Photochemical Characteristics Research Articles

Facile solvothermal approach to design synergetic effect between the BiVO4 and TiS2 to boost up the Z-scheme photocatalytic performance for water treatment and hydrogen production

An innovative and economically practical method was developed to create unique BiVO4/TiS2 structures in an ecologically friendly way. Novel BiVO4/TiS2 composites are created by combining as synthesized BiVO4 and freshly prepared titanium disulfide (TiS2). The BiVO4/TiS2 composites were thoroughly evaluated to investigate their physical, optical, morphological, and photochemical characteristics. Pure BiVO4 material, TiS2 nanostructures, and BiVO4/TiS2 nanocomposites were evaluated for their photocatalytic capabilities by observing the deterioration of MB beneath natural solar irradiation. The BiVO4/TiS2@50 % composite exhibited highly improved sunlight-striving photocatalytic activities. The cycle stability of the as-produced BiVO4/TiS2@50 % photocatalyst material and active species effects that areparticipating in the photocatalytic coursehave also been studied. The decrease in charge recombination time and increased visible light absorption of the BiVO4/TiS2@50 % may be the causes of the enriched photocatalytic activity. A thorough examination encompassing empirical evidence and theoretical computations, culminated in developing a Z scheme photocatalytic mechanism. The results obtained from repeated cycling experiments and electrochemical impedance spectroscopy provided additional support for this mechanism. Furthermore, after five consecutive cycles, BiVO4/TiS2@50 % photocatalyst sample exhibited commendable stability in an aqueous environment. Utilizing a highly efficient photocatalyst material (BiVO4/TiS2@50 %) further elucidates the degradation mechanism and scavenging effect of MB dyes. The BiVO4/TiS2@50 % photocatalyst achieved a hydrogen production rate of 15.5 mmolg−1h−1, which is higher than the single BiVO4 and TiS2 and other prepared composites. The excellent reductive and oxidative capabilities of our best material (BiVO4/TiS2@50 %) and its superior stability due to the Z scheme operation significantly enhance its potential for practical implementations in photocatalysis and hydrogen production.

Characteristics of Ozone Photochemical Reaction and Emission Reduction Strategies in Summer and Autumn in Shangqiu

Recently, ozone （O3） pollution in Shangqiu has become increasingly prominent, especially in summer and autumn, crucially affecting the local environmental air quality. Based on the monitoring data of O3 pollution days from the Environmental Monitoring Station in June and September 2022 （representing summer and autumn） in Shangqiu, an observation-based model （OBM） was used to study the causes and photochemical reaction characteristics of O3 pollution in the city and precursor emission reduction strategies were studied. The observation results indicated that during summer in Shangqiu, the ρ（O3） and O3 daily maximum 8 h moving concentrations [ρ（MDA8-O3）] were 149.7 μg·m-3 and 195.4 μg·m-3, whereas in autumn, ρ（O3） and ρ（MDA8-O3） were 119.8 μg·m-3 and 173.9 μg·m-3, respectively； the O3 concentration in summer was significantly higher than that in autumn. Ozone sensitivity research showed that the generation of O3 in summer and autumn in Shangqiu was controlled by volatile organic compounds （VOCs）. Among them, oxygen-containing volatile organic compounds （OVOCs）, aromatic hydrocarbons, and alkenes contributed the most to the ozone generation potential （OFP） and ·OH reactivity （L·OH）, and the control must have been strengthened. The OBM simulation results indicated that the maximum O3 generation rates in summer and autumn were 23.0×10-9 h-1 and 13.6×10-9 h-1, with maximum net generation rates of 17.4×10-9 h-1 and 10.4×10-9 h-1 and the maximum and maximum net generation rates of O3 in summer were 1.68 times higher than those in autumn, indicating that the photochemical reactions in summer were significantly stronger than those in autumn. Compared with that in summer, the generation of O3 in autumn was greatly influenced by regional inputs from other regions or cities, with a maximum input of 14.2×10-9 h-1. The prevention and control of O3 pollution in the summer and autumn seasons in Shangqiu should mainly focus on controlling VOCs. The reduction ratio of VOCs/nitrogen oxides （NOx） in autumn should be greater than that in summer and the reduction ratios of 3∶1 in summer and 4∶1 in autumn could be adopted for control.

