INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2023
·
IF 4.2
Qiongqiong Luo,Jinshun Lei,Ziyu Zhuang,Dewen Zeng
The solubility data of the MgF2–MnF2–MnSO4–H2O quaternary system and its subsystems are crucial for the removal of magnesium ions from a MnSO4 aqueous solution as the MgF2 precipitate. However, these data recorded at 298.15 K have not been reported, except for the MnF2–MnSO4–H2O system. In this study, the solubility isotherms of the MgF2–MnF2–H2O, MgF2–MnSO4–H2O, and MgF2–MnF2–MnSO4–H2O systems at 298.15 K and MnF2 solubility in pure water at various temperatures were systematically measured. The results show that MgF2 solubility initially decreases sharply followed by a gradual decrease as the MnF2 concentration increases. MgF2 solubility rises with increasing MnSO4 concentration in pure MnSO4 and the MnF2-saturated MnSO4 aqueous solution. MgF2 solubility in the MnF2-saturated MnSO4 aqueous solution decreases to 2.3–6.5% of its value in the pure MnSO4 aqueous solution at a certain MnSO4 concentration. MnF2 solubility increases with increasing temperatures in the MnF2–H2O system. A Pitzer–Simonson–Clegg model incorporated in the ISLEC software was used to simulate and predict the solubility curves of the MgF2–MnF2–MnSO4–H2O quaternary system and its subsystems. The model satisfactorily represented the solubility data of the subbinary and subternary systems of the MgF2–MnF2–MnSO4–H2O quaternary system within the analysis error, except for the solubility isotherms of the Mg(Mn)SO4·7H2O, Mg(Mn)SO4·4H2O, and Mg(Mn)SO4·H2O solid solutions. The predicted solubility data of the MgF2–MnSO4–H2O system at 298.15 K agree well with the experimental data with a slight deviation of the MgF2–MnF2–MnSO4–H2O system. Based on the established model, the variation of MgF2 solubility curves with the addition of anhydrous MnF2 in MnSO4 aqueous solutions at different concentrations was predicted. The study provides theoretical guidance for removing magnesium ions from a MnSO4 aqueous solution via MgF2 precipitation.
研究领域:
化学工程
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物理化学
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DOI
高影响因子
Frontiers of Environmental Science & Engineering
·
2021
·Vol. 16
·期 8
·1-10
·
IF 4.357
Shen Zhichao,Zhan Lu,Xu Zhenming
Current study proposes a green regeneration method of activated carbon (AC) laden with Perfluorochemicals (PFCs) from the perspective of environmental safety and resource regeneration. The defluorination efficiencies of AC adsorbed perfluorooctanesulfonate (PFOS), perfluorooctanoic acid (PFOA) and perfluorobutanesulfonate (PFBS) using three molten sodium salts and one molten alkali were compared. Results showed that defluorination efficiencies of molten NaOH for the three PFCs were higher than the other three molten sodium salts at lower temperature. At 700°C, the defluorination efficiencies of PFOS and PFBS using molten NaOH reached to 84.2% and 79.2%, respectively, while the defluorination efficiency of PFOA was 35.3%. In addition, the temperature of molten salt, the holding time and the ratio of salt to carbon were directly proportional to the defluorination efficiency. The low defluorination efficiency of PFOA was due to the low thermal stability of PFOA, which made it difficult to be captured by molten salt. The weight loss range of PFOA was 75°C–125°C, which was much lower than PFOS and PFBS (400°C–500°C). From the perspective of gas production, fluorine-containing gases produced from molten NaOH-treated AC were significantly reduced, which means that environmental risks were significantly reduced. After molten NaOH treatment, the regenerated AC had higher adsorption capacity than that of pre-treated AC.
研究领域:
环境科学
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化学工程
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DOI
高影响因子
Molecular Catalysis
·
2023
·
IF 4.6
Xiaoli Wei,Yifan Wei,Jiaqin Lu,Yunfan Huang,Yiwei Sun,Yu Wang,Lijia Liu,Bing Liu,Wenfeng Han
Transforming potent greenhouse gasses, hydrofluorocarbons (HFCs) to hydrofluoroolefins (HFOs) is an environmentally friendly and low energy input route compared with traditional incineration method. During the conversion process, Lewis acidity of the catalysts play a vital role in the activity. Here, inspired by the fluorinated metal oxide, a novel nonmetallic catalyst SiC was fabricated via sequentially mechanochemical treatment and fluorination. With series characterizations, it demonstrated that on the super surface of SiC, there are thin layers of graphite, COOH species, SiO 2 and Si 4 C 4-x O 2 substrates. Through the mechanochemical treatment, the layers of graphite, COOH species and partial SiO 2 could be grinded off. Hence, the exposed SiO 2 residue could be removed via the fluorination by HFC-152a and HF forming volatile SiF 4 . At the same time, the transition layer, Si 4 C 4-x O 2 was fluorinated to Si 4 C 4-x F 2 accompanied with enhanced Lewis acidity. As a result, the activity of the treated SiC was significantly superior than the unmilled SiC. These findings provide a feasible way to develop the catalytic performances of nonmetallic catalysts for the dehydrofluorination.
