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Chemosphere Jun 2024Temperature-dependent kinetics of OH radical and Cl atom-initiated reaction of an important halogenated alkene, 2,3-Dichloropropene (23DCP), were investigated using...
Temperature-dependent kinetics of OH radical and Cl atom-initiated reaction of an important halogenated alkene, 2,3-Dichloropropene (23DCP), were investigated using absolute and relative methods over 278-363 K. Pulsed laser photolysis - laser induced fluorescence technique and relative rate method using gas chromatography with flame ionization detector were employed for studying the kinetics of 23DCP with OH radical and Cl atom, respectively. The obtained Arrhenius expressions were k(expt)=(4.08 ± 1.63) × 10exp{(1043 ± 124)/T} cm molecule s and k(expt)=(1.54 ± 0.24) × 10exp{(705 ± 48)/T} cm molecule s. Computational calculations were conducted to validate our experimental kinetic results and provide new insights into the importance of a particular pathway among all based on thermodynamic parameters. The addition of OH/Cl to the terminal carbon of the double bond present in 23DCP proved to be the predominant pathway across the selected temperature range for the present study (200-400 K). The degradation mechanism of these reactions was proposed by analyzing the products with the aid of gas chromatography with mass spectrometry. Calculating various atmospheric implication parameters can help to understand how the release of 23DCP may affect the troposphere.
PubMed: 38851505
DOI: 10.1016/j.chemosphere.2024.142566 -
Journal of Environmental Management Jul 2024Defect engineering is regarded as an effective strategy to boost the photo-activity of photocatalysts for organic contaminants removal. In this work, abundant surface...
Defect engineering is regarded as an effective strategy to boost the photo-activity of photocatalysts for organic contaminants removal. In this work, abundant surface oxygen vacancies (Ov) are created on AgIO microsheets (AgIO-O) by a facile and controllable hydrogen chemical reduction approach. The introduction of surface Ov on AgIO broadens the photo-absorption region from ultraviolet to visible light, accelerates the photoinduced charges separation and migration, and also activates the formation of superoxide radicals (•O). The AgIO-O possesses an outstanding degradation rate constant of 0.035 min, for photocatalytic degrading methyl orange (MO) under illumination of natural sunlight with a light intensity is 50 mW/cm, which is 7 and 3.5 times that of the pristine AgIO and C-AgIO (AgIO is calcined in air without generating Ov). In addition, the AgIO-O also exhibit considerable photoactivity for degrading other diverse organic contaminants, including azo dye (rhodamine B (RhB)), antibiotics (sulflsoxazole (SOX), norfloxacin (NOR), chlortetracycline hydrochloride (CTC), tetracycline hydrochloride (TC) and ofloxacin (OFX)), and even the mixture of organic contaminants (MO-RhB and CTC-OFX). After natural sunlight illumination for 50 min, 41.4% of total organic carbon (TOC) for MO-RhB mixed solution can be decreased over AgIO-O. In a broad range of solution pH from 3 to 11 or diverse water bodies of MO solution, AgIO-O exhibits attractive activity for decomposing MO. The MO photo-degradation process and mechanism over AgIO-O under natural sunlight irradiation has been systemically investigated and proposed. The toxicities of MO and its degradation intermediates over AgIO-O are compared using Toxicity Estimation Software (T.E.S.T.). Moreover, the non-toxicity of both AgIO-O catalyst and treated antibiotic solution (CTC-OFX mixture) are confirmed by E. coli DH5a cultivation test, supporting the feasibility of AgIO-O catalyst to treat organic contaminants in real water under natural sunlight illumination.
Topics: Sunlight; Photolysis; Oxygen; Water Pollutants, Chemical; Azo Compounds; Catalysis; Rhodamines
PubMed: 38850920
DOI: 10.1016/j.jenvman.2024.121393 -
ChemSusChem Jun 2024A convenient and sustainable method for synthesizing sulfonyl-containing compounds through a catalyst-free aqueous-phase hydrosulfonylation of alkenes and alkynes with...
