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Journal ArticleDOI: 10.1016/J.JENVMAN.2021.112226

Wastewater remediation with ZnO photocatalysts: Green synthesis and solar concentration as an economically and environmentally viable route to application.

04 Mar 2021-Journal of Environmental Management (Academic Press)-Vol. 286, pp 112226-112226
Abstract: Green-synthesized materials and solar concentration technology for advanced oxidation processes (AOPs) offer important opportunities in water remediation by giving value to clean, renewable and potentially low-cost resources. Here, Zinc Oxide (ZnO) nanostructures (NSs) were prepared via a green synthesis method based on garlic bulbs (Allium Sativum) extract (ZnO-Green), resulting in crystalline (wurtzite) nanorods (NRs). ZnO nanoparticles (NPs) were also chemically prepared through a standard co-precipitation (ZnO-Chem) for comparative solar photocatalytic (PC) studies. The green-synthesized ZnO NRs exhibited a favorable photocatalytic activity (PCA) in colloidal suspension for the methylene blue (MB) dye degradation upon exposure to concentrated sunlight. Comparison with the chemically synthesized ZnO results in almost equal degradations of 94% in optimal loading condition. To explore the possibility to use immobilized photocatalyst in heterogeneous condition, green-synthesized ZnO NRs coatings were fabricated and compared with a 135 nm thick ZnO thin film produced by pulsed laser deposition (PLD) (ZnO-PLD). PCA on MB degradation (120 min experiments) resulted in degradations of 69% and 73%, respectively, proving the feasibility of the immobilized photocatalyst approach. Finally, an economic analysis of the process shows that the combination of green-synthesis and concentrated sunlight significantly reduces costs, paving the way for large-scale photocatalytic wastewater remediation.

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Topics: Photocatalysis (50%)
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Open accessJournal ArticleDOI: 10.2166/WST.2021.360
Abstract: In this study, zinc oxide and silver and copper-doped zinc oxide nanorods were synthesized by a simple template-free precipitation technique. In addition, meso-tetrakis-(4-sulfonatophenyl) porphyrin (TPPS4) was prepared and immobilized on ZnO nanorods (TPPS/ZnO). The synthesized photocatalysts were characterized by various techniques such as X-ray powder diffraction, scanning electron microscopy, UV-visible spectroscopy, diffuse reflectance spectroscopy, and Fourier transform Infrared spectroscopy. The potential of the obtained photocatalysts in the degradation of methylene blue was investigated under UV and visible light irradiation. The results revealed that the photocatalytic activity of TPPS/ZnO was higher than those of the pure ZnO and doped ZnO under visible light irradiation.

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1 Citations


Journal ArticleDOI: 10.1080/1040841X.2021.1977779
Abstract: Bio-based nanotechnology has its existence in biological dimensions e.g. microbial cell factories (bacteria, fungi. algae, yeast, cyanobacteria) plants, and biopolymers. They provide multipurpose biological platforms to supply well-designed materials for diverse nano-biotechnological applications. The "green or bio-based synthesis of nanoparticles (NPs)" has witnessed a research outburst in the past decade. The bio-based synthesis of NPs using microbial cell factories is a benign process and requires mild conditions for the synthesis with end products being less/non-toxic. As a result, its application has extended in multitudinous industries including environment, cosmetics, and pharmaceutical. Thus, the present review summarizes all the significant aspects of nanotechnology and the reason to switch towards the bio-based synthesis of NPs using microbial cell factories. It consists of a detailed description of the bio-based methods employed for the synthesis and classification of NPs. Also, a comprehensive study on the application of bio-based NPs in the various industrial and biotechnological domains has been discussed. The limitation and its solution would help identify the applicability of NPs to "identified and unidentified" sectors.

