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Keywords = UV–vis DRS

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10 pages, 1708 KiB  
Communication
N Simultaneously Doped TiO2@Carbon Hollow Spheres with Enhanced Photocatalytic CO2 Reduction Activity
by Weiwei Fu, Ziyun Wang, Xinjie Liu and Tianjiao Li
Catalysts 2025, 15(1), 39; https://doi.org/10.3390/catal15010039 - 4 Jan 2025
Viewed by 278
Abstract
Converting carbon dioxide (CO2) into solar fuels through photocatalysis represents an appealing approach to tackling the escalating energy crisis and mitigating the greenhouse effect. In this study, using melamine–formaldehyde (MF) nanospheres as a nitrogen source, a N element was simultaneously doped [...] Read more.
Converting carbon dioxide (CO2) into solar fuels through photocatalysis represents an appealing approach to tackling the escalating energy crisis and mitigating the greenhouse effect. In this study, using melamine–formaldehyde (MF) nanospheres as a nitrogen source, a N element was simultaneously doped into the TiO2 nanoparticle structure supported by carbon hollow spheres using a one-step carbonization method to form a heterojunction N-CHS@N-TiO2 (marked as (N-(CHS@TiO2)). The composite showed superior photocatalytic activity in reducing CO2 compared with TiO2 and N-CHS: after 6 h of visible light irradiation, the CO yield was 4.3 times that of N-CHS and TiO2; 6 h of UV irradiation later, the CO yield reached 2.6 times that of TiO2 and 7 times that of N-CHS. The substantial enhancement in photocatalytic activity was attributed to the nitrogen simultaneously doped carbon hollow spheres and TiO2, mesoporous structure, small average TiO2 crystal size, large surface areas, and the heterostructure formed by N-CHS and N-TiO2. The UV-vis diffuse reflectance spectra (DRS) exhibit a significant improvement in light absorption, attributed to the visible-light-active carbon hollow sphere and the N element doping, thereby enhancing solar energy utilization. Full article
(This article belongs to the Special Issue Catalytic Properties of Hybrid Catalysts)
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25 pages, 4510 KiB  
Article
Effect of Calcination Temperature on the Photocatalytic Activity of Precipitated ZnO Nanoparticles for the Degradation of Rhodamine B Under Different Light Sources
by Amira Saidani, Reguia Boudraa, Karim Fendi, Lamia Benouadah, Abderrahim Benabbas, Atmane Djermoune, Stefano Salvestrini, Jean-Claude Bollinger, Abdulmajeed Abdullah Alayyaf and Lotfi Mouni
Water 2025, 17(1), 32; https://doi.org/10.3390/w17010032 - 26 Dec 2024
Viewed by 400
Abstract
This research provides valuable insights into the application of ZnO nanoparticles in photocatalytic wastewater treatment. Process optimization was carried out by determining the ratio of the surface area to the energy band gap (S/E) in the photocatalysis rate under different sources of light [...] Read more.
This research provides valuable insights into the application of ZnO nanoparticles in photocatalytic wastewater treatment. Process optimization was carried out by determining the ratio of the surface area to the energy band gap (S/E) in the photocatalysis rate under different sources of light (UV light, visible light, sunlight). The nanoparticles were synthesized using the precipitation technique, and the calcination process was carried out within a temperature range of 400 to 700 °C. The structural, morphological, and optical properties of materials were investigated using X-ray powder diffraction (XRD), scanning electron microscopy (SEM), UV-Vis diffuse reflectance (UV-Vis DRS), Raman spectroscopies, and Fourier transform infrared (FTIR) spectroscopies. The study demonstrates that calcination temperature significantly influences the photocatalytic activity of ZnO nanoparticles by altering their size, surface properties, shape, and optical behavior. Optimal