UV Light Irradiation Research Articles

Metronidazole degradation mechanism by sono-photo-Fenton processes using a spinel ferrite cobalt on activated carbon catalyst

A heterogeneous catalyst was prepared by anchoring spinel cobalt ferrite nanoparticles on porous activated carbon (SCF@AC). The catalyst was tested to activate hydrogen peroxide (HP) in the Fenton degradation of metronidazole (MTZ). SCF nanoparticles were produced through the co-precipitation of iron and cobalt metal salts in an alkaline condition. Elemental mapping, physico-chemical, morphological, structural, and magnetic properties of the as-fabricated catalyst were analyzed utilizing EDX mapping, FESEM-EDS, TEM, BET, XRD, and VSM techniques. The porous structure of AC enhanced the catalytic activity of SCF by a significant decrease in the agglomeration of SCF nanoparticles. The effectiveness of SCF@AC in Fenton degradation improved substantially when UV light and ultrasound (US) irradiations were induced, most likely due to the strong synergistic effect between the catalyst and these irradiation sources. The photo-Fenton system was more efficient than the Fenton, sono-, and sono-photo-Fenton processes eliminating both MTZ and TOC. It was found that AC not only dispersed SCF nanoparticles and improved the stability of the catalyst, but also provided a high adsorption capacity of MTZ, resulting in a faster degradation. After 60 min of the photo-Fenton reaction, the elimination efficiencies of MTZ (30 mg L−1) and TOC were 97 and 42.1% under optimum operational conditions (pH = 3.0, HP = 4.0 mM, SCF@AC = 0.3 g L−1, and UV = 6 W). SCF@AC showed excellent stability with low leaching of metal ions during the reaction. Radical and non-radical (O2•–, HO•, and 1O2 species), alongside adsorption and photocatalysis mechanisms, were responsible for MTZ decontamination over the SCF@AC/HP/UV system. A comprehensive study on the HP activation mechanism and MTZ degradation pathway was obtained through scavenging tests. The findings demonstrate that SCF@AC is an effective, reusable, and environmentally sustainable catalyst for advanced oxidation processes that can effectively remove organic pollutants from wastewater. This study offers valuable insights into the feasibility of employing SCF@AC catalysts in Fenton-based processes for the degradation of MTZ.

Degradation of rhodamine B dye under visible and solar light on zinc oxide and nickel-doped zinc oxide thin films

The kinetic investigation of rhodamine B dye's photocatalytic degradation, chosen as a model pollutant, was conducted at room temperature using Zinc oxide (ZnO) and nickel-doped zinc oxide (Zn0.97Ni0.03O) photocatalysts synthesized through the spray pyrolysis method. XRD analysis confirmed the formation of hexagonal ZnO and Zn0.97Ni0.03O films, with crystallite sizes ranging from 19 to 29 nm and varying in mean average grain size from 72 nm to 88 nm. The surface morphology of the Ni-doped ZnO films was influenced by nickel doping, observed through SEM and TEM micrographs, revealing a dense structure of spherical-shaped crystals. Light transmission and optical band gap energy of the films ranged between specified values, ranging from 3.27 to 3.24 eV. The degradation process was assessed under various conditions, including different light sources (UV lamp and solar irradiation), pH levels, and substrate concentrations. Degradation followed a pseudo-first-order kinetic model, with rate constants (k) and half-life times (t1/2) calculated accordingly. The degradation efficiency of undoped ZnO and ZnO doped with nickel decreased with increasing concentration under UV irradiation from (0.1–0.5 M) under UV irradiation decreased from (34.29–45.02) (49.61–56.61), while under visible light are (40–45.07 %) (58.46–60.24 %), removal rates ranged within specific percentages. The porous Zn0.97Ni0.03O synthesized at 0.5 M exhibited the highest photocatalytic efficiency due to its enhanced crystallinity, resulting in degradation rates of 9.22 and 11.22 × 10−3 min−1 and half-life times of 75.18 and 61.77 min at 90 min specified for both UV and solar light irradiations, respectively. Acidification of the reaction medium accelerated the photocatalytic degradation kinetics, while alkalization slowed it down. These findings mark a significant advancement in the utilization of oxide semiconductors for water pollutant degradation under natural sunlight.