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Open accessDOI: 10.37636/RECIT.V44299313
30 Oct 2021-
Abstract: Zinc oxide (ZnO) is a material with a broad repertoire of optical, piezoelectric, antimicrobial activity, semi – conductivity, and photocatalytic properties that make it useful for many applications. However, increasing concern about environmental impact has led to the development of green processes for its production. In recent years, the green - synthesis of nanostructured materials has drawn attention as a non-complex, cost-effective, and environmentally friendly method in contrast to physical and chemical synthesis methods. Different nanomaterials have been developed using biological substrates among which the most studied are plant extracts that serve as a source of reducing agents and/or stabilizers. Therefore, the present review includes a summary of the different sources of plant extracts and methodologies applied to the green synthesis of zinc oxide nanoparticles and thin films and the advances of the photocatalytic activity of synthesized materials in terms of efficiency. In this work, we also present a bibliometric mapping of the growth of studies in the field for 10 years from 2011 to 2020.

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72 results found


Open accessJournal ArticleDOI: 10.1038/SREP21230
23 Feb 2016-Scientific Reports
Abstract: Scientific Reports 5: Article number: 10942; published online: 01 June 2015; updated: 23 February 2016 This Article contains typographical errors in Table 2 where ‘Week 2 (N = 32)’ was incorrectly given as ‘Week (N = 2)’.

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Topics: Typographical error (50%)

2,328 Citations


Open accessJournal ArticleDOI: 10.1126/SCIENCE.1137014
Nathan S. Lewis1Institutions (1)
09 Feb 2007-Science
Abstract: At present, solar energy conversion technologies face cost and scalability hurdles in the technologies required for a complete energy system. To provide a truly widespread primary energy source, solar energy must be captured, converted, and stored in a cost-effective fashion. New developments in nanotechnology, biotechnology, and the materials and physical sciences may enable step-change approaches to cost-effective, globally scalable systems for solar energy use.

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Topics: Solar energy (63%), Primary energy (61%), Energy storage (53%)

1,892 Citations


Journal ArticleDOI: 10.1002/JCTB.532
Abstract: Photocatalysis is a rapidly expanding technology for wastewater treatment. In this review the chemical effects of various variables on the rate of degradation of different pollutants are discussed in detail. The effects of adsorption, temperature, intensity of light, pH, and the presence of anions, cations, etc have been specifically covered. A critical analysis of the available literature data has been made and some general conclusions have been drawn concerning the above mentioned effects. The need for more work on specific points has been brought out. © 2001 Society of Chemical Industry

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1,078 Citations


Journal ArticleDOI: 10.1021/JA103843D
Fan Zuo1, Le Wang1, Wu Tao1, Zhenyu Zhang1  +2 moreInstitutions (1)
Abstract: Through a facile one-step combustion method, partially reduced TiO2 has been synthesized. Electron paramagnetic resonance (EPR) spectra confirm the presence of Ti3+ in the bulk of an as-prepared sample. The UV−vis spectra show that the Ti3+ here extends the photoresponse of TiO2 from the UV to the visible light region, which leads to high visible-light photocatalytic activity for the generation of hydrogen gas from water. It is worth noting that the Ti3+ sites in the sample are highly stable in air or water under irradiation and the photocatalyst can be repeatedly used without degradation in the activity.

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Topics: Photocatalysis (53%), Visible spectrum (52%), Hydrogen production (52%) ... read more

1,014 Citations


Journal ArticleDOI: 10.1016/J.RSER.2017.08.020
Abstract: Persistent organic pollutants (POPs) are carbon-based chemical substances that are resistant to environmental degradation and may not be completely removed through treatment processes. Their persistence can contribute to adverse health impacts on wild-life and human beings. Thus, the solar photocatalysis process has received increasing attention due to its great potential as a green and eco-friendly process for the elimination of POPs to increase the security of clean water. In this context, ZnO nanostructures have been shown to be prominent photocatalyst candidates to be used in photodegradation owing to the facts that they are low-cost, non-toxic and more efficient in the absorption across a large fraction of the solar spectrum compared to TiO 2 . There are several aspects, however, need to be taken into consideration for further development. The purpose of this paper is to review the photo-degradation mechanisms of POPs and the recent progress in ZnO nanostructured fabrication methods including doping, heterojunction and modification techniques as well as improvements of ZnO as a photocatalyst. The second objective of this review is to evaluate the immobilization of photocatalyst and suspension systems while looking into their future challenges and prospects.

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968 Citations