Reply to “Comment on ‘Measurement and Correlation of Solubility of Two Isomers of Cyanopyridine in Eight Pure Solvents from 268.15 to 318.15 K’”

Reply to “Comment on ‘Measurement and Correlation of Solubility of Two Isomers of Cyanopyridine in Eight Pure Solvents from 268.15 to 318.15 K’

Tribological Performance of an Imidazolium Ionic Liquid-Functionalized SiO₂@Graphene Oxide as an Additive

A graphene oxide (GO)-wrapped SiO2 nanosphere was modified with a 1-methylimidazolium bis­(salicylato)­borate (MEIMBScB) ionic liquid to form a SiO2@GO@MEIMBScB nanocomposite. The SiO2@GO@MEIMBScB nanocomposite exhibited a core–shell structure, which was characterized by Fourier transform infrared spectroscopy, ultraviolet–visible spectroscopy, photoluminescence spectroscopy, dynamic light scattering, X-ray photoelectron spectroscopy, scanning electron microscopy, and transmission electron microscopy. The SiO2@GO@MEIMBScB nanocomposite was dispersed into poly­(ethylene glycol) 400 (PEG400) as a lubricant additive, and its tribological performance was evaluated with a four-ball tribometer under 392 N at 1450 rpm for 30 min. The results showed that the SiO2@GO@MEIMBScB nanocomposite can reduce the friction coefficient by 57.27% and reduce the wear scar diameter by 16.98% at an optimized concentration. Its tribological performance was much better than the individual SiO2@GO and MEIMBScB ionic liquid and the SiO2@GO/MEIMBScB mixture. The SiO2@GO@MEIMBScB nanocomposite exhibited a synergistic effect, which was confirmed by surface analysis on a wear track. It showed that SiO2@GO@MEIMBScB can be adsorbed on the rubbing surface and form a tribo-boundary film to reduce friction and wear. A possible lubrication mechanism was proposed, which might guide the development of a novel nanolubricant additive

Core–Shell NiO@PdO Nanoparticles Supported on Alumina as an Advanced Catalyst for Methane Oxidation

An alumina-supported core–shell-structured NiO@PdO catalyst was prepared for lean CH₄ combustion. NiO@PdO plays two roles in promoting the reaction. First, the enhanced NiO-PdO interfacial action accelerates the regular tetragonal PdO lattice construction, stabilizes the PdO particles, and suppresses the hydroxyl/water adsorption during the reaction. Second, the dispersion of shell PdO particles over core NiO improves PdO exposure and utilization efficiency. NiO@PdO/Al₂O₃ with a molar Ni/Pd ratio of 2/1 exhibits a (>)­99% CH₄ conversion and a good stability at 400 °C with a low 0.2 wt % Pd loading amount, which is among the best of the state-of-the-art Pd-based catalysts with respect to turnover frequency, Pd utilization efficiency, and Ni addition amount. Such interface-promoted core–shell-structured catalyst design strategy is inspiring for improving noble metal utilization efficiency in CH₄ oxidation and other related reaction systems

Enhanced Photocatalytic Mineralization of Gaseous Toluene over SrTiO₃ by Surface Hydroxylation

Perovskite structured SrTiO₃ (STO) was synthesized by a hydrothermal method followed by a second hydrothermal treatment with H₂O or NaOH (STO-H₂O or STO-NaOH) for the photocatalytic mineralization of gaseous toluene. The second hydrothermal treatment enhances the light absorption and enriches the surface hydroxyl groups of STO. The surface hydroxyls’ enrichment of STO promotes the generation of hydroxyl radicals and the separation of photocarriers by the combination of hydroxyl with holes, induces a negative shift of its band edge, and benefits the reduction of adsorbed oxygen. The facile generation of reactive radical species, enhanced light absorption, and improved photocarrier separation together lead to greatly enhanced photocatalytic efficiency of STO-NaOH. Toluene was completely oxidized into CO₂ under ultraviolet light illumination for 6 h at room temperature, demonstrating better performance than STO and commercial P25 catalysts. Such a surface hydroxylation promotion strategy may lead to new perceptions of designing an efficient photocatalyst

Highly Efficient, Mild, Bromide-Free and Acetic Acid-Free Dioxygen Oxidation of <i>p</i>-Nitrotoluene to <i>p</i>-Nitrobenzoic Acid with Metal Phthalocyanine Catalysts

Four metal tetracarboxyl phthalocyanines were synthesized and characterized by elemental analysis and mass spectrometry. p-Nitrobenzoic acid was efficiently prepared in high yield from bromide-free and acetic acid-free aerobic oxidation of p-nitrotoluene using metal phthalocyanines as catalysts under mild conditions in alkali−methanol solution. Up to 88.8% isolated yield of p-nitrobenzoic acid was obtained with the catalysis of tetracarboxyl phthalocyanine cobalt (0.13 mol %, based on the moles of p-nitrotoluene) optionally combined with a small amount of dimethylformamide in the presence of 2.0 MPa dioxygen at 30−60 °C. The effect on catalytic performance of a carboxyl group introduced into the phthalocyanine ring was further discussed on the basis of metal coordination chemistry theory

