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1.
Environ Res ; 257: 119333, 2024 Jun 06.
Artigo em Inglês | MEDLINE | ID: mdl-38849000

RESUMO

This review is aimed at researchers in air pollution control seeking to understand the latest advancements in volatile organic compound (VOC) removal. Implementing of plasma-catalysis technology for the removal of volatile organic compounds (VOCs) led to a significant boost in terms of degradation yield and mineralization rate with low by-product formation. The plasma-catalysis combination can be used in two distinct ways: (I) the catalyst is positioned downstream of the plasma discharge, known as the "post plasma catalysis configuration" (PPC), and (II) the catalyst is located in the plasma zone and exposed directly to the discharge, called "in plasma catalysis configuration" (IPC). Coupling these two technologies, especially for VOCs elimination has attracted the interest of many researchers in recent years. The term "synergy" is widely reported in their works and associated with the positive effect of the plasma catalysis combination. This review paper investigates the state of the art of newly published papers about catalysis, photocatalysis, non-thermal plasma, and their combination for VOC removal application. The focus is on understanding different synergy sources operating mutually between plasma and catalysis discussed and classified into two main parts: the effect of the plasma discharge on the catalyst and the effect of the catalyst on plasma discharge. This approach has the potential for application in air purification systems for industrial processes or indoor environments.

2.
Heliyon ; 10(8): e28966, 2024 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-38638942

RESUMO

The cultivation of carob tree does not need many climatic and ecological requirements. The main limit to its large-scale cultivation is the defects for propagation with seeds. Addressing this, our study evaluated the effect of cold plasma pretreatment on carob seed germination. Impressively, cold plasma showcased beneficial effects by significantly increasing water uptake in seeds (CS: 1.71 ± 0.59; PS/3.99 ± 1.56) and decreasing the contact angle from 80.7° to 57.9°, enhancing the seed surface's hydrophilicity. While the germination rate enhancement was subtle, the treatment presented an innovative route to modifying the seed's physiochemical properties. Specifically, storage proteins like albumin, globulin, and prolamin were notably reduced (Albumin (from 7.67 to 4.95 mg/g DW), Globulin (from 8.52 to 5.80 mg/g DW) and Prolamin (from 3.53 to 1.66 mg/g DW)). Additionally, there was a decline in the overall content of polyphenols (from 846.88 to 760.94 mg GAE/100g DW) and flavonoids (from 790.93 to 502.95 mg GAE/100g DW) and a decrease in the ferric reducing power (from 34.48 to 26.39 mg AAE/g DW). However, radical scavenging activity remained consistent. Intriguingly, FTIR-ATR spectral analysis post plasma treatment indicated oxidative alterations in the seed coat, marked by a distinctive intensity at 1732 cm⁻1. This investigation suggests that the application of eco-friendly technology could provide improvements in seed surface's hydrophilicity, but appropriate conditions could be chosen to increase germination efficiency.

3.
Materials (Basel) ; 16(21)2023 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-37959454

RESUMO

This study investigates the pilot-scale combination of nonthermal plasma and photocatalysis for removing Toluene and dimethyl sulfur (DMDS), examining the influence of plasma energy and initial pollutant concentration on the performance and by-product formation in both pure compounds and mixtures. The results indicate a consistent 15% synergy effect, improving Toluene conversion rates compared to single systems. Ozone reduction and enhanced CO2 selectivity were observed when combining plasma and photocatalysis. This process effectively treats pollutant mixtures, even those containing sulfur compounds. Furthermore, tests confirm nonthermal plasma's in-situ regeneration of the photocatalytic surface, providing a constant synergy effect.

