Advanced Oxidation Processes for Wastewater Purification

Journal Name	Impact Factor	CiteScore	Launched Year	First Decision (median)	APC
Catalysts catalysts	3.8	6.8	2011	13.9 Days	CHF 2200	Submit
Molecules molecules	4.2	7.4	1996	15.1 Days	CHF 2700	Submit
Processes processes	2.8	5.1	2013	14.9 Days	CHF 2400	Submit
Sustainability sustainability	3.3	6.8	2009	19.7 Days	CHF 2400	Submit
Water water	3.0	5.8	2009	17.5 Days	CHF 2600	Submit
Nanomaterials nanomaterials	4.4	8.5	2010	14.1 Days	CHF 2400	Submit
Separations separations	2.5	3.0	2014	15.1 Days	CHF 2600	Submit

15 pages, 9675 KiB

Open AccessArticle

Regenerable Biochar Catalyst from Biogas Residue for Peroxymonosulfate Activation in Bisphenol A-Containing Wastewater Treatment

by Yating Pan, Xue Yang, Haijuan Wei, Xiang Liu, Pan Wang, Nina Duan and Miao Lin

Water 2025, 17(5), 744; https://doi.org/10.3390/w17050744 - 4 Mar 2025

Viewed by 672

Abstract

The biogas residue (BR) from the anaerobic digestion of sludge poses a threat to the environment due to the presence of toxic and hazardous substances. Furthermore, emerging contaminants, such as bisphenol A (BPA), are widespread in domestic and industrial wastewater, requiring efficient and [...] Read more.

The biogas residue (BR) from the anaerobic digestion of sludge poses a threat to the environment due to the presence of toxic and hazardous substances. Furthermore, emerging contaminants, such as bisphenol A (BPA), are widespread in domestic and industrial wastewater, requiring efficient and sustainable treatment technologies. In this study, the BR-based biochar was pyrolyzed from urea-modified BR and employed as a catalyst to activate peroxymonosulfate (PMS) for BPA degradation. With BR-based biochar pyrolyzed at 750 °C as a catalyst, 20 mg/L of BPA was completely removed. Free radical detection confirmed that hydroxyl radical (•OH) and sulfate radical (•SO₄⁻) generation decreased with the increase in catalyst reuse times. The X-ray photoelectron spectra showed that the catalyst deactivation mainly resulted from -COOH and C-OH group loss, which acted as active sites for generating •OH and •SO₄⁻, and HCl or NaOH regeneration for catalysts could recover oxygen-containing functional groups, boosting BPA removal from 54.7% to 91.5% and 100%, respectively. Thermal regeneration could only enlarge the catalyst’s specific surface area (SSA) to recover adsorption capacity, but might not restore the free radical generation capability. This research offered a theoretical basis for the sustainable utilization of BR and provided a reference for reusing catalysts in wastewater treatment. Full article

(This article belongs to the Topic Advanced Oxidation Processes for Wastewater Purification)

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26 pages, 11937 KiB

Open AccessArticle

Numerical Study on Force Mechanisms and Eddy Current Effect of Rayleigh–Taylor Instability in the Intrinsic Model of Activated Carbon

by Li Ye, Qidong Zhang, Yizeng Wang, Zhipeng Ye and Haoran He

Processes 2025, 13(2), 491; https://doi.org/10.3390/pr13020491 - 10 Feb 2025

Viewed by 495

Abstract

In industrial operations, fluid transport within activated carbon—as one kind of porous media—often involves nonlinear instabilities, notably Rayleigh–Taylor instability (RTI). Herein it has been investigated for the flows in its intrinsic model to analyze the generation of adverse factors in practical applications. By [...] Read more.

In industrial operations, fluid transport within activated carbon—as one kind of porous media—often involves nonlinear instabilities, notably Rayleigh–Taylor instability (RTI). Herein it has been investigated for the flows in its intrinsic model to analyze the generation of adverse factors in practical applications. By studying the mechanism of force influence, it can explore how porous medium parameters impact RTI dynamics. The results show that horizontal forces dominate RTI’s initial evolution, with porosity influencing peak flow velocity timing delays (0% to 22.39% delay). The varying pore scales, delays peak velocity timing (7.63% to 1.46% delay) during initial stages, converging at later stages. Notably, the vortex line rupture at ε = 0.999 triggers Taylor vortex formation, enhancing velocity by 9.8816 times and promoting bidirectional mass transfer. This study enhances understanding of mass transfer efficiency of catalyst in industrial applications, enabling tailored porous media designs for optimized heat and mass transfer. Full article

(This article belongs to the Topic Advanced Oxidation Processes for Wastewater Purification)

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14 pages, 1027 KiB

Open AccessArticle

Membrane Foulant Removal by Ozone-Biocarrier Pretreatment Technology for Industrial Wastewater Reclamation

by Ting-Ting Chang, Sheng-Yi Chiu, Chun-Chi Lee, Yuan-Liang Tai, Guan-You Lin, Chun-Hsi Lai and Po-Yu Chen

Water 2025, 17(2), 272; https://doi.org/10.3390/w17020272 - 19 Jan 2025

Viewed by 652

Abstract

During wastewater reclamation, organic matter is considered the dominant foulant that shortens the lifetime of ultrafiltration (UF) membranes during operation. Additionally, the mineralization efficiency of organic matter in secondary effluent is typically low due to nonbiodegradable carbon sources. Herein, a combination of ozone [...] Read more.