Improved photocatalytic performance of Sn/Cl co-doped TiO2 nanoparticles via a novel volatilization solid solution method

Sn/Cl co-doped TiO2 nanoparticles were synthesized via a novel volatile solid solution method. The effect of SnCl2·2H2O concentration (0–35.4 mol.%) and calcination temperature on thermal effect, crystal structure, morphology, composition, light absorption and photocatalytic performance of TiO2 nanoparticles was investigated by TG-DSC, XRD, SEM, EDS, TEM, HRTEM, SAED, UV–Vis, PL, photocurrent test, EIS and XPS. Results indicate that Sn and Cl are co-doped into TiO2 crystal lattice forming a mixed anatase-rutile TiO2 phase without SnO2 phase when SnCl2·2H2O concentration is below 17.7 mol.%, and excess SnCl2·2H2O caused the rutile SnO2 generation and simultaneous rutile TiO2 disappearance. The degradation efficiency of methyl orange reaches 98.7 % using 17.7 mol.% SnCl2·2H2O modified TiO2 calcined at 380 °C after 2 h of 15 W UV light irradiation, which is 19.72 % and increases by two times compared with that of pure TiO2 (8.98 %) after 2 h of 15 W visible light irradiation, both showing the maximum photocatalytic performance possibly due to the simultaneous increased active surface sites, enhanced light absorption and improved separation efficiency of photogenerated electron-hole pairs resulted from small particle size, reduced energy band gap and formation of mixed anatase-rutile TiO2 phases. Reactive species scavenging experiments revealed that O.-2 and h+ play a dominant role in photodegradation process.

Effect of lattice water on the photochromic property/photochromism of a Zn(II)-viologen coordination polymers

Electron transfer is crucial for the rapid response of viologen-based complexes and investigating the factors that affect electron transfer has always been a major challenge. Herein, a new viologen-based complex, formulated as {[Zn5(cbbbc)3(BTC)3(μ1,1-OH)(H2O)5]·22H2O}n, with a three-dimensional framework was successfully designed and synthesized by viologen ligand 1-(3-carboxybenzyl)-4,4′-bipyridinium chloride (Hcbbpy), trimesic acid (H3BTC) and Zn(NO3)2·6H2O. In particular, complex 1 does not exhibit photochromic properties. However, samples of complex 1 heated at 120 and 180 ℃ display tunable colors under UV light irradiation. The experimental results indicate that the compound's light response is less sensitive with higher water content in the lattice. The polarity and hydrogen bonding ability of lattice water in viologen-based complexes can interact with the donor of viologen, leading to a reduction in electron transfer. This study demonstrates the impact of lattice water on electron transfer in viologen-based complexes and offers insights for designing faster response complexes in the future.

Synergistic integration of ZrO2-enriched reduced graphene oxide-based nanostructures for advanced photodegradation of tetracycline hydrochloride.

The escalating demand for the antibiotic drug tetracycline hydrochloride (TCH) contributes to an increased release of its residues into land and water bodies, which poses risks to both aquatic life and human health. Therefore, it is precedence to effectively degrade TCH residues to protect environment from their long-term impacts. In this aspect, the present study entails the synthesis of zirconia (ZrO2) nanostructures and focuses on the enhancement in the catalytic performance of ZrO2 nanostructures by employing reduced graphene oxide (RGO) as a solid support to synthesize ZrO2-enriched RGO-based photocatalysts (ZrO2-RGO) for the degradation of TCH. The study delves into comprehensive spectroscopic and microscopic investigations and their photodegradation assessments. Powder XRD and HR-TEM studies depicted the phase crystallinity and also displayed uniform distribution of ZrO2 nanostructures with spherical morphology within ZrO2-RGO. This corresponds to high surface-to-volume ratios, providing a substantial number of active sites for light absorption and generation of e--h+ pairs. Moreover, the heterojunctions created between RGO and ZrO2 nanostructures promoted the interspecies electron transfer which prolonged the recombination time of e- and h+ than pure ZrO2 nanostructures, accounted for enhanced degradation of TCH using ZrO2-RGO. The photocatalytic activity of as-synthesized materials were examined under visible and UV light irradiation.Thedegradation efficiency of ~ 73.82% was achieved using ZrO2-RGO-based photocatalystwith rate constant k = 0.007023 min-1 under visible-light illumination.Moreover, under UV-light, the degradation rate was explicated to be k = 0.01017 min-1 with ~ 85.56% degradation of TCH antibiotics within 180 mins. Hence, the synthesized ZrO2-enriched RGO-based photocatalysts represents a promising potential for the effective degradation of pharmaceutical compounds, particularly TCH under visible and UV-light irradiation.