decomposition efficiencies of Rhodamine B were achieved at 400 °C, with yields of 24%, 92%, and 91% under visible, UV, and sunlight irradiation, respectively. Additionally, the surface area decreased from 12.556 to 8.445 m2/g, the band gap narrowed slightly from 3.153 to 3.125 eV, and crystal growth increased from 0.223 to 0.506 µm as the calcination temperature rose. The photocatalytic properties of ZnO nanoparticles were assessed to determine their efficiency in decomposing Rhodamine B dye under operational parameters, including pollutant concentration (C0), sample amount, pH level, and reaction time. The sample exhibited the best breakdown rates with C0 = 5 mg/L, solid-to-liquid ratio (S/L) = 50 mg/L, pH = 7, and reaction time = 1 h. Additionally, we combined two oxidation processes, namely H2O2 and photocatalytic oxidation processes, which significantly improved the Rhodamine B removal efficiency, where 100% of RhB was degraded after 60 min and 100 µL of H2O2. Full article
(This article belongs to the Special Issue Advanced Biotechnologies for Water and Wastewater Treatment)
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14 pages, 3394 KiB  
Article
Enhanced Diclofenac Removal from Constructed Wetland Effluent Using a Photoelectrocatalytic System with N-TiO2 Nanocrystal-Modified TiO2 Nanotube Anode and Graphene Oxide/Activated Carbon Photocathode
by Xiongwei Liang, Shaopeng Yu, Bo Meng, Xiaodi Wang, Chunxue Yang, Chuanqi Shi and Junnan Ding
Catalysts 2024, 14(12), 954; https://doi.org/10.3390/catal14120954 - 23 Dec 2024
Viewed by 362
Abstract
This investigation reports on the efficacy of a photoelectrocatalysis (PEC) system enhanced by a nitrogen-doped TiO2 nanocrystal-modified TiO2 nanotube array (N-TiO2 NCs/TNTAs) anode paired with a graphene oxide/activated carbon (GO/AC) photocathode for diclofenac removal from effluent. The FE-SEM and EDX [...] Read more.
This investigation reports on the efficacy of a photoelectrocatalysis (PEC) system enhanced by a nitrogen-doped TiO2 nanocrystal-modified TiO2 nanotube array (N-TiO2 NCs/TNTAs) anode paired with a graphene oxide/activated carbon (GO/AC) photocathode for diclofenac removal from effluent. The FE-SEM and EDX analyses validated the elemental composition of the anode—27.56% C, 30.81% N, 6.03% O, and 26.49% Ti. The XRD results confirmed the anatase phase and nitrogen integration, essential for photocatalytic activity enhancement. Quantum chemical simulations provided a comprehensive understanding of the red-shifted absorption bands in N-TiO2, and UV-vis DRS demonstrated a red-shift in absorption to the visible spectrum, indicating improved light utilization. The PEC configuration achieved a photocurrent density of 9.8 mA/dm2, significantly higher than the unmodified and solely nitrogen-doped counterparts at 4.8 mA/dm2 and 6.1 mA/dm2, respectively. Notably, this system reduced diclofenac concentrations by 58% within 75 min, outperforming standard photocatalytic setups. These findings underscore the potential of N-TiO2 NCs/TNTAs-AC-GO/PTFE composite material for advanced environmental photoelectrocatalytic applications. Full article
(This article belongs to the Special Issue Nanomaterials in Environmental Catalysis)
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14 pages, 4412 KiB  
Article
Mesoporous TiO2@g-C3N4 Nanostructure-Enhanced Photocatalytic Degradation of Tetracycline Under Full-Spectrum Sunlight
by Lizhe Ma, Zhiyong Fang, Jieli Duan, Jin Li, Kefu Zhu, Yinlong Jiang, Bang Ji and Zhou Yang
Molecules 2024, 29(24), 5981; https://doi.org/10.3390/molecules29245981 - 18 Dec 2024
Viewed by 475
Abstract
TiO2 has broad prospects in reducing the safety risks posed by emerging pollutants in water environments. However, the high recombination rate of photogenerated carriers limits the activity and photon utilization efficiency of TiO2. In this study, mesoporous TiO2 (m-TiO [...] Read more.