During wastewater reclamation, organic matter is considered the dominant foulant that shortens the lifetime of ultrafiltration (UF) membranes during operation. Additionally, the mineralization efficiency of organic matter in secondary effluent is typically low due to nonbiodegradable carbon sources. Herein, a combination of ozone and a porous biocarrier reactor was applied as a novel pretreatment system to enhance organic matter removal in the effluent in a lab-scale evaluation and pilot test. The results indicated that 70% of the biopolymer was removed, and the chemical oxygen demand (COD) removal efficiency was 1.8 times higher in this combined process than in the process with a porous biocarrier alone. The UF flux increased by 16% after the combined ozonation and porous biocarrier pretreatment process compared with the process with no pretreatment. Interestingly, the genus Flavobacterium (15.59%), containing biopolymer-degrading bacteria, was observed only in the combined ozone plus porous biocarrier process. Moreover, the results show that biopolymers can be removed through the combined ozone and porous biocarrier process due to partial ozone degradation, confirming that this combined process is one of the better pretreatment procedures for organic matter removal and improves the flux of UF during the wastewater reclamation process. Full article

(This article belongs to the Topic Advanced Oxidation Processes for Wastewater Purification)

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33 pages, 11696 KiB

Open AccessArticle

Indirect Detection of Degradation-Resistant Compounds on Groundwaters Forward-Facing to Current Global Consumerism and Climate Change

by Norzagaray Campos Mariano, López Rocha Saul, Muñoz Sevilla Patricia, Montiel Montoya Jorge, Llanes Cárdenas Omar, María de los Ángeles Ladrón de Guevara Torres and Luz Arcelia Serrano García

Sustainability 2024, 16(23), 10486; https://doi.org/10.3390/su162310486 - 29 Nov 2024

Viewed by 983

Abstract

This study addresses the environmental challenges posed by consumerism, evaluating the impact of Degradation-Resistant Organic Compounds (DROCs), such as fats and oils, on surface environments, the subsurface, groundwater, and aquifers. Climate variability has intensified the dispersion of these compounds, particularly in [...] Read more.

This study addresses the environmental challenges posed by consumerism, evaluating the impact of Degradation-Resistant Organic Compounds (DROCs), such as fats and oils, on surface environments, the subsurface, groundwater, and aquifers. Climate variability has intensified the dispersion of these compounds, particularly in open landfills and poorly managed sites, making it urgent to identify affected areas to plan remediation efforts and mitigate their effects on ecosystems and human health. The objective was to analyze the dispersion of DROCs in an abandoned landfill in northwestern Mexico and develop strategies to characterize the decomposition stages of these compounds. In 2021 and 2022, a two-dimensional geoelectric tomography (GT) was conducted using a SARIS-Scintrex resistivimeter, recording variations in the apparent resistivity of subsoil. Using resistivity measures, the progressive and regressive numerical interpolation of Newton for finite differences, combined with the Lévy-type diffusion operator, classified the invasion areas into three principal ranges: high (recent invasions), intermediate (transition phase), and low (mature invasions).. These ranges indicated how pollutants migrate from the surface to the saturated zones of the aquifer. To validate the presence of fats and oils, a 24-m-deep well was drilled, revealing a positive correlation (R² = 0.863) between the areas covered by the tomograms and the detected contaminants. The results emphasize the need for improved waste management and the careful selection of disposal sites to reduce environmental degradation. The methodology proved effective and rapid, facilitating remediation planning and highlighting the importance of sustainable practices in final disposal to mitigate the impacts of DROCs, reduce greenhouse gas emissions, and protect public and environmental health. Full article

(This article belongs to the Topic Advanced Oxidation Processes for Wastewater Purification)

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13 pages, 11209 KiB

Open AccessArticle

Natural Vanadium–Titanium Magnetite Activated Peroxydisulfate and Peroxymonosulfate for Acid Orange II Degradation: Different Activation Mechanisms and Influencing Factors

by Zheng Zhang, Libin Zhao, Jingyuan Tian, Shaojie Ren and Wei Zhang

Water 2024, 16(21), 3109; https://doi.org/10.3390/w16213109 - 30 Oct 2024

Viewed by 896

Abstract

Persulfate-based advanced oxidation processes have emerged as a promising approach for the degradation of organic pollutants in aqueous environments due to their ability to generate sulfate radicals (SO₄^−·) within catalytic systems. In this study, peroxydisulfate (PDS) and peroxymonosulfate (PMS) were [...] Read more.

