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17 pages, 2791 KiB

Open AccessArticle

Comprehensive Study on Environmental Behaviour and Degradation by Photolytic/Photocatalytic Oxidation Processes of Pharmaceutical Memantine

by Sandra Babić, Davor Ljubas, Dragana Mutavdžić Pavlović, Martina Biošić, Lidija Ćurković and Dario Dabić

Catalysts 2023, 13(3), 612; https://doi.org/10.3390/catal13030612 - 17 Mar 2023

Cited by 1 | Viewed by 1364

Abstract

Memantine is a pharmaceutical used to treat memory loss, one of the main symptoms of dementia and Alzheimer’s disease. The use of memantine is expected to continue to grow due to the increasing proportion of the elderly population worldwide. The aim of this [...] Read more.

Memantine is a pharmaceutical used to treat memory loss, one of the main symptoms of dementia and Alzheimer’s disease. The use of memantine is expected to continue to grow due to the increasing proportion of the elderly population worldwide. The aim of this work was to conduct a comprehensive study on the behaviour of memantine in the environment and the possibilities of its removal from wastewater. Abiotic elimination processes (hydrolysis, photolysis and sorption) of memantine in the environment were investigated. Results showed that memantine is stable in the environment and easily leached from river sediment. Therefore, further investigation was focused on memantine removal by advanced oxidation processes that would prevent its release into the environment. For photolytic and photocatalytic degradation of memantine, ultraviolet (UV) lamps with the predominant radiation wavelengths of 365 nm (UV-A) and 254/185 nm (UV-C) were used as a source of light. TiO₂ in the form of a nanostructured film deposited on the borosilicate glass wall of the reactor was used for photocatalytic experiments. Photodegradation of memantine followed pseudo-first-order kinetics. The half-life of photocatalytic degradation by UV-A light was much higher (46.3 min) than the half-life obtained by UV-C light (3.9 min). Processes degradation efficiencies and evaluation of kinetic constants were based on the results of HPLC-MS/MS analyses, which also enable the identification of memantine oxidation products. The acute toxicity of the reaction mixture during the oxidation was evaluated by monitoring the inhibition of the luminescence of Vibrio fischeri bacteria. The results showed that memantine and its oxidation products were not harmful to Vibrio fischeri. Full article

(This article belongs to the Special Issue Industrial Applications of Advanced Oxidation Technologies: Past and Future)

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16 pages, 2535 KiB

Open AccessArticle

Development of Nanomedicine from Copper Mine Tailing Waste: A Pavement towards Circular Economy with Advanced Redox Nanotechnology

by Amrita Banerjee, Ria Ghosh, Tapan Adhikari, Subhadipta Mukhopadhyay, Arpita Chattopadhyay and Samir Kumar Pal

Catalysts 2023, 13(2), 369; https://doi.org/10.3390/catal13020369 - 07 Feb 2023

Cited by 4 | Viewed by 1663

Abstract

Copper, the essential element required for the human body is well-known for its profound antibacterial properties, yet salts and oxides of copper metals in the copper mine tailings are reported to be a big burden in the modern era. Among other copper oxides, [...] Read more.

Copper, the essential element required for the human body is well-known for its profound antibacterial properties, yet salts and oxides of copper metals in the copper mine tailings are reported to be a big burden in the modern era. Among other copper oxides, CuO, in particular, is known to have beneficial effects on humans, while its slight nanoengineering viz., surface functionalization of the nanometer-sized oxide is shown to make some paradigm shift using its inherent redox property. Here, we have synthesized nanometer-sized CuO nanoparticles and functionalized it with a citrate ligand for an enhanced redox property and better solubility in water. For structural analysis of the nanohybrid, standard analytical tools, such as electron microscopy, dynamic light scattering, and X-ray diffraction studies were conducted. Moreover, FTIR and UV-VIS spectroscopy studies were performed to confirm its functionalization. The antibacterial study results, against a model bacteria (S. hominis), show that CuO nanohybrids provide favorable outcomes on antibiotic-resistant organisms. The suitability of the nanohybrid for use in photodynamic therapy was also confirmed, as under light its activity increased substantially. The use of CuO nanoparticles as antibiotics was further supported by the use of computational biology, which reconfirmed the outcome of our experimental studies. We have also extracted CuO nanogranules (top-down technique) from copper mine tailings of two places, each with different geographical locations, and functionalized them with citrate ligands in order to characterize similar structural and functional properties obtained from synthesized CuO nanoparticles, using the bottom-up technique. We have observed that the extracted functionalized CuO from copper tailings offers similar properties compared to those of the synthesized CuO, which provides an avenue for the circular economy for the utilization of copper waste into nanomedicine, which is known to be best for mankind. Full article

(This article belongs to the Special Issue Industrial Applications of Advanced Oxidation Technologies: Past and Future)

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15 pages, 3357 KiB

Open AccessArticle

Differently Prepared PbO₂/Graphitic Carbon Nitride Composites for Efficient Electrochemical Removal of Reactive Black 5 Dye

by Aleksandar Marković, Slađana Savić, Andrej Kukuruzar, Zoltan Konya, Dragan Manojlović, Miloš Ognjanović and Dalibor M. Stanković

Catalysts 2023, 13(2), 328; https://doi.org/10.3390/catal13020328 - 01 Feb 2023

Cited by 1 | Viewed by 1499

Abstract

In this paper, electrochemical degradation of Reactive Black 5 (RB5) textile azo dye was examined in regard to different synthesis procedures for making PbO₂–graphitic carbon nitride (g-C₃N₄) electrode. The reaction of

Pb {(OH)}_{3}^{-}

with ClO [...] Read more.