TiO2 has broad prospects in reducing the safety risks posed by emerging pollutants in water environments. However, the high recombination rate of photogenerated carriers limits the activity and photon utilization efficiency of TiO2. In this study, mesoporous TiO2 (m-TiO2) and ultra-thin g-C3N4 nanosheets were composited using a hydrothermal method, with the m-TiO2 tightly and uniformly wrapped by g-C3N4. The chemical structure, elemental composition, and optical properties of the heterojunction were analyzed by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR), and ultraviolet-visible diffuse reflectance spectroscopy (UV-vis-DRS). The activity of the m-TiO2@g-C3N4 was evaluated by the degradation of tetracycline hydrochloride (TCH). Results showed that the heterojunction exhibited significantly enhanced reactivity compared to pure m-TiO2 and g-C3N4, with kinetic rates of TCH being 1.48 and 6.84 times that of pure m-TiO2 and g-C3N4, respectively. The TCH degradation kinetic rate varied from 0.194 min−1 to 0.026 min−1 and then decreased to 0.015 min−1 on the scale of the bandgap and the number of absorbed photons in m-TiO2@g-C3N4. Concurrently, a 10wt% doping amount of g-C3N4 significantly increased the reaction rate of photogenerated carriers in the system compared to the recombination rate, corresponding to excellent photon efficiency. Reproducibility was evaluated, and a possible degradation mechanism is proposed. This study opens new perspectives for the optimization of catalyst preparation processes aimed at enhancing photon efficiency. Full article
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23 pages, 9728 KiB  
Article
Investigation of the Photocatalytic Activity of Copper-Modified Commercial Titania (P25) in the Process of Carbon Dioxide Photoreduction
by Konrad Sebastian Sobczuk, Iwona Pełech, Daniel Sibera, Piotr Staciwa, Agnieszka Wanag, Ewa Ekiert, Joanna Kapica-Kozar, Katarzyna Ćmielewska, Ewelina Kusiak-Nejman, Antoni Waldemar Morawski and Urszula Narkiewicz
Materials 2024, 17(24), 6139; https://doi.org/10.3390/ma17246139 - 15 Dec 2024
Viewed by 509
Abstract
The photocatalytic reduction of CO2 to useful products is an area of active research because it shows a potential to be an efficient tool for mitigating climate change. This work investigated the modification of titania with copper(II) nitrate and its impact on [...] Read more.
The photocatalytic reduction of CO2 to useful products is an area of active research because it shows a potential to be an efficient tool for mitigating climate change. This work investigated the modification of titania with copper(II) nitrate and its impact on improving the CO2 reduction efficiency in a gas-phase batch photoreactor under UV–Vis irradiation. The investigated photocatalysts were prepared by treating P25-copper(II) nitrate suspensions (with various Cu2+ concentrations), alkalized with ammonia water, in a microwave-assisted solvothermal reactor. The titania-based photocatalysts were characterized by SEM, EDS, ICP-OES, XRD and UV-Vis/DR methods. Textural properties were measured by the low-temperature nitrogen adsorption/desorption studies at 77 K. P25 photocatalysts modified with copper(II) nitrate used in the process of carbon dioxide reduction allowed for a higher efficiency both for the photocatalytic reduction of CO2 to CH4 and for the photocatalytic water decomposition to hydrogen as compared to a reference. Similarly, modified samples showed significantly higher selectivity towards methane in the CO2 conversion process than the unmodified sample (a change from 30% for a reference sample to 82% for the P25-R-Cu-0.1 sample after the 6 h process). It was found that smaller loadings of Cu are more beneficial for increasing the photocatalytic activity of a sample. Full article
(This article belongs to the Special Issue Advances in Photocatalyst Materials and Green Chemistry)
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22 pages, 5132 KiB  
Article
Zn-Layered Double Hydroxide Intercalated with Graphene Oxide for Methylene Blue Photodegradation and Acid Red Adsorption Studies
by Rahmah H. Al-Ammari, Salwa D. Al-Malwi, Mohamed A. Abdel-Fadeel, Salem M. Bawaked and Mohamed Mokhtar M. Mostafa
Catalysts 2024, 14(12), 897; https://doi.org/10.3390/catal14120897 - 6 Dec 2024
Viewed by 942
Abstract
This study focuses on the synthesis of a novel layered double hydroxide and its application in two environmental remediation processes. Graphene oxide, a two-dimensional material, has potential applications in this field. However, its tendency to agglomerate restricts its usability. Our objective was to [...] Read more.