4.
ACS Omega ; 8(15): 14144-14159, 2023 Apr 18.
Artigo em Inglês | MEDLINE | ID: mdl-37091426

RESUMO

The aim of this study is to evaluate the efficacy of mesoporous silica nanospheres as an adsorbent to remove doxorubicin (DOX) from aqueous solution. The surface and structural properties of mesoporous silica nanospheres were investigated using BET, SEM, XRD, TEM, ζ potential, and point of zero charge analysis. To optimize DOX removal from aqueous solution, a Box-Behnken surface statistical design (BBD) with four times factors, four levels, and response surface modeling (RSM) was used. A high amount of adsorptivity from DOX (804.84 mg/g) was successfully done under the following conditions: mesoporous silica nanospheres dose = 0.02 g/25 mL; pH = 6; shaking speed = 200 rpm; and adsorption time = 100 min. The study of isotherms demonstrated how well the Langmuir equation and the experimental data matched. According to thermodynamic characteristics, the adsorption of DOX on mesoporous silica nanospheres was endothermic and spontaneous. The increase in solution temperature also aided in the removal of DOX. The kinetic study showed that the model suited the pseudo-second-order. The suggested adsorption method could recycle mesoporous silica nanospheres five times, with a modest reduction in its ability for adsorption. The most important feature of our adsorbent is that it can be recycled five times without losing its efficiency.

5.
Materials (Basel) ; 16(6)2023 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-36984127

RESUMO

Indoor air quality has become a significant public health concern. The low cost and high efficiency of photocatalytic technology make it a natural choice for achieving deep air purification. Photocatalysis procedures have been widely investigated for environmental remediation, particularly for air treatment. Several semiconductors, such as TiO2, have been used for photocatalytic purposes as catalysts, and they have earned a lot of interest in the last few years owing to their outstanding features. In this context, this review has collected and discussed recent studies on advances in improving the photocatalytic activity of TiO2-based materials for indoor air treatment and bacterial inactivation. In addition, it has elucidated the properties of some widely used TiO2-based catalysts and their advantages in the photocatalytic process as well as improved photocatalytic activity using doping and heterojunction techniques. Current publications about various combined catalysts have been summarized and reviewed to emphasize the significance of combining catalysts to increase air treatment efficiency. Besides, this paper summarized works that used these catalysts to remove volatile organic compounds (VOCs) and microorganisms. Moreover, the reaction mechanism has been described and summarized based on literature to comprehend further pollutant elimination and microorganism inactivation using photocatalysis. This review concludes with a general opinion and an outlook on potential future research topics, including viral disinfection and other hazardous gases.

6.
Curr Org Synth ; 20(2): 238-245, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-35430994

RESUMO

AIMS: We have established this paper to recommend a novel way for the preparation of carbohydrates encompassing a 1,2,3-triazole motif that was prepared using an efficient click chemistry synthesis. BACKGROUND: The SARS-CoV-2 coronavirus epidemic continues to spread at a fast rate worldwide. The main protease (Mpro) is useful target for anti-COVID-19 agents. Triazoles are frequently found in many bioactive products, such as coronavirus inhibitors. OBJECTIVE: Click reactions are facilitated via the activation of copper nanoparticles, different substrates have been tested using this adopted procedure given in all cases, in high yields and purity. Other interesting comparative docking analyses will be the focus of this article. Calculations of quantitative structure-activity relationships will be studied. METHODS: Copper nanoparticles were produced by the reaction of cupric acetate monohydrate with oleylamine and oleic acid. To a solution, 5-(azidomethyl)-2,2,7,7-tetramethyltetrahydro-5Hbis([ 1,3]dioxolo)[4,5-b:4',5'-d]pyran 2 (200 mg, 0.72 mmol, 1 eq.) in toluene (15 mL) was added into a mixture of N-(prop-2-yn-1-yl)benzamide derivatives 1a-d (1.5 eq.) and copper nanoparticles (0.57 mg, 0.036 mmol, 0.05 eq.). RESULTS: A novel series of 1,2,3-triazole carbohydrate skeletons were modeled and efficiently synthesized. Based on the observations, virtual screening using molecular docking was performed to identify novel compounds that can bind with the protein structures of COVID-19 (PDB ID: 6LU7 and 6W41). We believed that the 1,2,3-triazole carbohydrate derivatives could aid in COVID-19 drug discovery. CONCLUSION: The formations of targeted triazoles were confirmed by different spectroscopic techniques (FT-IR, 1H NMR, 13C NMR, and CHN analyses). The docking scores of the newly synthesized triazole are attributed to the presence of hydrogen bonds together with many interactions between the ligands and the active amino acid residue of the receptor. The comparison of the interactions of the drugs, remdesivir and triazole, in the largest pocket of 6W41 and 6LU7 is also presented.