Lanthanide-Based Single-Chain Nanoparticles as "Visual" Pass/Fail Sensors of Maximum Permissible Concentration of Cu2+ Ions in Drinking Water.

The maximum permissible concentration (m.p.c.) of Cu2+ ions in drinking water, as set by the World Health Organization (WHO) is m.p.c. (Cu2+)WHO = 30 × 10-6m, whereas the US Environmental Protection Agency (EPA) establishes a more restrictive value of m.p.c. (Cu2+)EPA = 20 × 10-6m. Herein, for the first time ever,a family of m.p.c. (Cu2+) "visual" pass/fail sensors is developed based on water-soluble lanthanide-containing single-chain nanoparticles (SCNPs) exhibiting an average hydrodynamic diameter less than 10 nm. Both europium (Eu)- and terbium (Tb)-based SCNPs allow excessive Cu2+ to be readily detected in water, as indicated by the red-to-transparent and green-to-transparent changes, respectively, under UV light irradiation, occurring at 30 × 10-6m Cu2+ in both cases. Complementary, dysprosium (Dy)-based SCNPs show a yellow color-to-transparent transition under UV light irradiation at ≈15 × 10-6m Cu2+. Eu-, Tb-, and Dy-containing SCNPs prove to be selective for Cu2+ ions as they do not respond against other metal ions, such as Fe2+, Ag+, Co2+, Ba2+, Ni2+, Hg2+, Pb2+, Zn2+, Fe3+, Ca2+, Mn2+, Mg2+, or Cr3+. These new m.p.c. (Cu2+) "visual" pass/fail sensors are thoroughly characterized by a combination of techniques, including size exclusion chromatography, dynamic light scattering, inductively coupled plasma-mass spectrometry, as well as infrared, UV, and fluorescence spectroscopy.

Preparation of AC/TiO2 doped N-Ce Synthesized via Microwave Irradiation for Amoxicillin Photodegradation

Activated carbon (AC) supported with titanium dioxide (TiO2) doped with nitrogen (N) and cerium (Ce), denoted as AC/TiO2 doped N-Ce was synthesized for adsorption and photodegradation of amoxicillin (AMX) antibiotic. Photocatalyst was prepared using sol-gel approach assisted by microwave irradiation.30 experiment runs were generated for photocatalyst production and optimized via Central Composite Design-Response Surface Methodology (CCD-RSM) with observation of four types of variable parameters. The experimental variables consisted of the quantities of urea (N) (𝑥𝑥𝑖𝑖: 0.02–0.20 g), amount of cerium (III) nitrate hexahydrate (Ce) (𝑥𝑥𝑗𝑗: 0.02–0.20 g), amount of AC (𝑥𝑥𝑘𝑘: 0.10 –0.50 g), and microwave power (𝑥𝑥𝑙𝑙: 600–800 W). The analysis revealed that AC/TiO2 doped N-Ce photocatalyst, which was prepared with 0.50 g AC, 0.02 g N, and 0.20 g Ce, and activated with microwave power 600 W in 15 min, achieved a 93.6% AMX removal under UV light irradiation. The photocatalyst was initially subjected to a concentration of 10 mg L-1 at 30 °Cfor a duration of 60 min.

Effect of Heating Power on The Synthesis of Titanium Dioxide Particles by Direct Heating Method for Photodegradation of Methylene Blue Solution

Dyes are extensively used in the textile industry. Untreated dye-containing wastewater is hazardous to humans and the environment. Advanced oxidation processes (AOPs) based on heterogeneous TiO2photocatalyst is a technology that has been proven successful for effluent treatment. Nevertheless, use of TiO2 photocatalyst in particles form could result in loss of TiO2 photocatalyst over time during effluent treatment. Immobilization of TiO2 photocatalyst on substrates could address this problem. In this study, a method called direct heating (DH) was devised to deposit TiO2 particles on kanthal wires to prevent the particles from being washed away during effluent treatment. This method has low equipment cost and short synthesis duration when compared to others. The TiO2 particles synthesized at 50 W in 15 min gave the best photodegradation efficiency, which was 36.3 % under 90 mins of UV light irradiation. It contained a mixture of anatase (22.5 %) and brookite (77.5 %), with an average particle size of 139.34 ± 15.89 nm. The TiO2 particles had high surface coverage on kanthal wire with little agglomeration. The current work presents a captivating and low-cost setup, providing easy control over synthesis conditions and scaling potential for immobilizing TiO2 particles on the kanthal wires.