In this paper, electrochemical degradation of Reactive Black 5 (RB5) textile azo dye was examined in regard to different synthesis procedures for making PbO₂–graphitic carbon nitride (g-C₃N₄) electrode. The reaction of

Pb {(OH)}_{3}^{-}

with ClO⁻ in the presence of different surfactants, i.e., cetyltrimethylammonium bromide (CTAB) and tetrabutylammonium phosphate (TBAP), under conventional conditions, resulted in the formation of PbO₂ with varying morphology. The obtained materials were combined with g-C₃N₄ for the preparation of the final composite materials, which were then characterized morphologically and electrochemically. After optimizing the degradation method, it was shown that an anode comprising a steel electrode coated with the composite of PbO₂ synthesized using CTAB as template and g-C₃N₄, and using 0.15 M Na₂SO₄ as the supporting electrolyte, gave the best performance for RB5 dye removal from a 35 mg/L solution. The treatment duration was 60 min, applying a current of 0.17 A (electrode surface 4 cm², current density of 42.5 mA/cm²), while the initial pH of the testing solution was 2. The reusability and longevity of the electrode surface (which showed no significant change in activity throughout the study) may suggest that this approach is a promising candidate for wastewater treatment and pollutant removal. Full article

(This article belongs to the Special Issue Industrial Applications of Advanced Oxidation Technologies: Past and Future)

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18 pages, 5366 KiB

Open AccessFeature PaperArticle

A Comparison Study between Wood Flour and Its Derived Biochar for the Enhancement of the Peroxydisulfate Activation Capability of Fe₃O₄

by Yu Han and Lijie Xu

Catalysts 2023, 13(2), 323; https://doi.org/10.3390/catal13020323 - 01 Feb 2023

Cited by 3 | Viewed by 968

Abstract

In this study, both wood flour (WF) and wood flour-derived biochar (WFB) were used as supports for Fe₃O₄ to activate peroxydisulfate (PDS). The role of different carriers was investigated emphatically from the aspects of catalyst properties, the degradation kinetics of [...] Read more.

In this study, both wood flour (WF) and wood flour-derived biochar (WFB) were used as supports for Fe₃O₄ to activate peroxydisulfate (PDS). The role of different carriers was investigated emphatically from the aspects of catalyst properties, the degradation kinetics of bisphenol A (BPA), the effects of important parameters, and the generation of reactive oxygen species (ROS). Results showed that both WF and WFB could serve as good support for Fe₃O₄, which could control the release of iron into solution and increase the specific surface areas (SSAs). The WFB/Fe₃O₄ had stronger PDS activation capability than WF/Fe₃O₄ mainly due to the larger SSA of WFB/Fe₃O₄ and the PDS activation ability of WFB. Both radical species (•OH and SO₄^•−) and non-radical pathways, including ¹O₂ and high-valent iron-oxo species, contributed to the degradation of BPA in the WFB/Fe₃O₄–PDS process. Moreover, the WFB/Fe₃O₄ catalyst also showed stronger ability to control the iron release, better reusability, and higher BPA mineralization efficiency than WF/Fe₃O₄. Full article

(This article belongs to the Special Issue Industrial Applications of Advanced Oxidation Technologies: Past and Future)

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18 pages, 26072 KiB

Open AccessArticle

Enhanced Photodegradation of Organic Pollutants by Novel Samarium-Doped Zinc Aluminium Spinel Ferrites

by Ionela Grecu, Petrisor Samoila, Petronela Pascariu, Corneliu Cojocaru, Maria Ignat, Ioan-Andrei Dascalu and Valeria Harabagiu

Catalysts 2023, 13(2), 266; https://doi.org/10.3390/catal13020266 - 24 Jan 2023

Cited by 2 | Viewed by 1133

Abstract

ZnAlFe_1−xSm_xO₄ (x = 0, 0.02, 0.04, 0.06, 0.08) spinel ferrites were successfully obtained for the first time via a sol–gel autocombustion technique using citric acid as the combustion/chelating agent. These materials were then employed as photocatalysts for the [...] Read more.

ZnAlFe_1−xSm_xO₄ (x = 0, 0.02, 0.04, 0.06, 0.08) spinel ferrites were successfully obtained for the first time via a sol–gel autocombustion technique using citric acid as the combustion/chelating agent. These materials were then employed as photocatalysts for the degradation of Evans Blue, considered herein as a model organic pollutant. The XRD and FTIR analysis confirmed the achievement of pure spinel ferrite structures for all the materials. TEM analysis showed that the average particle sizes decline from about 27 for the undoped material to 17 nm for samarium-doped materials, and the magnetic characterization at room temperature indicated the paramagnetic conduct for the studied samples. All the photocatalysts were active in Evans Blue photodegradation. The best photocatalytic performances were observed for the ZnAlFe_0.94Sm_0.06O₄ formulation and explained by the smallest values calculated for lattice parameter, interplanar distance, and particle-size values. By adding H₂O₂ and applying the modelling and optimization of the photocatalytic process for the best material, the half-life of the pollutant decreased significantly from 115 min to about 7 min (about 16-times), and the colour-removal efficiency was almost 100%. Full article

(This article belongs to the Special Issue Industrial Applications of Advanced Oxidation Technologies: Past and Future)

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9 pages, 2891 KiB

Open AccessArticle

Real-Time Degradation of Indoor Formaldehyde Released from Actual Particle Board by Heterostructured g-C₃N₄/TiO₂ Photocatalysts under Visible Light

by Qing Jin, Youlin Xiang and Lu Gan

Catalysts 2023, 13(2), 238; https://doi.org/10.3390/catal13020238 - 19 Jan 2023

Cited by 3 | Viewed by 1268

Abstract

Indoor formaldehyde pollution causes a serious threat to human health since it is uninterruptedly released from wooden furniture. Herein, we prepared a g-C₃N₄-modified TiO₂ composite photocatalyst and coated it on the surface of a commercial artificial particle board [...] Read more.

