Photocatalysts for Treatment of Pollutants in Wastewater

A special issue of Catalysts (ISSN 2073-4344). This special issue belongs to the section "Environmental Catalysis".

Deadline for manuscript submissions: closed (29 February 2024) | Viewed by 4384

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Guest Editor
Department of Movement, Humane and Health Sciences, University of Rome Foro Italico, p.zza Lauro De Bosis, 6 Rome, Italy
Interests: advanced oxidation processes; water reuse; nanotechnology; wastewater disinfection; antibiotic resistance
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Special Issue Information

Dear Colleagues,

The rising competition for water resources increasingly pushes societies toward water reuse which, without the necessary precautions, may result in potential health risks for humans and the environment. Water scarcity, poor wastewater management, and high water demand for irrigation may transfer significant contaminant loads to farms and possibly to foodstuffs. On the other hand, contaminants of emerging concern (CECs) are even more ubiquitary due to the widespread use of personal care products, pharmaceuticals, drugs etc. all ove the world. The availability of reliable technologies for CECs removal from water and wastewater is a top priority to guarantee access to safe water for people worldwide.

Photocatalysis has recently emerged as an alternative or complementary process for degradation of several pollutants in wastewater. The ability of this advanced oxidation technology to inactivate microorganisms in water has been also widely demonstrated. The overall catalytic performance of the process depends on three factors: light irradiation, photogenerated charge carriers’ separation and transfer, and surface reaction. In order to improve process behaviours several innovative catalysts have been developed in the last years and are being tested in photocatalytic treatments of water and wastewaters

Dr. Giusy Lofrano
Guest Editor

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Keywords

  • synthesis, characterisation and test applications of catalysts in advanced oxidation and reduction processes (AOPs, AORs) for the removal of emerging contaminants
  • applications of photocatalytic processes in disinfection treatments
  • new generation photocatalysts for decontamination and disinfection applications

Published Papers (3 papers)