Persulfate-based advanced oxidation processes have emerged as a promising approach for the degradation of organic pollutants in aqueous environments due to their ability to generate sulfate radicals (SO₄^−·) within catalytic systems. In this study, peroxydisulfate (PDS) and peroxymonosulfate (PMS) were investigated with the natural vanadium–titanium magnetite (VTM) as the activator for the degradation of acid orange II. The degradation efficiency increased with higher dosages of VTM or persulfate (both PDS and PMS) at lower concentrations (below 10 mM). However, excessive PMS (higher than 10 mM) in the PMS/VTM system led to the self-consumption of free radicals, significantly inhibiting the degradation of acid orange II. The VTM-activated PDS or PMS maintained an effective degradation of acid orange II in a wide pH range (3~11), suggesting remarkable pH stability. The SO₄^−· was the main active species in the PDS/VTM system, while hydroxyl radical (·OH) also contributed significantly to the PMS/VTM system. In addition, PMS exhibited better thermal stability during VTM activation. Coexisting ions in an aqueous environment such as bicarbonate (HCO₃^–), carbonate (CO₃^2–), and hydrogen phosphate (HPO₄^2–) had obvious effects on persulfate activation. Our study systematically investigated the different activation processes and influencing factors associated with PDS and PMS when the natural VTM was used as a catalyst, thereby providing new insights into the persulfate-mediated degradation of organic pollutants in aqueous environments. Full article

(This article belongs to the Topic Advanced Oxidation Processes for Wastewater Purification)

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23 pages, 5897 KiB

Open AccessReview

Bibliometric Analysis of Research Status, Hotspots, and Prospects of UV/PS for Environmental Pollutant Removal

by Hanying Wang, Zheng Ji, Ruiqian Liu, Hongfeng Hu and Wanting Sun

Water 2024, 16(21), 3024; https://doi.org/10.3390/w16213024 - 22 Oct 2024

Cited by 1 | Viewed by 1429

Abstract

There are various methods for environmental organic pollutant degradation and removal, among which ultraviolet/persulfate has drawn significant attention due to its excellent oxidizing properties, high maneuverability, and less formation of by-products. To comprehensively assess the development of ultraviolet/persulfate, a bibliometric analysis was conducted [...] Read more.

There are various methods for environmental organic pollutant degradation and removal, among which ultraviolet/persulfate has drawn significant attention due to its excellent oxidizing properties, high maneuverability, and less formation of by-products. To comprehensively assess the development of ultraviolet/persulfate, a bibliometric analysis was conducted based on relevant literature indexed by Web of Science from 2002 to 2024. The findings revealed a growing number of publications, with China, Iran, and the United States being the top three countries with the highest total number of publications. Robust regional collaborations were evident. Additionally, Chinese and American scholars presented more significant activity in this field, and their publications exhibited higher quality. Furthermore, the current research hotspots, as indicated by keywords, primarily focused on the degradation mechanism of ultraviolet/persulfate and the reaction kinetic model simulation. Bibliometric results underscored that ultraviolet/persulfate, as an effective and environmentally friendly disinfection technology, possessed substantial potential for controlling diverse environmental pollutants, such as antibiotics, dyes, natural organic substances, heavy metals, microorganisms, and so on. Future research might concentrate on developing new catalytic composites and optimization of the photoactivation system. The practical application still needs to be investigated due to the complexity of the water matrix. The revival of microorganisms and the variation of toxicity should be considered further. Full article

(This article belongs to the Topic Advanced Oxidation Processes for Wastewater Purification)

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20 pages, 3105 KiB

Open AccessArticle

Preparation of Bimetallic CoFe@CSC-700 Carbonated Microspheres and Activated Peroxymonosulfate for Degradation of Levofloxacin

by Tongke Hu, Yazhen Chen, Xiaolan Guo, Yongjun Peng and Jianhua Cheng

Water 2024, 16(13), 1818; https://doi.org/10.3390/w16131818 - 26 Jun 2024

Viewed by 1423

Abstract

The exploration of efficient, low-leaching, and recyclable transition-metal-based catalysts is of great importance for the removal of pollutants from peroxymonosulfate (PMS) in water purification processes. In this study, a bimetallic CoFe@CSC-700 composite was prepared by an alkaline gel pyrolysis reduction method using chitosan [...] Read more.

The exploration of efficient, low-leaching, and recyclable transition-metal-based catalysts is of great importance for the removal of pollutants from peroxymonosulfate (PMS) in water purification processes. In this study, a bimetallic CoFe@CSC-700 composite was prepared by an alkaline gel pyrolysis reduction method using chitosan as a forming agent and applied to activate PMS to degrade levofloxacin (LEV). The leaching concentration of both cobalt and iron ions in the CoFe@CSC-700 catalyst was reduced by about 8-fold compared to the monometallic composite pellet catalyst. In addition, the removal efficiency of the CoFe@CSC-700 catalyst can still reach 90% after five cycles, showing good recyclability, recoverability and stability. Both free radical pathways (SO₄·⁻, ·OH, and ·O₂⁻) and non-free radical pathways (¹O₂) were detected in the oxidation reaction, with free radical pathways as the main contributor. The possible degradation pathways of LEV were proposed by LC-MS tests. Overall, this study provides new insights into the construction of efficient and stable PMS catalysts for wastewater treatment. Full article

(This article belongs to the Topic Advanced Oxidation Processes for Wastewater Purification)

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16 pages, 5033 KiB

Open AccessReview

Performance of Traditional and Emerging Water-Treatment Technologies in the Removal of Tetracycline Antibiotics

by Fanjin Wang, Ziyi Wang, Yue Zhao and Jian Zhang

Catalysts 2024, 14(4), 269; https://doi.org/10.3390/catal14040269 - 17 Apr 2024

Cited by 18 | Viewed by 3660

Abstract

Tetracycline antibiotics are widely used in human medical treatment, control of animal disease, and agricultural feed because of their broad spectrum of action, high efficiency, and low cost. The excessive use of antibiotics and arbitrary discharge of antibiotic wastewater have become increasingly serious [...] Read more.

