UV Power Research Articles

2,4-Dinitrotoluene (DNT) Removal Efficiency Using the Sono-photo-fenton Process Combined with Nano Zero Valent Iron (nZVI) Heterogeneous Catalysis

2,4-Dinitrotoluene (DNT) is a highly toxic compound of nitrotoluene group causing negative impacts on mammals, fish, and human health that needs to be treated before discharging. The study aimed to evaluate the affecting factors on efficiency of DNT treatment by Sono-Photo-Fenton process using zero-valent iron catalysts (nZVI), including: pH, intial DNT concentration, nZVI catalyst concentration, hydrogen peoxide concentration, light power, and ultrasonic power. After 20 minutes of Sono-Photo-Fenton reaction, the DNT removal efficiency was 100% with optimal operating conditions as following: pH=3.0, CDNT = 50 mg/L, CH2O2 = 20 mM, CnZVI = 1 mM, UV power of 10 W, ultrasonic power of 80 W.

Efficient photocatalytic decomposition of PFOA over BiOI1-x with low power LED light

In recent years, the academic community has shown significant interest in per- or polyfluoroalkyl compounds (PFAS) due to their challenging degradation and potential health risks. Photocatalysis has been investigated for PFAS decomposition due to its environmentally friendly nature. In this study, BiOI with abundant iodine vacancies was synthesized through solvothermal and calcination methods (referred to as BiOI1-x), and was used for PFAS degradation with a low power UV light source. Compared to pure BiOI, BIOI1-x showed higher photocatalytic activity towards PFOA (perfluorooctanoic acid). Within 5 h under 5 W LED light irradiation, the degradation rate of PFOA reached 51.9 % with BiOI1-x calcined at 440 °C (No significant degradation of PFAS was observed with pure BiOI). Capture experiments, electron paramagnetic resonance spectroscopy, and electrochemical experiments revealed that the main active species in the system were photogenerated holes, followed by hydroxyl radicals. Furthermore, the presence of iodine vacancies significantly improved the efficiency of charge carrier separation and enhanced the photocatalytic performance. Finally, a hypothetical degradation pathway for PFOA in this system was suggested. This study achieved efficient degradation of PFAS under low power LED light (5 W), emphasizing its significant practical importance in terms of energy conservation.

Photocatalytic activity of Nb2O5-α-Fe2O3 Nanocomposites Synthesized by Sol-gel Method

In this investigation, Nb2O5-α-Fe2O3 nanocomposites were synthesized by modified sol-gel method. The obtained materials were characterized by different techniques such as powder X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), Brunauer-Emmett-Teller (BET), UV-vis diffuse reflectance (UV-vis spectroscopy). The catalyst was found to have a particle size in the region of 20-42 nm with a high surface area. The effects of the catalyst dose, the pH value, UV power, addition of H2O2 and scavenger on the photocatalytic efficiency were investigated. This study presents a strategy to eliminate highly toxic and persistent dyes such as DB 199 dye. It was observed that the nanocomposites showed maximum response with more than 80% degradation of DB 199 dye in 100 min.

Development Of An Endoscopic, Absorption Corrected And Calibrated OH Laser Induced Fluorescence Probe System for High Pressure Combustion Diagnostics

