Light Irradiation Time Research Articles

Light‐Responsive Aldehyde‐Reduction Catalysis Through Catalyst Encapsulation

We report a light‐responsive tetrahedral metal–organic capsule that binds a perrhenate catalyst, which is released selectively upon irradiation with 350 nm light, turning on the catalytic reduction of organic carbonyls by hydrosilanes. The catalytic activity can be switched off by heating at 75 °C for 2.5 h, which stimulates capsule reformation and catalyst re‐encapsulation. Multiple on‐off cycles were shown, with a clear relationship between product yield and light irradiation time. Encapsulation thus enables the coupling of light‐responsiveness to catalysis in a manner that might be generalized to other catalysts and capsules.

Light-Responsive Aldehyde-Reduction Catalysis Through Catalyst Encapsulation.

We report a light-responsive tetrahedral metal-organic capsule that binds a perrhenate catalyst, which is released selectively upon irradiation with 350 nm light, turning on the catalytic reduction of organic carbonyls by hydrosilanes. The catalytic activity can be switched off by heating at 75 °C for 2.5 h, which stimulates capsule reformation and catalyst re-encapsulation. Multiple on-off cycles were shown, with a clear relationship between product yield and light irradiation time. Encapsulation thus enables the coupling of light-responsiveness to catalysis in a manner that might be generalized to other catalysts and capsules.

Visible light degradation of antibiotics catalyzed by nanoporous carbon/V2O5 nanocomposite: structural, optical and electrochemical properties

In this study, nanoporous carbon (NPC) decorated V2O5 (NPC/V2O5) nanocomposite synthesized by a hydrothermal technique using biomass-derived NPC nanoflakes towards the application of berberine hydrochloride (BH) dye degradation under visible light irradiation. The prepared samples were characterized by X-ray Diffraction (XRD), Raman spectroscopy, Field Emission Scanning Electron Microscopy (FE-SEM), Transmission Electron Microscopy (TEM), Energy-Dispersive X-ray (EDX), UV-Visible and Photoluminescence (PL) spectroscopy. Charge transfer resistance was measured by electrochemical impedance spectroscopy (EIS) and liner sweep voltammetry (LSV). XRD studies confirm the orthorhombic crystal structure of NPC/V2O5 nanocomposite. FE-SEM and TEM analysis validate their particle-like and sheet-like morphology of V2O5 and NPC respectively. Further, UV-visible DRS and PL spectra of the green synthesized NPC/V2O5 nanocomposite exhibited a low band-gap and reduced recombination rate compared to the pure counterpart which is better light-absorbing ability in the visible light region. Batch experiments represent the incorporation of NPC and V2O5 would lead to an increase the photocatalytic performance of NPC/V2O5 toward BH dye degradation. During the photocatalytic reaction, the NPC/V2O5 nanocomposite degraded rate around 97.7% against BH dye within 80 min while pure V2O5 degraded 92.5% of BH dye under same visible light irradiation time. Finally, the cyclic stability experiment exhibits the photocatalyst even stable after five consecutive tests.

Influence of excitation light wavelength and irradiation time on photothermal properties of photochemically synthesized colloidal gold

Influence of excitation light wavelength and irradiation time on photothermal properties of photochemically synthesized colloidal gold

Synthesis of alginate capped aluminum oxide (Al2O3) nanocomposite for efficient photocatalytic degradation of methylene blue

Abstract In the presence scenario, dye pollution has become a serious issue in present environment protection which need extensive attention of the scientific community. Methylene blue (MB) has been known for its toxic nature and widely used in various industries. In the present work, we reported the green synthesis of alginate capped alumina (Al2O3) nanocomposite (NC). The synthesized Alg@Al2O3 NC have been verified by various sophisticated characterization techniques (XRD, SEM, EDX, UV–vis TEM, FTIR, and XPS). The synthesized Alg@Al2O3 NC have been used as photocatalyst for the degradation of MB dye. Furthermore, photocatalytic activity of the Alg@Al2O3 NC has been studied under ultraviolet (UV) light. The obtained results exhibited excellent photocatalytic properties of the Alg@Al2O3 NC. The effect of photocatalyst doses (0.1–5 g l−1), pH−1 (1–10), MB dye concentration (50–120 ppm), and irradiation time (5–135 min) of UV light were also optimized. The highest efficiency of 99.2% has been observed for MB degradation via Alg@Al2O3 NC. The investigations of kinetics demonstrated that the photocatalytic degradation proceeded along a pseudo-first-order pathway in accordance with the Langmuir–Hinshelwood (L-H) kinetic model. The Alg@Al2O3 NC also exhibited excellent reusability for 4 cycles and suggested that Alg@Al2O3 NC can be used for various cycles. In this study, we proposed the cost-effective green synthetic method for the preparation of Alg@Al2O3 NC and its application as photocatalyst for the removal of MB dye under UV light.

