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International Journal of Molecular... Jun 2024"Core/shell" composites are based on a ferrite core coated by two layers with different properties, one of them is an isolator, SiO, and the other is a semiconductor,...
"Core/shell" composites are based on a ferrite core coated by two layers with different properties, one of them is an isolator, SiO, and the other is a semiconductor, TiO. These composites are attracting interest because of their structure, photocatalytic activity, and magnetic properties. Nanocomposites of the "core/shell" МFeO/SiO/TiO (М = Zn(II), Co(II)) type are synthesized with a core of MFeO produced by two different methods, namely the sol-gel method (SG) using propylene oxide as a gelling agent and the hydrothermal method (HT). SiO and TiO layer coating is performed by means of tetraethylorthosilicate, TEOS, Ti(IV) tetrabutoxide, and Ti(OBu), respectively. A combination of different experimental techniques is required to prove the structure and phase composition, such as XRD, UV-Vis, TEM with EDS, photoluminescence, and XPS. By Rietveld analysis of the XRD data unit cell parameters, the crystallite size and weight fraction of the polymorphs anatase and rutile of the shell TiO and of the ferrite core are determined. The magnetic properties of the samples, and their activity for the photodegradation of the synthetic industrial dyes Malachite Green and Rhodamine B are measured in model water solutions under UV light irradiation and simulated solar irradiation. The influence of the water matrix on the photocatalytic activity is determined using artificial seawater in addition to ultrapure water. The rate constants of the photocatalytic process are obtained along with the reaction mechanism, established using radical scavengers where the role of the radicals is elucidated.
Topics: Nanocomposites; Rosaniline Dyes; Catalysis; Water Pollutants, Chemical; Rhodamines; Titanium; Photolysis; Silicon Dioxide; Ferric Compounds; Photochemical Processes; X-Ray Diffraction
PubMed: 38928461
DOI: 10.3390/ijms25126755 -
Photodegradation of a Broad-Spectrum Antibiotic Azithromycin Using HO under Ultraviolet Irradiation.International Journal of Molecular... Jun 2024The photodegradation of azithromycin present was carried out in water using HO under UV irradiation. The reaction variables considered in this study were the amount of...
The photodegradation of azithromycin present was carried out in water using HO under UV irradiation. The reaction variables considered in this study were the amount of HO solution and the initial concentration of azithromycin to evaluate the performance of the photodegradation process. The azithromycin degradation was not observed in the dark during stirring for 20 min. The study showed an efficient photodegradation of azithromycin using HO as an oxidant in the presence of UV irradiation. The azithromycin degradation was altered significantly by the pH of the irradiated solution. The degradation was low at an acidic pH and showed an increasing trend as the pH changed to basic. The azithromycin degradation increased with a higher amount (higher concentration) of HO. The degradation of azithromycin decreased with a higher concentration of azithromycin in the reacting solution. The highest degradation of AZT was achieved in 1 h using a 1.0 ppm AZT solution containing 3 mL of HO. The experimental data obtained were well-fitted to zero-order reaction kinetics. The results of this study were found quite excellent. They showed 100% degradation in 1 h when compared with those reported in the literature, both with photocatalysis using nanomaterials and photolysis using light irradiation and/or HO. The UV/HO system was found to be quite efficient for the photodegradation of azithromycin, and this system can be applied to degrade other organic pollutants present in industrial wastewater.
Topics: Azithromycin; Hydrogen Peroxide; Ultraviolet Rays; Photolysis; Anti-Bacterial Agents; Hydrogen-Ion Concentration; Water Pollutants, Chemical; Kinetics
PubMed: 38928406
DOI: 10.3390/ijms25126702 -
International Journal of Molecular... Jun 2024Sulfonamides can be effectively removed from wastewater through a photocatalytic process. However, the mineralization achieved by this method is a long-term and...