Degradation of methyl orange dye using Fe3O4/GO photocatalyst with iron derived from coastal Glagah Kulon Progo ore

Water pollution by dyes is still a serious problem that needs to be solved. This study offers a solution to degrade methyl orange dye using a photocatalyst material, namely Fe3O4/GO nanocomposite. Magnetite (Fe3O4) was synthesized from iron sand from Glagah Kulon Progo beach, using the coprecipitation method. Graphene oxide (GO) was synthesized by Hummers’ method, while the manufacture of the Fe3O4/GO nanocomposite was done by sonication method. The resulting magnetite, graphene oxide and nanocomposite were then characterized by XRD, UV–Vis and SEM-EDX. The effect of nanocomposite mass variation and irradiation time on the percentage degradation of the synthetic dye methyl orange (MO) in wastewater was investigated. The results of UV-Vis’s characterization showed that the best results were obtained when MO dye was degraded using 0.175 g nanocomposite in 40 mL of wastewater containing 10 ppm MO. The degradation of MO dye reached 99.05% under UV light irradiation for 240 minutes. Then investigated reuse of the nanocomposite was evaluated for three cycles, with the results showing an average efficiency decrease of 5.30%. This research contributes to the development of sustainable and effective photocatalytic materials for the treatment of dye-polluted water, especially MO.

An Eco-friendly Approach to ZnO NP Synthesis Using Citrus reticulata Blanco Peel/Extract: Characterization and Antibacterial and Photocatalytic Activity.

Emission of greenhouse gases and infectious diseases caused by improper agro-waste disposal has gained significant attention in recent years. To overcome these hurdles, agro-waste can be valorized into valuable bioactive compounds that act as reducing or stabilizing agents in the synthesis of nanomaterials. Herein, we report a simple circular approach using Citrus reticulata Blanco (C. reticulata) waste (peel powder/aqueous extract) as green reducing and capping/stabilizing agents and Zn nitrate/acetate precursors to synthesize ZnO nanoparticles (NPs) with efficient antimicrobial and photocatalytic activities. The obtained NPs crystallized in a hexagonal wurtzite structure and differed clearly in their morphology. UV-vis analysis of the nanoparticles showed a characteristic broad absorption band between 330 and 414 nm belonging to ZnO NPs. Fourier transform infrared (FTIR) spectroscopy of ZnO NPs exhibited a Zn-O band close to 450 cm-1. The band gap values were in the range of 2.84-3.14 eV depending on the precursor and agent used. The crystallite size obtained from size-strain plots from measured XRD patterns was between 7 and 26 nm, with strain between 16 and 4%. The highly crystalline nature of obtained ZnO NPs was confirmed by clear ring diffraction patterns and d-spacing values of the observed lattice fringes. ZnNPeelMan_400 and ZnNExtrMan showed good stability, as the zeta potential was found to be around -20 mV, and reduced particle aggregation. Photoluminescence analysis revealed different defects belonging to oxygen vacancies (VO+ and VO+2) and zinc interstitial (Zni) sites. The presence of oxygen vacancies on the surface of ZnAcExtrMan_400 and ZnAcPeelMan_400 increased antimicrobial activity, specifically against Gram-negative bacteria Escherichia coli (E. coli) and Salmonella enteritidis (S. enteritidis). ZnNExtrMan with a minimal inhibitory concentration of 0.156 mg/mL was more effective against Gram-positive bacteria Staphylococcus aureus (S. aureus), revealing a high influence of particle size and shape on antimicrobial activity. In addition, the photocatalytic activity of the ZnO NPs was examined by assessing the degradation of acid green dye in an aqueous solution under UV light irradiation. ZnAcPeelMan_400 exhibited excellent photocatalytic activity (94%) within 90 min after irradiation compared to other obtained ZnO NPs.

