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Nanotechnology is one of the most interesting areas of research due to its flexibility to improve or form new products from nanoparticles (NPs), and as a fast, greener, more eco-friendly and sustainable solution to technological and environmental challenges. Among metal oxides of photocatalytic performance, the use of titania (TiO2) as photocatalys...
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The degradation of organic dye pollutants is a critical environmental issue that has garnered significant attention in recent years. To address this problem, we investigated the potential of CaCrO4 chromite (CCO) as a photocatalyst for the degradation of cationic and anionic dye solutions under sunlight irradiation. CaCrO4 was synthesized via a sol...
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... Titanium dioxide (TiO2) is a distinguished semiconductor with a very interesting properties, which enabled it to be one of the leader NPs in the all daily life applications. TiO2 NPs have a band gaps 3.2 eV for anatase, 3.02 eV for a rutile and 2.96 eV for a brookite phases (Rufai et al., 2020a). Because of its high stability, low cost and non-toxicity , TiO2 is used as a photovoltaic cells in dye sensitized solar cells (Said and Mar, 2021;Venkatesh et al., 2015), hydrogen production in photocatalytic splitting of water, hydrogen production from natural seawater, separate evolution of H2 and O2 from water under visible light irradiation (Said and Mar, 2021), hydrogen storage in reversible storage of H2 on nanotubular TiO2 arrays (Said and Mar, 2021). ...
... Titanium dioxide (TiO2) is a distinguished semiconductor with a very interesting properties, which enabled it to be one of the leader NPs in the all daily life applications. TiO2 NPs have a band gaps 3.2 eV for anatase, 3.02 eV for a rutile and 2.96 eV for a brookite phases (Rufai et al., 2020a). Because of its high stability, low cost and non-toxicity , TiO2 is used as a photovoltaic cells in dye sensitized solar cells (Said and Mar, 2021;Venkatesh et al., 2015), hydrogen production in photocatalytic splitting of water, hydrogen production from natural seawater, separate evolution of H2 and O2 from water under visible light irradiation (Said and Mar, 2021), hydrogen storage in reversible storage of H2 on nanotubular TiO2 arrays (Said and Mar, 2021). ...
Green nanotechnology is a new developed branch in the bionanotechnology filed. It provides an alternative method for synthesis of NPs with the economic and environmental benefits compared with chemical and physical methods. Titanium dioxide TiO2 NPs is one of the most common materials in the biomedical field due to its unique photocatalytic properties, excellent biocompatibility, high chemical stability, and low toxicity. The physicochemical characteristics Of TiO2 NPs synthesized using onion extract was characterized by XRD, , FTIR and HRTEM. In this manuscript we investigate the role of green synthesis of TiO2 NPs from plant extract (Onion) on the on its phytochemical properties.
... The fact that TiO2 NPs absorb 3 -4% of solar energy makes them the most effective solar collector [19], and therefore, they are well-known photocatalysts for the decomposition of hazardous chemical compounds in water [30]. In recent years, several studies have reported on the synthesis of TiO2 NPs facilitated by plant-based extracts, includi n g T r i g o n e l l a f o e n u m -g r a e c u m [31], Cinnamomum zeylanicum [30], Carica papaya [32], Cucurbita pepo [33], Justicia gendarussa [34], Matricaria chamomilla [35], Thymus migricus and Alcea [36], Tamarindus indica [37], Punica granatum, Lippia citriodora [38], Deinbollia pinnata [15], and Prunus domestica L. [5]. ...
The biosynthesis procedure for nanomaterial preparation is a promising alternative due to its simplicity and environmental friendliness. In this work, TiO2 NPs were biosynthesized using the aqueous leaf extract of Azadirachta indica. The influence of the extract volumes, solvents, and acetic acid on the properties of TiO2 NPs was studied. Phytochemical screening and ATR-FTIR spectrum confirmed the presence of phenolic compounds in the leaf extract. XRD patterns showed that the samples were mainly in the anatase phase. However, for the water-based samples and when 1 and 2 mL of extract volumes were used, anatase/brookite mixture was observed. FESEM images displayed almost spherical and agglomerated NPs. UV-Vis-NIR studies showed that the samples’ bandgaps values are within the range of anatase TiO2. The photocatalytic activity of the TiO2 NPs was evaluated in the photodegradation of methyl orange (MO) under UV light irradiation. The water-based sample synthesized using 2 mL of the extract achieved 98.62% of MO degradation within 270 min and demonstrated the highest pseudo-first-order photodegradation kinetic constant of 0.0147 min-1. These results indicate that the use of the plant-based biosynthesis method with water as the solvent successfully produced TiO2 NPs with good physicochemical properties and photocatalytic activity in the photodegradation of organic dye. Copyright © 2022 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).
... In the work by Rufai et al. [35], the synthesis of TiO 2 was examined using Deinbollia pinnata leaves for photocatalytic purposes. The plant extracts were prepared using sonication method. ...
... Finally, the samples were dried (95 • C for 24 h) and calcined at 500 • C for 5 h. For the characterization different techniques were used: XRD, SEM, EDX, UV-Vis spectrometry, BET, and FTIR [35]. The XRD results confirmed the anatase phase of TiO 2 NPs in great purity with average crystal size in the range of 19-21 nm. ...