Tetracycline antibiotics are widely used in human medical treatment, control of animal disease, and agricultural feed because of their broad spectrum of action, high efficiency, and low cost. The excessive use of antibiotics and arbitrary discharge of antibiotic wastewater have become increasingly serious problems, and the current sewage-treatment process is not ideal for treating water contaminated with tetracycline antibiotics, leading to increasingly prominent antibiotic pollution in water and the imminent need for its removal. In order to understand the necessity of removing tetracycline antibiotics from the water environment, this paper first expounds on their source, harms, and pollution status in oceans and in surface water, groundwater, wastewater, and drinking water. It next introduces the research status of conventional treatment methods such as adsorption methods, biological methods, and physical and chemical methods, then introduces new treatment methods such as advanced oxidation methods and comprehensive treatment technology in sewage plants. The degradation effects, mechanisms of action, and challenges of these methods were summarized. The advantages and disadvantages of each treatment technology are compared. Finally, potential future processing technologies are discussed. Full article

(This article belongs to the Topic Advanced Oxidation Processes for Wastewater Purification)

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42 pages, 7354 KiB

Open AccessReview

An Overview of Environmental Catalysis Mediated by Hydrogen Peroxide

by Monica Rigoletto, Enzo Laurenti and Maria Laura Tummino

Catalysts 2024, 14(4), 267; https://doi.org/10.3390/catal14040267 - 17 Apr 2024

Cited by 9 | Viewed by 3546

Abstract

The use of hydrogen peroxide (produced in situ or ex situ) as the main agent in oxidative processes of environmental pollutant removal is widely studied. The degradation of water pollutants, such as dyes, pharmaceuticals, cosmetics, petroleum derivatives, and even pathogens, has been successfully [...] Read more.

The use of hydrogen peroxide (produced in situ or ex situ) as the main agent in oxidative processes of environmental pollutant removal is widely studied. The degradation of water pollutants, such as dyes, pharmaceuticals, cosmetics, petroleum derivatives, and even pathogens, has been successfully obtained by different techniques. This review gives an overview of the more recent methods developed to apply oxidative processes mediated by H₂O₂ and other reactive oxygen species (ROS) in environmental catalysis, with particular attention to the strategies (Fenton-like and Bio-Fenton, photo- and electro-catalysis) and the materials employed. A wide discussion about the characteristics of the materials specifically studied for hydrogen peroxide activation, as well as about their chemical composition and morphology, was carried out. Moreover, recent interesting methods for the generation and use of hydrogen peroxide by enzymes were also presented and their efficiency and applicability compared with the Fenton and electro-Fenton methods discussed above. The use of Bio-Fenton and bi-enzymatic methods for the in situ generation of ROS seems to be attractive and scalable, although not yet applied in full-scale plants. A critical discussion about the feasibility, criticalities, and perspectives of all the methods considered completes this review. Full article

(This article belongs to the Topic Advanced Oxidation Processes for Wastewater Purification)

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23 pages, 7253 KiB

Open AccessArticle

Insight into the Catalytic Performance of a Zinc-Pillared Curcumin/Bentonite Composite for Enhanced Oxidation of Ibuprofen Residuals into Environmental Products: The Pathway and Toxicity

by Sarah I. Othman, Marwa H. Shemy, Haifa E. Alfassam, Haifa A. Alqhtani, Ahmed A. Allam, Mostafa R. Abukhadra and Stefano Bellucci

Catalysts 2024, 14(2), 129; https://doi.org/10.3390/catal14020129 - 7 Feb 2024

Cited by 1 | Viewed by 2018

Abstract

Environmental organo bentonite synthesis using curcumin-derived chemicals is used as catalyst support for zinc with a Zn-pillaring structure (Zn@CU/BEN). The obtained composite was assessed as an affordable, highly effective, and multifunctional photocatalyst for enhanced oxidation of ibuprofen (IBU) residuals in water supplies. The [...] Read more.

Environmental organo bentonite synthesis using curcumin-derived chemicals is used as catalyst support for zinc with a Zn-pillaring structure (Zn@CU/BEN). The obtained composite was assessed as an affordable, highly effective, and multifunctional photocatalyst for enhanced oxidation of ibuprofen (IBU) residuals in water supplies. The Zn@CU/BEN composite (0.4 g/L) displayed significant catalytic activities, resulting in the complete oxidation of IBU (25 mg/L) after 80 min. Then, the complete mineralization based on the full elimination of TOC content was recognized after 160 min, with significant indications about the formed intermediates. The identified intermediates, together with the identification of hydroxyl radicals as the essential oxidizing agent, declared an oxidation pathway of IBU over Zn@CU/BEN that involved three steps: hydroxylation, decarboxylation/demethylation, and ring-opening processes. The toxic properties of raw pollutants as well as the oxidizing product at different durations were assessed based on the cell viability results of kidney (HEK293T) and liver (HepG2) cell lines. The partially oxidized sample in the initial duration displayed a higher toxicity impact than the raw IBU. However, the treated sample after 160 min reflected high biosafety and non-toxic properties (cell viability > 97%). The synergetic impact of bentonite and bentonite organo-modified by curcumin extract reflects enhancements in the adsorption as well as the oxidation performance of pillared zinc as a catalyst. Full article