Indoor formaldehyde pollution causes a serious threat to human health since it is uninterruptedly released from wooden furniture. Herein, we prepared a g-C₃N₄-modified TiO₂ composite photocatalyst and coated it on the surface of a commercial artificial particle board with the assistance of melamine formaldehyde adhesive. The g-C₃N₄/ TiO₂ coating was then used to degrade formaldehyde which was released in real-time from the particle board under the irradiation of visible light. The results showed that compared with pure TiO₂, the g-C₃N₄/ TiO₂ composite with a heterojunction structure had a lower band gap energy (~2.6 eV), which could effectively capture luminous energy from the visible light region. Under continuous irradiation, the g-C₃N₄/ TiO₂ photocatalytic coating was capable of degrading more than 50% of formaldehyde constantly released from the particle board. In the meantime, the photocatalytic coating also exhibited promising catalytic stability towards various formaldehyde release speeds, air flow velocities and environmental humidities. The hydroxyl radical and superoxide radical were found to be the predominant active species which triggered formaldehyde degradation. This study provides a feasible and practical approach for the improvement in indoor air quality through photocatalyst surface engineering. Full article

(This article belongs to the Special Issue Industrial Applications of Advanced Oxidation Technologies: Past and Future)

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13 pages, 3097 KiB

Open AccessArticle

Photocatalytic Concrete Developed by Short Seedless Hydrothermal Method for Water Purification

by Marie Le Pivert and Yamin Leprince-Wang

Catalysts 2022, 12(12), 1620; https://doi.org/10.3390/catal12121620 - 09 Dec 2022

Cited by 2 | Viewed by 1111

Abstract

Stormwater runoff management and treatment are significant topics for designing a sustainable city. Therefore, photocatalytic, permeable, and removable concrete is a promising solution to reduce pollution through leaching with permeable and scalable road. The objective of this work was to develop cost-effective and [...] Read more.

Stormwater runoff management and treatment are significant topics for designing a sustainable city. Therefore, photocatalytic, permeable, and removable concrete is a promising solution to reduce pollution through leaching with permeable and scalable road. The objective of this work was to develop cost-effective and greener photocatalytic concretes that can be easily scaled-up, and to demonstrate their photocatalytic activities. To achieve this, seedless hydrothermal ZnO nanostructures (NSs) in 2 h were employed to functionalize a concrete surface by a soft functionalization process, avoiding overconsumption of energy and chemical products. In this work, two different concretes were studied and used for the degradation of organic dye in water. The results demonstrated the universality of the proposed functionalization process by showing similar gap values, ZnO NSs morphologies, and XRD pattern, compared to the concrete functionalized by the traditional two-step hydrothermal synthesis. The XRD results certified the presence of the ZnO Würtzite phase on the concrete surface. The synthesis feasibility was attributed to the basic pH and O⁻ groups’ presence in concrete. Then, their photocatalytic efficiency was proved for organic dye removal in water. An almost total degradation was recorded after 5 h under artificial solar light, even after several uses, demonstrating a similar efficiency to the photocatalytic concrete functionalized by the traditional two-step synthesis. Full article

(This article belongs to the Special Issue Industrial Applications of Advanced Oxidation Technologies: Past and Future)

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18 pages, 4394 KiB

Open AccessArticle

Enhanced Photoredox Activity of BiVO₄/Prussian Blue Nanocomposites for Efficient Pollutant Removal from Aqueous Media under Low-Cost LEDs Illumination

by Abrar Ali Khan, Leonardo Marchiori, Elias Paiva Ferreira-Neto, Heberton Wender, Rashida Parveen, Mohammad Muneeb, Bianca Oliveira Mattos, Ubirajara Pereira Rodrigues-Filho, Sidney José Lima Ribeiro and Sajjad Ullah

Catalysts 2022, 12(12), 1612; https://doi.org/10.3390/catal12121612 - 08 Dec 2022

Viewed by 1761

Abstract

Bismuth vanadate (BiVO₄, BV) is a widely explored photocatalyst for photo(electro)chemical applications, but its full photocatalytic potential is hindered by the fast recombination and low mobility of photogenerated charge carriers. Herein, we propose the photodeposition of different amounts of Prussian blue [...] Read more.

Bismuth vanadate (BiVO₄, BV) is a widely explored photocatalyst for photo(electro)chemical applications, but its full photocatalytic potential is hindered by the fast recombination and low mobility of photogenerated charge carriers. Herein, we propose the photodeposition of different amounts of Prussian blue (PB) cocatalysts on the surface of monoclinic BV to obtain BV-PB composite photocatalysts with increased photoactivity. The as-prepared BV and BV-PB composites were characterized by an array of analytic techniques such scanning eletron microscopy (SEM), transmission eletron microscopy (TEM), X-day diffraction (XRD), and spectroscopic techniques including Fourier-transform infrared spectroscopy (FTIR), diffuse reflectance spectroscopy (DRS), electrochemical impedance spectroscopy (EIS), photoluminescence (PL), and Raman spectroscopy. The addition of PB not only increases the absorption of visible light, as indicated by DRS, but also improves the charge carriers’ transfer across the photocatalysts/solution interface and hence reduces electron-hole (e⁻-h⁺) recombination, as confirmed by EIS and PL measurements. Resultantly, the BV-PB composite photocatalysts with optimum PB loading exhibited enhanced Cr(VI) photoreduction efficiency as compared to pristine BV under visible light illumination from low-power blue light-emitting diodes (LEDs), thanks to the cocatalyst role of PB which mediates the transfer of photoexcited conduction band (CB) electrons from BV to Cr(VI) species in solution. Moreover, as compared to pristine BV and BV + H₂O₂, a drastic increase in the methylene blue (MB) photo-oxidation efficiency was observed for BV-PB in the presence of a minute quantity of H₂O₂ due to a synergic effect between the photocatalytic and Fenton-like processes. While pure BV photodegraded around 70% of MB dye within 120 min, the BV-PB/H₂O₂ and BV/H₂O₂ system could degrade almost 100% of the dye within 20 min (k_obs. = 0.375 min⁻¹) and 40 min (k_obs. = 0.055 min⁻¹), respectively. The practical approach employed in this work may pioneer new prospects for synthesizing new BV-based photocatalytic systems with low production costs and high photoredox efficiencies. Full article