A convenient and sustainable method for synthesizing sulfonyl-containing compounds through a catalyst-free aqueous-phase hydrosulfonylation of alkenes and alkynes with sulfonyl chlorides under visible light irradiation is presented. Unactivated alkenes, electron-deficient alkenes, alkyl and aryl alkynes can be hydrosulfonylated with various sulfonyl chlorides at room temperature with excellent yields and geometric selectivities by using tris(trimethylsilyl)silane as a hydrogen atom donor and silyl radical precursor to activate sulfonyl chlorides. Mechanistic studies revealed that the photolysis of tris(trimethylsilyl)silane in aqueous solution to produce silyl radical is crucial for the success of this reaction.
PubMed: 38850152
DOI: 10.1002/cssc.202400650 -
Environmental Geochemistry and Health Jun 2024This study investigates the removal of amoxicillin micropollutants (AM) from hospital wastewater using CoMoO-modified graphitic carbon nitride (CMO/gCN). Consequently,...
This study investigates the removal of amoxicillin micropollutants (AM) from hospital wastewater using CoMoO-modified graphitic carbon nitride (CMO/gCN). Consequently, CMO/gCN exhibits notable improvements in visible light absorption and electron-hole separation rates compared to unmodified gCN. Besides, CMO/gCN significantly enhances the removal efficiency of AM, attaining an impressive 96.5%, far surpassing the performance of gCN at 48.6%. Moreover, CMO/gCN showcases outstanding reusability, with AM degradation performance exceeding 70% even after undergoing six cycles of reuse. The removal mechanism of AM employing CMO/gCN involves various photoreactions of radicals (•OH, •O) and amoxicillin molecules under light assistance. Furthermore, CMO/gCN demonstrates a noteworthy photodegradation efficiency of AM from hospital wastewater, reaching 92.8%, with a near-complete reduction in total organic carbon levels. Detailed discussions on the practical applications of the CMO/gCN photocatalyst for removal of micropollutants from hospital wastewater are provided. These findings underline the considerable potential of CMO/gCN for effectively removing various pollutants in environmental remediation strategies.
Topics: Amoxicillin; Wastewater; Graphite; Water Pollutants, Chemical; Oxidation-Reduction; Photolysis; Hospitals; Nitrogen Compounds; Catalysis; Water Purification
PubMed: 38849667
DOI: 10.1007/s10653-024-01990-9 -
Environmental Geochemistry and Health Jun 2024Pesticide micropollutants like 4-chlorophenol (4CP) and E. coli bacteria represent a substantial hazard, impacting both the environment and human health. This study...
Pesticide micropollutants like 4-chlorophenol (4CP) and E. coli bacteria represent a substantial hazard, impacting both the environment and human health. This study delves into the effectiveness of Ag-doped TiO (Ag@TiO) in removing both 4CP and E. coli. Ag@TiO has demonstrated remarkable effectiveness in removing 4CP under both solar and visible light conditions, earning degradation efficiencies of 91.3% and 72.8%, respectively. Additionally, it demonstrates outstanding photodegradation efficiency for 4CP (98.8%) at an initial concentration of 1 mg L. Moreover, Ag@TiO exhibited substantially higher removal performance for 4CP (81.6%) compared to TiO (27.6%) in wastewater. Analysis of the radicals present during the photodegradation process revealed that ·O primarily drives the decomposition of 4CP, with h and ·OH also playing significant roles in the oxidation reactions of the pollutant. Interestingly, even under dark conditions, Ag@TiO exhibited the capability to eliminate approximately 20% of E. coli, a percentage that increased to over 96% under solar light. In addition, the prospects for environmental and health impacts of utilizing Ag@TiO for pesticide micropollutant removal and bacteria were discussed.
Topics: Titanium; Pesticides; Escherichia coli; Sunlight; Silver; Chlorophenols; Water Pollutants, Chemical; Photolysis; Wastewater
PubMed: 38849639
DOI: 10.1007/s10653-024-02017-z -
Environmental Geochemistry and Health Jun 2024This study reported the synthesis and assessment of zinc oxide/iron oxide (ZnO/FeO) nanocomposite as photocatalysts for the degradation of a mixture of methylene red and...