Sulfonamides can be effectively removed from wastewater through a photocatalytic process. However, the mineralization achieved by this method is a long-term and expensive process. The effect of shortening the photocatalytic process is the partial degradation and formation of intermediates. The purpose of this study was to evaluate the sensitivity and transformation of photocatalytic reaction intermediates in aerobic biological processes. Sulfadiazine and sulfamethoxazole solutions were used in the study, which were irradiated in the presence of a TiO-P25 catalyst. The resulting solutions were then aerated after the addition of river water or activated sludge suspension from a commercial wastewater treatment plant. The reaction kinetics were determined and fifteen products of photocatalytic degradation of sulfonamides were identified. Most of these products were further transformed in the presence of activated sludge suspension or in water taken from the river. They may have been decomposed into other organic and inorganic compounds. The formation of biologically inactive acyl derivatives was observed in the biological process. However, compounds that are more toxic to aquatic organisms than the initial drugs can also be formed. After 28 days, the sulfamethoxazole concentration in the presence of activated sludge was reduced by 66 ± 7%. Sulfadiazine was practically non-biodegradable under the conditions used. The presented results confirm the advisability of using photocatalysis as a process preceding biodegradation.
Topics: Biodegradation, Environmental; Kinetics; Sulfonamides; Catalysis; Water Pollutants, Chemical; Titanium; Sulfamethoxazole; Photolysis; Wastewater; Sewage; Sulfadiazine; Water Purification
PubMed: 38928394
DOI: 10.3390/ijms25126688 -
International Journal of Molecular... Jun 2024Polyurethane/silk protein-bismuth halide oxide composite films were fabricated using a blending-wet phase transformationin situsynthesis method. The crystal structure,...
Polyurethane/silk protein-bismuth halide oxide composite films were fabricated using a blending-wet phase transformationin situsynthesis method. The crystal structure, micromorphology, and optical properties were conducted using XRD, SEM, and UV-Vis DRS characterize techniques. The results indicated that loaded silk protein enhanced the hydrophilicity and pore structure of the polyurethane composite films. The active species BiOX were observed to grow as nanosheets with high dispersion on the internal skeleton and silk protein surface of the polyurethane-silk protein film. The photocatalytic efficiency of BiOX/PU-SF composite films was assessed through the degradation of Rhodamine B under visible light irradiation. Among the tested films, the BiOBr/PU-SF composite exhibited the highest removal rate of RhB at 98.9%, surpassing the removal rates of 93.7% for the BiOCl/PU-SF composite and 85.6% for the BiOI/PU-SF composite. Furthermore, an active species capture test indicated that superoxide radical (•O) and hole (h) species played a predominant role in the photodegradation process.
Topics: Polyurethanes; Photolysis; Hydrophobic and Hydrophilic Interactions; Bismuth; Catalysis; Silk; Rhodamines; Coloring Agents; Oxides; Porosity; Light
PubMed: 38928359
DOI: 10.3390/ijms25126653 -
Chemosphere Jun 2024Dimethylsilanediol (DMSD) is the common degradation product of ubiquitous polydimethylsiloxane (PDMS) and volatile methylsiloxanes (VMS) in water and soil. Given the...
Dimethylsilanediol (DMSD) is the common degradation product of ubiquitous polydimethylsiloxane (PDMS) and volatile methylsiloxanes (VMS) in water and soil. Given the high solubility of DMSD in water, the further degradation of DMSD in this compartment is of particular importance. While DMSD appears relatively resistant to degradation in standard hydrolysis or biodegradation studies, it may degrade by indirect photolysis in surface waters through oxidation by hydroxyl radicals. The formation of hydroxyl radicals is governed by nitrate ions or other promoters in the presence of sunlight. In this study, we investigated the impact of nitrate ions on the oxidative decomposition of DMSD in water under simulated solar light. When exposed to solar light, DMSD can degrade all the way to the natural, mineralized substances, namely carbon dioxide (in the form of carbonic acid) and silicic acid, via the intermediate methylsilanetriol (MST).
PubMed: 38909861
DOI: 10.1016/j.chemosphere.2024.142670 -
ACS Applied Polymer Materials Jun 2024Four-dimensional printing with embedded photoluminescence is emerging as an exciting area in additive manufacturing. Slim polymer films patterned with three-dimensional...