(This article belongs to the Special Issue Industrial Applications of Advanced Oxidation Technologies: Past and Future)

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9 pages, 1821 KiB

Open AccessArticle

Constructing Active Sites on Self-Supporting Ti₃C₂T_x (T = OH) Nanosheets for Enhanced Photocatalytic CO₂ Reduction into Alcohols

by Shuqu Zhang, Man Zhang, Wuwan Xiong, Jianfei Long, Yong Xu, Lixia Yang and Weili Dai

Catalysts 2022, 12(12), 1594; https://doi.org/10.3390/catal12121594 - 06 Dec 2022

Cited by 1 | Viewed by 1123

Abstract

Ti₃C₂T_x (T = OH) was first prepared from Ti₃AlC₂ by HF etching and applied into a photocatalytic CO₂ reduction. Then, the Ti₃C₂T_x nanosheets present interbedded a self-supporting structure and [...] Read more.

Ti₃C₂T_x (T = OH) was first prepared from Ti₃AlC₂ by HF etching and applied into a photocatalytic CO₂ reduction. Then, the Ti₃C₂T_x nanosheets present interbedded a self-supporting structure and extended interlayer spacing. Meanwhile, the Ti₃C₂T_x nanosheets are decorated with abundant oxygen-containing functional groups in the process of etching, which not only serve as active sites but also show efficient charge migration and separation. Among Ti₃C₂T_x materials prepared by etching for different times, Ti₃C₂T_x-36 (Etching time: 36 h) showed the best performance for photoreduction of CO₂ into alcohols (methanol and ethanol), giving total yield of 61 μmol g catal.⁻¹, which is 2.8 times than that of Ti₃AlC₂. Moreover, excellent cycling stability for CO₂ reduction is beneficial from the stable morphology and crystalline structure. This work provided novel sights into constructing surface active sites controllably. Full article

(This article belongs to the Special Issue Industrial Applications of Advanced Oxidation Technologies: Past and Future)

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15 pages, 5527 KiB

Open AccessFeature PaperArticle

Photocatalytic Degradation of Tetracycline by Supramolecular Materials Constructed with Organic Cations and Silver Iodide

by Xing-Xing Zhang, Xiao-Jia Wang and Yun-Yin Niu

Catalysts 2022, 12(12), 1581; https://doi.org/10.3390/catal12121581 - 05 Dec 2022

Cited by 9 | Viewed by 1556

Abstract

Photocatalytic degradation, as a very significant advanced oxidation technology in the field of environmental purification, has attracted extensive attention in recent years. The design and synthesis of catalysts with high-intensity photocatalytic properties have been the focus of many researchers in recent years. In [...] Read more.

Photocatalytic degradation, as a very significant advanced oxidation technology in the field of environmental purification, has attracted extensive attention in recent years. The design and synthesis of catalysts with high-intensity photocatalytic properties have been the focus of many researchers in recent years. In this contribution, two new supramolecular materials {[(L1)·(Ag₄I₇)]CH₃CN} (1), {[(L2)·(Ag₄I₇)]CH₃CN} (2) were synthesized by solution volatilization reaction of two cationic templates 1,3,5-Tris(4-aminopyridinylmethyl)-2,4,6-Trimethylphenyl bromide (L1) and 1,3,5-Tris(4-methyl pyridinyl methyl)-2,4,6-trimethylphenyl bromide (L2) with metal salt AgI at room temperature, respectively. The degradation effect of 1 and 2 as catalyst on tetracycline (TC) under visible light irradiation was studied. The results showed that the degradation of TC by 1 was better than that by 2 and both of them had good stability and cyclability. The effects of pH value, catalyst dosage, and anion in water on the photocatalytic performance were also investigated. The adsorption kinetics fit the quasi-first-order model best. After 180 min of irradiation with 1, the degradation rate of TC can reach 97.91%. In addition, the trapping experiments showed that ·OH was the main active substance in the photocatalytic degradation of TC compared with ·O₂⁻ and h⁺. Because of its simple synthesis and high removal efficiency, catalyst 1 has potential value for the treatment of wastewater containing organic matter. Full article

(This article belongs to the Special Issue Industrial Applications of Advanced Oxidation Technologies: Past and Future)

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18 pages, 2920 KiB

Open AccessFeature PaperArticle

Study of Photocatalytic Oxidation of Micropollutants in Water and Intensification Case Study

by Lucija Radetić, Jan Marčec, Ivan Brnardić, Tihana Čižmar and Ivana Grčić

Catalysts 2022, 12(11), 1463; https://doi.org/10.3390/catal12111463 - 18 Nov 2022

Cited by 2 | Viewed by 1408

Abstract

During the last decades, heterogenous photocatalysis has shown as the most promising advanced oxidation process for the removal of micropollutants due to degradation rate, sustainability, non-toxicity, and low-cost. Synergistic interaction of light irradiation, photocatalysts, and highly reactive species are used to break down [...] Read more.