This study reported the synthesis and assessment of zinc oxide/iron oxide (ZnO/FeO) nanocomposite as photocatalysts for the degradation of a mixture of methylene red and methylene blue dyes. X-ray diffraction analysis confirms that the crystallite of zinc oxide (ZnO) has a hexagonal wurtzite phase and iron oxide (FeO) has a rhombohedral phase. Fourier Transform Infra-Red spectrum confirms the presence of Zn-O vibration stretching at 428, 480 and 543 cm stretching confirming Fe-O bond formation. Scanning Electron Microscope images exhibited a diverse size and shape of the nanocomposites. The ZnO-90%/FeO-10% and ZnO-10%/FeO-90% nanocomposites reveal good photocatalytic activity with reaction rate constants of 1.5 × 10 and 0.66 × 10; and 1.3 × 10 and 0.60 × 10 for methylene blue and methyl red dye respectively. The results revealed that the synthesized ZnO/FeO nanocomposite is the best catalyst for dye degradation and can be used for industrial applications in future.
Topics: Zinc Oxide; Nanocomposites; Methylene Blue; Ferric Compounds; Catalysis; Coloring Agents; X-Ray Diffraction; Microscopy, Electron, Scanning; Azo Compounds; Water Pollutants, Chemical; Photolysis; Spectroscopy, Fourier Transform Infrared
PubMed: 38849635
DOI: 10.1007/s10653-024-02000-8 -
Chemosphere Aug 2024Development of effective adsorbents for the removal of contaminants from wastewater is indispensable due to increasing water scarcity and a lack of pure drinking water,... (Review)
Review
Development of effective adsorbents for the removal of contaminants from wastewater is indispensable due to increasing water scarcity and a lack of pure drinking water, which are prevailing as a result of rapid industrialization and population growth. Recently, the development of new adsorbents and their effective use without generating secondary waste is receiving huge consideration. In order to protect the environment from primary and secondary pollution, the development of adsorbents from wastes and their recycling have become conventional practices aimed at waste management. As a result, significant progress has been made in the synthesis of new porous carbon and metal-organic frameworks as adsorbents, with the objective of using them for the removal of pollutants. While many different kinds of pollutants are produced in the environment, drug pollutants are the most vicious because of their tendency to undergo significant structural changes, producing metabolites and residues with entirely different properties compared to their parent compounds. Chemical reactions involving oxidation, hydrolysis, and photolysis transform drugs. The resulting compounds can have detrimental effects on living beings that are present in soil and water. This review stresses the development of adsorbents with adjustable porosities for the broad removal of primary drug pollutants and their metabolites, which are formed as a result of drug transformations in environmental matrices. This keeps adsorbents from building up in the environment and prevents them from becoming significant pollutants in the future. Additionally, it stops secondary pollution caused by the deterioration of the used adsorbents. Focus on the development of effective adsorbents with flexible porosities allows for the complete removal of coexisting contaminants and makes a substantial contribution to wastewater management. In order to concentrate more on the development of flexible pore adsorbents, it is crucial to comprehend the milestones reached in the research and applications of porous magnetic adsorbents based on metal and carbon, which are discussed here.
Topics: Porosity; Adsorption; Water Pollutants, Chemical; Metal-Organic Frameworks; Carbon; Wastewater; Water Purification; Metals; Pharmaceutical Preparations
PubMed: 38849099
DOI: 10.1016/j.chemosphere.2024.142533 -
Chemosphere Aug 2024This study aims the characterization of several tianeptine transformation products in ultrapure water by simulated sunlight irradiation. Tianeptine was completely...