研究领域:
催化化学
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环境科学
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DOI
高影响因子
JOURNAL OF PROSTHETIC DENTISTRY
·
2023
·
IF 4.6
Yaoxin Wang,Zijing Chang,Ning Ding,Zutai Zhang
Statement of problem Secondary caries is a major factor in the failure of dental restorations . However, studies on the fabrication of acid-resistant and antibacterial dentin to improve dentin bonding are sparse. Purpose The purpose of this in vitro study was to compare the effects of 2 types of fluoride-containing etchants on dentin bonding and explore the feasibility of formulating an altered dentin substrate to improve dentin bonding. Material and methods NaF-containing and SnF 2 -containing etchants were developed by adding sodium fluoride and stannous fluoride to a 35% phosphoric acid aqueous solution. Two groups (N1 and N2) containing NaF, 10 and 30 mg/mL respectively, and 2 groups (S1 and S2) containing SnF 2, 18.6 and 55.8 mg/mL respectively, were formulated. The etchant of the control group (C) was 35% phosphoric acid gel. Scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), Fourier transform infrared spectroscopy (FTIR), microhardness, antierosion, and antibacterial tests were performed on the treated dentin. Moreover, the microtensile bond strength (µTBS) of each group was tested, and the fracture mode was determined after testing. Statistical analysis was performed with the 2-way ANOVA test (α=.05). Results The exposed collagen fiber was observed in group C, and minerals were formed on the dentin in the experimental groups. SEM, FTIR, and the microhardness test indicated more remineralization in the SnF 2 -containing etchant groups. The µTBS of S1 (77.5 ±10.36 MPa) was the highest in all groups, and group C (38.5 ±9.01 MPa) was the lowest. Moreover, the antierosion and antibacterial properties of the S2 group were the best among all groups ( P <.05). Conclusions Compared with NaF-containing etchant, SnF 2 -containing etchant could improve the dentin substrate, increase remineralization, improve bonding strength, and enhance antibacterial ability, especially by increasing resistance to acid erosion.
研究领域:
牙科学
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材料科学
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生物医学工程
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DOI
PubMed
高影响因子
CHINESE JOURNAL OF ANALYTICAL CHEMISTRY
·
2021
·
IF 1.134
Yong-Sheng NIU,Li-Xin SUN,Cong-Wei HU,Jin-Hao ZHOU,Qiang DOU,Qing-Nuan LI
The fluorination behavior of molybdenum (Mo) powder with NF 3 , such as temperature dependence of reactivity, reaction mechanism and kinetics were investigated on a homemade fluoride volatility process (FVP) research device. The in-situ Fourier transform infrared (FTIR) spectroscopy was applied to determine the beginning and the end of reaction. The research demonstrated that near 500 K or lower, the reaction between Mo power and NF 3 occurred, meanwhile, the temperature had an important influence on the average reaction rate and the utilization of NF 3 . When the temperature increased from 500 K to 700 K, the average rate increased from 1.04 × 10 –2 mol/h to 2.40 × 10 –2 mol/h and the utilization of NF 3 increased from 21.2% to 49.0%. The in-situ FTIR and XRD analysis assisted by thermodynamic calculation indicated that Mo power was converted to MoF 6 through an intermediate product MoF 3 : 2NF 3 (g) + 2Mo (s) = 2MoF 3 (s) + N 2 (g), then 2MoF 3 (s) + 2NF 3 (g) = 2MoF 6 (g) + N 2 (g). Based on a mathematical model with unreacted shrinking core, the calculated reaction rate constant increased from 1.77 × 10 –2 min –1 to 3.48 × 10 –2 min –1 in the temperature range of 500–700 K, and the activation energy was 10.13 kJ/mol.