AI-Powered Mining of Highly Customized and Superior ESIPT-Based Fluorescent Probes.

Excited-state intramolecular proton transfer (ESIPT) has attracted great attention in fluorescent sensors and luminescent materials due to its unique photobiological and photochemical features. However, the current structures are far from meeting the specific demands for ESIPT molecules in different scenarios; the try-and-error development method is labor-intensive and costly. Therefore, it is imperative to devise novel approaches for the exploration of promising ESIPT fluorophores. This research proposes an artificial intelligence approach aiming at exploring ESIPT molecules efficiently. The first high-quality ESIPT dataset and a multi-level prediction system are constructed that realized accurate identification of ESIPT molecules from a large number of compounds under a stepwise distinguishing from conventional molecules to fluorescent molecules and then to ESIPT molecules. Furthermore, key structural features that contributed to ESIPT are revealed by using the SHapley Additive exPlanations (SHAP) method. Then three strategies are proposed to ensure the ESIPT process while keeping good safety, pharmacokinetic properties, and novel structures. With these strategies, >700 previously unreported ESIPT molecules are screened from a large pool of 570000 compounds. The ESIPT process and biosafety of optimal molecules are successfully validated by quantitative calculation and experiment. This novel approach is expected to bring a new paradigm for exploring ideal ESIPT molecules.

Uncovering excited state behaviours associated with electron-withdrawing CN and electron-donating TPA moieties on SAA derivatives: a theoretical study

Inspired by the excellent photochemical characteristics exhibited by salicylaldehyde azine (SAA) derivatives, our current endeavour primarily revolves around delving into the intricacies of photo-induced excited state reactions for its electron-donating and electron-withdrawing moieties derivatives (i.e. CN-SAA-CN, CN-SAA-TPA and TPA-SAA-TPA). Our simulations reveal push–pull-substituted-dependent photoexcitation that could significantly affect excited state intramolecular proton transfer (ESIPT) reaction for SAA derivatives. Constructing potential energy surfaces (PESs), we unveil the ultrafast ESIPT mechanism due to the low potential barriers. Additionally, by comparing the differences of barriers among CN-SAA-CN, CN-SAA-TPA and TPA-SAA-TPA, we present regulative manner for SAA derivatives by substituting electron-donating and electron-withdrawing moieties. We sincerely anticipate that the modulation of push–pull substitutions on excited state behaviours will pave the way for ground-breaking advancements in luminescent materials.

A review on green synthesis, biological applications of carbon dots in the field of drug delivery, biosensors, and bioimaging.

Since the beginning of nanoscience and nanotechnology, carbon dots (CDs) have been the foundational idea and have dominated the growth of the nano-field. CDs are an intriguing platform for utilization in biology, technology, catalysis, and other fields thanks to their numerous distinctive structural, physicochemical, and photochemical characteristics. Since several carbon dots have already been created, they have been assessed based on their synthesis process, and luminescence characteristics. Due to their biocompatibility, less toxic effects, and most significantly their fluorescent features in contrast to other carbon nanostructures, CDs have several benefits. This review focuses on the most recent advancements in the characterization, applications, and synthesis techniques used for CDs made from natural sources. It will also direct scientists in the creation of a synthesis technique for adjustable carbon dots that is more practical, effective, and environmentally benign. With low toxicity and low cost, CDs are meeting the new era's requirements for more selectivity and sensitivity in the detection and sensing of various things, such as biomaterial sensing, enzymes, chemical contamination, and temperature sensing. Its variety of properties, such as optical properties, chemiluminescence, and morphological analysis, make it a good option to use in bioimaging, drug delivery, biosensors, and cancer diagnosis.

4-[(E)-2-(1-Pyrenyl)Vinyl]Pyridine Complexes: How to Modulate the Toxicity of Heavy Metal Ions to Target Microbial Infections.