During the last decades, heterogenous photocatalysis has shown as the most promising advanced oxidation process for the removal of micropollutants due to degradation rate, sustainability, non-toxicity, and low-cost. Synergistic interaction of light irradiation, photocatalysts, and highly reactive species are used to break down pollutants toward inert products. Even though titanium dioxide (TiO₂) is the most researched photocatalyst, to overcome shortcomings, various modifications have been made to intensify photocatalytic activity in visible spectra range among which is modification with multiwalled carbon nanotubes (MWCNTs). Therefore, photocatalytic oxidation and its intensification by photocatalyst’s modification was studied on the example of four micropollutants (diclofenac, DF; imidacloprid, IMI; 1-H benzotriazole, BT; methylene blue, MB) degradation. Compound parabolic collector (CPC) reactor was used as, nowadays, it has been considered the state-of-the-art system due to its usage of both direct and diffuse solar radiation and quantum efficiency. A commercially available TiO₂ P25 and nanocomposite of TiO₂ and MWCNT were immobilized on a glass fiber mesh by sol-gel method. Full-spectra solar lamps with appropriate UVB and UVA irradiation levels were used in all experiments. Photocatalytic degradation of DF, IMI, BT, and MB by immobilized TiO₂ and TiO₂/CNT photocatalysts was achieved. Mathematical modelling which included mass transfer and photon absorption was applied and intrinsic reaction rate constants were estimated:

k_{DF} = 3.56 \times 10^{- 10} s^{- 1} W^{- 0.5} m^{1.5}

,

k_{IMI} = 8.90 \times 10^{- 11} s^{- 1} W^{- 0.5} m^{1.5}

,

k_{BT} = 1.20 \times 10^{- 9} s^{- 1} W^{- 0.5} m^{1.5}

,

k_{MB} = 1.62 \times 10^{- 10} s^{- 1} W^{- 0.5} m^{1.5}

. Intensification of photocatalysis by TiO₂/CNT was observed for DF, IMI, and MB, while that was not the case for BT. The developed model can be effectively applied for different irradiation conditions which makes it extremely versatile and adaptable when predicting the degradation extents throughout the year using sunlight as the energy source at any location. Full article

(This article belongs to the Special Issue Industrial Applications of Advanced Oxidation Technologies: Past and Future)

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9 pages, 2376 KiB

Open AccessArticle

Sepiolite-Supported WS₂ Nanosheets for Synergistically Promoting Photocatalytic Rhodamine B Degradation

by Jiaxuan Bai, Kaibin Cui, Xinlei Xie, Baizeng Fang and Fei Wang

Catalysts 2022, 12(11), 1400; https://doi.org/10.3390/catal12111400 - 09 Nov 2022

Cited by 3 | Viewed by 1226

Abstract

Pristine tungsten disulfide (WS₂) nanosheets are extremely prone to agglomeration, leading to blocked active sites and the decrease of catalytic activity. In this work, highly dispersed WS₂ nanosheets were fabricated via a one-step in situ solvothermal method, using sepiolite nanofibers [...] Read more.

Pristine tungsten disulfide (WS₂) nanosheets are extremely prone to agglomeration, leading to blocked active sites and the decrease of catalytic activity. In this work, highly dispersed WS₂ nanosheets were fabricated via a one-step in situ solvothermal method, using sepiolite nanofibers as a functional carrier. The ammonium tetrathiotungstate was adopted as W and S precursors, and N,N-dimethylformamide could provide a neutral reaction environment. The electron microscope analysis revealed that the WS₂ nanosheets were stacked compactly in the shape of irregular plates, while they were uniformly grown on the surface of sepiolite nanofibers. Meanwhile, the BET measurement confirmed that the as-prepared composite has a larger specific surface area and is more mesoporous than the pure WS₂. Due to the improved dispersion of WS₂ and the synergistic effect between WS₂ and the mesoporous sepiolite mineral which significantly facilitated the mass transport, the WS₂/sepiolite composite exhibited ca. 2.6 times the photocatalytic efficiency of the pure WS₂ for rhodamine B degradation. This work provides a potential method for low-cost batch preparation of high-quality 2D materials via assembling on natural materials. Full article

(This article belongs to the Special Issue Industrial Applications of Advanced Oxidation Technologies: Past and Future)

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17 pages, 2639 KiB

Open AccessArticle

Ultrasound/Chlorine: A Novel Synergistic Sono-Hybrid Process for Allura Red AC Degradation

by Oualid Hamdaoui, Slimane Merouani, Hadjer C. Benmahmoud, Meriem Ait Idir, Hamza Ferkous and Abdulaziz Alghyamah

Catalysts 2022, 12(10), 1171; https://doi.org/10.3390/catal12101171 - 04 Oct 2022

Cited by 2 | Viewed by 1320

Abstract

Herein, we present an original report on chlorine activation by ultrasound (US: 600 kHz, 120 W) for intensifying the sonochemical treatment of hazardous organic materials. The coupling of US/chlorine produced synergy via the involvement of reactive chlorine species (RCSs: Cl^•, ClO [...] Read more.