Four-dimensional printing with embedded photoluminescence is emerging as an exciting area in additive manufacturing. Slim polymer films patterned with three-dimensional lattices of multimode cylindrical waveguides (waveguide-encoded lattices, WELs) with enhanced fields of view can be fabricated by localizing light as self-trapped beams within a photopolymerizable formulation. Luminescent WELs have potential applications as solar cell coatings and smart planar optical components. However, as luminophore-photoinitiator interactions are expected to change the photopolymerization kinetics, the design of robust luminescent photopolymer sols is nontrivial. Here, we use model photopolymer systems based on methacrylate-siloxane and epoxide homopolymers and their blends to investigate the influence of the luminophore Lumogen Violet () on the photolysis kinetics of the Omnirad 784 photoinitiator through UV-vis absorbance spectroscopy. Initial rate analysis with different bulk polymers reveals differences in the pseudo-first-order rate constants in the absence and presence of , with a notable increase (∼40%) in the photolysis rate for the 1:1 blend. Fluorescence quenching studies, coupled with density functional theory calculations, establish that these differences arise due to electron transfer from the photoexcited to the ground-state photoinitiator molecules. We also demonstrate an in situ UV-vis absorbance technique that enables real-time monitoring of both waveguide formation and photoinitiator consumption during the fabrication of WELs. The in situ photolysis kinetics confirm that -photoinitiator interactions also influence the photopolymerization process during WEL formation. Our findings show that luminophores play a noninnocent role in photopolymerization and highlight the necessity for both careful consideration of the photopolymer formulation and a real-time monitoring approach to enable the fabrication of high-quality micropatterned luminescent polymeric films.
PubMed: 38903400
DOI: 10.1021/acsapm.4c00484 -
Pollutant Photodegradation Affected by Evaporative Water Concentration in a Climate Change Scenario.Molecules (Basel, Switzerland) Jun 2024Evaporative water concentration takes place in arid or semi-arid environments when stationary water bodies, such as lakes or ponds, prevalently lose water by...
Evaporative water concentration takes place in arid or semi-arid environments when stationary water bodies, such as lakes or ponds, prevalently lose water by evaporation, which prevails over outflow or seepage into aquifers. Absence or near-absence of precipitation and elevated temperatures are important prerequisites for the process, which has the potential to deeply affect the photochemical attenuation of pollutants, including contaminants of emerging concern (CECs). Here we show that water evaporation would enhance the phototransformation of many CECs, especially those undergoing degradation mainly through direct photolysis and triplet-sensitized reactions. In contrast, processes induced by hydroxyl and carbonate radicals would be inhibited. Our model results suggest that the photochemical impact of water evaporation might increase in the future in several regions of the world, with no continent likely being unaffected, due to the effects of local precipitation decrease combined with an increase in temperature that facilitates evaporation.
PubMed: 38893529
DOI: 10.3390/molecules29112655 -
Molecules (Basel, Switzerland) Jun 2024Chamazulene (CA) is an intensely blue molecule with a wealth of biological properties. In cosmetics, chamazulene is exploited as a natural coloring and soothing agent....
Chamazulene (CA) is an intensely blue molecule with a wealth of biological properties. In cosmetics, chamazulene is exploited as a natural coloring and soothing agent. CA is unstable and tends to spontaneously degrade, accelerated by light. We studied the photodegradation of CA upon controlled exposure to UVB-UVA irradiation by multiple techniques, including GC-MS, UHPLC-PDA-ESI-MS/MS and by direct infusion in ESI-MS, which were matched to in silico mass spectral simulations to identify degradation products. Seven byproducts formed upon UVA exposure for 3 h at 70 mW/cm (blue-to-green color change) were identified, including CA dimers and CA benzenoid, which were not found on extended 6 h irradiation (green-to-yellow fading). Photostability tests with reduced irradiance conducted in various solvents in the presence/absence of air indicated highest degradation in acetonitrile in the presence of oxygen, suggesting a photo-oxidative mechanism. Testing in the presence of antioxidants (tocopherol, ascorbyl palmitate, hydroxytyrosol, bakuchiol, γ-terpinene, TEMPO and their combinations) indicated the highest protection by tocopherol and TEMPO. Sunscreens ethylhexyl methoxycinnamate and particularly Tinosorb S (but not octocrylene) showed good CA photoprotection. Thermal stability tests indicated no degradation of CA in acetonitrile at 50 °C in the dark for 50 days; however, accelerated degradation occurred in the presence of ascorbyl palmitate.
