Journal of Saudi Chemical Society最新文献

An exceptional method of incorporating Sn ions into Zinc Oxide (ZnO) using a tandem system of Pulsed Laser Deposition (PLD) and Radio-Frequency Magnetron Sputtering (RFMS) to synthesize and functionalize ZnO nanostructures is demonstrated in this study for gas-sensing application. The RFMS power was varied up to 50 W to sputter a pure Sn metal target, while simultaneously or successively growing ZnO nanostructures on a templated MgO < 0001 > substrate and on an Au-plated Al₂O₃ gas sensor, via PLD process at the substrate temperature of 700 °C in 100–500 millitorr oxygen/argon gas background. The morphologies of the grown Sn-ZnO nanostructures were characterized by Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), and X-ray Diffraction (XRD), and while their chemical/oxidation states and optical properties were analyzed by X-ray photospectroscopy (XPS) and photoluminescence (PL), respectively. For simultaneous deposition, the resulting (0002)-dominated 2D grain-like ZnO nanostructures were influenced by the interaction of the dynamic PLD plasma with static RFMS plasma at different powers. For successive growth, at 50 W-RF power, a remarkable increase in the sensor response to 50-ppm carbon monoxide (CO) gas was observed at 250 °C, which could be attributed to the creation of more adsorption sites in the Sn-ZnO depletion region caused by the replacement of some Zn sites with Sn ions in the ZnO matrix. This study, therefore, exhibits the viability of this hybrid system to design, synthesize, and functionalize Sn-ZnO nanomaterials, either by simultaneous/successive deposition, for gas-sensing applications.

Antibiotic contamination is a global environmental problem. The emerging contaminant norfloxacin (NOR) may increase the risk of drug resistance and thereby harm human health. The practical application of metal–organic framework crystals is usually limited by their powder form and difficulty in recovery. In this study, a magnetic Co-MPS-800 composite was prepared from carbonization with ZIF-67@pine sawdust, and significantly raised the NOR removing ability from wastewater. The changes in functional group composition, elemental contents, morphology, thermal stability and adsorption mechanism of the magnetic Co-MPS-800 composite were interpreted using FT-IR, XRD, SEM, BET, TGA and XPS. The Co-MPS-800 has an isoelectric point of 9.15 and a large specific surface area (174.58 m²·g⁻¹). The impacts of pH, contact time, temperature and dosage on the performance of Co-MPS-800 were also studied. The adsorption capacity over NOR reached 221.98 mg·g⁻¹ at 303 K, pH=6.0. The NOR adsorption is best suited a pseudo-2nd-order kinetic model and the Freundlich isotherm. Co-MPS-800 also had excellent reusability, and the removal rate reached 82.94 % after four repeated uses. Therefore, the magnetic Co-MPS-800 composite is effective in removing NOR from aqueous solutions. Altogether, this functional MOF-derived porous carbon may serve as a promising pollutant biosorbent, and its preparation strategy may provide insights for future studies.

Sulfamethoxazole (SMX) is an extensively applied antibacterial drug, and it is also a pollutant that poses a serious threat to human and ecosystem health. In this research, a 3D hierarchical hollow ball-flower structure catalyst (CoAl-LDHs@CoS_x-rGO) was tailored for the first time to efficiently degrade SMX via visible light coupling PMS activation. A series of characterizations confirm that the target catalyst is successfully prepared and the optimized 0.1CoAl-LDHs@CoS_x-rGO sample possesses superior specific surface area of 306.0 m²/g, and significantly higher photocurrent response and lower electrochemical impedance. More importantly, 0.5 g/L of the sample can degrade 98.59 % of SMX within 50 min via visible light coupling PMS activation, and after 7 degradation cycles, the degradation rate only decreased by 8.49 %. A series of parameters that affect degradation rate have been optimized in detail. Capture experiments and ESR indicate that e⁻, •OH and SO₄^•− make major contributions to degradation, and visible light coupling PMS activation generates stronger signals than alone visible-light or PMS system. LC-MS, TEST toxicity assessment and theoretical calculation were conducted to elucidate degradation route and intermediate toxicity. The research provides a new approach to design catalysts with highly exposed activity sites for efficiently removing SMX from environmental water.

The Cr/Al₂O₃ catalyst, a prevalent system in commercial applications, plays a significant role in propane dehydrogenation (PDH). Notable improvements in this catalyst’s efficiency are essential for its continued use. In order to examine the effect of alkaline earth metals on the catalyst performances in the propane dehydrogenation reaction, a series of Cr/η-Al₂O₃ were synthesized by the impregnation method. The synthesized catalysts were designated as Cr-T/η-Al₂O₃, where T represents Ca, Mg, Sr, and Ba. The supports and the catalysts were studied using the following techniques: XRD, N₂ adsorption–desorption, temperature-programmed desorption and reduction, UV–Vis and Raman spectroscopy, and XPS analyses. The findings reveal that the Cr-Ba/η-Al₂O₃ catalyst exhibits better catalytic performance, with significantly higher propane conversion and propylene selectivity (with initial values of 66 % and 86.2 %, respectively) compared to other catalysts. The enhanced performance is attributed to the increased dispersion of Cr species, stabilization of Cr⁶⁺ species, and reducing the total amount of acid sites and strong acid sites, which are crucial for maintaining active sites and minimizing coke deposition. The Ba-modified catalyst also demonstrated excellent stability, with a lower deactivation rate (Ba(0.201 h⁻¹) < Sr(0.213 h⁻¹) < Ca(0.270 h⁻¹) < Mg(0.310 h⁻¹) < parent(0.338 h⁻¹)) and robust regenerative capacity over multiple cycles.