This study focuses on the synthesis of a novel layered double hydroxide and its application in two environmental remediation processes. Graphene oxide, a two-dimensional material, has potential applications in this field. However, its tendency to agglomerate restricts its usability. Our objective was to increase the morphology and performance of layered double hydroxide (LDH) by combining GO with hydrotalcite. The LDH/GO nanohybrids were utilized as photocatalysts for the degradation of methylene blue (MB) dye and were investigated as sorbents for acid red (A.R) dye in water. In order to achieve this objective, ZnAl-NO3 LDH was synthesized using the co-precipitation method, with a Zn:Al ratio of ~3. Subsequently, the LDH was intercalated with varying ratios of as-received graphene oxide. An array of analytical techniques, including X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS) measurements, N2 physisorption, scanning electron microscopy–energy-dispersive X-ray analysis (SEM-EDX), and diffuse reflectance UV–vis spectra (DR UV-vis), were employed to examine the physicochemical properties of the synthesized LDH. These techniques confirmed that the obtained material is zinc-aluminum hydrotalcite intercalated with GO. The addition of graphene oxide (GO) to the layered double hydroxide (LDH) structure improved the performance of the hydrotalcite. As a result, the composite ZnAl-LDH-10 shows significant potential in the field of photocatalytic degradation of MB. Additionally, the incorporation of GO enhanced the absorption of light in the visible region of the spectra, leading to improved elimination of A.R compared to LDH without GO or other ratios of GO. Full article
(This article belongs to the Special Issue Green Chemistry and Catalysis)
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22 pages, 8434 KiB  
Article
Highly Efficient Visible-Light Photocatalysts: Bi2O3@TiO2 Derived from Ti-MOFs for Eriochrome Black T Degradation: A Joint Experimental and Computational Study
by Jing Meng, Asmaa G. Ashry, Ahmed S. Abou-Elyazed, Zhe Zhang, Xiaolin Li, Tamer Z. Sharara and Safinaz H. El-Demerdash
Catalysts 2024, 14(11), 829; https://doi.org/10.3390/catal14110829 - 17 Nov 2024
Viewed by 1178
Abstract
Herein, we synthesized Ti-MOF through a solvothermal method and subsequently calcined it to form anatase TiO2. We further developed a Bi2O3@TiO2 mixed oxide using impregnation and calcination processes. These oxides showed significant photocatalytic activity for degrading [...] Read more.
Herein, we synthesized Ti-MOF through a solvothermal method and subsequently calcined it to form anatase TiO2. We further developed a Bi2O3@TiO2 mixed oxide using impregnation and calcination processes. These oxides showed significant photocatalytic activity for degrading Eriochrome Black T (EBT) dye under visible light irradiation. We characterized the prepared samples using various techniques, including XRD, XPS, FTIR, BET, SEM, EDX, TEM, and UV-DRS analyses. Our results indicated that TiO2 and 10%Bi2O3@TiO2 achieved 80% and 100% degradation of EBT dye solution (50 ppm) within 30 min in acidic medium with a 50 mg catalyst dose, respectively. The calcination of the Ti-MOF into TiO2 improved its sensitivity to visible light. The Bi2O3@TiO2 composite was also effective in degrading other organic pollutants, such as Congo Red (degradation ~99%), Malachite Green (degradation ~95%), Methylene Blue (degradation ~81%), and Safranine O (degradation ~69%). The impregnation of Bi2O3 increased the surface acidity of TiO2, enhancing its photocatalytic activity by promoting hydroxyl group formation through increased water adsorption. Additionally, 10%Bi2O3@TiO2 demonstrated excellent chemical stability and reusability, maintaining high degradation efficiency over four cycles. Density Functional Theory (DFT) and Time-Dependent DFT (TD-DFT) calculations were performed to understand the degradation mechanisms. UV-Vis absorption spectrum simulations suggested that the anionic HEB−2 (O24) or EB−3 forms of the EBT dye are likely to undergo degradation. This study highlights the potential of Bi2O3@TiO2 composites for effective photocatalytic applications in environmental remediation. Full article
(This article belongs to the Section Photocatalysis)
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12 pages, 816 KiB  
Article
Analysis of Solid Formulates Using UV-Visible Diffused Reflectance Spectroscopy with Multivariate Data Processing Based on Net Analyte Signal and Standard Additions Method
by Nicholas Kassouf, Alessandro Zappi, Michela Monticelli and Dora Melucci
Chemosensors 2024, 12(11), 227; https://doi.org/10.3390/chemosensors12110227 - 1 Nov 2024
Viewed by 1283
Abstract
Quality control in pharmaceutical manufacturing necessitates rigorous testing and approval, adhering to Current Good Manufacturing Practices before commercialization. The production of solid drugs presents significant industrial challenges regarding uniformity, homogeneity, and consistency. Traditional quality guidelines rely on classical analytical methods such as liquid [...] Read more.
