CRYSTENGCOMM
·
2020
·Vol. 23
·期 3
·671-677
·
IF 3.117
Sanzhao Song,Jian Sun,Jing Zhou,Chengzhi Guan,Zhiwei Hu,Ting-Shan Chan,Xian-Long Du,Xiao Lin,Jun Hu,Linjuan Zhang,Jian-Qiang Wang
Molten salts have been reported to be excellent media for the preparation of multicationic oxides, which require harsh conditions to crystallize. Molten salt synthesis provides a wider operational temperature range (usually extends to 1000 °C) and faster mass transport and nucleation processes, thus allowing the preparation of crystalline solids, which require higher temperatures, such as perovskites. However, the mechanisms that control the solid-state formation and phase selection are poorly understood. Herein, several typical molten alkali metal halide (Cl−) and oxosalt (CO32− and SO42−) systems were employed as the reaction media for the synthesis of LaCoO3 (LCO) crystals, and the effects of ionic salt species on the morphological, geometric and electronic structures of LCO crystals were examined by using X-ray diffraction (XRD), scanning electron microscopy (SEM) and X-ray absorption spectroscopy (XAS). The LCO perovskite was successfully synthesized in a molten NaCl–KCl eutectic mixture at 700 °C, which was lower than that used for the conventional mixed oxide synthesis. Our results show that in the molten salt synthesis, the type of reaction medium, calcination temperature, the ratio of salt, and reaction time govern the microscopic mechanisms in the preparation of multicationic oxides. Most importantly, we observed that LaOCl was formed as an intermediate, which plays a key role in the reaction pathway for the phase-selective synthesis of perovskite LCO.
研究领域:
材料科学
·
化学
✓ 已验证
产品关联
DOI
高影响因子
Geoenergy Science and Engineering
·
2024
·
IF 0
Shuai Liu,Yuan Geng,Chao Li,Min Hu,Jiang Liu,Qi Gao,Xingguang Xu
Enhancing oil recovery (EOR) from sandstone reservoirs with high formation salinity and high temperature has gained prominence as most of the easy-to-produce oil has already been produced.It has been approved that the surfactants-assisted nanofluids (SAN) perform well as a viable EOR technique. Most of the studies have macroscopically presented that surfactants-assisted nanofluids (SAN) can enhance oil recovery by reducing interfacial tension and wettability alteration. The effect of nanoparticles on the phase behaviour of microemulsions and the mechanism of surfactants-assisted nanofluids (SAN) to enhance oil recovery at the micro-scale are not clear. In this study, the performance in EOR of alcohol ethoxylate (AEO-15)/sodium alpha-olefin sulfonate (AOS) and hydrophobic nanoparticles (S16) was analysed. 2D visualization experiments systematically elucidated the mechanism of surfactants-assisted nanofluids (SAN) mobilisation of residual oil in the pores. Dynamic light scattering and zeta potential measurements showed that when the S16 concentration was less than 0.1 wt%, the SAN remained stable at 70 °C with a particle size of 64.27 nm and a zeta potential of −30.88 mV.Contact angle and adsorption experiments demonstrated that the addition of 0.1 wt% S16 decreased the contact angle by 21.72°, making the rock surface more water wet and the surfactants adsorption on the sample surface was decreased by 16.9%. The microemulsion induced by the SAN had lower interfacial tension (IFT) and exhibited wider “salinity window” compared to the surfactants-induced microemulsions, which might make the proposed SAN more applicable in reservoirs with high salinity and residual oil saturation. Furthermore, spontaneous swelling of trapped oil in the dead end and elongation of oil droplets were clearly observed in 2D visual microscopic model during the SAN flooding, which somehow explained the exceptional EOR performance of the developed SAN in the core flooding experiment at 70 °C and 80 g/L of salt. This study is expected to provide useful insights into the development of SAN involving hydrophobic nanoparticles and deepen the EOR mechanism of SAN at the microscopic scale.
