UV Vis DRS Analysis Research Articles

Co2-Fe8-BTC/g-C3N4/Bi2O3/Ti photoanode for visible light responsive photocatalytic fuel cell degradation of rhodamine B and electricity generation

The Co2-Fe8-BTC/g-C3N4/Bi2O3/Ti photoanode with the double Z-type heterojunction was produced by hydrothermal technique and to assemble visible light responsive photocatalytic fuel cell (PFC) with Cu cathode. The synthesized photoanode was characterized by SEM, FT-IR, XPS, XRD and UV–vis DRS analysis. The maximum photocurrent density, maximum power density, and rhodamine B degradation rate of the PFC were 0.53 mA·cm-2, 33.56 μW·cm-2, and 96.89 % (60 min), respectively, which were much higher than these of PFCs with g-C3N4/Bi2O3/Ti photoanode (0.19 mA·cm-2, 11.64 μW·cm-2, 55.37 %, respectively) and Bi2O3/Ti photoanode (0.15 mA·cm-2, 6.63 μW·cm-2, 41.67 %, respectively). The electricity generation performance and rhodamine B degradation of this PFC system is greatly enhanced by the double Z-type heterojunctions of the photoanode among Co2-Fe8-BTC, g-C3N4 and Bi2O3, which accelerates the isolation of photogenerated carriers, and also retains good redox capability, thus obtaining high photocatalytic activity. This work can serve as reference for the design and heterojunction construction of high-efficiency photoanode of PFC with visible light response.

High-Efficiency Photo-Fenton-like Catalyst of FeOOH/g-C3N4 for the Degradation of PNP: Characterization, Catalytic Performance and Mechanism Exploration.

The composite photocatalyst FeOOH/g-C3N4 was prepared through thermal polycondensation and co-precipitation methods, followed by XRD, SEM and UV-vis characterization. The stability of FeOOH/g-C3N4 was explored by the recycling test. The active species in the reaction system were investigated by the capture experiment. The results indicated that the optimal preparation condition for g-C3N4 involved calcination at 600 °C for 4 h. XRD analysis revealed that g-C3N4 exhibits a high-purity phase, and Fe in FeOOH/g-C3N4 exists in a highly dispersed amorphous state. SEM analysis showed that FeOOH/g-C3N4 has a rough surface with an irregular layered structure. Element composition analysis confirmed that the content of elements in the prepared catalyst is consistent with the theoretical calculation. FeOOH/g-C3N4 possesses the largest specific surface area of 143.2 m2/g and a suitable pore distribution. UV-vis DRS analysis showed that the absorption intensity of FeOOH/g-C3N4 is stronger than that of g-C3N4. When the catalyst dosage was 1.0 g/L, the H2O2 dosage was 4 mmol/L, the PNP initial concentration was 10 mg/L and the initial pH value was 5, the PNP removal could reach 92% in 120 min. Even after 5 cycles, the efficiency of PNP removal by FeOOH/g-C3N4 remains nearly 80%. The capture experiment indicated that both •OH and •O2- play roles in the photocatalytic degradation of PNP, with •OH being more significant. These findings affirm that FeOOH has been successfully incorporated into g-C3N4, resulting in a conspicuous catalytic effect on the degradation of PNP in the visible light-assisted Fenton-like reaction.

Photodegradation of dye wastewater by Ti doped Bi2O3/montmorillonite composites

Ti-doped Bi2O3/montmorillonite composites (TBM) were synthesized via chemical solution decomposition using tetrabutyl titanate and bismuth nitrate pentahydrate as titanium and bismuth sources, with sodium montmorillonite as the carrier. The active brilliant blue KN-R, carmine, and rose red B solutions were employed for adsorption and degradation experiments. Characterization of the composite was done through XRD, SEM, BET, and UV-Vis DRS analyses. Results indicate that the optimal degradation performance is achieved when the Ti doping ratio is 4 % (4TBM). The removal rates for active brilliant blue KN-R, carmine, and rose red B solutions were 98.17 %, 98.29 %, and 96.77 %, respectively. Bi2O3 was found in a tetragonal phase, with Ti ions doping into the lattice of Bi2O3 as Ti4+ inhibiting grain growth. The montmorillonite flakes in the composite were exfoliated, leading to an increased specific surface area of 4.16 m2/g. Following Ti doping, Ti 3d, O 2p, and Bi 6 s orbitals combined to form a valence band of 4TBM, reducing the band gap from 2.59 eV to 2.52 eV. This enhancement in light absorption capacity improved the photocatalytic degradation performance of 4TBM.