研究领域:
化学工程
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材料科学
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DOI
高影响因子
SCIENCE OF THE TOTAL ENVIRONMENT
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2021
·
IF 7.963
Min Yang,Xiaolei Zhang,Yicheng Yang,Qiang Liu,Long D. Nghiem,Wenshan Guo,Huu Hao Ngo
This study investigated the degradation of perfluorooctanoic acid (PFOA) on zerovalent iron-laden biochar (BC-ZVI) prepared by carbothermal reduction. Results show that over 99% PFOA can be removed by BC-ZVI in hydrothermal conditions under 240 °C within 6 h. The maximum defluorination rate of 63.2% was achieved after 192 h, and this outcome was significantly better than biochar (BC) and zero-valent iron (ZVI) alone. The short-chain perfluorinated compounds (PFCs) and perfluoroheptanal were detected in the liquid phase after degradation, suggesting that the degradation of PFOAs by BC-ZVI followed the Kobel decarboxylation process. XRD and SEM-EDS analyses strongly suggested that carbothermal reduction could avoid the agglomeration of ZVI loaded onto biochar, which helped make the PFOA degradation more efficient. The frontier molecular orbital theory calculated by density functional theory revealed there were two possibilities for ZVI loading on BC (edged or internal loading), while the edge loaded ZVI had a greater tendency to provide electrons for the defluorination of PFOA than internally loaded ZVI.
研究领域:
环境科学
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化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ACS Applied Energy Materials
·
2021
·
IF 6.024
Jun Ban,Xingxing Jiao,Yangyang Feng,Jing Xue,Cheng He,Jiangxuan Song
Lithium/fluorinated carbon (Li/CFx) batteries have received widespread attention due to their high specific energy density. However, the development of Li/CFx primary batteries is seriously hampered owing to the low electrical conductivity and poor wettability against the fluorinated carbon electrolyte. Here, we report a CFx-compatible fluorinated ether-containing electrolyte for all-temperature high-energy-density Li/CFx primary batteries. Specifically, a CFx-philic 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether (TTE) is introduced to the carbonate-based electrolyte as a cosolvent. Benefiting from the low viscosity and low freezing point of TTE, the conductivity and wettability are drastically improved, contributing to a lowered charge-transfer resistance. Thus, the modified electrolyte with TTE endows Li/CFx batteries with high energy density of 850 Wh kg–1 at 25 °C and 745 Wh kg–1 at 55 °C under the current density of 5000 mA g–1, accompanied by high power density of 9931 and 10046 W kg–1, respectively. Even at the freezing temperature of −50 °C, Li/CFx batteries can still exhibit a high middle value of voltage of 1.91 V, and the discharge capacity is 299 mAh g–1 at 100 mA g–1. The improvement of electrochemical performance over a wide temperature range from −50 to 55 °C has greatly expanded the application of Li/CFx batteries.
研究领域:
材料科学
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电化学
·
能源存储
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DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2020
·
IF 6.182
Wenfeng Han,Hong Yang,Linzhe Wang,Bing Liu,Xiaoli Wei,Aimin Chen,Weiyu Song,Haodong Tang,Ying Li
Aluminum fluoride layers (AlFx) were prepared by the in situ etching of Ti 3 AlC 2 with 1,1-difluoroethane at elevated temperatures. During etching, Ti layers were fluorinated to stable TiF 3 interacting with C to confine the Al species and sublimable TiF 4 . Al layers were fluorinated to unsaturated AlFx with relatively weak Lewis acidity. Due to the sublimation of TiF 4 , more AlFx acting as the main active centers were exposed to the reactants, and the surface areas of the confined-AlFx were increased, which contributed to the enhanced activity of the catalyst. The evaluation of the dehydrofluorination reaction showed that confined-AlFx layers presented higher reaction rate than F-γ-Al 2 O 3 and AlF 3 . Besides, it was unexpected that TiF 3 also exhibited activity for the reaction, even though the activity was much lower than confined-AlFx. Finally, the experimental results were confirmed by DFT calculations.
研究领域:
材料科学
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催化化学
✓ 已验证
产品关联
DOI
高影响因子
ELECTROCHIMICA ACTA
·
2025
·
IF 5.6
Sha Zhou,Jing Cao,Ziye Xiang,Yi Liu,Xiaoyu Ma,Min Hu
This study examined the efficacy of tetramethyl ammonium fluoride (TMAF), ethylammonium fluoride (TEAF), and n-butyl ammonium fluoride (TBAF) additives with different chain lengths in soluble lead redox flow batteries. This research explains how the molecular structure of quaternary ammonium fluoride salts affects the performance of soluble lead redox flow (SLRFB) batteries. The fluoride adsorption layer affects electron transfer at the electrode interface was explained. Notably, the addition of TEAF significantly improves the electrodeposition of PbO 2 . Short-chain TMAF increases electrical conductivity but causes lead aggregation. TEAF increases battery Coulombic efficiency to 99.2 % and cycle life by over threefold. This research adopts a chain length-modulated design strategy to compare the influence of chain length on the performance of SLRFB.
