Purificação da Água/métodos
9.
Int J Biol Macromol ; 241: 124546, 2023 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-37086766

RESUMO

A nanohybrid prepared from the lignocellulosic residue is a feasible approach to synthesize blue light emitting fluorescent doped TiO2 quantum dot nanocomposite (C-TiO2 QDs) by microwave techniques using Mandarin orange (Citrus reticulata) peel powder with titanium isopropoxide precursors. With a greater orange peel colloidal medium, the structure of the TiO2-NPs changed from a mixture of rutile and anatase phases to exclusively the anatase phase. The optical and morphological properties of as-prepared C-TiO2 QDs were characterized by HR-TEM, XRD, FT-IR, UV-visible, PL spectra, DLS, and Zeta potential techniques. The reaction condition was optimized by changing substrate composition, pH, and reaction time. C-TiO2 QDs exhibit outstanding stability at pH 7 and remain sustained for at least 180 days without aggregation. As prepared C-TiO2 QDs have distinct emission and excitation activities with an average particle size of 2.8 nm. Cell viability was performed on normal L929 cells, where it showed excellent biocompatibility (<90 %) even at the concentration of 200 µg/mL after 24 h treatment. Additionally, the synthesized C-TiO2 QDs were used with L929 cells as a fluorescent probe for bio-imaging applications. The results revealed that neither of the cell lines' morphologies had significantly changed, proving the biocompatibility of the synthetic C-TiO2 QDs.


Assuntos
Citrus sinensis , Pontos Quânticos , Pontos Quânticos/química , Micro-Ondas , Carbono , Espectroscopia de Infravermelho com Transformada de Fourier , Titânio/química , Corantes Fluorescentes
10.
Chemosphere ; 310: 136825, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36241102

RESUMO

Herein, we synthesized in-situ Zr-doped Fe2O3 NRs photocatalyst by successive simple hydrothermal and air quenching methods. The synergistic roles of CoOx (1 wt%) and Zr-doping on bacteria inactivation and model organic pollutants over Fe2O3 NRs photocatalyst were studied in detail. Initially, rod-like Zr ((0-8) %)-doped Fe2O3 NRs were produced via a hydrothermal method. CoOx was loaded onto the Zr ((0-8) %)-doped Fe2O3 NRs) surface by a wet impregnation approach. The Zr-doping conditions and CoOx loadings were judiciously optimized, and a highly photoactive CoOx(1 wt%)/Zr(6%)-doped Fe2O3 NRs photocatalyst was developed. The CoOx(1 wt%) loaded Zr(6%)-doped Fe2O3 NRs photocatalyst revealed 99.4% inactivation efficiency compared with (0, 4 and 8)% Zr-doped Fe2O3 NRs, respectively. After CoOx(1 wt%)/Zr(6%)-doped Fe2O3 NRs photocatalyst treatment, Bio-TEM images of bacterial cells showed extensive morphological deviations in cell membranes, compared with the non-treated ones. Additionally, the optimum CoOx(1 wt%)/Zr(6%)-doped Fe2O3 NRs photocatalyst exhibited 99.2% BPA and 98.3% orange II dye degradation after light radiation for 3 h. This work will provide a rapid method for the development of photostable catalyst materials for bacterial disinfection and organic degradation.


Assuntos
Poluentes Ambientais , Nanotubos , Óxidos , Bactérias
11.
Chemosphere ; 311(Pt 1): 136928, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36272623

RESUMO

The use of dyes and segments has increased widely in recent years, but it poses a serious health risk to ecosystems. In this work, TiO2 and two-dimensional g-C3N4 nanosheets (g-CN) were fabricated through co-precipitation and thermal polymerization technique, respectively. The g-CN-TiO2 photocatalyst (1: 3, 2: 2, 3: 1) in various weight percentages was prepared using a simple impregnation process. The photocatalytic behaviour of the g-CN, TiO2 NPs, and different weight percentages of g-CN-TiO2 photocatalyst was evaluated against methylene blue (MB) dye under UV-visible light illumination. Compared to pristine and other weight percentages of the g-CN-TiO2 nanocomposite, the optimized g-CN-TiO2 nanocomposite (3:1) showed promoted performance against MB dye. The enriched catalytic efficiency can be accredited to the low amount of TiO2 nanoparticles deposited on gCN nanosheets, possibly due to the boosted transport properties of the electron-hole pairs. The enriched photocatalytic behaviour can be attributed to the development of the Z-scheme system between TiO2 and g-CN. The current study is an outstanding demonstration of the development of maximum catalytic efficiency for destroying hazardous chemical dyes.