Herein, we present an original report on chlorine activation by ultrasound (US: 600 kHz, 120 W) for intensifying the sonochemical treatment of hazardous organic materials. The coupling of US/chlorine produced synergy via the involvement of reactive chlorine species (RCSs: Cl^•, ClO^• and Cl₂^•−), resulting from the sono-activation of chlorine. The degradation of Allura Red AC (ARAC) textile dye, as a contaminant model, was drastically improved by the US/chlorine process as compared to the separated techniques. A synergy index of 1.74 was obtained by the US/chlorine process for the degradation of ARAC (C₀ = 5 mg·L⁻¹) at pH 5.5 and [chlorine]₀ = 250 mM. The synergistic index increased by up to 2.2 when chlorine concentration was 300 µM. Additionally, the synergetic effect was only obtained at pH 4–6, where HOCl is the sole chlorine species. Additionally, the effect of combining US and chlorine for ARAC degradation was additive for the argon atmosphere, synergistic for air and negative for N₂. An air atmosphere could provide the best synergy as it generates a relatively moderate concentration of reactive species as compared to argon, which marginalizes radical–radical reactions compared to radical–organic ones. Finally, the US/chlorine process was more synergistic for low pollutant concentrations (C₀ ≤ 10 mg·L⁻¹); the coupling effect was additive for moderate concentrations (C₀~20–30 mg·L⁻¹) and negative for higher C₀ (>30 mg·L⁻¹). Consequently, the US/chlorine process was efficiently operable under typical water treatment conditions, although complete by-product analysis and toxicity assessment may still be necessary to establish process viability. Full article

(This article belongs to the Special Issue Industrial Applications of Advanced Oxidation Technologies: Past and Future)

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11 pages, 4578 KiB

Open AccessArticle

Fenton-like Remediation for Industrial Oily Wastewater Using Fe₇₈Si₉B₁₃ Metallic Glasses

by Yulong Liu, Bowen Zhao, Guofeng Ma, Shiming Zhang, Haifeng Zhang and Zhengwang Zhu

Catalysts 2022, 12(9), 1038; https://doi.org/10.3390/catal12091038 - 12 Sep 2022

Cited by 1 | Viewed by 1336

Abstract

Metallic glasses (MGs) with a unique atomic structure have been widely used in the catalytic degradation of organic pollutants in the recent years. Fe₇₈Si₉B₁₃ MGs exhibited excellent catalytic performance for the degradation of oily wastewater in a Fenton-like [...] Read more.

Metallic glasses (MGs) with a unique atomic structure have been widely used in the catalytic degradation of organic pollutants in the recent years. Fe₇₈Si₉B₁₃ MGs exhibited excellent catalytic performance for the degradation of oily wastewater in a Fenton-like system for the first time. The oil removal and chemical oxygen demand (COD) removal from the oily wastewater were 72.67% and 70.18% within 60 min, respectively. Quenching experiments were performed to verify the production of active hydroxyl radicals (·OH) by activating hydrogen peroxide (H₂O₂). The formation of ·OH species can significantly contribute to the degradation reaction of oily wastewater. Fe₇₈Si₉B₁₃ MG ribbons were highly efficient materials that exhibited superior reactivity towards H₂O₂ activation in oily wastewater treatment. The study revealed the catalytic capability of metallic glasses, presenting extensive prospects of their applications in oily wastewater treatment. Full article

(This article belongs to the Special Issue Industrial Applications of Advanced Oxidation Technologies: Past and Future)

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15 pages, 1874 KiB

Open AccessFeature PaperArticle

High-Temperature Abatement of N₂O over FeOx/CeO₂-Al₂O₃ Catalysts: The Effects of Oxygen Mobility

by Larisa Pinaeva, Igor Prosvirin, Yuriy Chesalov and Victor Atuchin

Catalysts 2022, 12(9), 938; https://doi.org/10.3390/catal12090938 - 24 Aug 2022

Cited by 7 | Viewed by 1497

Abstract

CeO₂-Al₂O₃ oxides prepared by co-precipitation (Ce+Al) or CeOx precipitation onto Al₂O₃ (Ce/Al) to obtain dispersed CeO₂ and samples with further supported FeOx (2.5–9.9 weight% in terms of Fe) were characterized by XRD, XPS, DDPA [...] Read more.

CeO₂-Al₂O₃ oxides prepared by co-precipitation (Ce+Al) or CeOx precipitation onto Al₂O₃ (Ce/Al) to obtain dispersed CeO₂ and samples with further supported FeOx (2.5–9.9 weight% in terms of Fe) were characterized by XRD, XPS, DDPA and Raman. Fe/Ce/Al samples with lower surface concentrations of Fe³⁺ were substantially more active in N₂O decomposition at 700–900 °C. It was related to higher oxygen mobility, as estimated from ¹⁶O/¹⁸O exchange experiments and provided by preferential exposing of (Fe-)Ce oxides. Stabilization of some Ce as isolated Ce³⁺ in Fe-Ce-Al mixed oxides dominating in the bulk and surface layers of Fe/(Ce + Al) samples retards the steps responsible for fast additional oxygen transfer to the sites of O₂ desorption. Full article

(This article belongs to the Special Issue Industrial Applications of Advanced Oxidation Technologies: Past and Future)

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36 pages, 5646 KiB

Open AccessReview

Metallocavitins as Advanced Enzyme Mimics and Promising Chemical Catalysts

by Albert A. Shteinman

Catalysts 2023, 13(2), 415; https://doi.org/10.3390/catal13020415 - 15 Feb 2023

Cited by 1 | Viewed by 1961

Abstract

The supramolecular approach is becoming increasingly dominant in biomimetics and chemical catalysis due to the expansion of the enzyme active center idea, which now includes binding cavities (hydrophobic pockets), channels and canals for transporting substrates and products. For a long time, the mimetic [...] Read more.