... The obtained results showed that 97.53% of MO was degraded after 150 min of UV irradiation. These data indicate that a high performance can be reached within a short time thanks to the enhanced charge carrier's separation and increased surface area [35]. ...
Polluting the natural water resources is a serious global issue, which is confirmed by the fact that today at least 2 billion people consume water from contaminated sources. The conventional wastewater treatment methods cannot effectively remove the persistent pollutants (e.g., drugs, organic dyes, pesticides) from the aqueous environment. Heterogeneous photocatalysis is a promising and sustainable alternative for water remediation. It is based on the interaction be-tween light irradiation and the semiconductors (e.g., TiO2, ZnO) as photocatalysts, but these compounds, unfortunately, have some disadvantages. Hence, great attention has been paid to the nanotechnology as a possible way of improvement. Nanomaterials have extraordinary properties; however, their conventional synthesis is often difficult and requires a significant amount of dangerous chemicals. This concise topical review gives recent updates and trends in development of sustainable and green pathways in the synthesis of nanomaterials, as well as in their application for water remediation. In our review we put emphasis on the eco-friendly, mostly plant extract-based materials. The importance of this topic, including this study as well, is proved by the growing number of publications since 2018. Due to the current serious envi-ronmental issues (e.g., global warming, shortage of pure and quality water), it is necessary for the traditional TiO2 and ZnO semiconductors to be replaced with the harmless, non-toxic, and more powerful nanocomposites as photocatalysts. Not only because of their higher efficiency as compared to the bulk semiconductors, but also because of the presence of biomolecules that can add up to the pollutant removal efficiency, which has been already confirmed in many research-es. However, despite the fact that the application of heterogeneous photocatalysis together with green nanotechnology is absolutely the future in water purification, there are some challenges which have to be overcome. The exact effects of the biomolecules obtained from plants in the synthesis of nanoparticles, as well as in the photocatalytic processes, are not exactly known and require further investigation. Furthermore, heterogeneous photocatalysis is a well-known and commonly examined process; however, its practical use outside the laboratory is expensive and difficult. Thus, it has to be simplified and improved in order to be available for everyone. The aim of our review is to suggest and prove that using these bio-inspired compounds it is possible to reduce human footprint in the nature.
... where Dp is the crystal size (nm), K is the Scherrer constant, like 0.89 for cubic crystallite shape [25], λ is the x-ray wavelength (Cu Kα radiation source, 0.154178 nm), β is the full width at half maximum (FWHM), and θ is the diffraction angle (2θ of peak (101) of anatase is 25.30°). ...
In this work, novel Z-scheme Zn0.5Cd0.5S/BiOCl (ZCS-BC) heterostructures are established with a facile hydrothermal method. Zn0.5Cd0.5S (ZCS) nanoparticles are loaded on the surface of BiOCl sheets uniformly and have a close contact with BiOCl. Compared with pure ZCS and BiOCl, ZCS-BC heterojunctions show more efficient photocatalytic behavior for rhodamine B (RhB) decomposition under simulative sunlight. The obtained 15%ZCS-BC heterojunction has optimal photocatalytic activity, and the RhB removal efficiency exceeds 98% when exposed to light source for 40 min. The successful construction of Z-scheme heterostructure between ZCS and BiOCl enhances the migration abilities of photogenerated carriers, leading to the reinforcement of photocatalytic property of ZCS-BC. Additionally, the 15%ZCS-BC heterojunction also exhibits desired photodegradation stability after four cycles. In the photocatalytic reaction system, photo-induced holes (h⁺) and superoxide radical (·O2⁻) play a critical role, followed by hydroxyl radical (·OH). A probable photocatalytic mechanism of ZCS-BC composite towards RhB decomposition is discussed.
Fly ash is readily available and cheaply generated as 47a by-product of the combustion of organic matter. A tremendous amount of fly ash is generated worldwide, and its disposal has imposed 47a severe environmental concern. Its good adsorption capacities attracted several researchers to study the use of fly ash as 47a support for photocatalysts for the degradation of contaminants from wastewater. Undoubtedly the photocatalysts supported on fly ash have represented excellent degradation efficiencies due to the synergistic effect of adsorption and photocatalytic capacity. The utilization of fly ash as 47a precursor has solved the problem of disposal and added value to the waste by-product. Various preparation techniques for fly ash–based nanocomposites such as the sol-gel method, hydrothermal method, solvothermal method, precipitation and co-precipitation, modified metalorganic decomposition, electrospinning, incipient impregnation, and wet chemical synthesis, along with 47a brief study of their characterization using scanning electron microscopy, X-ray diffraction technique and Fourier transform infrared (FTIR) spectroscopy, and the mechanism of photodegradation of dyes have been discussed in this paper. The literature shows that SiO2, TiO2, and Al2O3 present in fly ash play an essential role in the photodegradation of dyes. Factors affecting the degradation of dyes, their kinetic studies, and methods to enhance photodegradation efficiency have also been discussed.