Assuntos
COVID-19 , Humanos , Simulação de Acoplamento Molecular , Cobre , SARS-CoV-2 , Espectroscopia de Infravermelho com Transformada de Fourier
7.
Environ Sci Pollut Res Int ; 30(13): 35745-35756, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36538222

RESUMO

Photocatalytic oxidation (PCO) using a TiO2 catalyst is an effective technique to remove gaseous volatile organic compounds (VOCs). Herein, a lab-scale continuous reactor is used to investigate the photocatalytic performance toward ethylbenzene (EB) vapor removal over TiO2 nanoparticles immobilized on glass fiber tissue. The role of the reactive species in the removal of EB and the degradation pathway were studied. Firstly, the effect of key operating parameters such as EB concentration (13, 26, 60 mg/m3), relative humidity levels (From 5 to 80%), gas carrier composition (dry air + EB, O2 + EB and N2 + EB) and ultraviolet (UV) radiation wavelength (UV-A 365 nm, UV-C 254 nm) were explored. Then, using superoxide dismutase and tert-butanol as trapping agents, the real contribution of superoxide radical anion (O2.-) and hydroxyl radicals (OH.) to EB removal was quantified. The results show that (i) small water vapor content enhances the EB degradation; (ii) the reaction atmosphere plays an important role in the photocatalytic process; and (iii) oxygen atmosphere/UV-C radiation shows the highest EB degradation percentage. The use of radical scavengers confirms the major contribution of the hydroxyl radical to the photocatalytic mechanism with 75% versus 25% for superoxide radical anion.


Assuntos
Nanopartículas , Superóxidos , Espécies Reativas de Oxigênio , Gases , Titânio , Raios Ultravioleta , Catálise
8.
RSC Adv ; 12(52): 33516-33524, 2022 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-36505725

RESUMO

A one dimensional (1D) perovskite-type (C6H7NBr)3[CdBr5] (abbreviated 4-BAPC) was synthesized by slow evaporation at room temperature (RT). 4-BAPC crystalizes in the monoclinic system with the space group P21/c. The 1D inorganic chains are formed by corner sharing CdBr6 octahedra. Thermal measurement shows that 4-BAPC is stable up to 190 °C. Optical characterization demonstrates that the grown crystal is an indirect bandgap material with a bandgap value of 3.93 eV, which is consistent with theoretical calculations. The electronic structure, calculated using density functional theory, reveals that the valence band originates from a combination of Br-4p orbitals and Cd-4d orbitals, whereas the conduction band originates from the Cd-5s orbitals. The photoluminescence spectroscopy shows that the obtained material exhibits a broad-band white light emission with extra-high CRI of 98 under λ exc = 380 nm. This emission is mainly resulting from the self-trapped exciton recombinations within the inorganic CdBr6 octahedron, and the fluorescence within the organic conjugated ammonium salt.

9.
Nanomaterials (Basel) ; 12(22)2022 Nov 09.
Artigo em Inglês | MEDLINE | ID: mdl-36432231

RESUMO

Removing toxic metal ions arising from contaminated wastewaters caused by industrial effluents with a cost-effective method tackles a serious concern worldwide. The adsorption process onto metal oxide and carbon-based materials offers one of the most efficient technologies adopted for metal ion removal. In this study, mesoporous MgO/g-C3N4 sorbent is fabricated by ultrasonication method for the uptake Pb (II) and Cd (II) heavy metal ions from an aqueous solution. The optimum conditions for maximum uptake: initial concentration of metal ions 250 mg g-1, pH = 5 and pH = 3 for Pb++ and Cd++, and a 60 mg dose of adsorbent. In less than 50 min, the equilibrium is reached with a good adsorption capacity of 114 and 90 mg g-1 corresponding to Pb++ and Cd++, respectively. Moreover, the adsorption isotherm models fit well with the Langmuir isotherm, while the kinetics model fitting study manifest a perfect fit with the pseudo-second order. The as fabricated mesoporous MgO/g-C3N4 sorbent exhibit excellent Pb++ and Cd++ ions uptake and can be utilized as a potential adsorbent in wastewater purification.