Quality control in pharmaceutical manufacturing necessitates rigorous testing and approval, adhering to Current Good Manufacturing Practices before commercialization. The production of solid drugs presents significant industrial challenges regarding uniformity, homogeneity, and consistency. Traditional quality guidelines rely on classical analytical methods such as liquid chromatography coupled with mass spectrometry. However, the emergence of Process Analytical Technology introduced non-destructive, rapid, and cost-effective methods like UV-Visible Diffuse Reflectance Spectroscopy. The present study aimed to develop a chemometric method for quantifying Active Pharmaceutical Ingredients (APIs) in Neo Nisidine®, a solid mixture drug, using spectrophotometric data. The Net Analyte Signal (NAS) method, combined with standard additions, allowed the creation of a pseudo-univariate standard addition model, overcoming some challenges in solid-phase analysis. Successful quantifications of APIs in ideal laboratory samples and real pharmaceutical tablets were obtained. NAS-based chemometric models showed high precision and reliability, whose results were validated by comparisons with HPLC ones. The study revealed that solid-phase spectrophotometric analyses can be considered a valid alternative to API analyses. Solid-phase analysis offers non-destructive, cost-effective, and environmentally friendly benefits, enabling its integration into pharmaceutical production to improve quality control. Full article
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14 pages, 3432 KiB  
Article
Extended Interfacial Charge Transference in CoFe2O4/WO3 Nanocomposites for the Photocatalytic Degradation of Tetracycline Antibiotics
by Suiying Dong, Jiafu Dai, Ying Yang, Amir Zada and Kezhen Qi
Molecules 2024, 29(19), 4561; https://doi.org/10.3390/molecules29194561 - 25 Sep 2024
Viewed by 729
Abstract
The large-scale utilization of antibiotics has opened a separate chapter of pollution with the generation of reactive drug-resistant bacteria. To deal with this, in this work, different mass ratios of CoFe2O4/WO3 nanocomposites were prepared following an in situ [...] Read more.
The large-scale utilization of antibiotics has opened a separate chapter of pollution with the generation of reactive drug-resistant bacteria. To deal with this, in this work, different mass ratios of CoFe2O4/WO3 nanocomposites were prepared following an in situ growth method using the precursors of WO3 and CoFe2O4. The structure, morphology, and optical properties of the nanocomposite photocatalysts were scrutinized by X-ray diffraction (XRD), UV-visible diffuse reflectance spectra (UV-Vis DRS), photoluminescence spectrum (PL), etc. The experimental data signified that the loading of CoFe2O4 obviously changed the optical properties of WO3. The photocatalytic performance of CoFe2O4/WO3 composites was investigated by considering tetracycline as a potential pollutant. The outcome of the analyzed data exposed that the CoFe2O4/WO3 composite with a mass ratio of 5% had the best degradation performance for tetracycline eradication under the solar light, and a degradation efficiency of 77% was achieved in 20 min. The monitored degradation efficiency of the optimized photocatalyst was 45% higher compared with the degradation efficiency of 32% for pure WO3. Capturing experiments and tests revealed that hydroxyl radical (·OH) and hole (h+) were the primary eradicators of the target pollutant. This study demonstrates that a proper mass of CoFe2O4 can significantly push WO3 for enhanced eradication of waterborne pollutants. Full article
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12 pages, 1543 KiB  
Article
Photocatalytic Degradation of Levofloxacin and Inactivation of Enterococci Levofloxacin-Resistant Bacteria Using Pure Rare-Earth Oxides
by Lorenzo Saviano, Antonietta Mancuso, Alice Cardito, Olga Sacco, Vincenzo Vaiano, Maurizio Carotenuto, Giovanni Libralato and Giusy Lofrano
Separations 2024, 11(9), 272; https://doi.org/10.3390/separations11090272 - 18 Sep 2024
Viewed by 587
Abstract
In this study, La2O3 and CeO2 nanopowders were prepared using a simple and cost-effective precipitation method. Wide-angle X-ray diffraction (WAXD), UV-Visible reflectance diffuses (UV-Vis DRS), Raman spectroscopy, and specific surface area were used to characterize the photocatalysts, evidencing that [...] Read more.