Ingenious development of bandgap engineered MIL-101(Fe) core-shell supported on SnO2/ZnO heterojunction and its photocatalytic activity towards azo dye degradation: Process optimization and mechanistic insight

Water pollution is a pressing global concern, exacerbated by industrial effluents containing hazardous azo-dyes such as Trypan blue (TB) and Methyl orange (MO), which contaminate water bodies and threaten ecosystems. The scarcity of pure water intensifies the urgency to develop effective remediation strategies to tackle the toxic dye pollutants. In the present work, an attempt has been made to fabricate and utilize a novel ternary MOF-based SnO2/ZnO@MIL-101(Fe) photocatalyst for the removal of TB and MO dyes from an aqueous medium. The photocatalyst was characterized using various analytical techniques, like XRD, FTIR, UV–vis DRS, PL, SEM, TEM, and XPS, which provide insights into the composites’ crystal structure, morphology, and optical properties, which are crucial for understanding their photocatalytic behavior. The photocatalytic performance of the heterojunction was investigated under various reaction parameters such as catalyst dosage, initial concentration of dyes, and light irradiation time. The results demonstrated the superior performance of the SnO2/ZnO@MIL-101(Fe) composites in degrading the mono-azo and di-azo dyes under visible light irradiation via a photo-fenton process. The maximum degradation efficiency of 97.44 % and 98.8 % were obtained for TB and MO within 30 and 55 min, respectively. Furthermore, the change in the total organic carbon (TOC) was monitored to verify the degree of mineralization of the azo dyes. The extremely high dye degradation activity and TOC removal can be attributed to the formation of a suitable heterojunction interface between the components of the photocatalyst, leading to effective charge carrier transport and the generation of active radicals. Finally, based on the radical scavenging experiments, ESR, and VB-XPS analysis, a plausible mechanism for the photodegradation process was derived. This research contributes to the advancement of sustainable water treatment technologies by providing insights into the design, fabrication, and utilization of novel composites for efficient remediation of dye-contaminated wastewater.

Enhanced photodielectric effect of Na1/2Bi1/2TiO3-based ceramics by poling and quenching treatment

The photodielectric effects of rare earth elements Er, Eu, and Ho doped Na1/2Bi1/2TiO3 (NBT) ceramics are investigated. The dependence of light intensity and irradiation time on the photodielectric effects were clarified, and the thermal-induced and photo-induced changes in permittivity are distinguished. At 1 kHz, the Δεr/εdark (Δεr = εphoto-εdark) of NBT-Er/Eu and NBT-Er/Ho are 2.57 % and 2.08 %, respectively. Furthermore, poling and quenching treatments are employed to improve the photodielectric effect of NBT-Er/Ho ceramics. At 1 kHz, the Δεr/εdark of poled and quenched NBT-Er/Ho increase to 5.22 % and 2.71 %, respectively. The increase of Δεr/εdark of poled sample is resulted from the lattice distortion of the ceramics while the increase of Δεr/εdark of quenched sample is due to the increase in oxygen vacancies. This work is conducive to understand the unconventional optical and dielectric effects in ferroelectric ceramics.

