Cobalt oxide nanoparticles (Co3O4 NPs) were synthesized using leaf extracts of Teucrium oliverianum, Thymus vulgaris (thyme), and Cercis siliquastrum, and compared with chemically synthesized Co3O4 NPs prepared by co-precipitation. The nanoparticles were characterized by UV–Vis spectroscopy, diffuse reflectance spectroscopy (DRS) with Tauc-plot analysis, FTIR, X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM) with energy-dispersive X-ray (EDX) analysis, transmission electron microscopy (TEM), and dynamic light scattering (DLS). The green-synthesized Co3O4 NPs exhibited smaller crystallite sizes (18.20–23.39 nm, XRD) and particle sizes (20–25.6 nm, TEM) than the chemically synthesized Co3O4 NPs (26.82 nm and approximately 32 nm, respectively), together with larger zeta-potential magnitudes (− 35.7 to − 60 mV vs. − 30 mV), indicating greater colloidal stability. DRS-Tauc analysis yielded optical band gaps of 1.76–2.07 eV for the green-synthesized Co3O4 NPs, wider than that of the chemically synthesized sample (1.61 eV), consistent with their smaller crystallite size and higher defect/surface-state density. Under UV irradiation (50 W, < 400 nm), the green-synthesized Co3O4 NPs degraded methylene blue (MB, 50 mg/L) with efficiencies of 98.99
This study explores the synthesis, characterization, and photocatalytic application of a TiO2/Polyaniline nanocomposite for degrading organic compounds in wastewater from a vegetable oil factory. Various characterization methods confirmed the successful combination of TiO2 and Polyaniline, with structural and optical qualities suitable for light-driven photocatalysis. Response surface methodology with central composite design was used to optimize five key factors, pH, temperature, contact time, catalyst amount, and H2O2 concentration, to maximize chemical oxygen demand (COD) removal. At optimal conditions (pH 5, 30 °C, 60 min, 0.4 g catalyst, 80 mg/L H2O2), the system achieved an 87.42
The photo-Fenton process (Fe3⁺/H2O2/UV) was investigated for the removal of NH4⁺, NO3⁻, NO2⁻, and PO43⁻ ions from synthetic landfill leachate under different irradiation systems, including UV-A (210 and 113 W) and UV-C (75 W). The influence of operating parameters, particularly Fe3⁺ and H2O2 concentrations, on treatment performance was evaluated. The results demonstrated that Fe3⁺ acts as an efficient homogeneous catalyst, with removal efficiencies significantly increasing as the catalyst concentration increased. Process optimization revealed a strong interaction between Fe3⁺ and H2O2 concentrations, and the highest treatment performance was achieved using 1.5 mmol/L Fe3⁺ and 0.2 mol/L H2O2 under UV-C irradiation (75 W). Under these optimal conditions, removal efficiencies after 24 h reached 90.1
This note examines the mathematical derivation presented by Rani et al. for the steady-state analysis of a nonlinear reaction–diffusion model arising in homogeneous electrocatalysis. The principal contribution of the original paper is the derivation of closed-form expressions for the concentration profiles and the associated current–potential response. Since all subsequent analytical results of Rani et al. depend upon these expressions, it is important that the underlying boundary-value problem be solved rigorously. Herein, I show that the derivation of Rani et al. does not establish that the proposed trial functions satisfy the governing nonlinear differential equations throughout the spatial domain. In particular, the derivation reduces the differential equations to algebraic relations at the electrode surface, but does not demonstrate that the governing equations are satisfied on the semi-infinite interval. I further identify inconsistencies in the published analytical formulae and discuss the extent to which the accompanying numerical computations provide an independent validation of the proposed solution. These observations suggest that the analytical results require further mathematical justification before they may be regarded as established solutions of the nonlinear model.
