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Ecotoxicology and Environmental Safety Nov 2023Mechanochemistry and photocatalysis are emergent technologies for the remediation of polycyclic aromatic hydrocarbons (PAHs) in soils. In this work, mechanochemistry and...
Mechanochemistry and photocatalysis are emergent technologies for the remediation of polycyclic aromatic hydrocarbons (PAHs) in soils. In this work, mechanochemistry and photocatalysis are combined for pyrene degradation. The photodegradation of pyrene, when in contact with sepiolite under pressure application, is studied. The mechanical treatment leads to a pyrene crystal phase transformation. In this new phase, pyrene undergoes a fast photodegradation in the 320-420 nm range. We show that sepiolite is superior as a photocatalyst in pyrene degradation to TiO, the most exploited photocatalyst. A broad physicochemical characterization is carried out to propose a mechanism in which the photoexcitation of mechanically altered pyrene leads to an electron transfer to sepiolite matrix, which triggers the PAH degradation. Finally, we want to highlight that the pyrene/sepiolite combination is a simplified system to shed light on how PAH photodegradation may occur in soils.
Topics: Photolysis; Polycyclic Aromatic Hydrocarbons; Pyrenes; Light; Soil
PubMed: 37856983
DOI: 10.1016/j.ecoenv.2023.115573 -
Scientific Reports Aug 2023Whether a tire crumb rubber (TCR) playground would expose children to potentially harmful chemicals such as heavy metals is an open question. The released metals...
Whether a tire crumb rubber (TCR) playground would expose children to potentially harmful chemicals such as heavy metals is an open question. The released metals available for pickup on the surface of TCR tiles was studied by accelerated 2-year aging of the TCRs in the NIST-SPHERE (National Institute of Standards and Technology Simulated Photodegradation via High Energy Radiant Exposure). The dermal contact was mimicked by a method of composite surface wiping from US Environmental Protection Agency throughout the weathering process. The surface release of ten most concerned harmful metals (Be, Cr, Cu, As, Se, Cd, Sb, Ba, Tl, Pb) was monitored through the course of aging. The cumulative release of Cu, As, Tl, and Sb reached potentially harmful levels at various times within 3 years, although only Cr was found at a harmful level on the surface of the tiles. Taking the cleansing effect of precipitation or periodic cleansing with rain into account, TCR playgrounds may still be safe for use.
Topics: United States; Humans; Child; Rubber; Photolysis; Metals; Weather; Rain
PubMed: 37620365
DOI: 10.1038/s41598-023-38574-z -
Scientific Reports Mar 2023The global degradation of coral reefs is steadily increasing with ongoing climate change. Yet coral larvae settlement, a key mechanism of coral population rejuvenation...
The global degradation of coral reefs is steadily increasing with ongoing climate change. Yet coral larvae settlement, a key mechanism of coral population rejuvenation and recovery, is largely understudied. Here, we show how the lipophilic, settlement-inducing bacterial pigment cycloprodigiosin (CYPRO) is actively harvested and subsequently enriched along the ectoderm of larvae of the scleractinian coral Leptastrea purpura. A light-dependent reaction transforms the CYPRO molecules through photolytic decomposition and provides a constant supply of hydrogen peroxide (HO), leading to attachment on the substrate and metamorphosis into a coral recruit. Micromolar concentrations of HO in seawater also resulted in rapid metamorphosis, but without prior larval attachment. We propose that the morphogen CYPRO is responsible for initiating attachment while simultaneously acting as a molecular generator for the comprehensive metamorphosis of pelagic larvae. Ultimately, our approach opens a novel mechanistic dimension to the study of chemical signaling in coral settlement and provides unprecedented insights into the role of infochemicals in cross-kingdom interactions.
Topics: Animals; Anthozoa; Photolysis; Hydrogen Peroxide; Coral Reefs; Acceptance and Commitment Therapy; Larva
PubMed: 36864107
DOI: 10.1038/s41598-023-30470-w -
Inorganic Chemistry Mar 2016Cobalamins are known to react with thiols to yield stable β-axial Co(III)-S bonded thiolato-cobalamin complexes. However, in stark contrast to the Co-C bond in...
Cobalamins are known to react with thiols to yield stable β-axial Co(III)-S bonded thiolato-cobalamin complexes. However, in stark contrast to the Co-C bond in alkylcobalamins, the photolability of the Co-S bond in thiolato-cobalamins remains undetermined. We have investigated the photolysis of N-acetylcysteinyl cob(III)alamin at several wavelengths within the ultraviolet and visible spectrum. To aid in photolysis, we show that attaching fluorophore "antennae" to the cobalamin scaffold can improve photolytic efficiency by up to an order of magnitude. Additionally, electron paramagnetic resonance confirms previous conjectures that the photolysis of thiolato-cobalamins at wavelengths as long as 546 nm produces thiyl radicals.