10.
Materials (Basel) ; 15(14)2022 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-35888433

RESUMO

The present work aims to study the photocatalytic properties of nanohybrids composed of silicon nanowires (SiNWs) decorated with PbS nanoparticles (NPs). The elaborated material was intended to be utilized in wastewater treatment. The SiNWs were elaborated from the Metal Assisted Chemical Etching route (MACE), while the PbS NPs were deposited at room temperature onto SiNWs using the pulsed laser deposition (PLD) technique. The influence of decorating SiNWs (having different lengths) with PbS-NPs on their structural, morphological, optoelectronic, and photocatalytic properties was scrutinized. PbS/SiNWs nanohybrids exhibited enhanced photocatalytic degradation towards Black Amido (BA) dye for 20 µm SiNWs length and 0.2% of BA volume concentration. These optimized conditions may insinuate that this nanocomposite-like structure is a promising efficient photocatalytic systems contender, cost-effective, and recyclable for organic compound purification from wastewaters.

11.
Environ Sci Pollut Res Int ; 29(37): 55321-55335, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35661305

RESUMO

Nowadays, in parallel to the appearance of the COVID-19 virus, the risk of viruses in water increases leading to the necessity of developing novel disinfection methods. This review focuses on the route of virus contamination in water and introduces non-thermal plasma technology as a promising method for the inactivation of viruses. Effects of essential parameters affecting the non-thermal discharge for viral inactivation have been exposed. The review has also illustrated a critical discussion of this technology with other advanced oxidation processes. Additionally, the inactivation mechanisms have also been detailed based on reactive oxygen and nitrogen species.


Assuntos
COVID-19 , Vírus , Desinfecção/métodos , Humanos , Inativação de Vírus , Água
12.
Curr Org Synth ; 19(8): 930-936, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35450529

RESUMO

AIMS: This study aimed to recommend a novel way for the preparation of carbohydrates containing triazole derivatives. BACKGROUND: Triazoles containing derivatives have numerous biological activities. Ball milling is a fast, modest, green process with massive potential. One of the greatest interesting applications of this technique is in the arena of heterocycles. OBJECTIVE: Solvent-free click reactions are facilitated via the activation of copper powder using a ball milling mechanochemical procedure. An optimization study of parameters affecting the reaction rate, such as reaction time, size, and milling ball number, has been conducted. Different substrates have been tested using this adopted procedure considering in all cases, in high yields and purity, the corresponding chiral optically pure five-membered glycoconjugates containing 1,2,3-triazole. METHODS: Three milling balls of 10 mm in diameter were placed in the milling jar (50 mL; stainless steel). 1 mmol of alkyne, 2 mmol of azide, and 1 mmol of Cu powder (63 mg) were added, respectively, in the presented order. Milling was assured for 25 min at 650 rpm deprived of solvent. RESULTS: The cycloaddition results and the deprotection of the cycloadducts were affected by the selection of the protective groups. Cleavage of the acetyl protecting groups provided water-soluble triazoles. The four 1,4-di-substituted 1,2,3-triazoles synthesized via deacetylation were tested against glycogen phosphorylase. The best inhibitor of rabbit muscle glycogen phosphorylase was 2-Amino-3-{2-[1-(3,4,5,6-tetrahydroxytetrahydro- pyran-2-ylmethyl)-1H-[1,2,3]triazol-4-yl]-ethylsulfanyl}-propionic acid b (Ki = 40.8 ± 3.2 µM). This novel procedure affords an eco-friendly reaction profile (catalyst-free) affording high yields and short reaction times. CONCLUSION: In this work, acetyl protective groups were used to the corresponding deprotected watersoluble triazole analogous to recognizing glycogen phosphorylase inhibitors. Triazole 6a was the most effective inhibitor of RMGP b with a Ki value of 40.8 µM.