研究领域:
石油工程
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化学工程
·
材料科学
✓ 已验证
产品关联
DOI
ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY
·
2021
·
IF 6.291
Wenyan Shi,Yuting Chu,Mingzhu Xia,Fengyun Wang,Chenlu Fu
MoS 2 /montmorillonite (MoS 2 /Mt) composite was successfully synthesized through a simple hydrothermal method, and its adsorption performance for two emerging contaminants-atenolol (ATE) and acebutolol (ACE) was researched. The batch experiments revealed that the adsorption process can be described by the Pseudo-second order model and Langmuir model, and the adsorption capacity of MoS 2 /Mt, MoS 2 and Mt for ATE were 132.08 mg/g, 60.68 mg/g and 74.23 mg/g, for ACE were 113.82 mg/g, 33.01 mg/g and 36.05 mg/g, respectively. Besides, Fourier-transform infrared spectroscopy (FTIR), BET specific surface area measurement and X-ray photoelectron spectroscopy (XPS) were also employed to analyze the adsorption mechanism. Moreover, quantitative molecular surface analysis and weak intermolecular interaction analysis with independent gradient model were combined to probe the microscopic interaction between the adsorbent and adsorbate. The results indicated the interactions included hydrogen bonding and vdW interaction. Mt and MoS 2 interacted more strongly with ATE than ACE, which revealed the reason MoS 2 /Mt, Mt and MoS 2 possessed higher adsorption capacity for ATE.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
TRANSACTIONS OF TIANJIN UNIVERSITY
·
2018
·Vol. 25
·期 1
·52-65
·
IF 0
Li Wang,Zhang Qingjun,Zeng Aiwu
In this study, liquid-phase aerobic oxidation of toluene catalyzed by Mn–Mo oxide was conducted in a 1.0 L batch reactor. The macroscopic kinetics of toluene consumption and benzaldehyde generation at 413–443 K were obtained from a combination of experimental observation and hypothetical models. The results clearly showed that both the oxidation rate of toluene and generation rate of the aromatic product were proportional to the concentration of the substrate, the partial pressure of oxygen and the surface area of the catalyst. The energy barrier of toluene oxidation to benzyl alcohol was the highest (≈ 81 kJ mol −1 ), while that of benzyl alcohol oxidation to benzaldehyde was the lowest (≈ 57 kJ mol −1 ). Moreover, the activation energy of further oxidation of benzaldehyde in an acetic acid solvent was only slightly lower (≈ 1.9 kJ mol −1 ) than that of toluene oxidation. Significantly, the transformation of benzyl alcohol indeed contributed to the generation of benzaldehyde and this step conformed to a first-order parallel-consecutive model. Increased reaction temperature and residence time favored the transformation of benzyl alcohol to benzaldehyde. In addition, doping with molybdenum at Mn/Mo = 3/1 enhanced the catalytic performance of the heterogeneous catalyst and was attributed to the presence of a synergetic effect between different metal cations. Regarding the microscopic kinetics, the LH-OS-ND mechanism (Langmuir–Hinshelwood adsorption of reagents on the same type of active sites and non-dissociative adsorption of oxygen) was verified as responsible for the heterogeneous oxidation of toluene. Oxygen and benzaldehyde were weakly adsorbed (Δ H ads,Oxy ≈ − 15 kJ mol −1 , Δ H ads,Bald ≈ − 30 kJ mol −1 ), but showed strong mobility (Δ S ads,Oxy ≈ − 22 J mol −1 K −1 ), Δ S ads,Bald ≈ − 39 J mol −1 K −1 ). The fundamental intrinsic rates were deduced based on the LH-OS-ND mechanism and showed great consistency with the macroscopic results.
