CERAMICS INTERNATIONAL
·
2025
·
IF 5.6
Yanzi Tang,Jincui Ren,Weixiang Yang,Yunuo Yang
TaC whiskers were prepared using the molten salt method with Ta 2 O 5 , activated carbon, NaCl/NaF, and nano Ni powders as raw materials. The study examined the effects of the ratios of these raw materials, reaction temperature, and reaction time on the phase composition and microstructure of the TaC whiskers, as well as their growth mechanisms. The results indicated that production and length-diameter ratio of the TaC whiskers initially increased with higher carbon content until a certain point, after which they began to decrease. The prepared TaC whiskers using NaCl as molten salt were acicular and had a low length-diameter ratio. The TaC whiskers prepared by NaF were quadrangular prism-shaped and had a high ratio of length to diameter. Insufficient molten salt resulted in poor diffusion and uneven distribution of the reactants, while an excessive amount led to increased whisker diameters and agglomeration of the TaC whiskers. When the content of Ni was low, there were not enough nucleation points for whisker growth, resulting in only a small quantity of TaC whiskers. Conversely, a high Ni concentration caused a decrease in the length-to-diameter ratio of the whiskers. As reaction temperature rose, both the production and length-diameter ratio of the TaC whiskers first rose and then fell. Prolonging reaction time could increase production and length-diameter ratio of the TaC whiskers. When the molar ratio of Ta:C:F:Ni was 1:4:1:25:0.10, with a reaction temperature of 1300 °C and a reaction time of 2 h, the TaC whiskers exhibited the highest production, purity and length-to-diameter ratio. These whiskers had with an average diameter of 0.8 μm and lengths spanning several microns. The TaC whiskers had a single crystal structure, with their growth direction aligned along the [001] crystal direction. The growth mechanisms of the TaC whiskers were controlled by both the vapor-liquid-solid and solid-liquid-solid mechanisms.
研究领域:
材料科学
·
晶体生长
✓ 已验证
产品关联
DOI
高影响因子
PROCESS SAFETY AND ENVIRONMENTAL PROTECTION
·
2020
·
IF 4.966
Dachao Ma,Liwu Liang,Erfeng Hu,Huaquan Chen,Dongbo Wang,Chao He,Qingge Feng
Hydrothermal treatment (HTT) is able to remove chlorine effectively from polyvinyl chloride (PVC), however, the reaction temperature is critical in practical application. Less energy-intensive hydrothermal dechlorination condition with cupric ion (Cu 2+ ) has been proposed in this study. In particular, Cu 2+ was applied in HTT of PVC at temperature ranging from 200 °C to 240 °C. It has been found that the introduction of Cu 2+ distinctly accelerated PVC decomposition and dechlorination at 220 °C. When Cu 2+ concentration was increased from 0.01 mol/L to 0.20 mol/L, the dechlorination efficiency was significantly improved from 15.46 %–67.89 %. Dramatic dechlorination occurred as residence time was longer than 15 min during HTT. Besides, both elimination and substitution dominated the HTT dechlorinaton. The facilitated dechlorination after the addition of Cu 2+ was mainly due to the enhanced dispersion and formation of micropores in hydrochar. On the whole, HTT could be a promising pretreatment technology for copper-containing PVC in electronic wastes to prepared chlorine free hydrochar for combustion or pyrolysis applications, the optimal HTT condition would be 220 °C, 60 min with 0.1 mol/L Cu 2+ .
研究领域:
环境科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF REFRACTORY METALS & HARD MATERIALS
·
2023
·
IF 3.6
Meng-Chao Li,Lu Wang,Zheng-Liang Xue
The influences of different parameters, such as reaction temperature, yttrium (Y) content, and H 2 concentration, on the particle size and morphological structure of Mo powder prepared via the H 2 reduction of MoO 2 , were investigated in the work. TG, XRD , FE-SEM, laser particle size analysis , model fitting, and orthogonal design experiment methods were adopted to analyze the reaction kinetic and reduction mechanism. The results showed that the optimum conditions for preparing ultrafine Mo powder were recognized as 1073 K, 1 mass% Y content, and a H 2 concentration of 0.000576 mol·cm −2 ·min −1 , which enabled the as-prepared Mo powder with a particle size as small as 107 nm. A new interfacial chemical reaction model with the consideration of reaction temperature, H 2 concentration, and sample thickness, was proposed to analyze the reaction kinetic. It was found that the curves predicted by the model agreed well with the experimental data, with the apparent activation energy extracted to be 94.686 kJ/mol. The effect of different individual parameter on the reaction rate and the possible reduction mechanism were also elucidated.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
MICROCHEMICAL JOURNAL
·
2024
·
IF 4.9
Liming Fu,Cheng Zhang,Haitao Li,Ke Jian,Yunhai Han,Xihui Zhao
Although carbon dots (CDs) are a fluorescent nanomaterial with tremendous development potential, solid-state CDs have not been effectively explored due to the fluorescence quenching effect caused by aggregation. Herein, multi-color tunable aggregation-induced emission (AIE) CDs were constructed using dithiosalicylic acid (DTSA) and ammonium sulfate as raw materials by controlling the reaction temperature. Herein, the AIE behavior of CDs is mainly ascribed to the presence of disulfide bonds, which not only enhance the hydrophobicity of CDs, but also restrict the intramolecular rotation of the aggregated CDs, thus improving the surface state fluorescence of CDs, resulting in solid-state fluorescence (SSF) in longwave emission. More importantly, the emission behavior of the obtained CDs can be regulated by controlling the reaction temperature, which may be due to the synergistic effect caused by the differences in N, S content, functional group ratio, and size distribution of synthesized CDs at different temperatures, meanwhile producing different AIE behavior and fluorescence resonance energy transfer (FRET) efficiency, leading to the corresponding five different colors of AIE CDs . Furthermore, the synthesized AIE CDs have been successfully employed in various applications, including discoloration hydrogel, color-changing anti-counterfeit paper, and efficient latent fingerprints detection with enhanced details.