Pyrene derivatives are regularly proposed for use in biochemistry as dyes due to their photochemical characteristics. Their antibacterial properties are, however, much less well understood. New complexes based on 4-[(E)-2-(1-pyrenyl)vinyl]pyridine (PyPe) have been synthesized with metal ions that are known to possess antimicrobial properties, such as zinc(II), cadmium(II), and mercury(II). The metal ion salts, free ligand, combinations thereof, and the coordination compounds themselves were tested for their antibacterial properties through microdilution assays. We found that the ligand is able to modulate the antibacterial properties of transition metal ions, depending on the complex stability, the distance between the ligand and the metal ions, and the metal ions themselves. The coordination by the ligand weakened the antibacterial properties of heavy metal ions (Cd(II), Hg(II), Bi(III)), allowing the bacteria to survive higher concentrations thereof. Mixing the ligand and the metal ion salts without forming the complex beforehand enhanced the antibacterial properties of the cations. Being non-cytotoxic itself, the ligand therefore balances the biological consequences of heavy metal ions between toxicity and therapeutic weapons, depending on its use as a coordinating ligand or simple adjuvant.

Genomic, morphological, and physiological insights into coral acclimation along the depth gradient following an in situ reciprocal transplantation of planulae

Mesophotic coral reefs have been proposed as refugia for corals, providing shelter and larval propagules for shallow water reefs that are disproportionately challenged by global climate change and local anthropogenic stressors. For mesophotic reefs to be a viable refuge, firstly, deep origin larvae must survive on shallow reefs and, secondly, the two environments must be physically connected. This study tested the first condition. Planulae of the reef-building coral Stylophora pistillata from 5–8 and 40–44 m depth in the Gulf of Aqaba were tested in a long-term reciprocal transplantation experiment for their ability to settle and acclimate to depth in situ. We assessed survival rates, photochemical, physiological, and morphological characteristics in juveniles grown at either their parental origin or transplantation depth. Differences in gene expression patterns were compared between mesophotic and shallow corals at the adult, juvenile, and planula life stages. We found high mortality rates among all mesophotic-origin planulae, irrespective of translocation depth. Gene expression patterns suggested that deep planulae lacked settlement competency and experienced increased developmental stress upon release. For surviving shallow origin juveniles, symbiont photochemical acclimation to depth occurred within 8 days, with symbiont communities showing changes in photochemical traits without algal symbiont shuffling. However, coral host physiological and morphological acclimation towards the typical deep phenotype was incomplete within 60 days. Gene expression was influenced by both life stage and depth. A set of differentially expressed genes (DEGs) associated with initial stress responses following transplantation, latent stress response, and environmental effects of depth was identified. This study therefore refutes the Deep Reef Refugia Hypothesis, as the potential for mesophotic-origin S. pistillata planulae to recruit to the shallow reef is low. The potential remains for shallow planulae to survive at mesophotic depths.

Analysis of Photochemical Characteristics and Sensitivity of Atmospheric Ozone in Nanjing in Summer

Tropospheric ozone (O3) is mainly produced through a series of photochemical reactions of nitrogen oxides (NOx) and volatile organic compounds (VOCs). The reaction process presents complex non-linear relationships. In this work, datasets of atmospheric ozone and volatile organic compounds (VOCs) observed during the summer of 2018 in Nanjing were used. Combining with the framework for 0-D atmospheric model-master chemical mechanism (F0AM-MCM), the characteristics of photochemical reactions for ozone (O3) formation in Nanjing during the O3 episode days and non-episode days were investigated. The results showed that φ(O3) and φ(TVOCs) in the O3 episode days were 47.8×10-9 and 49.0×10-9, respectively, exceeding those in the non-episode days by factors of 1.8 and 1.6. Furthermore, F0AM, the empirical kinetic modeling approach (EKMA), and relative incremental reactivity (RIR) were utilized for the calculation of ozone chemical sensitivity. It was found that O3 formation in Nanjing was attributed to both VOCs and NOx limitation. In addition, the modeled ·OH and HO2 concentrations in the O3 episode days were 1.3 and 1.8 times higher than those in the non-episode days. The higher formation and loss rates of ·OH and HO2 were also found during O3 episode days. These findings reflected that the enhancements of atmospheric oxidation capacity resulted in increased production rates of O3, providing an explanation for the enhancements of O3 concentrations in Nanjing during the O3 episode days. The findings also improved the understanding of the O3 photochemical characteristics over Nanjing in the summer during the O3 episode days.