We present the design and preliminary results of an endoscopic OH laser-induced fluorescence (LIF) system that is capable of acquiring 1D-line measurements in high pressure combustion processes within large-scale test facilities. The system can be exploited to acquire line-of-sight OH-chemiluminescence images and absorption corrected absolute OH-species concentration from which additionally temperature distribution can be extracted in case of lean mixtures in chemical equilibrium. Different critical components, such as light guides for high power UV laser pulses and flexible UV image guides, were first tested and characterized in a laboratory setup. Optimization regarding pulse energy and beam quality led to the selection of an 1m long hollow core fiber for laser light delivery as a central element for the experimental setup despite high losses caused by bending the fiber. The image transfer is accomplished by a 7m long flexible UV image bundle, which is preferred to the use of a rigid borescope in harsh environments. We designed the endoscopic UV optics using readily available parts and achieved an approximated image resolution of 21.6 line pairs/mm. Additionally, post-processing methods, such as flat-field correction, can improve the image quality substantially and remove the pixilation effect of the fiber bundle structure nearly completely. To validate the complete system, probe-based qualitative OH-LIF measurements were performed in a well-known laminar flame of a matrix burner, which serves as a mock-up for anticipated applications in an industrial test environment with a technology readiness level (TRL) greater than 4. The final step consists of the integration of the miniaturized optics into a cooled probe system which protects the sensitive optics against the harsh environment of an aero-engine sector combustor. For this purpose, two probe systems were designed to include, on the one hand, the endoscope optics together with the fiber image bundle end tip and, on the other hand, the laser emitting and receiving system for performing an absorption measurement needed to quantify the recorded LIF signal.

The effect of UV365/Fenton process on the removal of gaseous ethylbenzene in a bubble column reactor

ABSTRACT As volatile organic compounds (VOCs), gaseous ethylbenzene has adverse effects on human health and ecology. Therefore, an effective degradation process is highly desirable. The Fenton process under UV 365 nm was selected as the first option to remove gaseous ethylbenzene in a bubble column reactor. The main parameters for the batch experiments were systematically studied, including H2O2 concentration, [H2O2]/[Fe2+], pH, UV wavelength, UV intensity, gaseous ethylbenzene concentration, gas flow rate, and process stability towards removal efficiency. The optimum conditions were found to be H2O2 concentration of 100 mmol·L−1, [H2O2]/[Fe2+] of 4, pH of 3.0, UV wavelength of 365 nm, UV power of 5 W, gas flow rate of 900 mL·min−1, and gaseous ethylbenzene concentration of 30 ppm, resulting in a removal efficiency of 76.3%. The study found that the Fenton process, when coupled with UV 365 nm, was highly effective in removing gaseous ethylbenzene. The degradation mechanism of gaseous ethylbenzene was proposed in the UV365/Fenton process based on EPR, radical quenching experiments, iron analysis, carbon balance, and GC-MS analysis. The results indicated that •OH played a crucial role in the process.

Floating MIL-88A(Fe)@expanded perlites catalyst for continuous photo-Fenton degradation toward tetracyclines under artificial light and real solar light

In this work, MIL-88A(Fe) was immobilized onto the expanded perlites to fabricate the floating MIL-88A(Fe)@expanded perlites (M@EP) catalyst via high throughput batch synthesis method under room temperature. The as-prepared M@EP could efficiently activate H2O2 to achieve 100% tetracycline antibiotics (TCs) removal under both artificial low power UV light (UVL) and real sunlight (SL) irradiation. The toxicological evaluation, growth experiment of mung beans and antimicrobial estimation revealed the decreasing aquatic toxicity of the TCs intermediates compared to those of the pristine TCs. A self-designed continuous bed reactor was employed to investigate the long-term operation of the M@EP. The findings demonstrated that the antibiotics mixture can be continuously degraded up to 7 days under UVL and 5 daytimes under SL irradiation, respectively. More importantly, ca. 76.9% and 81.6% of total organic carbon (TOC) removal efficiencies were accomplished in continuous bed reactor under UVL and SL irradiation, respectively. This work advances the immobilized MOFs on floating supports for their practical application in large-scale wastewater purification through advanced oxidation processes. Environmental implicationThis work presented the high throughput production and photo-Fenton degradation application of floating MIL-88A(Fe)@expanded perlites (M@EP). Three tetracycline antibiotics (TCs) were selected as model pollutants to test the degradation ability of M@EP in batch experiment and continuous operation under artificial light and solar light. The complete TCs degradation could be accomplished in self-designed device up to 7 d under UV light and 5 d under real solar light. This work tapped a new door to push MOFs-based functional materials in the real water purification.