研究领域:
材料科学
·
化学
·
生物医学工程
✓ 已验证
产品关联
DOI
高影响因子
CLEAN-Soil Air Water
·
2018
·Vol. 46
·期 12
·1800351
·
IF 1.338
Xueqian Wang,Langlang Wang,Zhentao Bian,Ping Ning,Ping Wang,Fei Wang,Yixing Ma
Removal efficiency of elemental mercury (Hg 0 ) over activated carbon (AC) modified with ferric chloride (FeCl 3 ) is investigated at low temperatures. The effects of impregnation concentration, reaction temperature, oxygen content, relative humidity, and hydrogen sulfide (H 2 S) on Hg 0 removal efficiency are investigated. The results indicate that the removal ability of Hg 0 can be significantly improved by the introduction of FeCl 3 . Furthermore, the FeCl 3 -modified AC exhibit the best removal efficiency toward Hg 0 when the concentration of FeCl 3 is 0.15 mol L −1 and reaction temperature is 50 °C. In addition, H 2 S shows a positive effect on Hg 0 removal, while H 2 O(g) can inhibit the removal of Hg 0 due to competitive adsorption. Fe 2 O 3 and C Cl are generated on FeCl 3 -modified AC (with FeCl 3 impregnation concentration of 0.15 mol L −1 ) catalyst and contribute to Hg 0 removal. Moreover, Hg exists mainly in the form of mercuric chloride (HgCl 2 ) and mercuric oxide (HgO) on the surface of the samples. Finally, the removal of Hg 0 is achieved through the following two pathways: by the reaction of Hg 0 with C Cl and reaction of Hg 0 with Fe 2 O 3 .
研究领域:
环境科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
TOXICON
·
2021
·
IF 3.033
Kun Ma,Enjie Diao,Hui Zhang,Shiquan Qian,Peng Xie,Ruifeng Mao,Huwei Song,Liming Zhang
The removal of patulin in phosphoric acid buffer solution by cysteine was investigated. Cysteine could effectively decrease the patulin concentration at high acidic condition (pH 3.0–5.0) with the help of high temperature greater than 90 °C. Three removal mechanisms of patulin by cysteine under high acidic and high temperature conditions were deduced. Reaction temperature, pH of reactive media, molar ratio between cysteine and patulin, and reaction time were all the obvious factors influencing the removal efficiency of patulin, and the increase of any one factor could significantly improve the removal efficiency of patulin. The removal process of patulin could be simulated by the zero-order kinetic model, logarithmic model, and pseudo-first-order kinetic model, respectively, and the corresponding correlation coefficients ( R 2 ) were all greater than 0.90. Presently, this method can only be applied for the removal of patulin in contaminated water from washing fruits in juice processing industry due to the high treatment temperature more than 120 °C and the long detoxification time greater than 1 h.
研究领域:
食品科学
·
生物化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ENERGY & FUELS
·
2021
·
IF 3.605
Hailing Sun,Liyuan Cao,Yuhao Zhang,Liang Zhao,Jinsen Gao,Chunming Xu
The effect of acid concentration and reaction temperature on the reaction of 1-hexene cracking to propylene was investigated. The catalysts with different acid concentrations were prepared by the alkali ion and phosphorus modification of ZSM-5 zeolite. It was observed that both decreasing the concentration of strong Brønsted acid sites (SBASs) and increasing reaction temperatures can enhance the selectivity and yield of propylene and hinder the formation of side products including hydrogen, C1∼C5 alkanes, aromatics, and coke. The hydrogen transfer reaction had an important effect on the selectivity of C3∼C5 olefins in the high concentration of SBASs. Besides, high temperatures intensified monomolecular reactions and hindered bimolecular or multimolecular reactions.On the basis of product distributions, possible main and side reaction routes were summarized under the real industrial reaction conditions. The conclusion was significant to optimize the catalyst design of olefin cracking or pyrolysis processes and operation conditions for increasing the yield of propylene.