Synthesis of porous TiO2 and Fe-doped TiO2 films for photocatalysis by a cooling enhanced plasma electrolytic oxidation approach

Porous TiO2 films are widely used in photocatalysis for pollutant remediation and synthetic chemistry applications, and the homogeneity and stability of the films are important parameters. Here, we show that porous TiO2 and Fe-doped TiO2 (Fe-TiO2) films on Ti foils with homogeneous structure and well-controlled doping can be synthesized by a cooling enhanced plasma electrolytic oxidation (CPEO) method. The anatase content within pristine TiO2 films and the concentration of Fe dopant in Fe-TiO2 films can be manipulated by simply adjusting the synthetic parameters, leading to an optimum photocatalytic performance under both UV and visible light irradiation for the decomposition of methylene blue.

Photocatalytic degradation of brilliant green and 4-nitrophenol using Ni-doped Gd(OH)3 nanorods

Gadolinium hydroxide (Gd(OH)3) was synthesized via a microwave-assisted synthesis method. Nickel ion (Ni2+) was doped into Gd(OH)3, in which 4–12% Ni-Gd(OH)3 was synthesized, to study the effect of doping. The structural, optical, and morphological properties of the synthesized materials were analyzed. The crystallite sizes of the hexagonal structure of Gd(OH)3 and Ni-Gd(OH)3, which were 17–30 nm, were obtained from x-ray diffraction analysis. The vibrational modes of Gd(OH)3 and Ni-Gd(OH)3 were confirmed using Raman and Fourier-transform infrared spectroscopies. The band gap energy was greatly influenced by Ni-doping, in which a reduction of the band gap energy from 5.00 to 3.03 eV was observed. Transmission electron microscopy images showed nanorods of Gd(OH)3 and Ni-Gd(OH)3 and the particle size increased upon doping with Ni2+. Photocatalytic degradations of brilliant green (BG) and 4-nitrophenol (4-NP) under UV light irradiation were carried out. In both experiments, 12% Ni-Gd(OH)3 showed the highest photocatalytic response in degrading BG and 4-NP, which is about 92% and 69%, respectively. Therefore, this study shows that Ni-Gd(OH)3 has the potential to degrade organic pollutants.

Synthesis of novel TiO2/CeFeO3 heterojunction using Mugwort (Artemisia vulgaris) leaves extracts with enhanced photocatalytic activity under visible light irradiation

TiO2 is a low-cost and biocompatible material with high oxidizing ability. However, their photocatalytic activity is limited to UV light irradiation. In this research, for the first time, a novel TiO2/CeFeO3 heterojunction was synthesized by the green synthesis method using an aqueous fraction of Artemisia vulgaris leaf extracts. TiO2/CeFeO3 shows enhanced photocatalytic performance under visible light irradiation. The vibrational, structural, optical, and compositional properties of TiO2/CeFeO3 were characterized. The as-prepared TiO2/CeFeO3 has spherical-shaped particles and shows a significantly diminished bandgap energy (3.25 eV to 2.75 eV). The photocatalytic performance of TiO2/CeFeO3 was investigated to degrade malachite green (MG) with an efficiency of up to 93.53% under its optimum dose. TiO2/CeFeO3 shows stable photocatalytic performance until the fourth cycle. The kinetics of the photodegradation of MG followed the pseudo-first-order reaction with a rate constant (kapp) of 2.14×10−2 min−1. The enhanced photocatalytic activity of TiO2/CeFeO3 was attributable to the creation of heterojunction, which suppresses the recombination rate of photogenerated electron-hole validated by the photoluminescence analysis. This work presents an eco-friendly approach to synthesizing novel heterojunction material with enhanced photocatalytic dye degradation.