In this study, La2O3 and CeO2 nanopowders were prepared using a simple and cost-effective precipitation method. Wide-angle X-ray diffraction (WAXD), UV-Visible reflectance diffuses (UV-Vis DRS), Raman spectroscopy, and specific surface area were used to characterize the photocatalysts, evidencing that the used preparation method was effective in the generation of crystalline CeO2 and La2O3. In particular, WAXD results showed that the average crystallite size of the achieved La2O3 and CeO2 samples were about 22 nm and 28 nm, respectively. The photocatalytic performances of the prepared catalysts were investigated in the degradation of levofloxacin (LEV) and the inactivation of a waterborne pathogen levofloxacin resistant (Enterococcus faecalis ATCC 29212) by using a photoreactor equipped with a solar simulator (SS). After 120 min, the CeO2 and La2O3 photocatalytic treatments allowed us to achieve between 75% and 83% of levofloxacin removal, respectively. A complete removal of 106 CFU/mL Enterococcus faecalis ATCC 29212 was achieved after 5 and 60 min of La2O3 and CeO2 photocatalytic processes, respectively. Full article
(This article belongs to the Special Issue Photocatalytic Materials for Pollutant Removal by Degradation)
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14 pages, 4880 KiB  
Article
Enhancement Study of the Photoactivity of TiO2 Photocatalysts during the Increase of the WO3 Ratio in the Presence of Ag Metal
by Sharah H. Aldirham, Ahmed Helal, Mohd Shkir, M. A. Sayed and Atif Mossad Ali
Catalysts 2024, 14(9), 633; https://doi.org/10.3390/catal14090633 - 18 Sep 2024
Cited by 1 | Viewed by 844
Abstract
Nanocomposites (NCs) consisting of 4%Ag/x%WO3/TiO2, with varied concentrations (x = 1, 3, 5, 7 wt.%) of WO3, were successfully synthesized using the sol-gel process to examine their photocatalytic performance. The synthesized 4%Ag/x%WO [...] Read more.
Nanocomposites (NCs) consisting of 4%Ag/x%WO3/TiO2, with varied concentrations (x = 1, 3, 5, 7 wt.%) of WO3, were successfully synthesized using the sol-gel process to examine their photocatalytic performance. The synthesized 4%Ag/x%WO3/TiO2 nanopowder was characterized using X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV–vis diffuse reflectance spectra (UV–vis DRS), photoluminescence (PL), and Brunauer–Emmett–Teller (BET) surface area analysis to elucidate its physicochemical properties. The photocatalytic evaluation revealed that the Ag/1%WO3/TiO2 nanocomposite exhibits 98% photoreduction efficiency for Cr(VI) after 2 h under visible light due to the impact of the plasmonic effect of Ag atoms. In addition, the Ag/4%WO3/TiO2 shows about 95% photooxidation efficiency for methylene blue (MB) dye after 4 h. Full article
(This article belongs to the Special Issue Cutting-Edge Photocatalysis)
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20 pages, 1236 KiB  
Article
Photo-Fenton Treatment under UV and Vis Light Reduces Pollution and Toxicity in Water from Madín Dam, Mexico
by Deysi Amado-Piña, Rubi Romero, Emmanuel Salazar Carmona, Armando Ramírez-Serrano, Leobardo Manuel Gómez-Oliván, Gustavo Elizalde-Velázquez and Reyna Natividad
Catalysts 2024, 14(9), 620; https://doi.org/10.3390/catal14090620 - 14 Sep 2024
Viewed by 968
Abstract
Water from Madín Dam in Mexico has been shown to contain a wide variety of pollutants such as drugs, pesticides, personal care products and compounds that are released into the environment as waste from production processes. In this work, the effect of the [...] Read more.