(This article belongs to the Topic Advanced Oxidation Processes for Wastewater Purification)

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22 pages, 6018 KiB

Open AccessArticle

Synergism of Artificial Intelligence and Techno-Economic for Sustainable Treatment of Methylene Blue Dye-Containing Wastewater by Photocatalysis

by Khumbolake Faith Ngulube, Amal Abdelhaleem, Manabu Fujii and Mahmoud Nasr

Sustainability 2024, 16(2), 529; https://doi.org/10.3390/su16020529 - 8 Jan 2024

Cited by 12 | Viewed by 2303

Abstract

Recently, removing dyes from wastewater by photocatalysis has been extensively studied by several researchers. However, there exists a research gap in optimizing the photocatalytic process parameters using artificial intelligence to maintain the associated techno-economic feasibility. Hence, this investigation attempts to optimize the photocatalytic [...] Read more.

Recently, removing dyes from wastewater by photocatalysis has been extensively studied by several researchers. However, there exists a research gap in optimizing the photocatalytic process parameters using artificial intelligence to maintain the associated techno-economic feasibility. Hence, this investigation attempts to optimize the photocatalytic degradation of methylene blue (MB) dye using an artificial neural network (ANN) model to minimize the capital and running costs, which is beneficial for industrial applications. A ZnO/MgO photocatalyst was synthesized, showing an energy band gap of 2.96 eV, crystallinity index of 71.92%, pore volume of 0.529 cm³/g, surface area of 30.536 m²/g, and multiple surface functional groups. An ANN model, with a 4-8-1 topology, trainlm training function, and feed-forward back-propagation algorithm, succeeded in predicting the MB removal efficiency (R² = 0.946 and mean squared error = 11.2). The ANN-based optimized condition depicted that over 99% of MB could be removed under C₀ = 16.42 mg/L, pH = 9.95, and catalyst dosage = 905 mg/L within 174 min. This optimum condition corresponded to a treatment cost of USD 8.52/m³ cheaper than the price estimated from the unoptimized photocatalytic system by ≈7%. The study outputs revealed positive correlations with the sustainable development goals accompanied by pollution reduction, human health protection, and aquatic species conservation. Full article

(This article belongs to the Topic Advanced Oxidation Processes for Wastewater Purification)

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18 pages, 7358 KiB

Open AccessArticle

Novel Fenton-like Catalyst HKUST-1(Cu)/MoS₂-3-C with Non-Equilibrium-State Surface for Selective Degradation of Phenolic Contaminants: Synergistic Effects of σ-Cu-Ligand and ≡Mo–OOSO₃⁻ Complex

by Xiaoze Yin, Huaqin Yin, Renjie Wang, Jinnan Wang and Aimin Li

Water 2024, 16(1), 121; https://doi.org/10.3390/w16010121 - 28 Dec 2023

Cited by 3 | Viewed by 1914

Abstract

Novel Fenton-like catalyst HKUST-1(Cu)/MoS₂-3-C with a non-equilibrium-state surface was constructed for selective degradation of phenolic contaminants. Electron-polarized distribution facilitated the formation of σ-Cu-ligand between electron-poor Cu centre and phenolic compounds, which not only enhanced radicals generation but also accelerated the Cu(I)/Cu(II) [...] Read more.

Novel Fenton-like catalyst HKUST-1(Cu)/MoS₂-3-C with a non-equilibrium-state surface was constructed for selective degradation of phenolic contaminants. Electron-polarized distribution facilitated the formation of σ-Cu-ligand between electron-poor Cu centre and phenolic compounds, which not only enhanced radicals generation but also accelerated the Cu(I)/Cu(II) redox. Meanwhile, ≡Mo–OOSO₃⁻ complexes formed by the electron-rich Mo centre and peroxymonosulfate (PMS), could directly oxidize phenolic contaminants with the generation of SO₄^•−. The radical quenching experiments and EPR tests indicated that both SO₄^•− and •OH played a dominant role in the reaction. Additionally, O₂ could be reduced to O₂^•− by OVs and subsequently converted into ¹O₂ over the Mo centre. DFT calculation, FT-IR, and in situ Raman spectra analysis results demonstrated that phenolic compounds and PMS were respectively adsorbed by electron-poor Cu centre and electron-rich Mo centre, favouring the electrons transfer from phenolic contaminants to Mo centre for PMS activation. With synergistic effects of σ-Cu-ligand and ≡Mo–OOSO₃⁻ complexes, HKUST-1(Cu)/MoS₂-3-C achieved a high degradation rate of phenolic contaminants and utilization efficiency of PMS. Full article

(This article belongs to the Topic Advanced Oxidation Processes for Wastewater Purification)