Topics: Azulenes; Oils, Volatile; Oxidation-Reduction; Photolysis; Ultraviolet Rays; Antioxidants; Achillea; Artemisia; Tandem Mass Spectrometry; Gas Chromatography-Mass Spectrometry
PubMed: 38893479
DOI: 10.3390/molecules29112604 -
International Journal of Molecular... May 2024Advanced oxidation processes, including photocatalysis, have been proven effective at organic dye degradation. Tailored porous materials with regulated pore size, shape,...
Advanced oxidation processes, including photocatalysis, have been proven effective at organic dye degradation. Tailored porous materials with regulated pore size, shape, and morphology offer a sustainable solution to the water pollution problem by acting as support materials to grafted photocatalytic nanoparticles (NPs). This research investigated the influence of pore and particle sizes of photocatalytic MICROSCAFS on the degradation of methyl orange (MO) in aqueous solution (10 mg/L). Photocatalytic MICROSCAFS are made of binder-less supported P25 TiO NPs within MICROSCAFS, which are silica-titania microspheres with a controlled size and interconnected macroporosity, synthesized by an adapted sol-gel method that involves a polymerization-induced phase separation process. Photocatalytic experiments were performed both in batch and flow reactors, with this latter one targeting a proof of concept for continuous transformation processes and real-life conditions. Photocatalytic degradation of 87% in 2 h (batch) was achieved, using a calibrated solar light simulator (1 sun) and a photocatalyst/pollutant mass ratio of 23. This study introduces a novel flow kinetic model which provides the modeling and simulation of the photocatalytic MICROSCAFS performance. A scavenger study was performed, enabling an in-depth mechanistic understanding. Finally, the transformation products resulting from the MO photocatalytic degradation were elucidated by high-resolution mass spectrometry experiments and subjected to an in silico toxicity assessment.
Topics: Catalysis; Water Purification; Titanium; Water Pollutants, Chemical; Porosity; Sunlight; Azo Compounds; Microspheres; Silicon Dioxide; Photolysis; Kinetics; Photochemical Processes
PubMed: 38892146
DOI: 10.3390/ijms25115958 -
Scientific Reports Jun 2024A composite of Zinc oxide loaded with 5-weight % silver decorated on carbon nanotubes (Ag-loaded ZnO: CNT) was synthesized using a simple refluxed chemical method. The...
A composite of Zinc oxide loaded with 5-weight % silver decorated on carbon nanotubes (Ag-loaded ZnO: CNT) was synthesized using a simple refluxed chemical method. The influence of deviation in the weight % of carbon nanotube loading on photocatalytic dye degradation (methylene blue and rose bengal) and antibiotic (antimicrobial and antifungal) performance was investigated in this study. The light capture ability of Ag-loaded ZnO:CNT in the visible region was higher in photocatalytic activity than that of Ag-loaded ZnO and ZnO:CNT. The bandgap of the Ag-loaded ZnO: CNT was tuned owing to the surface plasmon resonance effect. The photocatalytic degradation investigations were optimized by varying the wt% in CNTs, pH of dye solution, concentration of the dye solution, and amount of catalytic dose. Around 100% photocatalytic efficiency in 2 min against MB dye was observed for Ag doped ZnO with 10 wt% CNT composite at pH 9, at a rate constant 1.48 min. Bipolaris sorokiniana fungus was first time tested against a composite material, which demonstrated optimum fungal inhibition efficiency of 48%. They were also tested against the bacterial strains Staphylococcus aureus, Bacillus cerius, Proteus vulgaris, and Salmonella typhimurium, which showed promising antibacterial activity compared to commercially available drugs. The composite of Ag doped ZnO with 5 wt% CNT has shown competitive zone inhibition efficacy of 21.66 ± 0.57, 15.66 ± 0.57, 13.66 ± 0.57 against bacterial strains Bacillus cerius, Proteus vulgaris, and Salmonella typhimurium which were tested for the first time against Ag-loaded ZnO:CNT.
Topics: Zinc Oxide; Silver; Nanotubes, Carbon; Anti-Bacterial Agents; Catalysis; Antifungal Agents; Staphylococcus aureus; Methylene Blue; Coloring Agents; Rose Bengal; Microbial Sensitivity Tests; Salmonella typhimurium; Hydrogen-Ion Concentration; Photolysis; Photochemical Processes
PubMed: 38890495
DOI: 10.1038/s41598-024-64746-6