A Spectroscopic Correlative Analysis of Eu3+‐Substituted Zn1‐xSnO3 Nano Phosphors for Anticounterfeiting Applications

AbstractA series of orange–red phosphors Zn1‐xSnO3:xEu3+ synthesized using a sol–gel combustion process is used to study the modified local crystal structure by site‐selective substitution of Eu3+ ions. XRD with the Rietveld refinement analysis reveals an orthorhombic ZnSnO3 structure with a space group 61. SEM and TEM with EDAX analyses confirm the flower‐like morphology of Zn1‐xSnO3:xEu3+ nanorods. Photoluminescence (PL) spectroscopy gives substantial confirmation for the inclusion of Eu3+ ions into the ZnSnO3 host. Judd‐Ofelt analysis confirms the substitution of Eu3+ ion in an asymmetric environment in ZnSnO3, which is responsible for orange–red emission at 615 nm. UV–vis–DRS analysis shows that the addition of Eu3+ ions (1% to 17% in phases of 4%) results in the formation of confined energy states with an increased band gap from 2.78 to 3.29 eV. The ability of ZnSnO3 to host Eu3+ ions signifies that it can be used as an effective luminescent material. Cyclic voltammetry analysis reveals the enhanced charge separation in Zn1‐xSnO3:xEu3+(13%) nanophosphor. The optimized Zn1‐xSnO3:xEu3+(13%) nano phosphor mixed with silicone investigated for the generation of anti‐counterfeiting patterns indicates its potential to generate high‐resolution image patterns on various surfaces under monochromatic UV or visible‐LASER LED illumination.

Assessment of visible light sensitive La-doped BiOBr/ZnO for the effective degradation of malachite green dye

Environmental scientists across the globe are actively focused on developing novel materials to remove hazardous wastes from aqueous environments. Among the several methods available, photocatalysis stands out as a very efficient and environmentally beneficial process for removing organic dyes from wastewater. The present work involved the successful fabrication of lanthanum-doped bismuth oxy bromide/zinc oxide (La-doped BiOBr/ZnO, LBZ) as a photocatalyst through a facile hydrothermal technique. The synthesized LBZ composite exhibited enhanced photocatalytic degradation efficiency towards the malachite green (MG) dye molecules under visible light. The synthesized materials were characterized by different analytical techniques like FTIR, XRD, SEM, EDX, XPS, LC-MS, UV–Vis DRS, PL spectra, and mapping analysis, respectively. Various contributing factors, including irradiation time, solution pH, catalyst dosage, and initial dye concentration, were optimized using the batch mode for the maximum efficiency of the prepared catalyst. The prepared LBZ exhibited a bandgap energy of 2.78 eV as determined through UV–Vis DRS analysis. Among the prepared series of catalysts, the LBZ composite could degrade 99 % MG with a minimum irradiation time of 50 min under visible light irradiation. The involvement of h+ and O2− radicals proved to be significant during the degradation process of MG. Additionally, a proposed mechanism for the effective degradation of the photocatalytic degradation of MG was discussed, and successfully identified the mechanism pathway of MG was by employing LC-MS analysis. This investigation highlights the potential of prepared LBZ composite as an effective photocatalyst for removing toxic dye molecules commonly present in industrial effluents.