The present work describes the synthesis of zinc oxide nanoparticles (ZnO NPs) using Baccaurea macrocarpa peel extract and their potential applications as photocatalysts and antibacterial agents. The synthesis was conducted at different temperatures ranging from 25 to 120 °C. The chemical composition, crystal structure, optical characteristic, and surface morphology of the as-synthesized ZnO NPs, without subsequent calcination, were investigated using various spectroscopic and imaging techniques. Characterization results revealed that ZnO NPs synthesized at 25 and 40 °C formed semicrystalline nanolayers, whereas those synthesized at 90 and 120 °C exhibited a hexagonal wurtzite structure. Despite their difference in crystallinity, all the ZnO NPs exhibited comparable bandgap energies in the range of 3.26–3.45 eV and contained organic compounds likely originating from the B. macrocarpa peel extract. Among the synthesized samples, ZnO-90, consisting of wurtzite ZnO nanocrystals synthesized at 90 °C, exhibited the highest photocatalytic and antibacterial performance. They effectively degraded both anionic and cationic dyes, including methyl violet, indigo carmine, and methyl orange, under UV light irradiation and inhibited the growth of the Gram-positive bacterium Staphylococcus aureus and the Gram-negative bacterium Escherichia coli. These results indicate that the photocatalytic and antibacterial activities of ZnO NPs are strongly governed by the long-range atomic arrangement within their crystal structure.
The present study is the first report on the adsorption of methylene blue (MB), which is a cationic dye, using Mentha aquatica leaf powder (MALP). MALP was found to adsorb MB rapidly (reaching equilibrium in less than 90 min), with up to 96.8
Using a non-equilibrium approach (energy calculation level CCSD(T)/6–311 + G**//B3LYP/6–31 + G**), the thermal rate constants of the gas-phase reactions of methanol and formaldehyde with the methyl radical, and methane with the hydroperoxyl radical, were calculated. The discussion is based on the model [7], according to which: (1) the reaction complex is formed at zero translational energy of the reactants, (2) the transition of the H atom in the double-well potential is accompanied by a reorganization of the system, (3) the promoting contribution to the reaction comes from the vibration of heavy atoms of the three-center reaction center, and (4) the promoting effect depends on the lifetime of the collision complex. Taking these factors into account, it is possible to reproduce the experimental kinetic dependences with good accuracy over the entire temperature range studied.
In this study, magnesium–aluminum layered double hydroxides (Mg–Al LDHs) were synthesized via a one-pot method and subsequently modified by high-temperature calcination to efficiently remove tetracycline (TC) from water. The morphology, structure, and adsorption performance of the calcined products were systematically characterized. Results demonstrated that the one-pot method produced calcined hydrotalcite with uniform particle size, high crystallinity, and a hierarchical "thin sheet-cluster-spherical structure. After calcination at 400 °C, the layered structure collapsed, interlayer anions were removed, and MgO phases formed, significantly enhancing adsorption performance. Under optimal conditions (initial TC concentration of 30 mg/L, adsorbent dosage of 0.05 g, 30 °C, 2 h), the removal rate reached 85.03
The catalytic wet air oxidation (CWAO) of methyl tert-butyl ether (MTBE) was investigated over TiO2–CeO2 mixed oxides prepared by a sol–gel route. Structural and surface analyses (XRD, TEM/HRTEM, N2 physisorption, Py-FTIR, and H2–TPR) show that Ce incorporation preserves an anatase-dominant framework while inhibiting TiO2 crystallization and increasing the density of accessible Lewis acid sites, with an optimum at intermediate Ce loadings. In the untreated series, TiCe5 exhibited the highest MTBE oxidation performance, consistent with maximized Lewis acidity and enhanced interfacial redox functionality. HCl treatment primarily altered surface acidity without detectable bulk phase changes, generating Brønsted acidity on CeO2 and significantly enhancing its catalytic activity. Overall, the results support an acid–redox cooperation scenario under aqueous, O2-pressurized operation, where acid-site distribution and water–surface interactions influence MTBE activation and subsequent oxidation/mineralization.
Er-doped CuO thin films with different Er concentrations were successfully fabricated on glass substrates using the sol–gel dip-coating technique. The influence of Er incorporation on the structural, optical, UV photodetection, and photocatalytic properties of CuO thin films was systematically investigated. Structural analyses confirmed the formation of single-phase monoclinic CuO, while Er incorporation induced lattice distortion, grain refinement, and increased defect density without forming secondary phases. Optical measurements revealed improved transparency and tunable band-gap energy as a function of Er content. Moderate Er doping enhanced the UV photoresponse, whereas excessive doping increased the dark current and reduced the overall photodetection performance. Photocatalytic experiments demonstrated improved methylene blue degradation, with the highest reaction rate obtained at moderate Er concentration. Radical trapping experiments showed that Er incorporation modified the dominant photocatalytic oxidation pathway from superoxide radicals toward hydroxyl radicals and photogenerated holes. Recycling tests confirmed good photocatalytic stability of the optimized films. Overall, the results demonstrate that controlled Er incorporation effectively tailors the multifunctional properties of CuO thin films, making them promising materials for photocatalytic and optoelectronic applications.