Transition metals-doped g-C3N4 nanostructures as advanced photocatalysts for energy and environmental applications

Graphitic carbon nitride (g–C3N4)–based heterostructured photocatalysts have received significant attention for its potential applications in the treatment of wastewater and hydrogen evolution. The utilization of semiconductor materials in heterogeneous photocatalysis has recently received great attention due to their potential and eco-friendly properties. Doping with metal ions plays a crucial role in altering the photochemical characteristics of g-C3N4, effectively enhancing photoabsorption into the visible range and thus improving the photocatalytic performance of doped photocatalysts. As an emerging nanomaterial, nanostructured g-C3N4 represents a visible light-active semiconducting photocatalyst that has attracted significant interest in the photocatalysis field, particularly for its practical water treatment applications. To the best of our knowledge, investigations of functionalized photocatalytic (PC) materials on 3d transition metal-doped g-C3N4 remain unexplored in the existing literature. g-C3N4 based heterohybrid photocatalysts have demonstrated excellent reusability, making them highly promising for wastewater treatment applications. This paper describes the overview of numerous studies conducted on the heterostructured g-C3N4 photocatalysts with various 3d metals. Research studies have revealed that the introduction of element doping with various 3d transition metals (e.g., Ti, Mn, Fe, Co, Ni, Cu, Zn, etc.) into g-C3N4 is an efficient approach to enhance degradation efficacy and boost photocatalytic activity (PCA) of doped g-C3N4 catalysts. Moreover, the significance of g-C3N4 heterostructured nanohybrids is highlighted, particularly in the context of wastewater treatment applications. The study concludes by providing insights into future perspectives in this developing area of research, with a specific focus on the degradation of various organic contaminants.

Molecular effects of photodynamic therapy with curcumin on Leishmania major promastigotes.

Leishmaniasis is a neglected disease mainly affecting low-income populations. Conventional treatment involves several side effects, is expensive, and, in addition, protozoa can develop resistance. Photodynamic therapy (PDT) is a promising alternative in treating the disease. PDT involves applying light at a specific wavelength to activate a photosensitive compound (photosensitizer, PS), to produce reactive oxygen species (ROS). Curcumin and its photochemical characteristics make it a good candidate for photodynamic therapy. Studies evaluating gene expression can help to understand the molecular events involved in the cell death caused by PDT. In the present study, RNA was extracted from promastigotes from the control and treated groups after applying PDT. RT-qPCR was performed to verify the expression of the putative ATPase beta subunit (ATPS), ATP synthase subunit A (F0F1), argininosuccinate synthase 1 (ASS), ATP-binding cassette subfamily G member 2 (ABCG2), glycoprotein 63 (GP63), superoxide dismutase (FeSODA), and glucose-6-phosphate dehydrogenase (G6PDH) genes (QR). The results suggest that PDT altered the expression of genes that participate in oxidative stress and cell death pathways, such as ATPS, FeSODA, and G6PD. The ATP-F0F1, ASS, and GP63 genes did not have their expression altered. However, it is essential to highlight that other genes may be involved in the molecular mechanisms of oxidative stress and, consequently, in the death of parasites.

Fabrication of a Z-scheme Bi2MoO6/NiFe layered double hydroxide heterojunction for the visible light-driven degradation of tetracycline antibiotics