Fe3O4/ZnO/L-lysine functionalized graphene oxide a promising nanocomposite with double Z-scheme visible photocatalytic and dark catalytic activity for water remediation

Developing multifunctional catalysts for efficient pollutant degradation in dark and visible light conditions represents a significant advancement in water remediation technology. This study reports the synthesis of a novel Fe3O4/ZnO/Lys-rGO nanocomposite via environmentally friendly methods that exhibit catalytic-photocatalytic activity for efficient degradation of organic pollutants. The synergistic effect of compositing Lys-rGO, a bio-organic component with a narrow band gap (1.08 eV), into the Fe3O4/ZnO inorganic composite induces a double Z-scheme mechanism by providing two pathways for effective charge separation in the visible photocatalytic activity of the nanocomposite. Additionally, the stored electrons in the very conductive Lys-rGO layers offer active sites for the catalytic activity of the nanocomposite in the dark. Meanwhile, ZnO generates reactive oxygen species (ROS) through surface oxygen vacancies, further contributing to the nanocomposite’s dark catalytic activity. The degradation of various organic pollutants (Methylene Blue, Tetracycline, Ciprofloxacin, Rhodamine B, and their mixture), as well as Congo Red, with low catalyst dosage and visible light irradiation time, demonstrates the high performance and versatility of this nanocomposite. This research highlights the potential of Lys-rGO in compositing with semiconductors to design multifunctional catalysts for cost-effective sustainable water purification technologies.

Dissecting diazirine photo-reaction mechanism for protein residue-specific cross-linking and distance mapping

While photo-cross-linking (PXL) with alkyl diazirines can provide stringent distance restraints and offer insights into protein structures, unambiguous identification of cross-linked residues hinders data interpretation to the same level that has been achieved with chemical cross-linking (CXL). We address this challenge by developing an in-line system with systematic modulation of light intensity and irradiation time, which allows for a quantitative evaluation of diazirine photolysis and photo-reaction mechanism. Our results reveal a two-step pathway with mainly sequential generation of diazo and carbene intermediates. Diazo intermediate preferentially targets buried polar residues, many of which are inaccessible with known CXL probes for their limited reactivity. Moreover, we demonstrate that tuning light intensity and duration enhances selectivity towards polar residues by biasing diazo-mediated cross-linking reactions over carbene ones. This mechanistic dissection unlocks the full potential of PXL, paving the way for accurate distance mapping against protein structures and ultimately, unveiling protein dynamic behaviors.

Application of machine learning models to improve the prediction of pesticide photodegradation in water by ZnO-based photocatalysts

Pesticide pollution has been posing a significant risk to human and ecosystems, and photocatalysis is widely applied for the degradation of pesticides. Machine learning (ML) emerges as a powerful method for modeling complex water treatment processes. For the first time, this study developed novel ML models that improved the estimation of the photocatalytic degradation of various pesticides using ZnO-based photocatalysts. The input parameters encompassed the source of light, mass proportion of dopants to Zn, initial pesticide concentration (C0), pH of the solution, catalyst dosage and irradiation time. Additionally, physicochemical properties such as the molecular weight of the dopants and pesticides, as well as the water solubility of both dopants and pesticides, were considered. Notably, the numerical data were extracted from the literature via relevant tables (directly) or graphs (indirectly) using the web-based tool WebPlotDigitizer. Four ML models including multi-layer perceptron artificial neural network (MLP-ANN), particle swarm optimization-adaptive neuro fuzzy inference system (PSO-ANFIS), radial basis function (RBF), and coupled simulated annealing-least squares support vector machine (CSA-LSSVM) were developed. In comparison, RBF showed the best accuracy of modeling among all models, with the highest determination coefficient (R2) of 0.978 and average absolute relative deviation (AARD) of 4.80%. RBF model was effective in estimating the photocatalytic degradation of pesticides except for 2-chlorophenol, triclopyr and lambda-cyhalothrin, where CSA-LSSVM model demonstrated superior performance. Dichlorvos was completely degraded by ZnO photocatalyst under visible light. The sensitivity analysis by relevancy factor exhibited that light irradiation time and initial pesticide concentration were the most important parameters influencing photocatalytic degradation of pesticides positively and negatively, respectively. The new ML models provide a powerful tool for predicting pesticide degradation in wastewater treatment, which will reduce photochemical experiments and promote sustainable development.