Assuntos
Corantes , Poluentes Ambientais , Corantes/química , Ecossistema , Titânio/química , Azul de Metileno/química
12.
Chemosphere ; 311(Pt 2): 136983, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36306962

RESUMO

Herein, we report an Ag2Ox (3 wt%)-loaded ZnFe2O4 photocatalysts synthesized by co-precipitation and incipient wet impregnation approach for acetamiprid degradation, antibacterial, antioxidant, and toxicity assay. Initially, bare ZnFe2O4 nanostructures were made through a simple co-precipitation method. In the second step, 3 wt% of various transition metal oxides (CuOx, ZrOx, and Ag2Ox) were embedded on the surface of ZnFe2O4 photocatalysts via a wet impregnation method. Further, the prepared photocatalysts were systematically characterized using XRD, FTIR, FE-SEM, BET, HRTEM, and XPS analysis. The optimum Ag2Ox (3 wt%)-loaded ZnFe2O4 photocatalysts revealed higher degradation efficiencies for acetamiprid under sunlight irradiation. Additionally, the Ag2Ox (3 wt%)-loaded ZnFe2O4 photocatalysts showed more effective antioxidant and antibacterial activity than blank and bare ZnFe2O4 nanomaterials. The enriched catalytic efficiency can be accredited to the 3 wt% of Ag2Ox NPs loaded on ZnFe2O4 nanomaterials, possibly due to the boosted transport properties of the electron-hole pairs. This study will provide a new avenue for the development of simple and effective photocatalysts for efficiently saving polluted aquatic ecosystems.

13.
Microbiol Res ; 268: 127278, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36565686

RESUMO

Extensive use of neonicotinoid insecticides in recent decade had contaminated water and soil systems and poses serious environmental and health risk. Microbial degradation of toxic contaminants in the environment has been established as a sustainable tool towards its remediation. Under this context, the present study focused on the biodegradation of neonicotinoid insecticide acetamiprid, by bacterial strain Brucella intermedia PDB13 isolated from the gut of the acetamiprid exposed earthworms. To enhance acetamiprid biodegradation, suitable parameters such as pH, temperature, inoculum size and acetamiprid concentration range were optimised using Response Surface Methodology (RSM). The experimental results showed that the Brucella intermedium PDB13 can tolerate and degrade relatively high concentrations of acetamiprid (50 - 350 mg L-1). The results confirmed that maximum degradation of about 89.72% was achieved under optimized conditions. Further, confirmation of acetamiprid biodegradation was assessed through the occurrence of its degraded metabolites through HPLC, FTIR, and LCMS analysis. Based on this analysis, possible acetamiprid biodegradation pathway by Brucella intermedia PDB13 was proposed. Additionally, cytotoxicity, earthworm acute toxicity, and zebrafish embryo toxicity studies were also performed to assess the toxicity variations between the parent compound and its metabolites. The acetamiprid treated group resulted in cytotoxic effects apparently, with the increase in aberrant cells frequency (22.5 ± 3.3), when compared with its metabolites (2.3 ± 4.3) and control (1.9 ± 5.6) respectively. All these results evidently reported the degradation potential of Brucella intermedia PDB13, thereby establishing the scope for further advanced biodegradation studies towards mitigating the pesticide pollution.


Assuntos
Inseticidas , Oligoquetos , Animais , Inseticidas/metabolismo , Oligoquetos/metabolismo , Peixe-Zebra , Neonicotinoides/toxicidade , Neonicotinoides/química , Neonicotinoides/metabolismo , Bactérias/metabolismo , Biodegradação Ambiental
14.
Chemosphere ; 311(Pt 1): 136934, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36273614