Topics: Chromatography, Liquid; Electron Spin Resonance Spectroscopy; Fluorescent Dyes; Photolysis; Proton Magnetic Resonance Spectroscopy; Spectrometry, Mass, Electrospray Ionization; Sulfhydryl Compounds; Vitamin B 12
PubMed: 26848595
DOI: 10.1021/acs.inorgchem.5b02036 -
Biomolecules Mar 2023Aflatoxin B (AFB) is a highly toxic mycotoxin produced by aspergillus species under specific conditions as secondary metabolites. In this study, types of PCL...
Aflatoxin B (AFB) is a highly toxic mycotoxin produced by aspergillus species under specific conditions as secondary metabolites. In this study, types of PCL (Polycaprolactone) membranes anchored (or not) to g-CN/CQDs composites were prepared using electrospinning technology with (or without) the following surface modification treatment to remove AFB. These membranes and g-CN/CQDs composites were characterized by SEM, TEM, UV-vis, XRD, XPS and FTIR to analyze their physical and chemical properties. Among them, the modified PCL-g-CN/CQDs electrospun membranes exhibited an excellent ability to degrade AFB via synergistic effects of adsorption and photocatalysis, and the degradation rate of 0.5 μg/mL AFB solution was observed to be up to 96.88% in 30 min under visible light irradiation. Moreover, the modified PCL-g-CN/CQDs electrospun membranes could be removed directly after the reaction process without centrifugal or magnetic separation, and the regeneration was a green approach synchronized with the reaction under visible light avoiding physical or chemical treatment. The mechanism of adsorption by electrostatic attraction and hydrogen bonding interaction was revealed and the mechanism of photodegradation of AFB was also proposed based on active species trapping experiments. This study illuminated the highly synergic adsorption and photocatalytic AFB removal efficiency without side effects from the modified PCL-g-CN/CQDs electrospun membranes, thereby offering a continual and green solution to AFB removal in practical application.
Topics: Adsorption; Catalysis; Photolysis; Light
PubMed: 36979485
DOI: 10.3390/biom13030550 -
Journal of Fluorescence Jul 2022The MB and MR removal process by two mechanisms of adsorption using rice straw (absence of UV light) and photodegradation on TiO surfaces was investigated. MB and MR...
The MB and MR removal process by two mechanisms of adsorption using rice straw (absence of UV light) and photodegradation on TiO surfaces was investigated. MB and MR removal efficiency were further intensified upon the sequential operation of adsorption followed by photocatalytic degradation over TiO under visible light irradiation. The TiO was used to remove methylene blue (MB) and Maxilon Red (MR) dye from aqueous media by continuous mode at 25 ± 2 °C, at pH 6.8 ± 0.2. Photo-illumination study revealed 75.81 and 65.51% MB and MR removal with the dose of 1 g/L TiO with an initial concentration of 5 mg/L within 120 min. This study can be deemed of potential applications for the removal of MB and MR dyes on an industrial level using the synergistic adsorption-photocatalytic oxidation approach. A probable photodegradation mechanism was proposed.
Topics: Adsorption; Methylene Blue; Photolysis; Titanium; Ultraviolet Rays
PubMed: 35384544
DOI: 10.1007/s10895-022-02934-1 -
International Journal of Molecular... Jul 2022Triplet-triplet annihilation upconversion (TTA-UC) is a very promising technology that could be used to convert low-energy photons to high-energy ones and has been... (Review)
Review
Triplet-triplet annihilation upconversion (TTA-UC) is a very promising technology that could be used to convert low-energy photons to high-energy ones and has been proven to be of great value in various areas. Porphyrins have the characteristics of high molar absorbance, can form a complex with different metal ions and a high proportion of triplet states as well as tunable structures, and thus they are important sensitizers for TTA-UC. Porphyrin-based TTA-UC plays a pivotal role in the TTA-UC systems and has been widely used in many fields such as solar cells, sensing and circularly polarized luminescence. In recent years, applications of porphyrin-based TTA-UC systems for photoinduced reactions have emerged, but have been paid little attention. As a consequence, this review paid close attention to the recent advances in the photoreactions triggered by porphyrin-based TTA-UC systems. First of all, the photochemistry of porphyrin-based TTA-UC for chemical transformations, such as photoisomerization, photocatalytic synthesis, photopolymerization, photodegradation and photochemical/photoelectrochemical water splitting, was discussed in detail, which revealed the different mechanisms of TTA-UC and methods with which to carry out reasonable molecular innovations and nanoarchitectonics to solve the existing problems in practical application. Subsequently, photoreactions driven by porphyrin-based TTA-UC for biomedical applications were demonstrated. Finally, the future developments of porphyrin-based TTA-UC systems for photoreactions were briefly discussed.