Barleria lupulina leaf extract-assisted biosynthesis of cobalt ferrite nanoparticles: Characterization and anticancer activity against MCF-7 cells

This study reports the synthesis of Cobalt ferrite (CoFe2O4) nanoparticles (NPs) by a green synthesis method using the leaf extract of Barleria Lupulina. The X-ray diffraction (XRD) analysis confirms the formation of a single-phase cubic (Fd3m) structure and from the Scherrer formula the average crystallite size (30.07 nm) calculated matches with that obtained from W-H plot(34.66 nm). A bandgap of 2.02 eV was observed from the UV–Vis-DRS analysis. Fourier transform infrared spectroscopy (FTIR) was used to confirm the characteristic functional groups present in the spinel ferrite. The investigation using scanning electron microscopy (SEM) shows aggregates of nanoparticles and EDX analysis gives the chemical composition of the green synthesized ferrite sample. The distribution of particle-sizes and colloidal-stability were estimated by DLS and zeta-potential measurements. The M−H plot confirmed the ferromagnetic nature of the prepared nanoparticles. Beyond the realm of material science, we ventured into the realm of biological activity. Our synthesized cobalt ferrite nanoparticles were assessed for their toxicity on human breast cancer cell lines (MCF-7) as well as normal L929 fibroblast cell lines by MTT assay. The results show potent anti-cancer activity of the ferrite sample (LC50 value 77.92 µg/ml) while sparing normal cells from excessive toxicity (LC50 value 252.34 µg/ml). The results of cell viability, changes in cell morphology, and cell cycle analysis revealed that cobalt ferrite nanoparticles triggered apoptosis, and hindered cell adhesion and migration of MCF-7 cells, potentially through elevated reactive oxygen species generation. This dual action, where the nanoparticles combat cancer effectively while minimizing harm to healthy cells, holds significant promise in the field of oncology.

Efficiency and mechanistic insights of photocatalytic decomposition of tetracycline and rhodamine B utilizing Z-scheme g-C3N4/SnWO4 heterostructures under visible light irradiation

The hydrothermal approach was used in the design and construction of the SnWO4 (SW) nanoplates anchored g-C3N4 (gCN) nanosheet heterostructures. Morphology, optical characteristics, and phase identification were investigated. The heterostructure architect construction and successful interface interaction were validated by the physicochemical characteristics. The test materials were used as a photocatalyst in the presence of visible light to break down the antibiotic tetracycline (TC) and the organic Rhodamine B (RhB). The best photocatalytic degradation efficiency of TC (97%) and RhB (98%) pollutants was demonstrated by the optimized 15 mg of gCNSW-7.5 in 72 and 48 min, respectively, at higher rate constants of 0.0409 and 0.0772 min−1. The interface contact between gCN and SW, which successfully enhanced charge transfer and restricted recombination rate in the photocatalyst, is responsible for the enhanced performance of the gCNSW heterostructure photocatalyst. In addition, the gCNSW heterostructure photocatalyst demonstrated exceptional stability and reusability over the course of four successive testing cycles, highlighting its durable and dependable function. Superoxide radicals and holes were shown to be key players in the degradation of contaminants through scavenger studies. The charge transfer mechanism in the heterostructure is identified as Z-scheme mode with the help of UV–vis DRS analysis. Attributed to its unique structural features, and effective separation of charge carriers, the Z-scheme gCNSW-7.5 heterostructure photocatalyst exhibits significant promise as an exceptionally efficient catalyst for the degradation of pollutants. This positions it as a prospective material with considerable potential across various environmental applications.

Performance test of Zn-astaxanthin complex-sensitized solar cell: effect of light intensity on open-circuit voltage and short-circuit current values.

The sensitizer is one of the most essential dye-sensitized solar cell (DSSC) components. In the present research, a Zn-astaxanthin complex was investigated as a sensitizer, compared to pure astaxanthin. The complex with a 1:1 mole ratio between astaxanthin and Zn2+ was synthesized in a reflux reactor at 37-60 °C. The product was analyzed using Proton Nuclear Resonance (1H-NMR), which indicates the presence of chelate formation between Zn2+ with two atoms of oxygen on the terminal cyclohexane ring of astaxanthin. The interaction of sensitizers (astaxanthin and Zn-astaxanthin) on the photoelectrode surface in this study was analyzed using a Fourier Transform Infra-Red (FTIR) and Ultraviolet-Visible Diffuse Reflectance Spectroscopy (UV-Vis DRS). The FTIR spectra of photoelectrode immersed in Zn-astaxanthin show peaks of C=O stretching and vibration -OH group at 1730 and 1273 cm-1, respectively, and H-C-H stretching vibration with high intensity in 2939, 2923, and 2853 cm-1. The UV-Vis DRS analysis shows the band gap of photoelectrode (PE), photoelectrode immersed in astaxanthin (PE/astaxanthin), and Zn-astaxanthin (PE/Zn-astaxanthin) are 3.19, 1.65, and 1.59 eV, respectively. Under illumination intensity of 300 W/m2, the maximum energy conversion efficiency of DSSC with Zn-astaxanthin as sensitizer is (0.03 ± 0.0022)%, higher than DSSC with astaxanthin as sensitizer ((0.12 ± 0.0052)%). Up to 70 h of illumination, DSSC with Zn-astaxanthin as a sensitizer also has better stability than astaxanthin-based DSSC.