Heterojunction catalysts offer promising potential for efficient and sustainable remediation of polluted environments. In this study, Z-scheme Bi2MoO6/NiFe layered double hydroxide (BMO/NiFe) heterojunction catalysts were synthesized using solvothermal process. The surface morphology, crystalline structure, and photochemical characteristics of the synthesized photocatalyst were analyzed by several spectroscopic and electron microscopy methods. BMO, NiFe and BMO/NiFe were efficiently utilized for tetracycline (TC) antibiotics degradation under visible light irradiation. The experimental findings suggest that the BMO/NiFe15 heterojunction catalyst greatly enhances the TC degradation rate to 95 % under 300 W visible light irradiation for 120 min. The rate constant of 0.0219 min−1 indicates a rapid degradation process following pseudo first-order kinetics. Furthermore, the effect of active free radicals, the recyclability of the catalyst and the photocatalytic degradation mechanism of TC were proposed. This novel method opens up possibilities for creating advanced photocatalysts, which can effectively degrade TC in water bodies, addressing the urgent need for its removal from aquatic environments. The present work serves as a primary pathway to design and develop efficient Bi2MoO6-based direct Z-scheme photocatalysts with promising applications in simultaneous wastewater degradation with hydrogen evolution.

Effects of Temperature, Axial Ligand, and Photoexcitation on the Structure and Spin-State of Nickel(II) Complexes with Water-Soluble 5,10,15,20-Tetrakis(1-methylpyridinium-4-yl)porphyrin.

Water-soluble metalloporphyrins, depending on the metal center, possess special spectral, coordination, and photochemical features. In nickel(II) porphyrins, the Ni(II) center can occur with low-spin or high-spin electronic configuration. In aqueous solution, the cationic nickel(II) complex (Ni(II)TMPyP4+, where H2TMPyP4+ = 5,10,15,20-tetrakis(1-methylpyridinium-4-yl)porphyrin), exists in both forms in equilibrium. In this study, an equilibrium system involving the low-spin and high-spin forms of Ni(II)TMPyP4+ was investigated via application of irradiation, temperature change, and various potential axial ligands. Soret band excitation of this aqueous system, in the absence of additional axial ligands, resulted in a shift in the equilibrium toward the low-spin species due to the removal of axial solvent ligands. The kinetics and the thermodynamics of the processes were also studied via determination of the rate and equilibrium constants, as well as the ΔS, ΔH, and ΔG values. Temperature increase had a similar effect. The equilibrium of the spin isomers was also shifted by decreasing the solvent polarity (using n-propanol) as well as by the addition of a stronger coordinating axial ligand (such as ammonia). Since triethanolamine is an efficient electron donor in Ni(II)TMPyP4+-based photocatalytic systems, its interaction with this metalloporphyin was also studied. The results promote the development of efficient photocatalytic systems based on this complex.

Photocaging of amino acids and short peptides by arylidenethiazoles: mechanism, photochemical characteristics and biological behaviour.

A series of fluorophores based on the (5-methyl-4-phenylthiazol-2-yl)-3-phenylacrylonitrile (MPTA) core were designed and synthesised for photocaging of amino acids and peptides. The photophysical characteristics of these compounds and their hybrids with biomolecules were thoroughly investigated through a joint experimental, spectral and computational approach. The photorelease ability of the obtained amino acids-MPTA and peptides-MPTA hybrids was studied under various conditions, including different UV irradiation wavelength and power, and solvents. The main reaction products were identified using high-performance liquid chromatography combined with high-resolution mass spectrometry. Photo uncaging kinetics was quantitatively studied using absorption spectroscopy. The mechanism of photorelease of amino acids and peptides was elucidated through quantum mechanical calculations, which were also used for the exploration of photophysical properties of the excited states, and photodissociation energetics quantification. Relationships between the structure of fluorophores and photodissociation characteristics were estimated, and fluorophores with the good uncaging characteristics (biomolecule photoreleasing yield, uncaging rate, and effectiveness) were identified. Cell viability assays using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide or MTT showed a low cytotoxicity of the hybrids. Confocal microscopy revealed the easy penetration of the hybrids into living cells and their selective accumulation in the endoplasmic reticulum, lipid droplets and mitochondria, depending on their chemical structure.