Topics: Photolysis; Photons; Porphyrins; Water
PubMed: 35887385
DOI: 10.3390/ijms23148041 -
The Journal of Organic Chemistry May 2012Friedel-Crafts amidoalkylation was achieved by oxidation of dialkylamides using persulfate (S(2)O(8)(2-)) in the presence of the visible light catalyst, Ru(bpy)(3)Cl(2),...
Friedel-Crafts amidoalkylation was achieved by oxidation of dialkylamides using persulfate (S(2)O(8)(2-)) in the presence of the visible light catalyst, Ru(bpy)(3)Cl(2), at room temperature, via a reactive N-acyliminium intermediate. Alternatively, mild heating of the dialkylamides and persulfate afforded a metal and Lewis acid-free Friedel-Crafts amidoalkylation. Alcohols and electron-rich arenes served as effective nucleophiles, forming new C-O or C-C bonds. In general, photocatalysis provided higher yields and better selectivities.
Topics: Alkylation; Catalysis; Light; Organometallic Compounds; Oxidation-Reduction; Photochemistry; Photolysis; Ruthenium; Temperature; Thermogravimetry
PubMed: 22458307
DOI: 10.1021/jo300162c -
Molecules (Basel, Switzerland) Feb 2020Laser flash photolysis and high-resolution mass spectrometry were used to investigate the mechanism of one-electron oxidation of two -alkylglutathiones using...
Laser flash photolysis and high-resolution mass spectrometry were used to investigate the mechanism of one-electron oxidation of two -alkylglutathiones using 3-carboxybenzophenone (3CB) as a photosensitizer. This report indicates an unexpected reaction pathway of the α-aminoalkyl radical cation (αN) derived from the oxidation of -alkylglutathiones. Instead of a common hydrolysis reaction of αN reported earlier for methionine and other sulfur-containing aminoacids and peptides, an intramolecular ring-closure reaction was found for -alkylglutathiones.
Topics: Alkylation; Electrons; Glutathione; Lasers; Oxidation-Reduction; Photolysis
PubMed: 32079230
DOI: 10.3390/molecules25040877 -
Water Research May 2021Organic micropollutants (MPs) are increasingly detected in water resources, which can be a concern for human health and the aquatic environment. Ultraviolet (UV)...
Organic micropollutants (MPs) are increasingly detected in water resources, which can be a concern for human health and the aquatic environment. Ultraviolet (UV) radiation based advanced oxidation processes (AOP) such as low-pressure mercury vapor arc lamp UV/HO can be applied to abate these MPs. During UV/HO treatment, MPs are abated primarily by photolysis and reactions with hydroxyl radicals (OH), which are produced in situ from HO photolysis. Here, a model is presented that calculates the applied UV fluence (H) and the OH exposure (CT) from the abatement of two selected MPs, which act as internal probe compounds. Quantification of the UV fluence and hydroxyl radical exposure was generally accurate when a UV susceptible and a UV resistant probe compound were selected, and both were abated at least by 50 %, e.g., iopamidol and 5-methyl-1H-benzotriazole. Based on these key parameters a model was developed to predict the abatement of other MPs. The prediction of abatement was verified in various waters (sand filtrates of rivers Rhine and Wiese, and a tertiary wastewater effluent) and at different scales (laboratory experiments, pilot plant). The accuracy to predict the abatement of other MPs was typically within ±20 % of the respective measured abatement. The model was further assessed for its ability to estimate unknown rate constants for direct photolysis (k) and reactions with OH (k). In most cases, the estimated rate constants agreed well with published values, considering the uncertainty of kinetic data determined in laboratory experiments. A sensitivity analysis revealed that in typical water treatment applications, the precision of kinetic parameters (k for UV susceptible and k for UV resistant probe compounds) have the strongest impact on the model's accuracy.
Topics: Humans; Hydrogen Peroxide; Hydroxyl Radical; Oxidation-Reduction; Photolysis; Ultraviolet Rays; Water Pollutants, Chemical; Water Purification
PubMed: 33735627
DOI: 10.1016/j.watres.2021.116940