Synthesis and photocatalytic properties of zinc-copper bimetallic oxide nanoparticles for removal of reactive blue 19 dye in aqueous suspension

ABSTRACT This research investigates the photocatalytic removal of reactive blue 19 (RB19) dye utilising Zn-Cu (zinc-copper) bimetallic oxide nanocatalysts under UV irradiation. The nanocatalysts were prepared via the co-precipitation technique and thoroughly characterised using different procedures including XRD, FTIR, BET-BJH, FESEM, TEM, and EDX. BET-BJH analysis revealed a specific surface area of 59.774 m2/g for the Zn-Cu bimetallic oxide nanocatalyst. Response surface methodology (RSM) was employed to optimise operational factors such as catalyst amount, pH, H2O2 amount, and UV power, with a quadratic model showing high reliability (R2 = 0.89). Under optimal conditions (4 mg catalyst amount, pH 6.68, 0.42 mL H2O2 dose, 23 W UV power, and 45 min reaction time), the maximum RB19 removal reached 77.14%, increasing to 98.33% after 120 min. The kinetic study revealed a reaction rate constant of 0.884 min−1, indicating efficient removal. Zn-Cu bimetallic oxides demonstrated superior RB19 removal capacity, with only a 5.92% reduction in removal yield after 5 consecutive reuse cycles. This study underscores the potential of Zn-Cu bimetallic oxide nanocatalysts for efficient removal of RB19 dye in suspension media.

Preparation of CS-LS/AgNPs Composites and Photocatalytic Degradation of Dyes.

Synthetic dyes are prone to water pollution during use, jeopardizing biodiversity and human health. This study aimed to investigate the adsorption and photocatalytic assist potential of sodium lignosulfonate (LS) in in situ reduced silver nanoparticles (AgNPs) and chitosan (CS)-loaded silver nanoparticles (CS-LS/AgNPs) as adsorbents for Rhodamine B (RhB). The AgNPs were synthesized by doping LS on the surface of chitosan for modification. Fourier transform infrared (FT-IR) spectrometry, energy-dispersive spectroscopy (EDS), scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) were used to confirm the synthesis of nanomaterials. The adsorption and photocatalytic removal experiments of RhB were carried out under optimal conditions (initial dye concentration of 20 mg/L, adsorbent dosage of 0.02 g, time of 60 min, and UV power of 250 W), and the kinetics of dye degradation was also investigated, which showed that the removal rate of RhB by AgNPs photocatalysis can reach 55%. The results indicated that LS was highly effective as a reducing agent for the large-scale production of metal nanoparticles and can be used for dye decolorization. This work provides a new catalyst for the effective removal of dye from wastewater, and can achieve high-value applications of chitosan and lignin.

Zeolite 13X incorporated with Zn-Ce oxide nanocatalyst for removal of Reactive Red 120 dye: RSM-based approach.

In this study, the photocatalytic removal of Reactive Red 120 (RR120) dye was examined using zeolite 13X incorporated with Zn-Ce under UV irradiation. The synthesis of Zn-Ce nanoparticles incorporated with zeolite 13X was conducted through the co-precipitation method, and the features of the prepared nanocatalyst were analyzed using various techniques. The SEM and BET analyses indicated successful incorporation of ZnO-Ce oxides on the surface of zeolite 13X and a specific surface area of 359.39 m2/gm, respectively. Further, the average size of crystal grains was 28 nm. The response surface methodology (RSM) approach was employed to optimize operating parameters. The quadratic model suggested by the RSM approach, characterized by a high regression coefficient (R2 = 0.9632), indicates a high level of reliability. Moreover, under optimal conditions (catalyst loading of 4 mg, pH of 3, H2O2 amount of 0.2 mL, UV power of 25 W, and reaction time of 60 min), the highest RR120 dye removal percentage was 99.97%. Kinetic data indicated an increase in the reaction rate constant from 0.0631 to 0.1796 min-1. The zeolite 13X incorporated with Zn-Ce photocatalyst exhibited excellent stability over 5 cycles, with only a 5.50% decrease in RR120 dye removal yield. This study demonstrates the promising potential of zeolite 13X incorporated with Zn-Ce nanoparticles for the removal of RR120 dye from aqueous suspension.