Polluted River Water Treatment Via Pilot-Scale Membrane Photocatalytic Reactor (MPR) Incorporated Zno-Kaolin Under Different Light Intensity

Polluted river water treatment utilizes a mix of physical, chemical, and biological processes and activities. Conventional systems, including coagulation, flocculation, sedimentation, filtration, and disinfection, have several limitations. Hence, the Membrane Photocatalytic Reactor (MPR) is one of the most promising methods for polluted river water treatment. ZnO-Kaolin nanoparticles served as great photocatalysts for MPR performance. This study focuses on the pilot-scale hybrid MPR treatment of polluted river water under different light intensities (100, 125, and 225 watts) and irradiation times (20, 30, and 40 minutes). The treated water quality analysis is based on the Environmental Quality Act 1974 (EQA 1974). The kinetic rate was also investigated using pseudo-first-order and pseudo-second-order models. It was found that 225 watts and 30 minutes were the optimum values. The pilot scale hybrid MPR proved to fit well with the pseudo-second-order kinetic models, suggesting that the degradation follows a chemisorption mechanism. In conclusion, we believe the hybrid MPR pilot-scale system will enhance efficiency in cleaning dirty river water, all while meeting the standards of the EQA 1974.

Enhancement of photothermal effect of Cu2S@CuS homojunction and applications of crude oil–water separation and ice removal

The recycle of crude oil with high viscosity from wastewater and anti-icing of outdoor power transmission lines are still challenges. High photothermal responses with excellent superwetting properties are critical issues for solving these problems. In the paper, the porous nanosheet arrays of Cu2S@CuS homojunction with narrow band have been prepared by anodizing Cu foam. After the surface modification of stearic acid (STA), the array surface is endowed with excellent wetting states of super-hydrophobicity and super-lipophilicity, and is suitable for the oil–water separation. The narrow band and homojunction structure induce the excellent light absorption, and further increase the photothermal conversion efficiency of the prepared Cu2S@CuS nanoarray to the value of 8.81 %. Under the irradiation of Xe lamp with 0.1 W/cm2, the surface temperature of Cu2S@CuS nanosheet array in air promptly increases to 96.5 ℃ from room temperature of 20.9 ℃ within 30 s, and increases to 69 ℃ from room temperature within 45 s in crude oil. Obviously, the prepared Cu2S@CuS nanoarrays with excellent photothermal responses are very suitable to be used as filter film for the crude oil–water separation. With the increase of light irradiation time, the local temperature of crude oil near the filter film continues to be increased to 69 ℃ within 45 s, and the gradually warmed crude oil was continuously pumped to the oil collecting beaker through rubber pipe, showing the high efficiency and excellent stability. Of course, it is also used to efficiently separate the oil with low viscosity from oil-water mixtures and emulsion.

Transformed construction from type-II WO3/BaTiO3 heterojunction to Z-scheme WO3/Ba0.5Sr0.5TiO3 and WO3/SrTiO3 photocatalytic systems: Enhanced photocatalytic activity and mechanism insight

In this study, type-II heterojunction WO3/BaTiO3 and Z-scheme WO3/SrTiO3 or WO3/Ba0.5Sr0.5TiO3 nanocomposite photocatalysts were constructed for photodegradation of organic pollutants in wastewater under visible light. The photocatalytic performance of three WO3/titanate systems were estimated. Some influencing factors such as molar ratio of WO3 and titanates, light irradiation time, catalyst dose, and initial concentration of organic pollutants on the photocatalytic activity were investigated. The stability and reusability of three WO3/titanates systems were examined. Moreover, the production of some radicals in the three WO3/titanates photocatalytic systems was demonstrated, and the three WO3/titanates photocatalytic reaction mechanisms were compared. The results reveal that the configurations of WO3/titanates photocatalytic systems are transformed from type-II heterojunction WO3/BaTiO3 with lower activity to Z-scheme WO3/SrTiO3 and WO3/Ba0.5Sr0.5TiO3 with higher activity via the change of titanates. The WO3/titanate nanocomposites show higher photocatalytic activity at 3.0:1.0 M ratio of WO3 and titanates, and WO3/Ba0.5Sr0.5TiO3 nanoparticles have superior photocatalytic activity. The order of photocatalytic activity is as follows: WO3/Ba0.5Sr0.5TiO3 > WO3/SrTiO3 > WO3/BaTiO3. Several organic pollutants, such as rhodamine B, methyl parathion, direct brilliant yellow-4R, and methylene blue, can be efficiently degraded using WO3/Ba0.5Sr0.5TiO3 under visible light, and the RhB has higher degradation rate. After four cycles, WO3/titanate nanocomposites still have relatively high stability and reusability. •OH plays a major role in three WO3/titanates photocatalytic degradation. It is expected that the Z-scheme WO3/Ba0.5Sr0.5TiO3 photocatalytic technology creates a good foreground for disposing of dyes and pesticides in water and wastewater.