Sago-shaped embedded Nanolayers of WO3/NiO/gC3N4 Nanohybrids for natural degradation of environmental pollutants: A photocatalytic sunlight mediated approach

In recent years the applicability of semiconductor nanomaterials is almost in every field of science and technology. In the current study, hybrid nanomaterials containing tungsten trioxide (WO3) and nickel oxide (NiO) supported on graphitic carbon nitride (gC3N4) were prepared by a simple hydrothermal technique. Synthesis was sequential requiring the individual preparation of gC3N4 and WO3 as preliminary. The desired composition of gC3N4, WO3, nickel nitrate, and a base was transferred to an autoclave and maintained at 180°C for 18 h. The resulting inorganic/organic hybrid was filtered, washed, dried, and named as inorganic/organic hybrid nanocomposite (HNC). Various compositions of HNC were prepared and characterized by Fourier transform infrared spectrometer (FT-IR), Ultra Violet-Visible Diffuse reflectance spectrometer (UV–Vis-DRS), X-ray diffractometer (XRD), and Field emission scanning electron microscope (FE-SEM). The FE-SEM images showed a sago-shaped embedded particle in gC3N4 layers with a 40–60 nm particle size. The band gap energy was found to be 2.69 eV from UV–Vis-DRS analysis. This proves the promising activity of sago-shaped HNC under sunlight radiation. Various preliminary and kinetic studies were conducted, and HNC possessed excellent photocatalytic activity for the degradation of an organic dye under sunlight. The photocatalytic activity for the degradation of dye by the prepared HNC was found to be two-fold when compared to the activity of pristine gC3N4 under sunlight irradiation.

The X-ray peak profiling, optical and dielectric properties of Ag@ZnFe2O4/rGO ternary nanocomposites: LED assisted photocatalysis and humidity sensing

Ag@ZnFe2O4/reduced graphene oxide (Ag@ZnFe2O4/rGO) ternary nanocomposites were successfully synthesized (NCs) via hydrothermal method and explored the LED assisted photocatalytic performance for the degradation of organic dyes as well as humidity sensing properties of the material. For comparison, bare ZnFe2O4, and ZnFe2O4/rGO also synthesized. The freshly prepared samples were investigated using XRD, TEM, UV–vis–NIR spectroscopy, VSM, Impedance analyzer, and particle size analyzer. The detailed structural parameters were calculated through X-ray peak profiling using Classical Scherrer, Modified Scherrer, Williumson-Hall, Halder-Wagner, Size Strain Plot methods along with Rietveld refinement. From UV–vis–DRS analysis, optical energy gaps were obtained in the range of 1.58–1.92 eV. Ag@ZnFe2O4/rGO NCs showed significant photocatalytic activity and exceptional adsorption capacities for the breakdown of methylene blue (MB) 95.7% and rhodamine B (RhB) 77.7% after 100 min. The synergistic interactions of Ag, ZnFe2O4, and rGO minimized NCs agglomeration and small particle size with higher surface area, resulting in a higher absorption in both UV and visible light. The photocatalysis mechanism was explored by scavenger test using ascorbic Acid, NaHCO3, and isopropyl alcohol. The magnetic studies revealed the paramagnetic nature of NCs. Frequency dependent dielectric data obey the modified Debye model with relaxation time of ∼10−4 s and spreading factor of 0.534 (±0.08). Complex impedance measurements support the grain-interior process that contributes to dielectric properties. The impedance-type humidity sensing characteristics of the fabricated sensor were investigated by exposing in a wide humidity range of 11–98% RH at ambient temperature. The Ag@ZnFe2O4/rGO sensor displayed an ultrahigh sensitivity when compared to traditional humidity sensors. On the basis of, Ag@ZnFe2O4/rGO NCs are exciting nanomaterials for outstanding photocatalytic activity for the degradation of organic dyes along with potent humidity sensor.