The supramolecular approach is becoming increasingly dominant in biomimetics and chemical catalysis due to the expansion of the enzyme active center idea, which now includes binding cavities (hydrophobic pockets), channels and canals for transporting substrates and products. For a long time, the mimetic strategy was mainly focused on the first coordination sphere of the metal ion. Understanding that a highly organized cavity-like enzymatic pocket plays a key role in the sophisticated functionality of enzymes and that the activity and selectivity of natural metalloenzymes are due to the effects of the second coordination sphere, created by the protein framework, opens up new perspectives in biomimetic chemistry and catalysis. There are two main goals of mimicking enzymatic catalysis: (1) scientific curiosity to gain insight into the mysterious nature of enzymes, and (2) practical tasks of mankind: to learn from nature and adopt from its many years of evolutionary experience. Understanding the chemistry within the enzyme nanocavity (confinement effect) requires the use of relatively simple model systems. The performance of the transition metal catalyst increases due to its retention in molecular nanocontainers (cavitins). Given the greater potential of chemical synthesis, it is hoped that these promising bioinspired catalysts will achieve catalytic efficiency and selectivity comparable to and even superior to the creations of nature. Now it is obvious that the cavity structure of molecular nanocontainers and the real possibility of modifying their cavities provide unlimited possibilities for simulating the active centers of metalloenzymes. This review will focus on how chemical reactivity is controlled in a well-defined cavitin nanospace. The author also intends to discuss advanced metal–cavitin catalysts related to the study of the main stages of artificial photosynthesis, including energy transfer and storage, water oxidation and proton reduction, as well as highlight the current challenges of activating small molecules, such as H₂O, CO₂, N₂, O₂, H₂, and CH₄. Full article

(This article belongs to the Special Issue Industrial Applications of Advanced Oxidation Technologies: Past and Future)

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27 pages, 3303 KiB

Open AccessReview

State of Art and Perspectives in Catalytic Ozonation for Removal of Organic Pollutants in Water: Influence of Process and Operational Parameters

by Naghmeh Fallah, Ermelinda Bloise, Domenico Santoro and Giuseppe Mele

Catalysts 2023, 13(2), 324; https://doi.org/10.3390/catal13020324 - 01 Feb 2023

Cited by 3 | Viewed by 1488

Abstract

The number of organic pollutants detected in water and wastewater is continuously increasing thus causing additional concerns about their impact on public and environmental health. Therefore, catalytic processes have gained interest as they can produce radicals able to degrade recalcitrant micropollutants. Specifically, catalytic [...] Read more.

The number of organic pollutants detected in water and wastewater is continuously increasing thus causing additional concerns about their impact on public and environmental health. Therefore, catalytic processes have gained interest as they can produce radicals able to degrade recalcitrant micropollutants. Specifically, catalytic ozonation has received considerable attention due to its ability to achieve advanced treatment performances at reduced ozone doses. This study surveys and summarizes the application of catalytic ozonation in water and wastewater treatment, paying attention to both homogeneous and heterogeneous catalysts. This review integrates bibliometric analysis using VOS viewer with systematic paper reviews, to obtain detailed summary tables where process and operational parameters relevant to catalytic ozonation are reported. New insights emerging from heterogeneous and homogenous catalytic ozonation applied to water and wastewater treatment for the removal of organic pollutants in water have emerged and are discussed in this paper. Finally, the activities of a variety of heterogeneous catalysts have been assessed using their chemical–physical parameters such as point of zero charge (PZC), pKa, and pH, which can determine the effect of the catalysts (positive or negative) on catalytic ozonation processes. Full article

(This article belongs to the Special Issue Industrial Applications of Advanced Oxidation Technologies: Past and Future)

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34 pages, 4024 KiB

Open AccessReview

A Critical Review of Photo-Based Advanced Oxidation Processes to Pharmaceutical Degradation

by Isabelle M. D. Gonzaga, Caio V. S. Almeida and Lucia H. Mascaro

Catalysts 2023, 13(2), 221; https://doi.org/10.3390/catal13020221 - 18 Jan 2023

Cited by 5 | Viewed by 2545

Abstract

Currently, the production and consumption of pharmaceuticals is growing exponentially, making them emerging contaminants that cause hazards to the ecological environment and human health. These drugs have been detected in surface water and drinking water around the world. This indicates that the conventional [...] Read more.

Currently, the production and consumption of pharmaceuticals is growing exponentially, making them emerging contaminants that cause hazards to the ecological environment and human health. These drugs have been detected in surface water and drinking water around the world. This indicates that the conventional treatments used are ineffective for the removal of these compounds from the water, since they are very complex, with high stability and have high persistence in aquatic environments. Considering this problem, several types of alternative treatments, such as advanced oxidative processes, have been studied. Of these, AOPs using irradiation have received increasing interest due to their fast reaction rate and the ability to generate oxidizing species, which leads to an efficient degradation and mineralization of organic compounds, thus improving the quality of water and allowing its reuse. Therefore, in this review, we focus on the advances made in the last five years of irradiated AOPs in the degradation of different classes of pharmaceutical compounds. The articles address different study parameters, such as the method of the synthesis of materials, oxidants used, treatment time, type of light used and toxicity of effluents. This review highlights the success of irradiated AOPs in the removal of pharmaceuticals and hopes to help the readers to better understand these processes and their limitations for removing drugs from the environment. It also sheds light on some paths that future research must follow so that the technology can be fully applied. Full article

(This article belongs to the Special Issue Industrial Applications of Advanced Oxidation Technologies: Past and Future)

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27 pages, 3862 KiB

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Recent Advances in the Development of Novel Iron–Copper Bimetallic Photo Fenton Catalysts

by Gabriela N. Bosio, Fernando S. García Einschlag, Luciano Carlos and Daniel O. Mártire

Catalysts 2023, 13(1), 159; https://doi.org/10.3390/catal13010159 - 10 Jan 2023

Cited by 2 | Viewed by 1929

Abstract

Advanced oxidation processes (AOPs) have been postulated as viable, innovative, and efficient technologies for the removal of pollutants from water bodies. Among AOPs, photo-Fenton processes have been shown to be effective for the degradation of various types of organic compounds in industrial wastewater. [...] Read more.