RESUMO

Green synthesis of high-quality reduced graphene oxide (rGO) from agro-industrial waste resources remains attractive owing to its outstanding environmental benefits. The remarkable properties of rGO include excellent morphology, uniform particle size, good optical properties, high conductivity, nontoxicity, and extraordinary chemical stability. Traditional methods for the synthesis of rGO nanomaterials involve several chemical reactions including oxidation, carbonization, toxic solvent, and pyrolysis which produce harmful byproducts. Green preparation of rGO is an emerging area of research in graphene technology which is cost-effective and sustainable in the procedure. Owing to the uniform particle rGO particle size, these smart nanomaterials have wide applicability, including in metal ions and pollutant sensing and adsorption, photocatalysis, optoelectrical devices, medical diagnosis, and drug delivery. Here we review the physicochemical properties of rGO, the biowaste sources and green methods of rGO synthesis, and the diverse applications of rGO, including in water purification and the biomedical fields. With this review, covering more than 200 research articles published on rGO in the last eight years ending in 2022, we aim to provide a quick guide for researchers seeking up-to-date information on the properties, production, and applicability of rGO, with special attention to rGO applications in water purification and the biomedical fields.


Assuntos
Grafite , Nanoestruturas , Grafite/química , Óxidos/química , Nanoestruturas/química , Oxirredução
15.
Oxid Med Cell Longev ; 2022: 3088827, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36120599

RESUMO

A simple, efficient, and ecofriendly method was employed to synthesize TiO2/ZrO2/SiO2 ternary nanocomposites using Prunus × yedoensis leaf extract (PYLE) that shows improved photocatalytic and antibacterial properties. The characterization of the obtained nanocomposites was done by X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, field-emission scanning electron microscopy (FE-SEM), and energy-dispersive X-ray spectroscopic (EDS) analysis. The synthesized ternary nanocomposites with nanoscale pore diameters were investigated for the elimination of Reactive Red 120 (RR120) dye. The obtained results showed about 96.2% removal of RR120 dye from aqueous solution under sunlight irradiation. Furthermore, it shows promising antibacterial activity against Staphylococcus aureus and Escherichia coli. The improved photocatalytic and antibacterial activity of TiO2/ZrO2/SiO2 may bring unique insights into the production of ternary nanocomposites and their applications in the environment and biomedical field.


Assuntos
Nanocompostos , Prunus , Antibacterianos/química , Antibacterianos/farmacologia , Escherichia coli , Nanocompostos/química , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Dióxido de Silício/química , Titânio
16.
Environ Res ; 214(Pt 4): 113866, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-35952748

RESUMO

Hierarchical nanostructures play an important role in environmental clean-up and sustainability applications. The magnetic and photocatalytic characteristics of flower-like Mn-doped α-Fe2O3 nanostructures were prepared by using a polyol-assisted hydrothermal method. Crystallite sizes are in the range of 35-42 nm, and the existence of 3D hierarchical nanostructures was observed in FESEM pictures. The optical band gap energy varies between 2.08 and 2.16 eV, while XPS examination exposes the ions' charge states and validates Mn3+ inclusion in the Fe3+ lattice. At room temperature, the addition of Mn to α-Fe2O3 results in a spin disorder ferromagnetism and coercivity of about 600 Oe was achieved. Methylene blue (MB) dye solution degraded by 92% when 2.5% Mn doped with α-Fe2O3 under visible conditions for 120 min irradiation time.

17.
Environ Res ; 212(Pt B): 113283, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-35461844

RESUMO

Green synthesis of scalable, high-quality, fluorescent carbon quantum dots (CQDs) from natural biomass remains attractive due to their outstanding environmental application. CQDs are an emerging class of zero-dimensional carbon nanomaterials (<10 nm) that have recently attracted much attention due to their strong optical properties, biocompatibility, nontoxicity, uniform particle size, high photostability, low-cost synthesis, and highly tunable photoluminescence. The unique properties of CQDs possess a broad range of prospective applications in a number of fields such as metal ions detection, photocatalysis, sensing, medical diagnosis, bioimaging, and drug delivery. CQD nanostructures are synthesized using various techniques such as hydrothermal method, laser ablation, microwave irradiation, electrochemical oxidation, reflux method, and ultrasonication. However, this type of fabrication approach requires several chemical reactions including oxidation, carbonization, and pyrolysis. Green synthesis of CQDs has several advantages such as the use of low-cost and non-toxic raw materials, renewable resources, simple operations, and being environment-friendly. This review article will discuss the physicochemical properties of CQDs techniques used in the production of CQDs, and the stability of CQDs along with their applications in wastewater treatment and biomedical fields.