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14 pages, 4655 KiB

Open AccessArticle

In Situ Synthesis of Bi₂S₃/BiFeO₃ Nanoflower Hybrid Photocatalyst for Enhanced Photocatalytic Degradation of Organic Pollutants

by Rentao Zhou, Xinman Tu, Peng Zheng, Li Zhang and Zhenxing Zeng

Molecules 2023, 28(24), 8007; https://doi.org/10.3390/molecules28248007 - 8 Dec 2023

Cited by 2 | Viewed by 1499

Abstract

Photocatalytic degradation of Malachite Green oxalate (MG) in a water body is of significant importance to our health protection, as it could cause various serious diseases. However the photocatalytic activity of most catalysts is still unsatisfactory, due to the poor reactive oxygen species [...] Read more.

Photocatalytic degradation of Malachite Green oxalate (MG) in a water body is of significant importance to our health protection, as it could cause various serious diseases. However the photocatalytic activity of most catalysts is still unsatisfactory, due to the poor reactive oxygen species production as a result of sluggish charge separation. Here, innovative nanoflower-shaped Bi₂S₃/BiFeO₃ heterojunctions are prepared via a facile sol–gel method, exhibiting an enhanced reactive oxygen species generation, which leads to the excellent photocatalytic performance toward MG degradation. We verify that interfacing BiFeO₃ with Bi₂S₃ could form a fine junction and offers a built-in field to speed up charge separation at the junction area; as a result, this shows much higher charge separation efficiency. By virtue of the aforementioned advantages, the as-prepared Bi₂S₃/BiFeO₃ heterojunctions exhibit excellent photocatalytic performance toward MG degradation, where more than 99% of MG is removed within 2 h of photocatalysis. The innovative design of nanoflower-like Bi₂S₃/BiFeO₃ heterojunctions may offer new viewpoints in designing highly efficient photocatalysts for environmentally related applications. Full article

(This article belongs to the Topic Advanced Oxidation Processes for Wastewater Purification)

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15 pages, 4299 KiB

Open AccessArticle

S-Scheme WO₃/SnIn₄S₈ Heterojunction for Water Purification: Enhanced Photocatalytic Performance and Mechanism

by Pingfan Xu, Runqiu Zhang, Jiarong Gong, Yaofa Luo, Yihua Zhuang and Peikun Zhang

Catalysts 2023, 13(11), 1450; https://doi.org/10.3390/catal13111450 - 20 Nov 2023

Cited by 7 | Viewed by 1912

Abstract

Photocatalysis is a promising technology for removing micropollutants in water. However, developing efficient and stable catalysts remains a challenge. In this work, a novel step-scheme (S-scheme) heterojunction of WO₃/SnIn₄S₈ (WSI) was constructed through the combined process of in [...] Read more.

Photocatalysis is a promising technology for removing micropollutants in water. However, developing efficient and stable catalysts remains a challenge. In this work, a novel step-scheme (S-scheme) heterojunction of WO₃/SnIn₄S₈ (WSI) was constructed through the combined process of in situ precipitation with hydrothermal synthesis to simultaneously realize photocatalytic degradation of bisphenol A(BPA) and reduction of Cr(VI) in contaminated water. Results showed that the WSI S-scheme heterojuction has a synergistic effect for the removal of BPA and Cr(VI). An optimum case of the WSI-12% heterojunction exhibited the highest photocatalytic efficiency in the degradation of BPA under visible light, which is ca. 2.5 and 3.8 times more than the pure WO₃ and SIS, respectively. The enhanced photocatalytic activity is attributed to the formation of the WSI S-scheme heterojunctions which facilitate the spatial separation of charge carriers and preserve strong photoredox ability. Further, the S-scheme mechanism of enhanced photocatalysis was examined by the radical-trapping experiment and ESR, and superoxide and hydroxyl radicals were determined to be the major reactive oxygen species responsible for BPA degradation and Cr(VI) reduction by WSI. This work provides a novel strategy for tailoring high-performance S-scheme heterojunctions and shows the promising application in purifying wastewater with complex pollutants. Full article

(This article belongs to the Topic Advanced Oxidation Processes for Wastewater Purification)

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23 pages, 8807 KiB

Open AccessArticle

The Addition of Anthocyanin as a Sensitizer for TiO₂ Nanotubes in a Combined Process of Electrocoagulation and Photocatalysis for Methylene Blue Removal

by Indar Kustiningsih, Hendrini Pujiastuti, Denni Kartika Sari, Agus Rochmat and Slamet

Sustainability 2023, 15(21), 15384; https://doi.org/10.3390/su152115384 - 27 Oct 2023

Cited by 3 | Viewed by 1689

Abstract

Photocatalysis with TiO₂ semiconductors is one of several potential methods for removing Methylene Blue (MB) that is environmentally friendly, relatively cheap, and effective. The capability of TiO₂ photocatalysts for degrading MB can be improved by modifying the morphology of TiO₂ [...] Read more.