Preparation and utilization of Zn-La oxide nanocatalyst as a binary composite for photocatalytic degradation of methylene blue dye: Optimization through RSM-BBD

In this research, the photocatalytic degradation of methylene blue (MB) dye was explored by employing Zn-La (zinc-lanthanum) oxide nanocatalysts under UV irradiation. Preparation of Zn-La oxide nanocatalysts was executed utilizing the co-precipitation technique, and the surface and morphology of the fabricated nanocatalyst were examined via X-Ray diffraction analysis (XRD), Fourier-transform infrared spectroscopy (FTIR), Brunauer-Emmett-Teller (BET), Barrett-Joyner-Halenda (BJH), Field emission scanning electron microscopy (FESEM), Transmission electron microscopy (TEM), and energy dispersive X-ray (EDX) methods. BET-BJH analysis demonstrated that the specific surface area of the Zn-La oxide nanocatalyst was 20.43 m2/g. Moreover, the response surface methodology (RSM) procedure was utilized to influence the operational factors i.e., catalyst amount, pH, H2O2 dose, and UV power. The quadratic model proposed via the RSM technique with a high R2 value of 0.89, demonstrates its reliability. Besides, the maximum percentage of MB dye removal reached 75.18% under optimal conditions, which include a catalyst amount of 12.05 mg, pH of 9, H2O2 dose of 0.44 mL, UV power of 23 W, and a reaction time of 45 min. Further, under the mentioned conditions, after 120 min, the MB degradation efficiency reached 98.8%. The kinetic study exhibited that the reaction rate constant was 0.0363 min−1. According to the outcomes, Zn-La oxides have a higher ability to remove MB. After 5 consecutive reuse rounds, the reduction in the yield of MB removal using Zn-La oxide nanocatalysts was 5.4%. This study demonstrates that the Zn-La oxide nanocatalyst can be promisingly utilized for the degradation of MB dye suspension solution.

Synthesizing cationic polymers and tuning their properties for microalgae harvesting

This study reports a facile technique to synthesize and tune the cationic polymer, poly(3-acrylamidopropyl)trimethylammonium chloride (PAPTAC), in terms of molecular weight and surface change for harvesting three microalgae species (Scenedesmus sp., P.purpureum, and C. vulgaris). The PAPTAC polymer was synthesised by UV-induced free-radical polymerisation. Polymer tuning was demonstrated by regulating the monomer concentration (60 to 360 mg/mL) and UV power (36 and 60 W) for polymerisation. The obtained PAPTAC polymer was evaluated for harvesting three different microalgae species and compared to a commercially available polymer. The highest flocculation efficiency for Scenedesmus sp. and P. purpureum was observed at a dosage of 25 mg-polymer/g of dry biomass by using PAPTAC-90, resulting in higher flocculation efficiency than the commercial polymer. Results in this study show evidence of effective neutralisation of the negative charge surface of microalgae cells by the produced cationic PAPTAC polymer and polymer bridging for effective flocculation. The obtained PAPTAC polymer was less effective for harvesting C. vulgaris, possibly due to other factors such as cell morphology and composition of extracellular polymeric substances of at the cell membrane that may also influence harvesting performance.

High Power Sunlight‐Simulated UV‐Induced Radical Polymerization: Self‐Initiation and Self‐Crosslinking

AbstractUnder high power UV irradiation, radicals can be generated from double bonds through photodissociation, H‐abstraction, or oxygen initiation mechanisms. This eliminates the need for externally added initiators in photopolymerization. This study investigates high‐power sunlight‐simulated UV‐induced free radical polymerization under various experimental conditions, including the presence of inhibitors, open or closed systems, and partial degassing. Additionally, high‐power sunlight‐simulated UV‐induced atom transfer radical polymerization is explored by externally adding CuBr2/ligand (1:2) catalyst at 100 or 1000 ppm molar concentration of copper. Delicate fabrication of real‐world thin films, coatings, and delicate 3D composites further demonstrates the high reliability and versatility of this technology.