研究领域:
化学工程
·
催化科学
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物理化学
✓ 已验证
产品关联
DOI
ACS Omega
·
2021
·
IF 3.512
Jie Tang,Guohua You,Lu Ruan,Yi Lu,Bianying Wen,Sizhu Wu
Natural antioxidants are essential potential sources for protecting the oxidation of food oils. However, until now, the mechanisms are still not very clear, especially from the quantitatively theoretical level to analyze the antioxidant behavior. In this work, the micromechanisms of the antioxidant behavior affected by polarity in the olive oil were systematically investigated by experimental and computational methods. The results showed that the polarity of antioxidants decreased with the growth of the alkyl chains, which had multiple impacts on the effectiveness of antioxidants. The excessive polarity gap between the antioxidant and oil molecules would cause the antioxidant to be dispersed at the oil–air interface, which could enhance their antioxidant ability. Meanwhile, the antioxidants with longer alkyl chains had lower polarity and better dispersibility but decreased mobility. Hence, compared with other antioxidants, medium polarity antioxidants presented both good dispersion and relatively suitable migration, indicating that they would have an optimal antioxidant effect.
研究领域:
食品科学
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化学
·
分子模拟
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CONSTRUCTION AND BUILDING MATERIALS
·
2025
·
IF 8
Mei Deng,Wenli Zhang,Xinli Gan,Xuejuan Cao,Boming Tang,Xinqiang Zhang
Asphaltene aggregates depolymerization is a critical factor in aged asphalt rejuvenation, yet the impact of major rejuvenator components remains unclear due to asphaltenes’ complex structure. Unlike previous simulation-based investigations, this study employs various characterization techniques to reveal asphaltene aggregate behaver during oxidative aging and the microscopic depolymerization mechanism and structure-activity relationships of 10 representative bio-based and petroleum-based rejuvenator compounds. The results revealed that oxidative aging increased the stacking density and order of aromatic layers within asphaltene aggregates and promoted O-H···O hydrogen bond formation. Additionally, oxidation reduced the critical micelle concentration of asphaltenes and caused fluorescence quenching, resulting in the development of dendritic three-dimensional aggregates with equidistant, layered, and porous structures. However, the introduction of rejuvenators disrupted the stacking of aromatic layers but had minimal impact on the arrangement of aliphatic chains. Rejuvenators containing heteroatoms further promoted depolymerization by forming hydrogen bonds with asphaltene molecules, reducing the aggregate size and producing more dispersed and irregular structures. The bio-rejuvenators with heteroatom functional groups exhibited superior depolymerization efficiency. This study provides mechanistic insights into rejuvenator-induced asphaltene depolymerization and establishing a foundational reference for the molecular design of efficient rejuvenators in recycled asphalt applications.
研究领域:
土木工程
·
材料科学
·
化学工程
·
高分子科学
·
石油工程
✓ 已验证
产品关联
DOI
高影响因子
WATER AIR AND SOIL POLLUTION
·
2021
·Vol. 232
·期 2
·1-15
·
IF 2.52
Zhang Hongling,Shi Mingxing,Xia Mingzhu,FengyunWang,Zhao Feng
Previous researches investigated the adsorption properties and mechanism of clay minerals on antibiotic pharmaceuticals and personal care products (PPCPs) via batch adsorption experiments and X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) characterization, but many PPCPs exhibit different ionization states under different pH conditions; the research on the microscopic mechanism of different ionized PPCPs species adsorbed by clay minerals is very scarce. In this work, as a typical PPCPs contaminant, the common tetracycline (TC) was chosen as the study target; the adsorption micro mechanism of montmorillonite (MMT) on different TC species in aqueous solution was explored in details. Especially outstanding, for the first time, with the help of Multiwfn wavefunction program, quantitative analysis of molecular surface analysis and basin analysis were applied to quantitatively investigate the electrostatic interaction between MMT and different TC species, the possible positions of lone pair electrons. Independent gradient model (IGM) analysis and Hirshfeld surface analysis including local surface analysis were integrated to visualize the binding sites, interaction types, and relative strength between MMT and TC +/− or TC +/2− species, which can insight into the interaction essence from the microscopic perspective at the atomic level.
研究领域:
环境科学
·
化学
·
材料科学
·
药学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）