Simple and cost efficient Anodization thchinque was employed to produce a nanostructured nickel oxide surface on nickel foil. An ultrasound-assisted deposition technique was employed to uniformly decorat the Co nanoparticles onto the NiO, yielding a Co3O4/NiO junction electrode. The structural properties of the materials were analyzed using X-ray diffraction, and the surface morphology was evaluated using FESEM. FE-SEM images demonstrate that Co3O4 nanoparticles decorated on NiO significantly influence the photoelectrochemical properties. The diameter of the particles is influenced, measuring between 21 and 68 nm for NiO and 75 to 461 nm for Co3O4/NiO, while also modifying the overall structure of the nanocomposite. Absorption escalates with layer thickness in the UV–vis spectrum. The energy gap diminished from 3.48 to 2.6 eV with the augmentation of layer thickness, as corroborated by the PL analysis. The photocurrent density values for the NiO and Co3O4/NiO electrodes are 4.0 mA cm−2 and 7.29 mA cm−2. The photon-to-current conversion efficiency of Co3O4/NiO was determined to be 94.2
A highly active and recyclable heterogeneous catalyst consisting of nickel anchored multi-walled carbon nanotubes (Ni-MWCNTs) was synthesized and utilized for the preparation of aryl esters through carbonylative coupling of aryl halides with phenol using Co2(CO)8 as a carbon monoxide source. MWCNTs serves as an effective support, facilitating homogeneous distribution of nickel nanoparticles with high activity due to its large specific surface area, and chemical stability. The catalyst was systematically characterized for surface morphology, surface area, nickel nanoparticle size distribution, crystal phase, nickel oxidation state and nickel content. Under optimized reaction conditions, the Ni-MWCNTs system demonstrated remarkable catalytic performance with wide range of substrates, showing activity with both electron-donating and electron-withdrawing substituents. The catalyst also displayed excellent recyclability and could be reused for up to five consecutive cycles with minimal reduction in catalytic efficiency.
Herein, Ru-doped V2O5-WO3/TiO2 (VWTi) catalysts were prepared to study the impact of Ru doping on chlorobenzene (CB) oxidation activity. The introduction of Ru weakens the V–O bond strength, resulting in neutralizing the Lewis acid effect and optimizing the overall acid balance of the VWTi catalyst. Moreover, the presence of RuO2 can significantly enhance the redox capability and surface lattice oxygen mobility. Hence, a significant improvement in both low-temperature activity and CO2 selectivity has been achieved with the Ru-doped VWTi catalyst, reaching a CB conversion of 50
A series of CeCuOx@C catalysts with different Ce contents was prepared from Ce-Cu-BTC precursors by hydrothermal synthesis followed by pyrolysis under an N2 atmosphere. The influence of Ce incorporation on the phase composition, textural properties, surface redox states, and catalytic behavior in glycerol conversion to lactic acid was systematically investigated. XRD results confirmed the coexistence of metallic Cu and Cu2O phases, while XPS analysis revealed Cu0/Cu+ and Ce3+/Ce4+ redox pairs together with oxygen-vacancy-related surface oxygen species. Among the catalysts studied, 5
In this study, Bi2₋ₓLaₓWO6 mixed oxides (x = 0 and 0.3) were successfully synthesized by the ceramic method. The obtained materials were comprehensively characterized using X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, UV–Vis diffuse reflectance spectroscopy (DRS), scanning electron microscopy (SEM), atomic force microscopy (AFM), and photoluminescence (PL) spectroscopy. XRD analysis revealed that partial substitution of Bi3+ by La3+ induced a structural transition from the orthorhombic phase of Bi2WO6 to a well-crystallized monoclinic phase in the Bi1.7La0.3WO6 sample. This substitution also resulted in a reduction of the average crystallite size. The photocatalytic performance of the synthesized materials was evaluated through the degradation of rhodamine B (RhB) and methyl orange (MO) under visible-light irradiation. The Bi1.7La0.3WO6 sample exhibited superior photocatalytic activity, achieving degradation efficiencies of 92.26