Assuntos
Pontos Quânticos , Biomassa , Carbono/química , Íons , Tamanho da Partícula , Pontos Quânticos/química
18.
Chemosphere ; 300: 134460, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35430198

RESUMO

Metal sulfide - semiconductor nanocomposites synthesized with well-defined tin metal, exhibited the wide bandgap, the absorptions are limited to the UV-vis region for reduction of Reactive Blue 160 (RB 160) under solar light irradiation. The prepared samples were characterized using optoelectronic techniques. Conveniently, a wider range of wavelengths and physical properties can be enabled by doping these metal oxide nanoparticles. Whereas the photoreduction of RB 160 is unambiguously associated within charge separation and transmission progression from the excited Sn doped ZnO/CdS. Furthermore, Photocatalytic degradation efficiency for the Sn doped ZnO/CdS composites still reliant on the excitation strength, indicating the several electrons and protons were precise as a result of charge separation and transmission in prepared catalyst. Sn doped ZnO/CdS composites shows 94% Photocatalytic degradation efficiency within 120 min under sunlight irradiation. This photocatalytic nanocomposites may find capable applications in solar cells to power stretchable and also in wearable electronics.


Assuntos
Nanopartículas Metálicas , Nanocompostos , Óxido de Zinco , Catálise , Luz , Luz Solar
19.
Chemosphere ; 299: 134366, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35318014

RESUMO

This Paper describes the synthesis of nickel doped ZnO is planned by chemical co-precipitation techniques. The prepared nanostructured nickel doped zinc oxide samples were analyzed by thermogravimetric differential thermal analysis (TG/DTA), X-ray diffraction (XRD), Fourier transform infra red (FTIR), field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM), electron paramagnetic resonance (EPR), and cyclic voltametry (CV). Nanostructure nickel doped ZnO materials have developed as promising for the basis of its broad range of employing in diverse areas. The attractive properties of nickel doped ZnO materials are highly demanded in high-energy potential applications. The nickel doped zinc oxide materials are hexagonal wurtzite arrangement is confirmed by XRD. The morphological -features of FE-SEM show nickel doped zinc oxide NPs are the structure of spherical type with agglomeration. The calculated particle size 11 nm is confirmed by HR-TEM. EPR spectra of nickel doped zinc oxide nanoparticles are ferromagnetic nature. Further, CV studies of Ni doped ZnO materials of the specific capacitance value is 133 Fg-1 at the scan rate 10 mVs-1 it is suitable for super capacitor application. The quantum chemical calculations were done by using DFT techniques through B3LYP/LANL2DZ level of basis set.

20.
Chemosphere ; 299: 134363, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35358554

RESUMO

Herein, we report a CoOx-loaded Zr-doped ZnFe2O4 (CoOx/Zr-ZFO) NR photocatalyst synthesized by successive microwave and wet impregnation methods for bacterial inactivation and degradation of organic pollutants. For the first time, microwave treatment was used for Zn attachment on hydrothermally synthesized self-assembled Zr-FeOOH NRs to produce Zr-doped ZnFe2O4 (Zr-ZFO) NRs. The lowest bandgap energy (1.96 eV) enables for significant absorption in the visible light region, which helps to improve bacteria degradation inactivation efficiency. Further, various metal oxides (Cu, Ag and Co) were loaded onto the surface of photocatalysts (Zr-ZFO NRs) by a wet impregnation method. As-synthesized CoOx/Zr-ZFO-3 NRs were systematically characterized and used as photocatalysts for inactivation of E. coli and S. aureus and degradation of organic pollutants. The CoOx/Zr-ZFO-3 NR photocatalyst exhibited better inactivation efficiency (99.4 %) than other metal oxide-loaded Zr-ZFO NRs (Ag2Ox-loaded Zr-ZFO NRs (33.6 %), CuOx-loaded Zr-ZFO NRs (77.6 %)). Additionally, the optimum CoOx/Zr-ZFO-3 NR photocatalyst showed 98.3 % and 98.1 % degradation efficiencies for BPA and orange II dye, respectively, under visible light irradiation (λ ≥ 420 nm). Therefore, this work affords a novel, simple and rapid approach for the development of photocatalysts which active in visible light for bacterial disinfection and organic degradation.


Assuntos
Poluentes Ambientais , Nanotubos , Catálise , Desinfecção , Escherichia coli , Luz , Micro-Ondas , Óxidos , Staphylococcus aureus
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