Rapid UV-curable preparation of durable soybean oil-based superhydrophobic anti-icing surfaces with excellent photothermal deicing property

Photothermal superhydrophobic coatings are promising for anti-icing/deicing. However, preparing such coatings from environmentally friendly and sustainable strategies is challenging. Herein, a bio-based and durable photothermal superhydrophobic coating is prepared via layer-by-layer strategy. Bio-based methacrylic acid epoxidized soybean oil oligomers are synthesized as an alternative to petroleum-based binders. Meanwhile, efficient photothermal conversion of hydrophobic particles are enabled by oxidative self-polymerization of dopamine to decorate hydrophobic silica particles grafted with hydrophobic long-chain alkanes and photo-curable methacrylic acid moieties. Ultimately, the superhydrophobic coating is achieved by spraying photothermal hydrophobic particles onto an oxygen-inhibited layer of pre-cured bio-based binder followed by thorough photocuring treatment. The coating exhibits powerful water repellency (WCA of 158.2 ± 1.6°, SA of 4.6 ± 0.8°), good robustness, chemical and UV irradiation resistance. Moreover, under NIR laser irradiation (808 nm, 1 W/cm2), the coating features excellent photothermal conversion efficiency (ΔT of 41.0 °C at 30 s) and stable photothermal conversion performance. And in frigid conditions (-15 °C, ∼73 ± 5 % RH), the coating delivers rapid defrosting (few seconds) and deicing (20 μL water droplet melts in 42 s) performance under NIR irradiation of 1 W/cm2. Therefore, the as-prepared coating provides valuable insight into global anti-icing/deicing action.

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.

AlN interlayer-induced reduction of dislocation density in the AlGaN epilayer

The ultrawide-bandgap AlGaN alloy system shows great potential for advancing the next generation of UV optoelectronic devices.

Nitric oxide/PDT combination therapy by the fluorescent self-reporting Co-delivery platforms

Nitric oxide (NO) combined with photodynamic therapy (PDT) is a promising tumor treatment method. Herein, the cationic lipid DPNO(Zn) was developed as co-delivery carrier of NO and photosensitizer Chlorin e6 (Ce6). The target CNO lipid nanoparticles (LNPs) were obtained by solvent exchange method as a NO/PDT combination therapy platform, and biocompatible polymer γPGA could be easily coated to form PCNO for in vivo applications. Fluorescence spectra and confocal imaging experiments showed that the Ce6-loaded LNPs could release NO rapidly under low power UV irradiation with fluorescence self-reporting ability. On the other hand, under the irradiation of 660 nm laser, the LNPs could effectively produce singlet oxygen (1O2). In vitro and in vivo antitumor assays showed that the combination treatment of NO/PDT was more effective in tumor growth inhibition compared with individual NO or PDT treatment. Mechanism studies of NO/PDT combined therapy revealed that 1O2 could increase the level of p53 protein, thus activating the caspase 3 apoptosis pathway. And the rapid release of NO could amplify the effect of this pathway by reducing the level of HIF-1α. The NO and 1O2 released under laser irradiation could not only directly damage DNA and mitochondria, resulting in tumor cell dysfunction, but also induce the upregulation of iNOS to further enhance the gas therapy efficiency. This study proved that the light-triggered NO/1O2 generation system can be used as an effective NO/PDT synergistic therapy platform for cancer treatment.