Chicken Eggshell Powder as Antibacterial Against Staphylococcus aureus and Escherichia coli Through In Vitro Studies

Identifying the most effective material with antibacterial properties against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) is a challenging task considering the rising concerns about drug resistance. Various experiments through in vitro and in vivo studies to obtain antibacterial agents using abundant and easily available raw material sources have been conducted. Therefore, this study aimed to acquire semiconducting nanoparticle material derived from purebred chicken eggshell waste that could effectively function as an antibacterial agent. The waste treatment was carried out using a top-down method applying the thermal decomposition method with calcination temperatures of 700 and 800 ºC for 30 hours. XRD analysis results showed CaO as a major phase and this was further supported by Rietveld calculation. The size of the crystalline phases obtained ranged from 10–45 nm, while FTIR analysis showed the appearance of CaO bond at a wave number of 715.65 cm-1. Furthermore, SEM analysis showed a rough folded particle surface with a pore percentage of 48.20%. Based on the UV-Vis DRS analysis results, chicken eggshell powder had band gap energy characteristics of 2.07, 2.74, 3.71, and 5.96 eV for sample B, as well as 4.60 and 5.82 eV for sample C. Activation of purebred chicken eggshell powder as antibacterial was performed both qualitatively and quantitatively using photocatalytic and non-photocatalytic methods. Qualitatively, both samples showed antibacterial activity, with a minimal inhibitory concentration (MIC) of 1,000 µg/mL.

Well-dispersed copper and molybdenum co-doped g-C3N4 as an excellent persulfate activator for highly efficient removal of bisphenol a in wastewater

Degradation of endocrine disrupting compounds by optimizing advanced oxidation processes is highly feasible, but remains a daunting challenge. In this work, a novel copper and molybdenum co-doped g-C3N4 (Cu/Mo@CN) were successfully synthesized via a simple dip-calcination approach, of which highly dispersed Cu and Mo atom sites were doped in the ring of g-C3N4. The Cu/Mo@CN catalysts were characterized by XRD, SEM, TEM, XPS, UV–vis DRS analyses, etc. The optimized system of Cu1/Mo3@CN catalyst in the visible light-persulfate oxidation (Vis + PS + Cu1/Mo3@CN system) had high photocatalytic activity to remove 97.2 % of bisphenol A (BPA, 5 mg/L) within 60 min. Compared to pure g-C3N4, Cu/Mo@CN has better visible-light (Vis) response function and narrower band gap (2.58 eV), which are easier to get excited by Vis illuminate. The results showed that reactive oxygen species of SO4• −, •OH and •O2− could be stably produced to contribute to the BPA degradation in Vis + PS + Cu/Mo@CN systems. Meanwhile, the Cu and Mo elements co-doped in g-C3N4 can also effectively activate PS to promote the production of reactive oxygen substances. In addition, the continuous production of photoelectrons enhanced the cycling of Cu2+/Mo6+ and Cu+/Mo4+, which could be further improved the removal efficiency of Vis + PS + Cu/Mo@CN towards BPA. The degradation mechanism of BPA were proposed according to the identification of intermediate products and DFT calculation. Overall, this study provides a viable pathway for BPA abatement in actual wastewater treatment applications.

Superior adsorptive removal of ciprofloxacin by graphene oxide modified Ni-Al layered double hydroxide composites