Water from Madín Dam in Mexico has been shown to contain a wide variety of pollutants such as drugs, pesticides, personal care products and compounds that are released into the environment as waste from production processes. In this work, the effect of the main process variables on the percentage of total organic carbon (TOC) removal in water samples from the Madín reservoir was studied by applying a photo-Fenton treatment catalyzed with iron-pillared clays. The catalyst was characterized by XRD, N2 physisorption, DRS and XPS. The sampling and characterization of the water from the Madín reservoir was carried out according to Mexican standards. The system for treatment tests was 0.1 L of reaction volume and a controlled temperature of 23–25 °C, and the reaction system was kept under constant stirring. After 4 h of treatment time under UV light, the TOC removal was 90%, and it was 60% under Vis light. The main ROS involved in the photo-Fenton process driven by UVC light were hydroxyl radicals, while hydroperoxyl radicals predominate in the Vis-light-driven process. Evidence of superoxide anion participation was not found. The toxicity of untreated and treated water was assessed on Danio rerio specimens, and it was observed to be reduced after the photo-Fenton treatment. Full article
(This article belongs to the Section Photocatalysis)
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14 pages, 4950 KiB  
Article
Z-Scheme Heterojunction of Phosphorus-Doped Carbon Nitride/Titanium Dioxide: Photocatalytic Performance
by Jinyu Yang, Yanglin Zhang, Kun Liu, Dongxu Tang, Shizhong Zhou, Xiaojie Yang, Yuesheng Li and Yi Liu
Molecules 2024, 29(18), 4342; https://doi.org/10.3390/molecules29184342 - 12 Sep 2024
Viewed by 793
Abstract
With increasingly serious environmental pollution problems, the development of efficient photocatalytic materials has become a hotspot in current research. This study focused on phosphorus-doped carbon nitride/titanium dioxide (PCT) Z-type heterojunctions, aiming to deeply investigate their photocatalytic degradation and photosensitive antimicrobial properties. A PCT [...] Read more.
With increasingly serious environmental pollution problems, the development of efficient photocatalytic materials has become a hotspot in current research. This study focused on phosphorus-doped carbon nitride/titanium dioxide (PCT) Z-type heterojunctions, aiming to deeply investigate their photocatalytic degradation and photosensitive antimicrobial properties. A PCT Z-type heterojunction was successfully fabricated using melamine phosphate, cyanuric acid, and titanium dioxide. The structure, morphology, and optical properties of PCT Z-type heterojunctions were explored by FTIR, XRD, XPS, BET, SEM, UV-Vis DRS, TEM, EIS, and PL. A comprehensive and in-depth analysis of the structure, morphology, and optical properties of PCT Z-type heterojunctions was carried out. The photocatalytic degradation experiments revealed that PC3T Z-type heterojunctions exhibited an excellent degradation capability for methylene blue (MB) under visible light. The effect of PC3T on the adsorption–photocatalytic degradation of MB is more than 1.5 times that of a single titanium dioxide and P-doped carbon nitride. In the photosensitive antimicrobial performance study, PC3T reduced the survival rate of E. coli to 7%, after 120 min. Through free radical trapping experiments, it was shown that the hydroxyl radicals and superoxide radicals exerted an influence on the photocatalytic process. This study offers new ideas and approaches to address environmental pollution problems and holds significant theoretical and applied value. Full article
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21 pages, 9854 KiB  
Article
Investigation of Synergistic Influence of Ultrasound and Co-Doping to Degrade Toluene from Polluted Air in Construction Sites—An Experimental Approach
by Omid Akbarzadeh, Yahya Rasoulzadeh, Mohammad Haghighi, Azadeh Talati and Hamed Golzad
Buildings 2024, 14(9), 2876; https://doi.org/10.3390/buildings14092876 - 11 Sep 2024
Viewed by 717
Abstract
Background: Toluene exposure in construction workers can lead to several health problems, primarily affecting the nervous system, respiratory system, and skin. Utilizing advanced photocatalytic materials to degrade gaseous toluene aims to significantly mitigate its negative impact. Methods: In this research, photocatalysts [...] Read more.