Assuntos
Azidas , Triazóis , Animais , Coelhos , Triazóis/farmacologia , Cobre , Solventes , Aço Inoxidável , Pós , Inibidores Enzimáticos/farmacologia , Glicogênio Fosforilase , Alcinos , Glicoconjugados , Piranos , Água
13.
Environ Sci Pollut Res Int ; 29(8): 12237-12248, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34562219

RESUMO

The discovery of the occurrence of inorganic pollutants in surface waters is identified in the system assessment quality. The most harmful elements are pesticides, persistent organic pollutants, pharmaceuticals, personal care products, and heavy metals are still dangerous to the environment due to their general uses. Chromate has the largest concentration compared to the other metals in the wastewater industries. This work evaluates the application of the spinel p-CoAl2O4 as a photocatalyst prepared by the nitrate synthesis process to reduce Cr(VI), a hazardous metal for the environment. The photocatalyst was characterized using thermal analysis (TG), X-ray diffraction, UV-diffuse reflectance spectroscopy, scanning electron microscopy, fluorescent X-ray, Fourier transform infrared spectroscopy, electrical conductivity, and photoelectrochemically. The results showed that the efficiency of optimum reduction of Cr(Vl) to Cr(IIl) photoreduction is more effective (77%) for pH = 3.6 than that at high pH values up to 8 (7%). Moreover, the effect of the hetero-system CoAl2O4/ZnO on photocatalytic efficiency was investigated. The photocatalytic activity increases up to 99% with 1 g L-1, a total catalyst dosage over the hetero-system CoAl2O4/ZnO at a ratio of 75%/25%. This data is better relative to CoAl2O4 or ZnO alone. The Cr(VI) photoreduction activity improvement was caused by the best separation and the photogeneration of electron-hole on the CoAl2O4/ZnO surfaces. Finally, the Lagergren pseudo-first-order and the Langmuir-Hinshelwood models fit well the experimental kinetics.


Assuntos
Óxido de Zinco , Óxido de Alumínio , Catálise , Cromo , Cobalto , Óxido de Magnésio , Espectroscopia de Infravermelho com Transformada de Fourier
14.
Environ Sci Pollut Res Int ; 29(4): 4880-4892, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34796437

RESUMO

Although several non-thermal plasmas (NTPs) technologies have been widely investigated in air treatment, very few studies have focused on the inactivation mechanism of viruses by NTPs. Due to its efficiency and environmental compatibility, non-thermal plasma could be considered a promising virus-inactivation technology. Plasma is a partly or fully ionized gas including some species (i.e., electrons, free radicals, ions, and neutral molecules) to oxidize pollutants or inactivate harmful organisms. Non-thermal plasmas are made using less energy and have an active electron at a much higher temperature than bulk gas molecules. This review describes NTPs for virus inactivation in indoor air. The different application processes of plasma for microorganism inactivation at both laboratory and pilot-scale was also reviewed This paper reports on recent advances in this exciting area of viral inactivation identifying applications and mechanisms of inactivation, and summarizing the results of the latest experiments in the literature. Moreover, special attention was paid to the mechanism of virus inactivation. Finally, the paper suggests research directions in the field of airborne virus inactivation using non-thermal plasma.


Assuntos
Coronavirus , Gases em Plasma , Temperatura Alta , Tecnologia , Inativação de Vírus
15.
Materials (Basel) ; 14(23)2021 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-34885496

RESUMO

This work reports on the effect of TiO2 nanotubes (TiO2-NTs), decorated wih platinum nanoparticles (Pt-NPs), on the removal of bacteria and volatile organic compounds (VOCs). The Pt-NPs were loaded onto the TiO2-NTs using the electrodeposition method at four decoration times (100, 200, 300, and 600 s). The realized Pt-NPs/TiO2-NTs nanocomposites were used for the degradation of cyclohexane, a highly toxic and carcinogenic VOC pollutant in the chemical industry. The achieved Pt-NPs/TiO2-NTs nanocomposites were characterized using X-ray diffraction (XRD), photoluminescence (PL), diffuse reflectance spectroscopy (UV-Vis), and scanning (SEM) and transmission (TEM) electron microscopy. To understand the photocatalytic and antibacterial behavior of the Pt-NPs/TiO2-NTs, simultaneous treatment of Escherichia coli and cyclohexane was conducted while varying the catalyst time decoration. We noticed a complete bacterial inactivation rate with 90% VOC removal within 60 min of visible light irradiation. Moreover, the Langmuir-Hinshelwood model correlated well with the experimental results of the photocatalytic treatment of indoor air.