Solid–Liquid Phase Equilibrium of Isophthalonitrile in 16 Solvents from <i>T</i> = 273.15 to 324.75 K and Mixing Properties of Solutions

The solid–liquid equilibrium of isophthalonitrile (IPN) in 16 solvents (methanol, ethanol, n-propanol, isopropanol, acetone, ethyl acetate, acetonitrile, chloroform, cyclohexanone, cyclopentanone, methyl acetate, ethyl formate, 2-pentanone, tetrahydrofuran, toluene, and diethyl ether) was measured by using a static equilibrium method at temperatures T = 273.15–324.75 K under atmospheric pressure. The results demonstrated that the solubility of IPN in these 16 monosolvents increased with increasing temperature. The largest solubility values of IPN were found in cyclopentanone, and the lowest were in isopropanol. The values of solubility in ketones were much larger than those in esters and alcohols. In alcohols, the solubility ranked as methanol > ethanol > n-propanol > isopropanol, and the sequence was identical to that of the solvent polarities. The polarity of the solvent is an important factor influencing the solubility profiles of IPN in alcohols, despite that the conclusion is not supported by other kinds of solvents studied. Moreover, the Apelblat equation, λh equation, Wilson model, and nonrandom two-liquid model were used to correlate the experimental values. The calculated values of four models all provided good fitting results with the experimental data, and the values of root-mean-square deviation and relative average deviation (RAD) were no more than 6.84 × 10–4 and 6.84 × 10–3, respectively. Furthermore, the thermodynamic properties of the mixing process for IPN in selected solvents were calculated, that is, mixing Gibbs energy (ΔmixG), molar enthalpy (ΔmixH), and molar entropy (ΔmixS). The results indicated that the mixing process of IPN was a spontaneous and entropy-driven process. The solid–liquid equilibrium data and solution thermodynamics would be helpful for the synthesis and purification of IPN in the industry

MnO₂ Promoted TiO₂ Nanotube Array Supported Pt Catalyst for Formaldehyde Oxidation with Enhanced Efficiency

Highly ordered pore-through TiO₂ nanotube arrays (TiNT) prepared by an electrochemical anodization method were modified with MnO₂ and used as the support for a Pt/MnO₂/TiNT catalyst. The monolith-like Pt/MnO₂/TiNT was then applied to low-concentration HCHO oxidation with enhanced efficiency. The effect of the MnO₂ promotion on its performance for HCHO oxidation was studied with respect to the behavior of adsorbed species on the catalyst surface using in situ diffuse reflectance Fourier transform spectroscopy. In comparison with Pt/TiNT, Pt/MnO₂/TiNT shows higher activity under parallel preparation and test conditions. A HCHO conversion of 95% with a more than 100 h stable performance is achieved over Pt/MnO₂/TiNT at 30 °C with a low 0.20 wt % Pt loading amount. The superior performance is related to the specific monolith-like structure and its confinement effect, metal–support interaction, and superior HCHO adsorption and storage properties of Pt/MnO₂/TiNT

Heavy metals pollution and potential ecological risk assessment in farmland soils from typical mining area: a case study

The research aimed to investigate HMS, utilizing the Pearson correlation coefficient for speciation distribution analysis, PCA for assessing pollution characteristics and identifying sources, the Muller index to evaluate ecological risk level, and the Hakanson potential ecological risk index to determine the order of risk from heavy metals. The topsoil near SA was collected, and the contents of seven kinds of HMS, As, Cd, Pb, Zn, Ni, Cu and Cr were determined, so as to evaluate the types of high-risk heavy metal pollution further accurately. The research recorded valuable data showing that the concentration values of all seven HMS in the investigated area exceeded prescribed agricultural soil contamination limits. The concentrations of As, Cd, and Pb were found to be 8.30, 46.20, and 6.08 times higher than the screening values in Hunan Province, respectively. In the GYB sampling area, the coefficient of variation (CV) values for Cu, Pb, As, Zn, and Cd are all between 0.50 and 1.00. Notably, the CV value for Cd reaches 0.82, indicating a significant variation. Significant correlations were found between Cd and Zn (Cd-Zn), Pb and Zn (Pb-Zn), Ni and Cr (Ni-Cr) in the tested soils. The ecological risk index (Eri) results showed that Cd was the primary pollutant in the study area, with the potential ecological hazards in the tested soils ranked as Cd>As>Pb>Cu>Zn>Ni>Cr. Combining both evaluation methods, the study area’s potential ecological risk order is SZY>GYB>CTL.</p