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Research

16 pages, 6503 KiB  
Article
Integration of WO3-Doped MoO3 with ZnO Photocatalyst for the Removal of 2-Nitrophenol in Natural Sunlight Illumination
by Sofia Mateen, Rabia Nawaz, Muhammad Tariq Qamar, Shahid Ali, Shahid Iqbal, Mohammad Aslam, Muhammad Raheel, Nasser S. Awwad and Hala A. Ibrahium
Catalysts 2023, 13(9), 1262; https://0-doi-org.brum.beds.ac.uk/10.3390/catal13091262 - 31 Aug 2023
Cited by 2 | Viewed by 952
Abstract
Environmental contamination has become the most pressing issue in recent years. The value of clean water to mankind has sparked interest in heterogeneous photocatalysis. In this study, a novel photocatalyst has been synthesized by integrating WO3-doped MoO3 (WDM) and ZnO [...] Read more.
Environmental contamination has become the most pressing issue in recent years. The value of clean water to mankind has sparked interest in heterogeneous photocatalysis. In this study, a novel photocatalyst has been synthesized by integrating WO3-doped MoO3 (WDM) and ZnO through composite formation. The composite nature of the synthesized photocatalyst was confirmed due to the presence of hexagonal ZnO and orthorhombic WDM phases in XRD pattern and scanning electron micrographs. Solid-state absorption spectra and a bandgap analysis showed that WDM-spectral ZnO’s response was better than that of pure ZnO. PL and EIS unveiled the effective role of WDM in suppressing the eh+ recombination process and charge-transfer resistance, respectively, in ZnO. The photocatalytic studies showed that WDM-ZnO was able to remove ~90% of 30 ppm 2-nitrophenol (2-NP) with a rate of 1.1 × 10−2 min−1, whereas ~65% 2-NP was removed by ZnO (6.1 × 10−3 min−1 rate) under the exposure of natural sunlight (800 × 102 ± 100 lx). Moreover, ~52% higher total organic carbon (TOC) removal was observed by WDM-ZnO as compared to ZnO. The photocatalytic removal of 2-NP by the produced photocatalysts followed the Langmuir–Hinshelwood kinetic model, as shown by the kinetic studies. The reactive oxygen species (ROS)-trapping established that the photocatalytic removal mechanism of 2-NP over WDM-ZnO in sunlight illumination was mainly triggered by the superoxide anion (O2•−) radical, however, the minor role of hydroxyl (OH) radicals cannot be completely ignored. Full article
(This article belongs to the Special Issue Photocatalysts for Treatment of Pollutants in Wastewater)
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17 pages, 4373 KiB  
Article
g-C3N4 for Photocatalytic Degradation of Parabens: Precursors Influence, the Radiation Source and Simultaneous Ozonation Evaluation
by Eryk Fernandes, Paweł Mazierski, Tomasz Klimczuk, Adriana Zaleska-Medynska, Rui C. Martins and João Gomes
Catalysts 2023, 13(5), 789; https://0-doi-org.brum.beds.ac.uk/10.3390/catal13050789 - 23 Apr 2023
Cited by 5 | Viewed by 1304
Abstract
Graphitic carbon nitride (g-C3N4) is a promising catalyst for contaminants of emerging concern removal applications, especially as a visible-light-driven material. In this study, g-C3N4 catalysts were effectively synthesized through a simple thermal polymerization method, using melamine, [...] Read more.
Graphitic carbon nitride (g-C3N4) is a promising catalyst for contaminants of emerging concern removal applications, especially as a visible-light-driven material. In this study, g-C3N4 catalysts were effectively synthesized through a simple thermal polymerization method, using melamine, urea, and thiourea as precursors to elucidate the influence of these compounds on the final product’s photocatalytic performance. The degradation of a mixture of three parabens was investigated under different types of radiation: two artificial, ultraviolet-A (UVA) and visible LED, and natural sunlight. The urea-based catalyst (UCN) presented better results under all radiation sources, followed by thiourea, and finally, melamine. Among the artificial light sources, the degradation of parabens under UVA was considerably higher than visible—up to 51% and 21%, respectively—using UCN; however, the broader spectrum of natural sunlight was able to achieve the highest removals, up to 92%, using UCN. Comparing artificial radiation sources, UVA lamps presented 45% lower energy consumption and associated costs. Photocatalytic ozonation was tested using UCN and MCN, with UCN once more possessing superior performance and a synergetic effect between photocatalysis and ozonation, with complete removal under 12 min. The use of g-C3N4 was then successfully tested in initial screening and found to be an efficient alternative in more low-cost and feasible solar photocatalysis water treatment. Full article
(This article belongs to the Special Issue Photocatalysts for Treatment of Pollutants in Wastewater)
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16 pages, 3236 KiB  
Article
Effect of Decoration of C@TiO2 Core-Shell Composites with Nano-Ag Particles on Photocatalytic Activity in 4-Nitrophenol Degradation
by Karol Sidor, Róża Lehmann, Anna Rokicińska, Tomasz Berniak, Marek Dębosz and Piotr Kuśtrowski
Catalysts 2023, 13(4), 764; https://doi.org/10.3390/catal13040764 - 17 Apr 2023
Viewed by 1643
Abstract
Photoactive TiO2 materials based on a C@TiO2 core-shell structure synthesized according to the bottom-up strategy using a spherical resin core were presented in relation to commercial TiO2 (P25) used as a reference material. The studied TiO2 materials were modified [...] Read more.
Photoactive TiO2 materials based on a C@TiO2 core-shell structure synthesized according to the bottom-up strategy using a spherical resin core were presented in relation to commercial TiO2 (P25) used as a reference material. The studied TiO2 materials were modified with Ag nanoparticles using two alternative methods: impregnation and precipitation. Depending on the deposition technique used, different distributions of the Ag modifier were achieved within the TiO2 structure. As confirmed by X-ray diffraction (XRD) and scanning electron microscopy (SEM) measurements, the precipitation technique resulted in the formation of almost twice smaller, highly dispersed Ag nanoparticles compared to impregnation. Furthermore, the effect of the performed modification on the textural properties (low-temperature N2 adsorption) and surface composition (X-ray photoelectron spectroscopy) was determined. The phase composition of the TiO2 support as well as the dispersion of the Ag modifier significantly affected the energy gap determined from UV–Vis spectra and, consequently, their performance in the process photodegradation of 4-nitrophenol tested as a model molecule. In the case of the @TiO2 material modified with highly dispersed Ag, significantly higher photoactivity in the visible light range was observed than in the presence of analogous P25-based materials. Full article
(This article belongs to the Special Issue Photocatalysts for Treatment of Pollutants in Wastewater)
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