研究领域:
化学工程
·
催化科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF SUPERCRITICAL FLUIDS
·
2021
·
IF 4.577
Yuhang Yang,Liang Zhao,Jun Zhang,Runzhou Huang
Experimental analysis and quantitative kinetic modeling were performed on methanol gasification in supercritical water using continuous reactor at different reaction temperatures (550–650 ℃), pressures (21–25 MPa), residence times (6–60 s), and initial methanol concentrations (0.05–0.2 mol L −1 ) to investigate the mechanism underlying methanol gasification and conversion. The kinetic model consisted of eight separate reaction pathways. Simultaneously, reaction rate and sensitivity analyses were conducted. Higher temperatures, longer residence times and lower feedstock concentrations were beneficial for the yields of H 2 and CO 2 . Kinetic analysis showed that H 2 and CO 2 generation mainly occurred through the hydrolysis of methanol. CO was mainly consumed during the forward water-gas shift reaction, and the production of CH 4 depended primarily on methanol methanation. Additionally, methanol hydrolysis was identified as an important elementary reaction for CH 4 production by sensitivity analysis.
研究领域:
化学工程
·
能源科学
✓ 已验证
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2019
·
IF 3.375
Mingyuan Shao,Chaoquan Hu,Jiahan Sun,Shuanghao Xu,Maoqiao Xiang,Qingshan Zhu
This study investigated the dehydrogenation of butane over TiO2-based catalysts prepared by a co-precipitation method. The catalysts were characterized in detail using various surface techniques, such as XRD, XPS, SEM, and pyridine-FTIR. Their performances toward butane dehydrogenation showed that the product distribution was considerably affected by the reaction temperature and the composition of the catalysts. Two different selectivity regions were observed for most of the catalysts. A higher butene selectivity over butadiene was obtained at relatively low temperatures, while an opposite trend was observed at high temperatures. In situ DRIFT measurements did not find an obvious change in the reaction pathway for butane dehydrogenation over the TiO2-based catalysts. The variation in selectivity with temperature can be well correlated with the different types of oxygen species on the catalysts.
研究领域:
催化化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
MOLECULES
·
2024
·Vol. 29
·期 22
·5459
·
IF 4.2
Hao Peng,Zonghui Qin,Guixuan Jin,Jingjing Wang,Jielin Qin,Lihua Ao,Bing Li
In this paper, tartaric acid (C4H6O6) was used as a reductant to treat chromium (VI)-containing solution. Several independent experimental parameters, including reaction temperature, concentration of H2SO4, concentration of C4H6O6and reaction time, on the reduction process were studied. The results showed that 100% of the Cr (VI) could be reduced by C4H6O6in a strong acidic environment under a high reaction temperature. All of the experimental parameters showed positive effects on the reduction process and followed the order [H2SO4] > [C4H6O6] > reaction temperature > reaction time. A higher concentration of tartaric acid and higher reaction temperature could facilitate the reduction process and reduce reaction time.
研究领域:
环境科学
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF LUMINESCENCE
·
2017
·
IF 2.686
Bin Dai,Chengxiao Wu,Yixuan Lu,Degang Deng,Shiqing Xu
The reaction temperature was controlled to investigate the formation process of S-doped CDs (CDs-S). Different low-molecule-weight organics were used as precursors, it reveals that the N and/or S atoms containing in the precursors are related to the formation and luminescence mechanism.
研究领域:
材料科学
·
化学
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2016
·
IF 3.611
Jian Zhou,Yun Xiong,Shihai Xu
In this paper, the PetroOXY method has been mainly used to determine the oxidation stability of biodiesel stabilized with five synthetic antioxidants . The differences in the antioxidant activity of these phenolic compounds could be clearly distinguished with this method. Pyrogallol (PY) and propyl gallate (PG) prove more efficient in inhibiting biodiesel oxidative degradation than butylated hydroxyanisol (BHA) and butylated hydroxytoluene (BHT). BHT and BHA act more efficiently in the PetroOXY test than in the Rancimat method with regard to stabilization factor. Tert -butylhydroquinone (TBHQ) displays the weakest antioxidant activity in PetroOXY, inconsistent with the best stabilizing effects shown in the Rancimat method. The influence of reaction temperature on the induction period is very pronounced. From the plots of logarithm of induction period against temperature, the storage life of biodiesel at ambient temperature can be predicted with the extrapolation method , and the temperature sensitivity of these antioxidants can also be obtained. Changes in the mechanism of the oxidation process with the introduction of antioxidants may give variations in the temperature dependence.
研究领域:
能源科学
·
化学工程
✓ 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）