16.
Materials (Basel) ; 14(18)2021 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-34576631

RESUMO

This work aims to synthesize and characterize a material that can be used as an effective catalyst for photocatalytic application to remove both organic and inorganic compounds from wastewater. In this context, sillenite Bi12ZnO20 (BZO) in a pure phase was synthesized using the sol-gel method. Before calcination, differential scanning calorimetry (DSC) analysis was done to determine the temperature of the formation of the sillenite phase, which was found to be 800 °C. After calcination, the phase was identified by X-ray diffraction (XRD) and then refined using the Rietveld refinement technique. The results prove that BZO crystals have a cubic symmetry with the space group I23 (N°197); the lattice parameters of the structure were also determined. From the crystalline size, the surface area was estimated using the Brunauer-Emmett-Teller (BET) method, which was found to be 11.22 m2/g. The formation of sillenite was also checked using the Raman technique. The morphology of the crystals was visualized using electron scanning microscope (SEM) analysis. After that, the optical properties of BZO were investigated by diffuse reflectance spectroscopy (DRS) and photoluminescence (PL); an optical gap of 2.9 eV was found. In the final step, the photocatalytic activity of the BZO crystals was evaluated for the removal of inorganic and organic pollutants, namely hexavalent chromium Cr(VI) and Cefixime (CFX). An efficient removal rate was achieved for both contaminants within only 3 h, with a 94.34% degradation rate for CFX and a 77.19% reduction rate for Cr(VI). Additionally, a kinetic study was carried out using a first-order model, and the results showed that the kinetic properties are compatible with this model. According to these findings, we can conclude that the sillenite BZO can be used as an efficient photocatalyst for wastewater treatment by eliminating both organic and inorganic compounds.

17.
J Environ Manage ; 299: 113588, 2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-34488111

RESUMO

Nowadays, air pollution is an increasingly important topic, as environmental regulations require limiting pollutant emissions. This problem requires new techniques to reduce emissions by either improving the current emission control systems and processes or installing new hybrid treatment systems. These are of broad diversity, and every system has its advantages and disadvantages. The tendency is, accordingly, to combine various techniques to achieve more acceptable and suitable treatment. Recent studies suggest that the combination of photocatalysis and plasma in a reactor can offer attractive pollutant treatment efficiency with a minimum of partially oxidized by-products than that of these processes taken separately. However, there is little review of the capability of this pairing to treat different brands of pollutants. Besides, available data concerning reactor design with flows treated 10 to 1000 times higher than those studied at the lab scale. This review paid particular attention to determine the reaction mechanisms in terms of engineering and design of combination reactors (plasma and catalysis). Likewise, we developed the effect of critical parameters such as pollutant load, relative humidity, and flow rate to understand the degradation kinetics of specific pollutants individually by using plasma and photocatalysis. Additionally, this review compares different designs of cold plasma reactors combination with heterogeneous catalysis with special attention on synergistic and antagonistic effects of using plasma and photocatalysis processes at the laboratory, pilot, and industrial scales. Therefore, the elements discussed in this review stick well to the first theme on pollution prevention of the special issue concerning pollution prevention and the application of clean technologies to promote a circular (bio) economy.


Assuntos
Poluentes Atmosféricos , Poluição do Ar , Poluentes Ambientais , Poluição do Ar/prevenção & controle , Catálise , Cinética , Oxirredução
18.
Environ Sci Pollut Res Int ; 28(41): 57543-57556, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34091851