Background: Toluene exposure in construction workers can lead to several health problems, primarily affecting the nervous system, respiratory system, and skin. Utilizing advanced photocatalytic materials to degrade gaseous toluene aims to significantly mitigate its negative impact. Methods: In this research, photocatalysts based on pure TiO2 and modified TiO2 were synthesized to evaluate their efficacy in degrading gaseous toluene, a prevalent air pollutant in construction settings. Two synthesis methods were employed. Sonoprecipitation was used to create Fe-N co-doped TiO2 nanoparticles in the first method, while the second method utilized co-precipitation and hydrothermal techniques without ultrasonic assistance to achieve Fe-N co-doping. Seven types of nanophotocatalysts were synthesized, including TiO2-U (with ultrasonic assistance), NTiO2-U, FeNTiO2 (2.5)-U, FeNTiO2 (5)-U, FeNTiO2 (7.5)-U, FeNTiO2 (10)-U, and FeNTiO2 (5) without ultrasonic assistance. Characterization of the synthesized photocatalysts involved various analyses, including XRD, SEM, EDX, UV–VIS DRS, FT–IR, BET, and N2 adsorption-desorption isotherm. Results: Ultrasonic assistance notably improved particle dispersion and prevented agglomeration on the photocatalyst surface. UV–VIS DRS analysis indicated a reduction in band gap energy due to Fe and N doping of TiO2. The study also investigated the influence of Fe doping, initial toluene concentration, light source, and residence time on the degradation rate of gaseous toluene. Experimental findings showed that FeNTiO2 (5)-U exhibited a higher degradation rate of toluene (63.5%) compared to FeNTiO2 (5) (50%) under visible light irradiation over 15 s. Conclusions: The study underscores the significant enhancement in photocatalytic activity for toluene degradation achieved through the combined effects of ultrasound and co-doping methods. Full article
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21 pages, 4751 KiB  
Article
Green Synthesis of LaMnO3-Ag Nanocomposites Using Citrus limon (L.) Burm Peel Aqueous Extract: Photocatalytic Degradation of Rose Bengal Dye and Antibacterial Applications
by Nazim Hasan
Catalysts 2024, 14(9), 609; https://doi.org/10.3390/catal14090609 - 11 Sep 2024
Viewed by 929
Abstract
Perovskites can absorb solar energy and are extensively used in various catalytic and photocatalytic reactions. However, noble metal particles may enhance the catalytic, photocatalytic, and antibacterial activities. This study demonstrates the cost-effective green synthesis of the photocatalyst perovskite LaMnO3 and its modification [...] Read more.
Perovskites can absorb solar energy and are extensively used in various catalytic and photocatalytic reactions. However, noble metal particles may enhance the catalytic, photocatalytic, and antibacterial activities. This study demonstrates the cost-effective green synthesis of the photocatalyst perovskite LaMnO3 and its modification with noble metal Ag nanoparticles. The green synthesis of nanocomposite was achieved through a hydrothermal method employing aqueous extract derived from Citrus limon (L.) Burm peels. The properties of fabricated perovskites LaMnO3 and LaMnO3-Ag nanocomposites were evaluated and characterized by Ultraviolet-Visible spectroscopy (UV-Vis), Diffuse Reflectance Spectroscopy (DRS), X-ray diffraction (XRD), Fourier-Transform Infrared Spectroscopy (FT-IR), High-Resolution Transmission Electron Microscopy (HRTEM), Scanning Electron Microscopy (SEM), Energy-Dispersive X-ray spectroscopy (EDX) and Brunauer–Emmett–Teller (BET) surface area techniques. The particle size distribution % of LaMnO3 and LaMnO3-Ag was observed to be 20 to 60 nm after using TEM images. The maximum percentage size distribution was 37 nm for LaMnO3 and 43 nm for LaMnO3-Ag. In addition, LaMnO3-Ag nanocomposite was utilized as a photocatalyst for the degradation of Rose Bengal (RB) dye and its antibacterial activities against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). The surface area and band gap for perovskite LaMnO3 nanoparticles were calculated as 12.642 m2/g and 3.44 eV, respectively. The presence of noble metal and hydrothermal-bio reduction significantly impacted the crystallinity. The BET surface area was found to be 16.209 m2/g, and band gap energy was calculated at 2.94 eV. The LaMnO3 nanocomposite with noble metal shows enhanced photocatalytic effectiveness against RB dye (20 PPM) degradation (92%, R2 = 0.995) with pseudo-first-order chemical kinetics (rate constant, k = 0.05057 min−1) within 50 min due to the ultimate combination of the hydrothermal and bio-reduction technique. The photocatalytic activity of the LaMnO3-Ag nanocomposite was optimized at different reaction times, photocatalyst doses (0.2, 0.4, 0.6, and 0.8 g/L), and various RB dye concentrations (20, 30, 40, and 50 ppm). The antibacterial activities of green synthesized LaMnO3 and LaMnO3-Ag nanoparticles were explored based on colony-forming unit (cfu) reduction and TEM images of bacterial and nanoparticle interactions for S. aureus and E. coli. An amount of 50 µg/mL LaMnO3-Ag nanocomposite was sufficient to work as the highest antibacterial activity for both bacteria. The perovskite LaMnO3-Ag nanocomposite synthesis process is economically and environmentally friendly. Additionally, it has a wide range of effective and exclusive applications for remediating pollutants. Full article
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