This study aims the characterization of several tianeptine transformation products in ultrapure water by simulated sunlight irradiation. Tianeptine was completely degraded after 106 h of exposition following pseudo-first-order kinetics (half-life time = 12.0 ± 2.4 h). Furthermore, an ultra-high-performance liquid chromatography coupled with a high-resolution quadrupole time-of-flight-mass spectrometry method was developed and fully validated taking into account different method performance parameters for the quantification of tianeptine in river water up to a concentration of 400 pg L. Following a non-targeted approach based on mass data-independent acquisition, eight different transformation products not previously reported in the literature were identified and accordingly elucidated, proposing a photodegradation mechanism based on the accurate tandem mass spectrometry information acquired. Irradiation experiments were replicated for a tianeptine solution prepared in a blank river water sample, resulting in the formation of the same transformation products and similar degradation kinetics. In addition, a toxicity assessment of the photoproducts was performed by in silico method, being generally all TPs of comparable toxicity to the precursor except for TP1, and showing a similar persistence in the environment except for TP2 and TP6, while TP4 was the only TP predicted as mutagenic. The developed method was applied for the analysis of four river water samples.
Topics: Water Pollutants, Chemical; Tandem Mass Spectrometry; Chromatography, High Pressure Liquid; Photolysis; Thiazepines; Rivers; Kinetics; Sunlight
PubMed: 38849097
DOI: 10.1016/j.chemosphere.2024.142534 -
Analytical Chemistry Jun 2024Biopharmaceuticals, such as monoclonal antibodies (mAbs), need to maintain their chemical and physical stability in formulations throughout their lifecycle. It is known...
Biopharmaceuticals, such as monoclonal antibodies (mAbs), need to maintain their chemical and physical stability in formulations throughout their lifecycle. It is known that exposure of mAbs to light, particularly UV, triggers chemical and physical degradation, which can be exacerbated by trace amounts of photosensitizers in the formulation. Although routine assessments of degradation following defined UV dosages are performed, there is a fundamental lack of understanding regarding the intermediates, transient reactive species, and radicals formed during illumination, as well as their lifetimes and immediate impact post-illumination. In this study, we used light-coupled NMR spectroscopy to monitor in situ live spectral changes in sealed samples during and after UV-A illumination of different formulations of four mAbs without added photosensitizers. We observed a complex evolution of spectra, reflecting the appearance within minutes of transient radicals during illumination and persisting for minutes to tens of minutes after the light was switched off. Both mAb and excipient signals were strongly affected by illumination, with some exhibiting fast irreversible photodegradation and others exhibiting partial recovery in the dark. These effects varied depending on the mAb and the presence of excipients, such as polysorbate 80 (PS80) and methionine. Complementary ex situ high-performance size-exclusion chromatography analysis of the same formulations post-UV exposure in the chamber revealed significant loss of purity, confirming formulation-dependent degradation. Both approaches suggested the presence of degradation processes initiated by light but continuing in the dark. Further studies on photoreaction intermediates and transient reactive species may help mitigate the impact of light on biopharmaceutical degradation.
Topics: Antibodies, Monoclonal; Ultraviolet Rays; Magnetic Resonance Spectroscopy; Photolysis; Drug Compounding; Drug Stability; Light
PubMed: 38847283
DOI: 10.1021/acs.analchem.4c01164 -
The Journal of Physical Chemistry. A Jun 2024The development of the velocity map ion imaging (VMI) technique has greatly advanced the study of photodissociation dynamics. The high-resolution imaging study of the...
The development of the velocity map ion imaging (VMI) technique has greatly advanced the study of photodissociation dynamics. The high-resolution imaging study of the photodissociation allows for the acquisition of precise and detailed information on the fragments. This information can further provide more insight into the energy partition and potential pathways involved in the photodissociation process. In this study, we report the investigation on the photodissociation of OCS via the AΠ states following the excitation of AΠ (ν 0 ν) ← XΠ (0 0 0) by using time-sliced VMI techniques in the ultraviolet region. Our investigation revealed significant mode-dependent recoil anisotropies and branching ratios of two product channels for both Ω = 1/2 and Ω = 3/2. The photolysis products also exhibited dramatic deviation in angular distributions and generally comparable kinetic energy distributions following the excitation to the same vibrational modes of AΠ states with two separate spin-orbit components. According to the observation in this study and previously reported photodissociation mechanisms of the OCS cations, the decay from the AΠ state was more likely via the internal conversion to high rovibrational states of the XΠ state, in comparison to the AΠ state.
PubMed: 38840312
DOI: 10.1021/acs.jpca.4c01358