RESUMO

This research aims to investigate the effect of copper doping on the photocatalysis performance of TiO2 nanoparticles for disposal wastewater from organic pollutants. X-ray diffraction analysis manifests the crystallization of a rutile phase for pure and copper-doped TiO2 except for 2% resulting in a rutile-to-anatase phase transformation. The crystallite size is found less affected by Cu doping, i.e., ~30 nm. BET analysis indicates a decrease in the specific surface area as the doping loading increases. Scanning electron microscopy observations reveal spherical particles at the nanometer range for pure TiO2 and then larger agglomerates of ultrafine particles with Cu doping. FTIR analysis notifies the existence of hydroxyl groups, which will promote the photocatalysis process. The photodegradation of azucryl red (AR) has been investigated under different conditions; i.e., Cu-loading, initial concentration of AR, and pH. The kinetics of the photodegradation process is further found to comply with the Lagergren kinetic law, regardless the experimental conditions. Nevertheless, the photodegradation process is not only controlled by the intra-particle diffusion mechanism, but also by mass transfer through a liquid film boundary. The maximum degradation of AR, i.e., 86%, has been achieved at pH = 5.0 during 60 min of contact time for the 2% Cu doping, with effective regeneration. The Freundlich model exhibits a better fitting for AR dye photodegradation equilibrium data, compared to Langmuir, Temkin, and Dubinin-Radushkevich.


Assuntos
Cobre , Nanopartículas , Catálise , Fotólise , Titânio
19.
Langmuir ; 37(24): 7285-7294, 2021 Jun 22.
Artigo em Inglês | MEDLINE | ID: mdl-34102848

RESUMO

Ba-loaded ZnO nanoparticles (Ba/ZnO) were obtained by the co-precipitation process and employed as a sorbent for Congo Red (C32H22N6Na2O6S2) dye (CR). Physicochemical parameters such as particle size, pH, and contact time were checked to characterize the adsorption process. The maximum adsorption capacity of Ba/ZnO NPs for CR (1614.26 mg/g) proves its potential utility in the elimination of CR dye from wastewater. The adsorption mechanism was studied via infrared spectroscopy and density functional theory calculations. The geometrical parameters and electronic properties of the CR-Ba/ZnO complex, particularly the interaction energy, the density of states, and the charge transfer, highlighted the Ba-ion mediation in the chemical bond formation between CR and the surface. The interaction between CR and Ba-doped ZnO has found to show strong chemisorption with charge transfer between the SO3- group and adsorbed Ba2+ ion on the surface.

20.
Environ Sci Pollut Res Int ; 28(11): 13900-13912, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33205269

RESUMO

The heterogeneous photocatalysis process has been known to provide significant levels of degradation and mineralization of emerging contaminants including antibiotics. For that, nanoparticle CuCr2O4 (CCO) ceramics were successfully prepared via sol-gel (SG) and co-precipitation (CP) methods to obtain spinel with desired structural features and properties and also to improve the photocatalytic performances. The CCO crystallite phase was produced at 750 °C all ceramics, disregarding the synthesis route. CCO physical and chemical properties were checked by X-ray diffraction (XRD) with Rietveld refinement, Brunauer-Emmett-Teller (BET), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM), transmission electron microscope (TEM), and diffuse reflectance solid (DRS). The XRD patterns demonstrated that the synthesized catalysts displayed a small crystallite size between 17.45 and 26.24 nm for SG and 20.97 and 36.86 nm for the CCOCP samples. The observation by SEM and TEM of the nanopowders showed a typical morphology with comparable particle sizes for both synthesized routes (20-30 nm). SG agglomeration rates were higher, and particles stick together more efficiently considering the CP method, while the CCOCP method led to a more significant porosity. Their photocatalytic and adsorption performances were examined for cefaclor (CFC) removal chosen as a target pharmaceutical contaminant in water. The results obtained by the methods differed since nanoparticles prepared by SG led to high photocatalytic activity. In contrast, a high CFC adsorption was observed for those prepared via the CP method, and that agreed with the findings of the characterization analysis. The kinetics of the adsorption process was found to follow the pseudo-second-order rate law. In contrast, the data of the photodegradation process were further found to comply with the Lagergren kinetic law. Nevertheless, the global reaction rate is probably controlled by the intra-particular diffusion of CFC, regardless of the elimination process.


Assuntos
Antibacterianos , Nanopartículas , Catálise , Cerâmica , Microscopia Eletrônica de Varredura , Espectroscopia de Infravermelho com Transformada de Fourier
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