Pharmaceutical drug removal from industrial wastewater has become a major challenge in recent years. To address this concern, an eco-friendly, non-toxic, renewable, low-cost, and simple-to-synthesize catalyst called Ni-Al LDH (Layered Double Hydroxide) was synthesized using the co-precipitation method. LDH was further constructed with GO (Graphene Oxide) using the electro-self-assembly method for its effective performance in the removal of ciprofloxacin from wastewater. XRD, FESEM, EDX, Raman, FTIR, UV-Vis DRS, and BET analysis were used to characterize the as-prepared Ni-Al LDH and composites of GO@LDH. Using bare LDH and its composite with GO, several parameters such as adsorbent dosage, contact time, adsorbate concentration, and pH were optimized. GO(5)@LDH shows complete adsorption of 87.4% in 180 min for ciprofloxacin solution. The SBET for Ni-Al LDH, GO(1)@LDH, and GO(5)@LDH was determined to be in the order 3.5456 m2/g, 19.575 m2/g, and 22.5591 m2/g, suggesting that the surface area of the LDH increases upon GO loading. According to the calculation based on Langmuir isotherm, GO(5)@LDH (1968.5 mg/g) has a greater maximum adsorption capacity than Ni-Al LDH (332.2 mg/g). The kinetic analysis reveals that it adheres to a pseudo-second-order kinetic model. The catalyst was effectively employed for four repeating cycles with only a 10% decrease in removal rate, demonstrating that it can be easily regenerated. The morphology of the catalyst GO(5)@LDH remained the same before and after use, as seen by the XRD spectra, indicating the stability of the catalyst. As a result, LDH-GO composites are ideal catalysts for the treatment of ciprofloxacin wastes in the environment.

Facile one-pot combustion synthesis of CuCo2S4 binary nanocomposite for synergetic photodegradation of CR dye and reduction of nitroarenes

A one-pot combustion method was employed for the synthesis of branch-like CuCo2S4 (CCS) without any surfactant, polymerizing, or capping agent. Most of the studies were conducted on CCS material for electrochemical performances. Herein, we demonstrated CCS is an efficient catalyst for the photodegradation of toxic CR dye and also, the reduction of nitroarenes. The cubic structural phase of the symphonized material was confirmed by using XRD analysis. The scanning electron microscopy (SEM) and transmission electron microscopy (TEM) results interpret that the uniform skull-like structures were formed during the combustion method. The bandgap was about 1.41 eV, which was analyzed from UV–Vis DRS analysis. FT-IR confirms the presence of Cu-S, Co-S, and Cu-Co bonding. Photoluminescence (PL spectrofluorometer) is evidence, of the ability of electrons and hole recombination. A significant surface area and the pore diameter were found to be 4.072 m2/g and 34.75 nm respectively, by BET (Brunauer -Emmett-Teller) and BJH (Barret-Joyner-Halenda) analysis. Herein, we report CCS material, for the photodegradation of Congo red (CR) dye with a photodegradation efficiency of 91.2 % in 80 min (min). And retains its stability for up to 4- cycles. Further, CCS material also exhibits a good catalyst for the reduction of nitrobenzene and 4- nitro phenol (4-NP) with reduction rate constants of 0.07056 min−1 and 0.194 min−1. The degradation products were confirmed by using LC-MS, and TOC (Total Organic Carbon) analysis. These reports are evident that the synthesized CCS nanostructures are latent material for the removal of hazardous dyes from wastewater as well as catalyzed the reduction of nitrobenzene and 4-NP.

Degradation evolution of tetracycline-HCl/Fluoroquinolones and CO2 reduction over novel Z-scheme NCQDs-black NiO/Bi7O9I3 mesopores nanosheet heterojunction

The novel mesopores nanosheet Z-scheme NCQDs-BNiO/Bi7O9I3 (NCQDs: nitrogen doped carbon quantum dots & BNiO: black nickel oxide) heterojunction nanophotocatalyst has been synthesized by the facile sono-solvothermal method in order to remove antibiotic/fluoroquinolones and solid/liquid phase photocatalytic reduction of CO2 under the irradiation of simulated solar light. Several analyzes, have been performed to investigate the physical, chemical and optical properties of the synthesized photocatalysts. Raman analysis of NCQDs-BNiO/Bi7O9I3 sample shows the increase of structural defects which is the result of the presence of NCQDs in the structure of this sample. The characteristics of the pore volume, surface area and pore diameter of the optimal photocatalyst have been estimated at about 0.209 cm3/g, 44.6 m2/g and 18.8 nm, respectively. The UV–vis DRS analysis indicated the increase in optical absorption range and two absorption edges (373.7 and 526.4 nm). Pharmaceutical pollutants like tetracycline hydrochloride (TCH), ofloxacin, levofloxacin, and ciprofloxacin were removed by the photocatalytic degradation process in the order of 81.6%, 73.6%, 73.4% and 71.5%, respectively by NCQDs-BNiO/Bi7O9I3 photocatalyst which it can be asserted because of efficacious happening of surface reactions, facilitation of mass transfer and surface adsorption, which shows the key effect of the created structural model and the usage of ultrasound waves. At the end the photoreduction activity of the quintessential photocatalyst was evaluated which could produce 43.437 µmol/gcatalyst methanol after 8 h.