Sulfonated poly (ether ether ketone) (SPEEK) ion exchange membranes for VRFB are promising alternatives to Nafion, but require improved mechanical and chemical stability for long-term operation. Here, we have fabricated composite membranes using SPEEK as proton conductive medium and TiO₂ nanopapers as reinforcing framework to improve the mechanical and chemical stabilities of SPEEK membranes. The SPEEK/TiO₂ nanopaper composite membranes exhibited almost twice the tensile strength and only one-third the vanadium ion permeability compared to pristine SPEEK (DS=60 %). Due to the excellent cell performance such as high EE, slow capacity degradation and long-term lifetime, these high durable composite membranes could be found their potential use as ion exchange membranes for commercial VRFBs.

This study employs the grand canonical ensemble Monte Carlo (GCMC) method to investigate the effect of small-molecule organic matter on methane adsorption in anthracite. Specifically, the adsorption characteristics of methane in anthracite are analyzed considering the type and concentration of single-component and multi-component small-molecular organic matter, alongside parameters such as adsorption heat, adsorption potential energy, interaction energy, and charge transfer amount. Results indicate that methane adsorption exhibits physical adsorption behavior, with adsorption heat decreasing with increasing temperature and adsorption potential energy inversely correlated with adsorption capacity. The influence of different types and concentrations of small-molecular organic matter on methane adsorption varies. The presence of small-molecular organic matter alters the charge transfer amount of methane, with a greater absolute value corresponding to enhanced anthracite adsorption capacity. The interaction hierarchy among single-component small-molecule organic compounds and methane is as follows: methyl benzene > tetrahydrofuran > n-hexane. Additionally, in the presence of multi-component small-molecule organic matter, the simultaneous occurrence of methyl benzene and n-hexane or tetrahydrofuran inhibits adsorption due to chemical reactions.

In search of innovative antifungal solutions for the control of plant diseases, a series of cyanoacrylate derivatives containing naphthalene groups were designed and synthesized, and their inhibition activity against four plant pathogenic fungi was evaluated. The results of in vitro bioassay revealed that some target compounds possessed obvious antifungal effect against Fusarium graminearum. As the most prominent one, compound A2 showed a inhibition rate of 98.46 % at 10 µg/mL and an EC₅₀ value of 0.26 µg/mL, which was close to that of the positive control phenamacril (with a inhibition rate of 100 % at 10 µg/mL and EC₅₀ value of 0.14 µg/mL). The compound A2 also markedly inhibited the growth of F. graminearum inoculated on rice leaves at 200 μg/mL with the protective and curative efficiencies of 89.03 % and 90.91 %, respectively, which were close to that of the positive control phenamacril (with the protective and curative efficiencies of 94.54 % and 96.36 %, respectively). The observation under scanning electron microscopy and measurement of relative conductivity revealed that compound A2 caused the hyphal surface become shrunken and rough, and made the cell membrane permeability increased. Molecular docking and molecular dynamics simulation analyses showed that compound A2 interacted with the key residues in the active site of myosin-5 in a similar mode as phenamacril. These results suggested that target compounds were potential myosin-5 inhibitors, they could serve as the lead compounds for further structural optimization to develop new fungicides against F. graminearum.

With the rapid development of global digital economy and aerospace, the gap between the supply and demand of germanium is expanding, and the establishment of a new process for the deep leaching of germanium from hard zinc slag is imminent. In this paper, on the basis of analyzing the reasons for the low germanium leaching rate from hard zinc slag, a new process of germanium leaching enhanced by HNO₃ dissolution of externally wrapped ZnFe₂O₄ is established, and response surface optimization is carried out. The PbggGe₄O₇ phase in hard zinc slag is externally wrapped with ZnFe₂O₄ phase, and the non-reaction between ZnFe₂O₄ and hydrochloric acid is the main reason for the low leaching rate of germanium from hard zinc slag, so it is necessary to add HNO₃ to dissolve the external ZnFe₂O₄ in leaching, and then use hydrochloric acid to leach the PbGe₄O₇ containing germanium in the interior. The potential pH diagram of the Pb-Ge-Cl-H₂O system was also plotted, indicating that increasing the concentration of chloride ions during hydrochloric acid leaching contributes to the generation of GeCl₄ at low acidity. When the hydrochloric acid concentration was 134.65 g/L, the liquid–solid ratio was 6, the theoretical dosage of HNO₃ was 0.3, and the leaching time was 236 min, the optimum leaching rate of germanium was 93.72%, which was 23.72% higher than that of germanium leaching from hard zinc slag.

Carbazole is a heterocyclic aromatic organic compound that has vast applications in pharmaceuticals, and in biological and material sciences. Carbazole derivatives show various biological activities such as antibiotic, anti-inflammatory, anti-tumor and anti-oxidant activities etc. Synthesis of N-arylated carbazoles has become a major area of interest for scientists due to their applications in organic light-emitting diodes, dye-sensitized solar cells, and other organic electronics. The N-arylated carbazoles have unique properties such as high thermal stability, wide band gap, and excellent electrical and optical properties. The methods used for the N-arylation of carbazoles include transition metal-catalyzed reactions and metal-free reactions. The most common and classical methods for the N-arylation of carbazoles are copper-catalyzed Ullmann coupling reactions, while palladium, nickel, and iron catalysts are also used. This review focuses on all the synthetic methods used for the N-arylation of carbazoles and their applications.