研究领域:
电化学
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能源材料
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电池技术
✓ 已验证
产品关联
DOI
高影响因子
Analytical Methods
·
2017
·Vol. 9
·期 47
·6645-6652
·
IF 1.9
Fan Li,Weili Wei,Die Gao,Zhining Xia
This is the first report on the fabrication of oxidized fluorinated graphene sheets supported on silica (OFG@silica) for the selective adsorption of perfluorochemicals (PFCs). To increase the affinity towards PFCs, oxidized fluorinated graphene (OFG) was grafted onto amino-terminated alkyl chain modified silica (NH2-silica), thus producing a mixed-mode material combining fluorophilicity and hydrophobic affinity with anion-exchange properties. The adsorption behavior and mechanism of OFG@silica towards PFCs were explored using a solid phase extraction (SPE) method. For demonstration, several organic analytes including perfluorinated fatty acids (PFFAs), aromatic analytes and fatty acids (FAs) were employed as adsorbates. By analysing the physicochemical properties of analytes, we found that the adsorption amount of analytes was negatively correlated with their molecular acidity coefficient (pKa) and positively correlated with their octanol–water distribution coefficient (log D) at pH 7, suggesting that the anion-exchange effect and hydrophobic affinity played a major role in adsorption. Moreover, compared with FAs, PFFAs exhibited a higher adsorption amount which benefited from fluorous–fluorous interactions between PFFAs and OFG@silica. These findings suggested that OFG@silica might be a potential adsorbent for the enrichment of PFCs.
研究领域:
材料科学
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环境科学
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DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2015
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IF 2.711
Xiaohang Zeng,Yanqiong Ma,Yuechuan Wang
Stabilizing long-term, low energy surface properties is a key issue in designing fluorinated polymer network, because the fluorinated surface could reorganize or hydrolyze upon contact with water. Here we report an exploring to enhance the low energy surface performance by bonding a dangling shell of fluorinated block copolymer, poly((1H,1H,2H,2H-perfluorodecyl acrylate)-b-poly(caprolactone) (PFDA-b-PCL)), to the polyurethane network. The PFDA and PCL block are the fluorinated shell and the dangling chain, respectively. The fluorinated shell protects the surface from rearrangements and hydrolysis when in contact with water, while the soft polyester block provides the required flexibility for fluorinated components to segregate to the surface. Surfaces with water contact angle up to 120° and surface energy down to 18 mN/m were obtained. We then evaluated the effects of fluorinated species on the surface properties of the polyurethane network both with and without the fluorinated shell or polyester spacer. The surfaces functionalized with the fluorinated dangling shell are highly hydrophobic and exhibited better hydrophobic stability. The oligoester spacer connecting the fluorinated shell to the polymer network is critical for the segregation and rebuilding of low energy surfaces.
研究领域:
材料科学
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高分子化学
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产品关联
DOI
高影响因子
POLYMER INTERNATIONAL
·
2020
·Vol. 69
·期 5
·457-466
·
IF 2.574
Haoyang Sun,Tao Li,Fan Lei,Meng Yang,Dandan Li,Xianhang Huang,Dazhi Sun
Fluorographene (FG) with layer numbers of 3–4 was successfully prepared through facile microwave-assisted liquid phase exfoliation of raw graphite fluoride (GrF). The raw GrF and the as-prepared FG were then directly incorporated into polyamide 66 (PA66) by melt processing without using any surfactants. Microstructural, mechanical and tribological properties of the prepared PA66 composites were investigated. Various characterization results showed that both GrF and FG, as novel solid lubricants, can effectively improve the mechanical and anti-wear performances of the PA66 matrix. It was also found that FG is better at improving mechanical properties and reducing the friction of PA66 than GrF at low concentrations owing to the large surface–volume ratio. The addition of 0.5 wt% FG into PA66 exhibits a ca 13% increase in tensile modulus, ca 5% increase in tensile strength, ca 18% reduction in coefficient of friction (COF) and ca 43% reduction in wear rate. However, at relatively high concentrations, such as 1.0 wt%, GrF shows a better reinforcement effect than FG owing to a uniform dispersion of GrF in the PA66 matrix. The addition of 1.0 wt% GrF into PA66 exhibits a ca 18% increase in tensile modulus, ca 5% increase in tensile strength, ca 37% reduction in COF and ca 46% reduction in wear rate. Wear tests also show that the excellent wear resistance of the PA66 composites is due to the improved mechanical properties and the lubrication of GrF and FG between the worn surfaces. Our current work demonstrates the tremendous potentials of fluorinated carbon materials for enhancing mechanical and anti-wear properties of polymeric materials. © 2020 Society of Chemical Industry
研究领域:
材料科学
·
高分子化学
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产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）