Hydrothermal preparation of NiO/La–NaTaO3 composite photocatalyst for degradation of ammonium dibutyl dithiophosphate wastewater

The discharge of a large amount of flotation reagents wastewater can cause significant environmental pollution. In this study, NiO/La–NaTaO3 nano-photocatalyst was prepared and applied to degrade synthetic flotation reagent ammonium dibutyl dithiophosphate wastewater. Various characterization results confirmed the successful synthesis of NiO/La–NaTaO3, and UV–vis DRS analysis revealed a band gap of 3.96 eV for 4 wt% NiO/2.5% La–NaTaO3. Under UV light, the degradation rate of 20 mg 4 wt% NiO/2.5% La–NaTaO3 photocatalyst reached its optimum within 4.5 h at pH=3, exhibiting a 1.45 times improvement compared to pure NaTaO3. Radical trapping experiments and EPR results showed that ·OH and·O2− showed major contribution to the degradation. Furthermore, photocatalytic mechanisms and toxicity evolution were investigated, demonstrating the potential application of photocatalytic methods for treating flotation reagent wastewater.

Facile synthesis of different metals doped α-PbO nanoparticles for photocatalytic degradation of Methylene Blue dye

In recent days, metallic oxide semiconductor nanoparticles have drawn attention to the photocatalytic degradation of organic pollutants. In the present work, undoped and different metals (Sn, Co, Cu, Ni, and Li)-doped of α-PbO nanoparticles were successfully synthesized by a facile chemical precipitations method. The obtained nanoparticles were further studied by using different characterization techniques. The XRD results confirmed that the prepared nanoparticles were a tetragonal, α-PbO phase crystal structure without mixing other PbO phases. The obtained optical band gaps from UV–vis DRS analysis were 2.03 eV, 2.68 eV, 1.61 eV, 1.78 eV, 1.67 eV, and 2.00 eV for pristine α-PbO, Sn, Co, Cu, Ni, and Li doped α-PbO respectively. From the PL emission, the lowest PL intensity of the doped samples indicated the low recombination of the electron-hole pairs that improved the photocatalytic performance of pristine α-PbO. SEM and EDX were used to analyze the surface morphology and composition of the synthesized nanoparticles, respectively. The photocatalytic activities of the prepared nanoparticles were assessed through the degradation of the Methylene Blue (MB) dye under visible light irradiation. The UV–visible spectrophotometer analysis showed that the MB dye concentration decreased as the irradiation time varied from 20 to 100 min. The results showed that within 100 min, the Sn-doped α-PbO nanoparticles possessed the maximum degradation efficiency compared to other metal-doped α-PbO nanoparticles, with 100% MB dye degradation compared to 94.76% by pristine α-PbO. This was due to the increased visible light harvesting, which aided in the photocatalytic degradation of MB dye.

Surface-Enhanced Raman scattering (SERS) filter paper substrates decorated with silver nanoparticles for the detection of molecular vibrations of Acyclovir drug