Natural Phytochemical and Visible Light at Different Wavelengths Show Synergistic Antibacterial Activity against Staphylococcus aureus.

As the risk of antibiotic-resistant bacteria increases, interest in non-antibiotic treatment is also increasing. Among the methods used in non-antibiotic therapy, natural antibiotics such as essential oils have disadvantages such as low efficiency. In the case of phototherapy, the light used for antibacterial activities has low penetration into the human body because of its short wavelength, making it of low medical utility. To solve this problem, this study aimed to determine conditions for enhancing the antibacterial activity of natural phytochemicals and visible light. Four natural phytochemical extracts that showed high antibacterial properties in previous studies were analyzed. Synergistic effects on antibacterial activity and cytotoxicity were determined when natural phytochemical extracts and visible light were simultaneously used. As a result, it was confirmed that the antibacterial activity increased by four times when Sanguisorba officinalis L. was irradiated with 465 nm for 10 min and 520 nm for 40 min, and Uncaria gambir Roxb. was irradiated with 465 nm for 10 min and 520 nm for 60 min compared to when Sanguisorba officinalis L. and Uncaria gambir Roxb. were used alone. The synergistic effect on antibacterial activity was independent of the absorption peak of the natural phytochemical extracts. In addition, in the case of natural phytochemical extracts with improved antibacterial activity, it was confirmed that the improvement of antibacterial activity was increased in inverse proportion to the light irradiation wavelength and in proportion to the light irradiation time. The antibacterial activity was enhanced regardless of antibiotic resistance. In the case of cytotoxicity, it was confirmed that there was no toxicity to A549 cells when treated with 465 nm, the shortest wavelength among the natural phytochemical extracts. These results show how to replace blue light, which has been underutilized due to its low transmittance and cytotoxicity. They also demonstrate the high medical potential of using natural phytochemical and visible light as a combination therapy.

Coal fly ash-supported ZnO-promoted TiO2 towards UV photocatalytic degradation of anthraquinone dye: Parametric optimization, kinetics and mechanism studies

Heterogeneous photocatalysis via combination of catalyst and UV irradiation is one of the most promising advanced oxidation processes for degradation of water-soluble organic contaminants. Herein, different photocatalysts (ZnO/CFA, TiO2/CFA, and TiO2-ZnO/CFA) were synthesized via sol-gel and impregnation techniques and applied for the degradation of acid blue 25 (AB25) dye in aqueous solution under UV light in a photoreactor. Various spectroscopic techniques (XRF, XRD, BET, FTIR, UV–vis DRS, TEM and EDS) were employed to evaluate the chemical structure, functional groups, textural, and optical properties of the binary and ternary composites. TiO2-ZnO/CFA displayed rapid degradation of AB25 as compared to ZnO/CFA and TiO2/CFA, owing to the dualistic photocatalytic sites. The prepared TiO2-ZnO/CFA composite was used in synergy with the photoreactor for photocatalytic degradation process optimization, and the optimum degradation conditions in relation to initial AB25 concentration (10 mg/L), UV light intensity (18 W/m2), flow rate (12.5 L/h), and irradiation time (150 min) as input parameters were determined using Taguchi design approach. The maximum photocatalytic degradation efficiency was 98.79±0.94% under those aforementioned conditions, indicating that the synergies between the photoreactor and the TiO2-ZnO/CFA photocatalyst resulted in the effective destruction of AB25 dye molecules. Furthermore, the spent photocatalyst was easily removed from the degraded solution and reused up to nine times. After 150 mins of UV irradiation with TiO2-ZnO/CFA photocatalyst, almost complete mineralization of AB25 solution was achieved.