UV assisted 3D fabrication of hollow ceramic with single-channel direct ink writing

The inherent brittleness of ceramics poses significant challenges in the fabrication of hollow ceramic fibers, severely constraining their practical applications. In this study, a novel method for creating three-dimensional hollow fiber ceramic structures using UV-assisted single-channel direct ink writing was demonstrated. A concentric single-channel nozzle featuring shell/core structure was devised through the coaxial embedding method, and this specially designed nozzle was manufactured using digital light processing technology. During the UV-assisted direct ink writing process, the photosensitive ceramic slurry can be rapidly cured in place under the irradiation of UV light, ensuring high fidelity of the printed components. The hollow fiber structure produced in this study has a circular, pentagram, triangular and quadrilateral inner core, which can be adjusted according to the designed nozzle structure. This approach facilitates a straightforward and expedited creation of scaffolds featuring small-diameter hollow fiber structures, broadening the scope of potential applications for direct ink writing.

Cation Radical Induced Photochlorination of Naphthalene in Saline Water under UV Light Irradiation

Cation Radical Induced Photochlorination of Naphthalene in Saline Water under UV Light Irradiation

Synthesis and Characterization of Iron-Doped TiO2 Nanotubes (Fe/TiNTs) with Photocatalytic Activity

One of the most significant global challenges for humans is environmental pollution. The technology to control this problem is the utilization of semiconductors as photocatalysts. In the current study, iron-doped titania nanotubes (Fe/TiNTs) with increased photocatalytic effect were synthesized via a modified hydrothermal method. The products were characterized by X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy (TEM), gas adsorption, electron spin resonance (ESR) and UV–Vis diffuse reflectance spectroscopy (DRS). TEM results indicated that Fe/TiNTs have a tubular and uniform structure with an average outer diameter of 23–48 nm and length of 10–15 µm. ESR and DRS revealed that Fe3+ ions were successfully introduced into the TiNT structure by replacing Ti4+ ions. An enhanced light absorption in the range of 400–600 nm additionally indicated successful doping. The band gap was narrowed as iron wt% was increased. The photocatalytic activity was evaluated by the degradation of methyl orange (MO) in the presence of Fe/TiNTs and TiTNs by monitoring the degradation of MO under UV light irradiation. An acceleration on the hydration of Portland cement was observed in the presence of 2.0 wt% Fe/TiNTs. Fe/TiNTs can be used as a nanomaterial in cement-based building materials to provide self-cleaning properties to the surface of concrete even in indoor environments.

Effect of Copper Inclusion in Zinc sulfide Thin Films for Photocatalytic Applications

Transparent and well-adhered pure zinc sulfide (ZnS) and different concentrations of copper-doped zinc sulfide thin films were obtained on glass substrates by the Chemical bath deposition process. Zinc acetate, copper acetate and thiourea were employed as sources of Zn2+, Cu2+ and S2- ions, respectively; ammonia and hydrazine hydrate served as complexing agents for the preparation of pure zinc sulfide and different concentrations of copper-doped zinc sulfide thin films. By adjusting the ammonia concentration, the prepared solution pH was maintained at 11. The prepared samples were deposited at the rates of 60 and 90 minutes each, with the bath temperature being held at 80 °C. The structural, morphological and optical properties of the prepared films were characterized by XRD, FE-SEM and EDX, and the results were reported. The XRD patterns revealed that all thin films possess a polycrystalline cubic zinc blended structure and that the prepared pure and copper-doped ZnS thin films have good crystallinity; the crystallite sizes were less than 20 nm. From the FE-SEM spectra, it is understood that the pure and Cu-doped ZnS thin films were uniformly coated with spherical morphology. The surface morphology, optical characteristics and deposition mechanism were all obviously impacted by the ammonia concentration. Additionally, under UV light irradiation, the effect of the photocatalytic property of the prepared thin films with methylene blue dye was studied and the corresponding dye degradation graphs were reported.

Spectroscopic Identification and Photochemistry of Astrochemically Relevant Phosphorus-bearing Molecules [O, C, N, P] and [2O, C, N, P