Acyclovir (ACV) drug, a common antiviral agent, is frequently used as the primary clinical treatment method for treating hepatitis B, herpes simplex, and varicella zoster viruses due to its potent therapeutic effect. In patients with compromised immune systems, this medication can stop cytomegalovirus infections, and high doses of this drug are required; however, such prescription leads to kidney toxicity. Therefore, timely and accurate detection of ACV is crucial in many areas. Surface-Enhanced Raman Scattering (SERS) is a reliable, rapid, and precise approach for the identification of trace biomaterials and chemicals. Filter paper substrates decorated with silver nanoparticles (AgNPs) were applied as SERS biosensors to detect ACV and control its adverse effects. Initially, a chemical reduction procedure was utilized to produce AgNPs. Afterward, UV–Vis, FE-SEM, XRD, TEM, DLS, and AFM were employed to examine the properties of prepared AgNPs. In order to prepare SERS-active filter paper substrates (SERS-FPS) to detect Molecular vibrations of ACV, AgNPs prepared by immersion method were coated on filter paper substrates. Moreover, the UV–Vis DRS analysis was carried out to assess the stability of filter paper substrates and SERS-FPS. The AgNPs reacted with ACV after being coated on SERS-active plasmonic substrates and could sensitively detect ACV in small concentrations. It was discovered that the limit of detection of SERS plasmonic substrates was 10-12 M. Moreover, the mean RSD for ten repeated tests was calculated as 4.19%. The enhancement factor for detecting ACV using the developed biosensors was calculated to be 3.024 × 105 and 3.058 × 105 experimentally and via simulation, respectively. According to the Raman results, SERS-FPS for the detection of ACV, fabricated by the present methods, showed promising results for SERS-based investigations. Furthermore, these substrates showed significant disposablity, reproducibility, and chemical stability. Therefore, the fabricated substrates are capable to be employed as potential SERS biosensors to detect trace substances.

Investigation of structural, morphological, thermal, and thermoelectric properties of Zn1−xCuxAl2O4 (0.0 ≤ x ≤ 0.1)

Most promising oxide thermoelectric (TE) materials such as perovskites, layered oxide materials, Al-doped ZnO, etc, have been reported. In the present work, Zn1−x Cu x Al2O4 (0.0 ≤ x ≤ 0.1) samples were synthesized by a simple hydrothermal method. The structural, optical, morphological, and TE properties of Zn1−x Cu x Al2O4 (0.0 ≤ x ≤ 0.1) have been investigated. XRD analysis reveals that ZnAl2O4 has a single-phase cubic structure and Cu is completely dissolved in the ZnAl2O4 lattice. Thermal analysis shows that ZnAl2O4 has high thermal stability up to 1000 °C. From the UV–vis DRS analysis, the energy band gap of ZnAl2O4 decreased from 3.30 eV to 2.82 eV with increasing the content of Cu. Carrier concentration and mobility of the samples were measured by the Hall effect. The values of a carrier concentration of undoped ZnAl2O4 and Zn0.9Cu0.1Al2O4 are obtained to be 3.836 × 1013 cm−3 and 3.3 × 1016 cm−3 at 313 K and 9.6 × 1013 cm−3 for pure and 5.5 × 1016 cm−3 for Zn0.9Cu0.1Al2O4 at 673 K. TE properties of the synthesized samples have been analyzed as a function of temperature. With the optimum values of Seebeck coefficient and electrical conductivity, Zn0.9Cu0.1Al2O4 shows the highest power factor of 0.50 μW/mK2 while the pure ZnAl2O4 shows a maximum power factor of 0.19 μW/mK2 at 673 K. The Zn0.9Cu0.1Al2O4 exhibits a relatively high zT of 2.4 × 10−4 at 673 K, while pure ZnAl2O4 has a zT value of 0.4 × 10−4 at 673 K. The obtained values reveal the improvement of TE properties by increasing the Cu content in the sample.

Construction of a novel ZnO/rGO hybrid composite for efficient degradation of CV, Cr (VI) and 2, 4-D under visible light irradiation

The pristine ZnO and ZnO-Graphene hybrid composites at various graphene ratios were synthesized via facile ultrasonic assisted solution approach. The crystal structure is identified by powder XRD technique and disclosed the hexagonal wurtzite structure. The synthesized ZnO exhibited uniform spherical like morphology with low degree of aggregation. The formation of hybrid composite of graphene and ZnO could improve the light absorption ability and separation of photo generated carriers of ZnO, which is confirmed through photoluminescence and UV–Vis DRS analysis. The photo catalytic degradation of Crystal violet, Cr (VI) and 2, 4 D were evaluated under visible light irradiation. The Zn-Graphene hybrid composite exhibited higher photo catalytic activity towards CV dye, Cr (VI) and 2, 4-D, such as high photo degradation efficiency and good stability than bare ZnO. This could be due to the high surface area and synergic effect between the graphene and ZnO p–n junctions. The mechanism of enhanced photo catalytic activity of Zn-Graphene composite discussed in detail.