Advanced oxidation processes (AOPs) have been postulated as viable, innovative, and efficient technologies for the removal of pollutants from water bodies. Among AOPs, photo-Fenton processes have been shown to be effective for the degradation of various types of organic compounds in industrial wastewater. Monometallic iron catalysts are limited in practical applications due to their low catalytic activity, poor stability, and recyclability. On the other hand, the development of catalysts based on copper oxides has become a current research topic due to their advantages such as strong light absorption, high mobility of charge carriers, low environmental toxicity, long-term stability, and low production cost. For these reasons, great efforts have been made to improve the practical applications of heterogeneous catalysts, and the bimetallic iron–copper materials have become a focus of research. In this context, this review focuses on the compilation of the most relevant studies on the recent progress in the application of bimetallic iron–copper materials in heterogeneous photo–Fenton-like reactions for the degradation of pollutants in wastewater. Special attention is paid to the removal efficiencies obtained and the reaction mechanisms involved in the photo–Fenton treatments with the different catalysts. Full article

(This article belongs to the Special Issue Industrial Applications of Advanced Oxidation Technologies: Past and Future)

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22 pages, 3436 KiB

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Chalcogenides and Chalcogenide-Based Heterostructures as Photocatalysts for Water Splitting

by Mohammad Mansoob Khan and Ashmalina Rahman

Catalysts 2022, 12(11), 1338; https://doi.org/10.3390/catal12111338 - 01 Nov 2022

Cited by 13 | Viewed by 2609

Abstract

Chalcogenides are essential in the conversion of solar energy into hydrogen fuel due to their narrow band gap energy. Hydrogen fuel could resolve future energy crises by substituting carbon fuels owing to zero-emission carbon-free gas and its eco-friendliness. The fabrication of different metal [...] Read more.

Chalcogenides are essential in the conversion of solar energy into hydrogen fuel due to their narrow band gap energy. Hydrogen fuel could resolve future energy crises by substituting carbon fuels owing to zero-emission carbon-free gas and its eco-friendliness. The fabrication of different metal chalcogenide-based photocatalysts with enhanced photocatalytic water splitting have been summarized in this review. Different modifications of these chalcogenides, including coupling with another semiconductor, metal loading, and doping, are fabricated with different synthetic routes that can remarkably improve the photo-exciton separation and have been extensively investigated for photocatalytic hydrogen generation. In this direction, this review is undertaken to provide an overview of the enhanced photocatalytic performance of the binary and ternary chalcogenide heterostructures and their mechanisms for hydrogen production under irradiation of light. Full article

(This article belongs to the Special Issue Industrial Applications of Advanced Oxidation Technologies: Past and Future)

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32 pages, 5363 KiB

Open AccessFeature PaperReview

Recent Development in Non-Metal-Doped Titanium Dioxide Photocatalysts for Different Dyes Degradation and the Study of Their Strategic Factors: A Review

by Parveen Akhter, Abdullah Arshad, Aimon Saleem and Murid Hussain

Catalysts 2022, 12(11), 1331; https://doi.org/10.3390/catal12111331 - 31 Oct 2022

Cited by 43 | Viewed by 3957

Abstract

Semiconductor titanium dioxide in its basic form or doped with metals and non-metals is being extensively used in wastewater treatment by photocatalysis due to its versatile nature. Other numerous characteristics including being environmentally friendly, non-pernicious, economical, multi-phase, highly hydrophilic, versatile physio-chemical features, chemical [...] Read more.

Semiconductor titanium dioxide in its basic form or doped with metals and non-metals is being extensively used in wastewater treatment by photocatalysis due to its versatile nature. Other numerous characteristics including being environmentally friendly, non-pernicious, economical, multi-phase, highly hydrophilic, versatile physio-chemical features, chemical stability, suitable band gap, and corrosion-resistance, along with its low price make TiO₂ the best candidate in the field of photocatalysis. Commercially, semiconductor and synthesized photocatalysts—which have been investigated for the last few decades owing to their wide band gap—and the doping of titania with p-block elements (non-metals) such as oxygen, sulfur, nitrogen, boron, carbon, phosphorus, and iodine enhances their photocatalytic efficiency under visible-light irradiation. This is because non-metals have a strong oxidizing ability. The key focus of this review is to discuss the various factors affecting the photocatalytic activity of non-metal-doped titania by decreasing its band gap. The working parameters discussed are the effect of pH, dyes concentration, photocatalyst’s size and structure, pollutants concentration and types, the surface area of photocatalysts, the effect of light intensity and irradiation time, catalyst loading, the effect of temperature, and doping impact, etc. The mechanism of the photocatalytic action of several non-metallic dopants of titanium dioxide and composites is a promising approach for the exploration of photocatalysis activity. The various selected synthesis methods for non-metallic-doped TiO₂ have been reviewed in this study. Similarly, the effect of various conditions on the doping mode has been summarized in relation to several sorts of modified TiO₂. Full article

(This article belongs to the Special Issue Industrial Applications of Advanced Oxidation Technologies: Past and Future)

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