Photocatalysis with TiO₂ semiconductors is one of several potential methods for removing Methylene Blue (MB) that is environmentally friendly, relatively cheap, and effective. The capability of TiO₂ photocatalysts for degrading MB can be improved by modifying the morphology of TiO₂ into nanotubes and adding anthocyanin sensitizers. The objective of this study was to investigate the effect of anthocyanin sensitizer addition for TiO₂ nanotubes on MB removal using a combined process of electrocoagulation and photocatalysis. TiO₂ nanotubes were prepared through an anodization method with a glycerol electrolyte containing NH₄F of 0.5% w/v and water of 25% v/v. The cathode and anode used in the electrocoagulation process were 316 stainless steel and aluminum, respectively. The characteristics of the resulting TiO₂ nanotubes were analyzed using SEM-EDX, UV–Vis DRS, and XRD analyses. The results showed that the electrocoagulation at a pH of 10 and a voltage of 50 volts resulted in an MB removal efficiency of 57.88%. In the photocatalysis process, sensitizer addition can increase the MB removal efficiency from 19.71% to 29.06%. Furthermore, a combined process of electrocoagulation and photocatalysis without and with sensitizer addition resulted in MB removal efficiencies of 59.66% and 64.30%, respectively. Full article

(This article belongs to the Topic Advanced Oxidation Processes for Wastewater Purification)

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17 pages, 3274 KiB

Open AccessArticle

Study of the Process of Electrochemical Oxidation of Active Pharmaceutical Substances on the Example of Nitrofurazone ((2E)-2-[(5-Nitro-2-furyl)methylene]hydrazine Carboxamide)

by Vitalyi Vladimirovich Kuznetsov, Natalya Andreevna Ivantsova, Evgenii Nikolaevich Kuzin, Andrey Vladimirovich Pirogov, Yaroslav Olegovich Mezhuev, Elena Alexeevna Filatova and Yulia Michailovna Averina

Water 2023, 15(19), 3370; https://doi.org/10.3390/w15193370 - 26 Sep 2023

Cited by 5 | Viewed by 1930

Abstract

The effective mineralization of nitrofurazone (10–100 mg L⁻¹) was performed in aqueous solutions in the presence of chloride ions by electrochemical treatment. The destruction of the organic pollutant molecules was due to their interaction with active oxygen- and chlorine-containing species forming [...] Read more.

The effective mineralization of nitrofurazone (10–100 mg L⁻¹) was performed in aqueous solutions in the presence of chloride ions by electrochemical treatment. The destruction of the organic pollutant molecules was due to their interaction with active oxygen- and chlorine-containing species forming at the inert anode (Pt/Ti or BDD) during electrolysis. Measurements of nitrofurazone concentration, chemical oxygen demand (COD) and total organic carbon (TOC) were used to estimate the removal efficiency of the pollutant. Both the pollutant oxidation rate and the degree of its mineralization were higher for the BDD anode due to the higher anode potentials on it in the course of electrolysis, which provides a high rate of active oxidizer species generation. As a result, practically full nitrofurazone molecule destruction (>99%) was achieved in 30 min at an anodic current density of 0.1 A cm⁻², a volume current density of 1.33 A L⁻¹ and pH 2 using BDD anodes. On the other hand, the nitrafurazone degradation efficiency was about 95% for Pt/Ti anodes under the same conditions. Additionally, byproducts of nitrofurazone electrooxidation were investigated by means of liquid chromato-mass-spectrometry (LC/MS). It was found that the initial decolorization of nitrofurazone solution, which occurs during the first 5 min of electrolysis, is due to the formation of a dichloro derivative of nitrofurazone, which causes the destruction of the π−conjugated bond system. Further electrolysis resulted in the almost complete destruction of the dichloro derivative within 30 min of electrochemical treatment. Full article

(This article belongs to the Topic Advanced Oxidation Processes for Wastewater Purification)

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24 pages, 6748 KiB

Open AccessReview

Metal-Based Electrocatalysts for Selective Electrochemical Nitrogen Reduction to Ammonia

by Yi-Zhen Zhang, Peng-Hui Li, Yi-Nuo Ren, Yun He, Cheng-Xu Zhang, Jue Hu, Xiao-Qiang Cao and Michael K. H. Leung

Nanomaterials 2023, 13(18), 2580; https://doi.org/10.3390/nano13182580 - 18 Sep 2023

Cited by 3 | Viewed by 2684

Abstract

Ammonia (NH₃) plays a significant role in the manufacture of fertilizers, nitrogen-containing chemical production, and hydrogen storage. The electrochemical nitrogen reduction reaction (e-NRR) is an attractive prospect for achieving clean and sustainable NH₃ production, under mild conditions driven by renewable [...] Read more.