A high efficiency gas phase photoreactor for eradication of methane from low-concentration sources

Despite the urgent need, very few methods are able to efficiently remove methane from waste air with low cost and energy per unit volume, especially at the low concentrations found in emissions from e.g. wastewater treatment, livestock production, biogas production and mine ventilation. We present the first results of a novel method based on using chlorine atoms in the gas phase, thereby achieving high efficiency. A laboratory prototype of the methane eradication photochemical system (MEPS) technology achieves 58% removal efficiency with a flow capacity of 30 l min−1; a reactor volume of 90 l; UV power input at 368 nm of 110 W; chlorine concentration of 99 ppm; and a methane concentration of 55 ppm; under these conditions the apparent quantum yield (AQY) ranged from 0.48% to 0.56% and the volumetric energy consumption ranged from 36 to 244 kJ m−3. The maximum achieved AQY with this system was 0.83%. A series of steps that can be taken to further improve performance are described. These metrics show that MEPS has the potential to be a viable method for eliminating low-concentration methane from waste air.

The Study on the Fundamental of Fiber Bragg Grating (FBG) Sensing Principle

Abstract: A single mode fibre core is laterally exposed to a periodic pattern of powerful UV laser light to create an optical sensor called an FBG. The exposure results in a long-lasting rise in the fiber's core's refractive index (ncore), producing fixed index modulation known as grating (Λ). A specific wavelength of input light, known as the Bragg wavelength or Bragg related to grating period, must be reflected by the grating inside the fibre optic core while transmitting all other wavelengths. FBG operates as intended by using the regular variations in the single mode fibre core's refractive index, a Bragg reflector can be constructed on an optical fibre. A specific wavelength of light will be reflected and all others will be transmitted as it passes through the FBG. A shift in the wavelength of the light reflected when the temperature or strain surrounding the grating changes is seen.

Design and research of wireless optical power meter based on IoT big data and physical quantity

In response to the problems of low accuracy, high radiation, and high power consumption in industrial UV power detection, the author proposes a design scheme based on a low-power microcontroller MSP430 as the core controller, two UV photoelectric sensors as detectors, and wireless LoRa as the data transmission method. This scheme adopts dual sensors and achieves photoelectric conversion and ambient light filtering through a subtractive amplification circuit. It also uses high-precision programmable AD acquisition chips to achieve controllable amplification of the signal and convert analog signals into digital quantities for transmission to the main controller MSP430. The improved sliding average filtering method is used to perform digital filtering on the collected data and calculate the corresponding power value, data is transmitted to the upper computer for real-time display through wireless Lora. Research and experiments have shown that the dual sensors have a good agreement with the standard values. The difference between the measured values after digital filtering and the standard values is small, and the linearity of digital filtering is good. It can be seen from the two figures that the higher the power value, the higher the lighting temperature. It has been proven that the entire system operates stably, with high accuracy, low power consumption, and can remotely and real-time detect changes in ultraviolet light power. It can be widely used in the field of industrial ultraviolet light detection.

Effect of ZnO Nanoparticles on the Kinetics and Photo-degradation of Certain Textile Effluent Dyes

Untreated effluents especially in discharges from textiles and fabric industries, usually contain dyes. Synthetic dyes have adverse effects on all forms of life when discharged directly into the environment. This paper investigates the photo-degradation of a mixture of direct orange 39, chlorantine fast red 5B, Viscose Black B and direct sky blue K, all present in a real textile effluent based on the influence of ZnO photocatalyst dose and irradiation time at a specific UV power source. The photo-degradation experiments were conducted in a batch stirred photoreactor equipped with UV lamp of rated at 30 W, a magnetic stirring system and a thermometer. The photocatalyst used was zinc oxide nanopowder (ZnO) The results showed that changes in these parameters influenced the efficiency of the photo-degradation. The kinetic studies showed that the dyes degradation followed the Langmuir-Hinshelwood model that has been modified to accommodate reactions occurring at the solid-liquid interphase. At the catalyst dose of 0.5 g/l, the apparent first order rate constant, was 0.00411 ; but at 2.5 g/l, this reduced to . The best degradation was at the catalyst dose of 2.0 g/l with rate constant of .