Removal of Dibenzothiophene from Liquid Fuels by Photocatalytic Desulfurization over Zn‐Terephthalate Complex: A Process Modelling and Optimization by Response Surface Methodology

AbstractThe Zn‐terephthalate complex was synthesized by hydrothermal method at 180 °C and applied as a novel macroporous photocatalyst in the desulfurization of dibenzothiophene (DBT) from a fuel model to produce DBT sulfone. The physical‐chemical properties of the photocatalyst were characterized by Fourier Transform Infrared (TIR), Raman spectroscopy, powder X‐ray diffraction (XRD), field‐emission scanning electron microscopy (FESEM), photoluminescence spectroscopy and UV‐Vis diffuse reflectance spectroscopy (UV‐Vis DRS). The characterization results indicated the formation of mono‐nuclear paddlewheel metal‐organic framework (MOF) as Zn [COO]2 frameworks. The photocatalytic experiments were designed by the Box‐Behnken method of response surface methodology (RSM) and the photocatalytic process was modelled and optimized. Three independent process variables i. e. concentration of dibenzothiophene, the amount of photocatalyst and light irradiation time were considered in the experimental design. The determination coefficient (R2) of the model is 0.97. The optimum removal of DBT (50.4 %) resulted in a fuel model containing 50 ppm DBT, desulfurized by 0.060 g of Zn‐MOF photocatalyst under visible light for 180 min. The predicted response (DBT removal%) by the RSM model was 50.68 %. According to the Pareto analysis, the order of importance of independent factors on the response was as follows: Irradiation time>m(photocatalyst)>C(DBT).

Synthesis of graphitic carbon nitride modified kaolin-carboxyl graphene for the degradation of pharmaceutical waste under sunlight.

Graphitic carbon nitride modified with kaolin-carboxyl graphene (g-C3N4/KG) was successfully synthesized using urea as the precursor and was applied for the photocatalytic degradation of pharmaceutical compound, "cefepime." Structural and optical characteristics of g-C3N4/KG were analyzed using various characterization techniques such as FT-IR, XRD, TEM, SEM, EDX, TG, BET, DRS, and PL. The PL studies confirmed that g-C3N4/KG catalyst exhibits strong charge separation and electron flow, and enhanced visible light absorption capacity was revealed by DRS studies. Studies on the active radical species demonstrate that superoxide and hydroxy radicals play a major role in the photocatalytic degradation of cefepime and dye pollutants. g-C3N4/KG showed the complete removal MB and 85% of degradation of cefepime under solar light irradiation time of 75min and 135min, respectively. Additionally, possible mechanism for the breakdown of the antibiotic cefepime was presented, along with identification of the intermediates produced during the degradation process. The study demonstrates that this novel photocatalyst could be utilized to remove dyes as well as medical wastes from water under solar light.

In vitro performance of an autocured universal adhesive system in bonding to dentin

BackgroundThe successful integration of resin-based dental adhesives significantly impacts restorative dentistry, providing efficient and aesthetically pleasing caries treatments. Among various adhesives, one-step self-etching adhesives (1-SEAs) have gained popularity due to their simplicity and short application time. However, concerns have been raised regarding their bonding performance and marginal adaptation characteristics, which differ from two-step self-etching adhesives (2-SEAs) and three-step etch-and-rinse adhesives. Additionally, light-cured bonding materials may encounter challenges in deep cavities and inaccessible areas, necessitating extended light irradiation time. Autocured bonding materials are a potential solution, but limited comparative studies have been conducted on their performance.MethodsIn this in vitro study, we evaluated a new autocured universal bonding material (Bondmer Lightless 2) and compared the results with recent light-cured bonding materials. Microshear bond strength (μSBS) tests were performed on 25 human molars using five different combinations of adhesives and composite resins: Bondmer Lightless 2 with Estelite Bulk Fill Flow (BE group), Bondmer Lightless 2 with a prototype composite resin (BO group), Prime&Bond Universal with SDR flow + (PS group), Scotchbond Universal with Filtek Bulk Fill (SF group), and G-Premio Bond with Gracefil BulkFlo (GG group). The bond strengths and failure modes were assessed using a universal testing machine and scanning electron microscope (SEM), respectively. Marginal adaptation was evaluated using swept-source optical coherence tomography (SS-OCT) and confocal laser scanning microscopy (CLSM) on 40 sound bovine maxillary incisors.ResultsThe μSBS test showed no significant differences in bond strength among the tested groups. Most failure modes were observed at the bond interface between the adhesive and the dentin. The autocured bonding material demonstrated significantly higher marginal adaptation (SI%) than PS, SF, and GG. The CLSM images corresponded with gaps observed in the SS-OCT images, indicating improved marginal sealing in the autocured group.ConclusionsThe new autocured universal bonding material exhibited comparable bond strength to a conventional light-cured material while demonstrating a superior marginal adaptation level. This finding suggested that the autocured material could be a valuable alternative, especially when extended light irradiation would pose a challenge. Further clinical studies would be warranted to evaluate the performance of the autocured bonding material in actual restorative dental practice.