Ammonia (NH₃) plays a significant role in the manufacture of fertilizers, nitrogen-containing chemical production, and hydrogen storage. The electrochemical nitrogen reduction reaction (e-NRR) is an attractive prospect for achieving clean and sustainable NH₃ production, under mild conditions driven by renewable energy. The sluggish cleavage of N≡N bonds and poor selectivity of e-NRR are the primary challenges for e-NRR, over the competitive hydrogen evolution reaction (HER). The rational design of e-NRR electrocatalysts is of vital significance and should be based on a thorough understanding of the structure–activity relationship and mechanism. Among the various explored e-NRR catalysts, metal-based electrocatalysts have drawn increasing attention due to their remarkable performances. This review highlighted the recent progress and developments in metal-based electrocatalysts for e-NRR. Different kinds of metal-based electrocatalysts used in NH₃ synthesis (including noble-metal-based catalysts, non-noble-metal-based catalysts, and metal compound catalysts) were introduced. The theoretical screening and the experimental practice of rational metal-based electrocatalyst design with different strategies were systematically summarized. Additionally, the structure–function relationship to improve the NH₃ yield was evaluated. Finally, current challenges and perspectives of this burgeoning area were provided. The objective of this review is to provide a comprehensive understanding of metal-based e-NRR electrocatalysts with a focus on enhancing their efficiency in the future. Full article

(This article belongs to the Topic Advanced Oxidation Processes for Wastewater Purification)

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8 pages, 2353 KiB

Open AccessArticle

ZIF-67(Co)-Loaded Filter Paper for In Situ Catalytic Degradation of Bisphenol A in Water

by Zhimin Cai, Yutao Luo and Lu Gan

Separations 2022, 9(11), 340; https://doi.org/10.3390/separations9110340 - 3 Nov 2022

Cited by 3 | Viewed by 1948

Abstract

Herein, we loaded cobalt-based zeolite imidazolate frameworks, ZIF-67 (Co), onto commercial filter paper to prepare catalytic filter paper (ZFP) for the in situ degradation of bisphenol A (BPA) in water by activating peroxymonosulfate. The results showed that ZIF-67 (Co) was densely and uniformly [...] Read more.

Herein, we loaded cobalt-based zeolite imidazolate frameworks, ZIF-67 (Co), onto commercial filter paper to prepare catalytic filter paper (ZFP) for the in situ degradation of bisphenol A (BPA) in water by activating peroxymonosulfate. The results showed that ZIF-67 (Co) was densely and uniformly distributed on the surface of the filter paper. The prepared ZFP could effectively degrade BPA in situ through a gravity-driven filtration process. Specifically, when the flow rate of the BPA solution passing through ZFP was lower than 10 mL/min, 0.02 mM of BPA could be completely degraded by ZFP. Furthermore, ZFP showed promising water matrix adaptability, which could provide promising BPA degradation efficiency in a wide pH range or in the existence of multiple anions. The scavenging tests demonstrated that both sulfate radical and hydroxyl radical were generated for BPA degradation, in which hydroxyl radical was the dominant active species. The ZFP also exhibited promising long-time use stability with a high mineralization rate. This study provides a novel method to prepare high-efficient catalyst paper for the in situ organic pollutant removal in water media via a prompt filtration process. Full article

(This article belongs to the Topic Advanced Oxidation Processes for Wastewater Purification)

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16 pages, 3022 KiB

Open AccessArticle

Effect of Anions and Cations on Tartrazine Removal by the Zero-Valent Iron/Peroxymonosulfate Process: Efficiency and Major Radicals

by Wenqi You, Liang Liu, Junjie Xu, Tao Jin, Lichun Fu and Yuwei Pan

Catalysts 2022, 12(10), 1114; https://doi.org/10.3390/catal12101114 - 26 Sep 2022

Cited by 17 | Viewed by 1846

Abstract

Zero-valent iron/peroxymonosulfate (Fe⁰/PMS) has been considered as a promising approach for wastewater treatment. Anions and cations are widely present in wastewater and have significant effects on the performance of the Fe⁰/PMS system for wastewater treatment. Thus, in the present [...] Read more.

Zero-valent iron/peroxymonosulfate (Fe⁰/PMS) has been considered as a promising approach for wastewater treatment. Anions and cations are widely present in wastewater and have significant effects on the performance of the Fe⁰/PMS system for wastewater treatment. Thus, in the present study, tartrazine was selected as the target model; SO₄²⁻, NO₃⁻, HCO₃⁻, and Cl⁻ were selected as representative anions and Ca²⁺, Cu²⁺, Mg²⁺, and Mn²⁺ were chosen as representative cations. The effect of these anions and cations on tartrazine removal and major radicals in the Fe⁰/PMS were systematically investigated. The presence of a certain concentration of SO₄²⁻ and Cl⁻ had positive, NO₃⁻ had negative, and HCO₃⁻ had negligible effects on tartrazine removal in the Fe⁰/PMS system. SO₄²⁻ and HCO₃⁻ had a small effect on the contribution proportion of reduction, SO₄^•− and ^•OH; a certain concentration of Cl⁻ could enhance the contribution proportion of ^•OH; and NO₃⁻ would decrease the contribution proportion of SO₄^•− and ^•OH. A certain concentration of each of Ca²⁺, Cu²⁺, Mg²⁺, and Mn²⁺ could enhance the tartrazine removal in the Fe⁰/PMS system. Ca²⁺, Cu²⁺, and Mg²⁺ had no effect of the contribution of reduction, SO₄^•− and ^•OH, while a certain concentration of Mn²⁺ could enhance the contribution proportion of SO₄^•−. These results can provide some references for the Fe⁰/PMS system to treat actual wastewater containing anions and cations. Full article

(This article belongs to the Topic Advanced Oxidation Processes for Wastewater Purification)

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