In this study the Melia Composite (MC) was synthesized from local Melia azedarach fruit raw and local clay, batch adsorption method used for removal of Cyflumetofen (CYF) (Danisaraba) pesticide by adsorption. MC were characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Scanning electron microscope (SEM), Energy dispersive x-ray spectrometry (EDX), BET surface area and thermal analysis (TGA, DTG). The performance of MC was elevated at four different temperatures (20, 30, 40 and 50 °C), and the effect of various parameters such as contact time, biosorbent dosage, adsorption isotherm and initial CYF concentration (50–1000 mg L⁻1) on its removal efficiency was investigated. The highest CYF removal efficiency of 70.84 R^2 = 0.9883–0.9957) provide a better fit for kinetic analysis, the Freundlich isotherm model ( R^2 = 0.9749–0.9867) provided a better fit than the Langmuir model for adsorption of CYF by MC. The maximum adsorption capacity reached 143.69 mg g⁻1at 50 °C, while the desorption efficiency reached 84.8 ΔH^∘ of 18.82 kJ mol−1 and ΔS^∘ of 56.95 J mol−1 K−1. The adsorption process was identified as spontaneous, indicated by the negative ΔG^∘ , and endothermic, as evidence by the positive of ΔH^∘ . The MC achieved 100
This paper presents a simulation and performance analysis of a heavy-naphtha hydrotreating unit at Basrah Refinery in Aspen HYSYS with real industrial operating data. The model includes specific feed characterization, reactor kinetics of hydrodesulfurization (HDS) and hydrodenitrogenation (HDN), and proper models of separation and hydrogen recycle systems. Comparison with plant data indicates a high level of agreement (R2 = 0.9994) confirming the capability of the developed model to reproduce the measured outlet composition at the investigated industrial steady state operating condition. The performance of the hydrotreating was assessed using a systematic sensitivity analysis to determine how temperature, pressure, and hydrogen mass flowrate impacted the performance. It was found that temperature and pressure have strong effects on impurity removal only at certain operating ranges where it becomes less effective due to kinetic saturation and refractory properties of the sulfur and nitrogen containing species that remain. The greatest effect was found in H2 mass flow rate, which resulted in steady decreases in H2S and NH3, and excess hydrogen in the effluent. Lastly, Aspen HYSYS was used to find an operating window that could be implemented to enhance desulfurization within real refinery conditions, through constrained multi-variable optimization by the use of SQP algorithm, the optimized conditions reduced the outlet H2S concentration from 7.9 × 10−5 to 4.27 × 10−5 wt
This study investigates the molecular modification effects of stepwise Friedel–Crafts (FC) alkylation and Diels–Alder (DA) cycloaddition using the light fraction of low-temperature coal tar as feedstock. It is postulated that the Lewis acid catalyst AlCl3 may stabilize the carbocation intermediate and the furan diene transition state via potential π-cation interactions. Experiments using 1-methylnaphthalene as a model compound revealed a synergistic effect when the FC reaction preceded the DA reaction. Following this order, the conversion rates of 1-methylnaphthalene and 2,5-dimethylfuran were 45.18 and 98.05
A series of CuxMn5−xCe10 ternary composite oxides were rationally engineered via co-precipitationto activate peroxymonosulfate (PMS) for tetracycline (TC) degradation. Characterization confirms that Cu/Mn isomorphic incorporation into the CeO2 lattice induces lattice distortion, forming a composite oxide with a high specific surface area (73.52 m2/g for optimal Cu3Mn2Ce10). Systematic evaluation shows the optimal Cu3Mn2Ce10/PMS system achieves exceptional performance, with a rate constant (k = 0.124 min⁻1 at 30 °C) 2.22-fold higher than its Cu-free counterpart. The apparent activation energy (Eₐ = 30.03 kJ/mol) is significantly reduced. Mechanistic and transition-state thermodynamic analyses suggest a plausible associative inner-sphere pathway, wherein the porous architecture is proposed to assist in the pre-enrichment of TC, while surface-bound radical species (primarily SO₄⁻· and ·OH) are facilitated by the coupled Cu+/Cu2+, Mn4+/Mn3+ and Ce4+/Ce3+ redox cycles for subsequent degradation. This catalyst maintains > 90
The thermal degradation of poly (lactic acid) (PLA) with the incorporation of different amounts of cellulose acetate (CA) (0–10