Greening of barley seedlings under changed gravity conditions

Plants possess sensitive mechanisms for detecting gravitational changes, and altered gravity conditions can affect metabolic processes, including photosynthesis. Photosynthesis in higher plants occurs in chloroplasts, where pigment-binding proteins play a crucial role in capturing and transferring light energy. Microgravity's impact on the photosynthetic apparatus has been studied in space-flight experiments, but results have been contradictory. This study investigates the influence of clinorotation on barley seedlings' photosynthetic apparatus during greening. The study examines pigment biosynthesis, chloroplast membrane formation, and photochemical characteristics. Results show that clinorotation affects pigment accumulation, and the differences are more pronounced in the early stages of greening, highlighting the importance of gravity in plant photosynthesis.

Effects of hydroxychromone rings with chalcogen atoms on ESIPT for 3-hydroxy-2-(5-(5-(5-(3-hydroxy-4-oxo-4H-chromen-2-yl)thiophen-2-yl)thiophen-2-yl)thiophen-2-yl)-4H-chromen-4-one derivatives: A theoretical study

Inspired by fascinating photochemical and photophysical characteristics of novel organic molecules with chalcogenide substitution, this study focuses on exploring the effects of atomic electronegativity of chalcogens (O, S, and Se) on hydrogen bond interactions and proton transfer reaction mechanisms for 3-hydroxy-2-(5-(5-(5-(3-hydroxy-4-oxo-4H-chromen-2-yl)thiophen-2-yl)thiophen-2-yl)thiophen-2-yl)-4H-chromen-4-one (FT). By comparing structural changes and infrared (IR) spectra, combined with preliminary detection of hydrogen bond interaction by core-valence bifurcation (CVB) index, we conclude S1-state hydrogen bond is strengthened, which is favorable for occurrence of ESIPT reaction. Charge recombination and constructed potential energy surfaces (PESs) reveal atomic electronegativity has a regulatory effect on ESIPT behavior for FT derivatives.

Determinants of photochemical characteristics of the photosynthetic electron transport chain of maize.

The photosynthetic electron transport chain (ETC) is the bridge that links energy harvesting during the photophysical reactions at one end and energy consumption during the biochemical reactions at the other. Its functioning is thus fundamental for the proper balance between energy supply and demand in photosynthesis. Currently, there is a lack of understanding regarding how the structural properties of the ETC are affected by nutrient availability and plant developmental stages, which is a major roadblock to comprehensive modeling of photosynthesis. Redox parameters reflect the structural controls of ETC on the photochemical reactions and electron transport. We conducted joint measurements of chlorophyll fluorescence (ChlF) and gas exchange under systematically varying environmental conditions and growth stages of maize and sampled foliar nutrient contents. We utilized the recently developed steady-state photochemical model to infer redox parameters of electron transport from these measurements. We found that the inferred values of these photochemical redox parameters varied with leaf macronutrient content. These variations may be caused either directly by these nutrients being components of protein complexes on the ETC or indirectly by their impacts on the structural integrity of the thylakoid and feedback from the biochemical reactions. Also, the redox parameters varied with plant morphology and developmental stage, reflecting seasonal changes in the structural properties of the ETC. Our findings will facilitate the parameterization and simulation of complete models of photosynthesis.

Photochemistry of the Retinal Chromophore in Microbial Rhodopsins.

Microbial rhodopsins are photoreceptive membrane proteins of microorganisms that express diverse photobiological functions. All-trans-retinylidene Schiff base, the so-called all-trans-retinal, is a chromophore of microbial rhodopsins, which captures photons. It isomerizes into the 13-cis form upon photoexcitation. Isomerization of retinal leads to sequential conformational changes in the protein, giving rise to active states that exhibit biological functions. Despite the rapidly expanding diversity of microbial rhodopsin functions, the photochemical behaviors of retinal were considered to be common among them. However, the retinal of many recently discovered rhodopsins was found to exhibit new photochemical characteristics, such as highly red-shifted absorption, isomerization to 7-cis and 11-cis forms, and energy transfer from a secondary carotenoid chromophore to the retinal, which is markedly different from that established in canonical microbial rhodopsins. Here, I review new aspects of retinal found in novel microbial rhodopsins and highlight the emerging problems that need to be addressed to understand noncanonical retinal photochemistry.