Diatomic molecules phosphorus monoxide (PO) and phosphorus mononitride (PN) are the main reservoirs of gas-phase phosphorus in interstellar and circumstellar environments, indicating the possibility of forming new phosphorus-bearing molecules through reactions with other interstellar species. To explore the astrochemistry of PO and PN, new simple phosphorus-bearing molecules [O, C, N, P] and [2O, C, N, P] were generated in the gas phase and isolated in cryogenic matrices for characterization with matrix-isolation IR and UV/vis spectroscopy in combination with calculations at the CCSD(T)-F12a/VTZ-F12 level of theory. In an inert argon matrix, OPCN isomerizes to OPNC upon UV-light irradiation at 365 nm, followed by successive isomerizations to PNCO and POCN with concomitant dissociation to diatomic PN and CO under further irradiation at 193 nm. By analogy, the isomerization of O2PCN to O2PNC and OPNCO followed by fragmentation to OPN/CO and PN/CO2 occurs in the matrix upon irradiation at 193 nm. In a chemically active CO ice, the photolytic reaction of OPCN with CO yields CO2 and PCN, and O2PCN reacts with CO by forming OPCN and CO2, in which the photochemical networks for these P-bearing species linking the astrochemically important PN and PO have been proposed. The experimental identification of these phosphorus-bearing molecules is supported by quantum chemical calculations, and the spectroscopic data may aid in their detection in the interstellar and circumstellar medium.

A Polyvinylpyrrolidone Nanofibrous Sensor Doubly Decorated with Mesoporous Graphene to Selectively Detect Acetic Acid Vapors.

An original approach has been proposed for designing a nanofibrous (NF) layer using UV-cured polyvinylpyrrolidone (PVP) as a matrix, incorporating mesoporous graphene carbon (MGC) nanopowder both inside and outside the fibers, creating a sandwich-like structure. This architecture is intended to selectively adsorb and detect acetic acid vapors, which are known to cause health issues in exposed workers. The nanocomposite MGC-PVP-NFs layer was fabricated through electrospinning deposition onto interdigitated microelectrodes (IDEs) and stabilized under UV-light irradiation. To enhance the adhesion of MGC onto the surface of the nanocomposite polymeric fibers, the layer was dipped in a suspension of polyethyleneimine (PEI) and MGC. The resulting structure demonstrated promising electrical and sensing properties, including rapid responses, high sensitivity, good linearity, reversibility, repeatability, and selectivity towards acetic acid vapors. Initial testing was conducted in a laboratory using a bench electrometer, followed by validation in a portable sensing device based on consumer electronic components (by ARDUINO®). This portable system was designed to provide a compact, cost-effective solution with high sensing capabilities. Under room temperature and ambient air conditions, both laboratory and portable tests exhibited favorable linear responses, with detection limits of 0.16 and 1 ppm, respectively.

Amine functionalized graphene oxide decorated with ZnO-WO3 nanocomposites for remediation of organic dye from wastewater

Photocatalytic degradation is as an efficient technique to eradicate toxic chemical pollutants from contaminated water sources. However, the selectivity and photocatalytic activity are the challenging targets to explore the new photocatalysts. Therefore, our research goal is to develop a suitable photocatalyst to satisfy the recent photocatalytic degradation demand. In this work, amine functionalized graphene oxide (NH2-GO) supported heterojunction ternary novel nanocomposites (NH2-GO/ZnO-WO3) were prepared via simple solvothermal method. Structural and morphological investigations of the prepared composites are systematically observed by Field Emission Scanning Electron Spectroscopy (FE-SEM), X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FT-IR), and Ultraviolet–Visible (UV–vis) Spectroscopy. FT-IR analysis confirmed the effective functionalization of amine on graphene oxide. The XRD results indicated that the prepared nanocomposites were free from any impurities and the binary composite (NH2-GO/ZnO) showed hexagonal wurtzite structure, whereas the ternary composite (NH2-GO/ZnO-WO3) exhibited mix crystal structure of monoclinic and hexagonal phase of WO3 and ZnO, respectively. The synthesized ternary photocatalyst (NH2-GO/ZnO-WO3) demonstrated superior photocatalytic efficiency towards various organic dyes such as cationic dye methylene blue (MB, 85.89%) and anionic dye methyl orange (MO, 60.98%) compared to binary photocatalyst (NH2-GO/ZnO) that showed only 52.28% of MB and 25.8% of MO dye degradation under UV light irradiation. The enhanced photocatalytic performance was mainly due to the low recombination rate of photogenerated electron-hole pair, narrow band gap, and large surface area of ternary composite. The presence of lone pair electrons in amino group provides a negative-charged surface composite resulting good interaction with cationic dye is the key to upgrade the photocatalytic performance. The ternary nanocomposite NH2-GO/ZnO-WO3 has the capacity to be a competent and acceptable photocatalyst for the photodegradation of organic dyes used in industries.