Ultrasonic-assisted synthesis of TiO2/MWCNT/Pani nanocomposite: Photocatalyst characterization and optimization of efficient variables in the degradation of benzene via RSM-CCD

Nowadays, volatile organic compounds (VOCs) are the primary cause of rising contamination in groundwater, surface water, and wastewater. On the other hand, photocatalysis technology is among the best ways to treat wastewater because of its ability to rapidly mineralize a range of pollutants into non-toxic chemicals using sunlight as an energy source and its ecological friendliness. Herein, the TiO2/MWCNT/Pani nanocomposite was synthesized by combining ultrasonic and in-situ polymerization methods to decompose benzene, a prevalent and harmful VOC. The nanocomposite was characterized by XRD, FTIR, BET, SEM, and UV–Vis analysis. The response surface methodology (RSM), based on Central Composite Design (CCD), was used to investigate and optimize the effects of the independent factors on photocatalytic degradation, including initial benzene concentration, catalyst dosage, pH, and light irradiation time. The optimal conditions (benzene concentration = 700 mg. L−1, pH = 6, irradiation time = 80 min, and photocatalyst dosage = 1.5 g. L−1) resulted in maximum benzene degradation (84.90%). Trapping test and EPR analysis were also utilized to detect reactive species, and the findings indicated that the breakdown of benzene through photocatalysis is caused by the presence of hydroxyl radicals (•OH) and superoxide radicals (•O2−). Furthermore, the kinetics of the reaction and the stability of the nanocomposite (4 cycles) were examined. Finally, the results of this study provide convincing evidence for using TiO2/MWCNT/Pani as highly efficient and promising photocatalysts for removing benzene from aqueous solutions.

Environmentally persistent free radicals on photoaged nanopolystyrene induce neurotoxicity by affecting dopamine, glutamate, serotonin and GABA in Caenorhabditis elegans

Microplastics are widely detected in the environment and induce toxic effects in various organisms. However, the properties and toxicity associated with environmentally persistent free radicals (EPFRs) in photoaged nanopolystyrene (NPS) remain largely unknown. We investigated the generation of EPFRs on photoaged NPS and their neurotoxicity and underlying mechanism in Caenorhabditis elegans. The results suggested that photoaging induces the generation of EPFRs and reactive oxygen species (O2•−, •OH, and 1O2), which altered the physicochemical properties (morphology, crystallinity, and functional groups) of NPS. Acute exposure to 1 μg/L of NPS-60 (NPS with light irradiation time of 60 d) significantly decreased locomotion behaviors and neurotransmitter contents (e.g., glutamate, serotonin, dopamine, and γ-aminobutyric acid). Treatment with N-acetyl-L-cysteine (NAC) by radical quenching test significantly reduced EPFRs levels on the aged NPS, and the toxicity of NAC-quenching NPS was decreased in nematodes compared to those in photoaged NPS. EPFRs also caused dysfunction of neurotransmission-related gene expression in C. elegans. Thus, EPFRs generated on photoaged NPS contributed to neurotoxicity by affecting dopamine, glutamate, serotonin, and γ-aminobutyric acid neurotransmission. The study highlights the potential risks of photoaged NPS and the contributions of EPFRs to toxicity.