Differential cytotoxicity to human cells in vitro of tire wear particles emitted from typical road friction patterns: The dominant role of environmental persistent free radicals

Tire wear particles (TWPs) have been recognized as one of the major sources of microplastics (MPs), however, effects of initial properties and photochemical behavior of TWPs on cytotoxicity to human cells in vitro have not been reported. Therefore, here, three TWPs generated from typical wear of tires and pavements (i.e., rolling friction (R-TWPs) and sliding friction (S-TWPs)) and cryogenically milled tire tread (C-TWPs), respectively, and their photoaging counterparts were used to study the reasons for their differential cytotoxicity to 16HBE cells in vitro. Results showed in addition to changes of surface structure and morphology, different preparation methods could also induce formation of different concentration levels of environmental persistent free radicals (EPFRs) (from 1.24 to 3.06 × 1017 spins/g with g-factors ranging 2.00307–2.00310) on surfaces of TWPs, which contained 7.3%–65.8% of reactive EPFRs (r-EPFRs). Meanwhile, photoaging for 90 d could strengthen formation of EPFRs (from 4.03 to 4.61 × 1017 spins/g) with containing 74.7%–78.1% r-EPFRs on surfaces of TWPs and improve their g-factor indexes (ranging 2.00309–2.00313). At 100 μg mL−1 level, compared to C-TWPs, both R-TWPs and S-TWPs (whether photoaging or not) carried higher intensity EPFRs could significantly inhibit 16HBE cells proliferation activity, cause more cells oxidative stress and induce more cell apoptosis/necrosis and secretion of inflammatory factor (P < 0.05). However, regardless of how TWPs were prepared, photoaged or not, exposure at a concentration of 1 μg mL−1 appeared to be non-acute cytotoxic. Correlation analysis suggested dominant toxicity of TWPs was attributed to the formation of r-EPFRs on their surfaces, which could promote accumulation of excess reactive oxygen species in cells and the massive deposition of intracellular particles. This study provides direct evidence of TWPs cytotoxicity, and underlining the need for a better understanding of the influences of initial properties and photochemical characteristics on risk assessment of TWPs released into the environment.

Study on photodissociation and photoconversion characteristics of CS2 in O2/O3 environment using real-time conversion products obtained by UV-DOAS

Carbon disulfide (CS2) is extremely susceptible to decomposition by ultraviolet radiation, and its decomposition products affect the concentration of trace gases in the atmosphere, which disrupts the balance of atmospheric chemistry. It is essential to elucidate the photochemical reaction characteristics of CS2 for more in-depth study of the complex chemical and physical changes in the atmosphere. Therefore, this paper firstly provides a clear visualization of the evolution process of CS2 and conversion products by UV differential optical absorption spectroscopy combined with multi-wavelength least squares method, and then the photodissociation and photoconversion characteristics of CS2 under trace-oxygen, additional-oxygen and additional-ozone conditions are explained. The results show that the generation of SO2 from CS2 is about 100 ppm when only trace-oxygen is present, and the main channels of the reaction are CS2+hv→CS+S and CS+4O→SO2+CO2. The SO2 concentration increased from 138 ppm to 150 ppm as the oxygen concentration increased with the main reaction channels CS2+6O→2SO2+CO2 and CS+4O→SO2+CO2. However, in the additional-ozone environment, the main reaction channels CS2+2O3→2SO2+CO2 and CS+4/3O3→SO2+CO2 gradually dominate as the ozone concentration increases, at which point the SO2 concentration decreases from 140 ppm to 125 ppm. The results indicate that in the photochemical reaction of CS2, the unstable products O atoms and CS directly affect the photochemical reaction rate and the concentration of SO2. This study not only enables real-time monitoring of the evolution process and conversion products of CS2, but also lays the foundation for future studies on the conversion properties of CS2 in photochemical reactions.

Synthesis, photophysical and photochemical features of a Morita-Baylis-Hillman adduct derivative bearing a triphenylamine moiety

A new Morita-Baylis-Hillman Adduct (MBHA) derivative 7 was designed and synthesized to obtain a reactive molecule potentially capable of labelling basic amino acid residues. Compound 7 was easily prepared and characterized from the point of view of its photophysical and photochemical features before then to be used in labelling experiments with amino acid.