CHEMICAL RESEARCH IN CHINESE UNIVERSITIES
·
2021
·Vol. 37
·期 5
·1137-1142
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IF 1.307
Zhao Lei,Yang Ge,Guo Hailing,Wang Chunzheng,Wang Lijuan,Mintova Svetlana
T he relationship between the concentration of sodium cations and the properties of faujasite(FAU) zeolite was investigated using a two-step synthesis procedure including (1) formation of amorphous aluminosilicate precursors and separation of amorphous nanoparticles, and (2) transformation of these amorphous particles into zeolite crystals by treatment with alkali solutions(NaOH). Three representative samples including two nano-sized zeolites and one micron-sized zeolite were prepared using different concentrations of sodium hydroxide. The crystallization process of these zeolites was studied in detail by Fourier transform infrared(FTIR) spectrometry, nuclear magnetic resonance spectroscopy(NMR), X-ray diffraction(XRD), scanning electron microscopy (SEM), transmission electron microscopy(TEM), and N 2 adsorption. The results indicated that minor changes in the concertation of inorganic cations can significantly shorten the induction period and crystallization time and thus affect the morphology, size and chemical composition of the zeolite crystals.
研究领域:
材料科学
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化学工程
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产品关联
DOI
高影响因子
Entropy
·
2022
·Vol. 24
·期 6
·765
·
IF 2.738
Haopeng Zeng,Yu Zhang,Lei Zhang,Zhaoyang Chen,Xiaosen Li
Depressurization combined with brine injection is a potential method for field production of natural gas hydrate, which can significantly improve production efficiency and avoid secondary formation of hydrate. In this work, the experiments of hydrate production using depressurization combined with brine injection from a simulated excess-water hydrate reservoir were performed, and the effects of NaCl concentration on hydrate decomposition, temperature change, and heat transfer in the reservoir were investigated. The experimental results indicate that there is little gas production during depressurization in a excess-water hydrate reservoir, and the gas dissociated from hydrate is trapped in pores of sediments. The high-water production reduces the final gas recovery, which is lower than 70% in the experiments. The increasing NaCl concentration only effectively promotes gas production rate in the early stage. The final cumulative gas production and average gas production rate have little difference in different experiments. The NaCl concentration of the produced water is significantly higher than that which is in contact with hydrate in the sediments because the water produced by hydrate decomposition exists on the surface of undissociated hydrate. The high concentration of NaCl in the produced water from the reactor significantly reduces the promoting effect and efficiency of NaCl solution on hydrate decomposition. The injection of NaCl solution decreases the lowest temperature in sediments during hydrate production, and increases the sensible heat and heat transfer from environment for hydrate decomposition. The changes of temperature and resistance effectively reflect the distribution of the injected NaCl solution in the hydrate reservoir.
研究领域:
能源科学
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地质学
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化学工程
✓ 已验证
DOI
高影响因子
JOURNAL OF PHYSICAL CHEMISTRY B
·
2010
·
IF 3.471
Shaoling Song,Naifei Hu
In this work, poly(N-isopropylacrylamide) (PNIPAm) films were synthesized on a Au electrode surface through the electrochemically induced free-radical polymerization method. The “coil-to-globule” phase transition of PNIPAm films was sensitive to both environmental temperature and sodium sulfate (Na2SO4) concentration in solution and was detected by cyclic voltammetry (CV) of ferrocenecarboxylic acid (Fc(COOH)) probe. For example, in solutions containing no Na2SO4 at 25 °C, the probe demonstrated a well-defined CV peak pair with large peak currents, showing the “on” state; at 35 °C, the CV response was significantly suppressed, showing the “off” state. By switching the film electrodes in solution between 25 and 35 °C, the CV peak currents cycled between the on and off states, demonstrating the reversible thermosensitive switching function of the films. Similarly, the reversible Na2SO4−concentration-sensitive “on−off” property of PNIPAm films toward Fc(COOH) was also observed. In particular, the influence of temperature and Na2SO4 concentration on the on−off behavior of the films was not independent or separate, but synergetic or cooperative. The dual-responsive property of the films could also be used to switch the on−off bioelectrocatalysis. That is, the electrochemical oxidation of glucose catalyzed by glucose oxidase (GOx) and mediated by Fc(COOH) in solution could be controlled or modulated by changing the surrounding temperature, Na2SO4 concentration, or both. This dual- and synergetic-triggered bioelectrocatalysis based on the “smart” PNIPAm interface system may establish a foundation for fabricating novel multiple factor-controllable biosensors.
研究领域:
生物化学
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材料科学
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分析化学
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产品关联
DOI
PubMed
高影响因子
LWT-FOOD SCIENCE AND TECHNOLOGY
·
2018
·
IF 3.129
Liyuan Fan,Xiao Dong Chen,Ruben Mercadé-Prieto
The dairy industry has long known that highly concentrated alkaline solutions should not be used to clean whey protein rich fouling deposits. At >0.1 mol L −1 NaOH dissolution and cleaning rates decrease markedly to very low values, particularly at low-mid temperatures. It is shown here that it is caused by the incapacity of the hydroxide ion to destroy non-covalent interactions between protein aggregates at high alkali concentrations. HPLC is used to quantify the breakdown kinetics of soluble whey protein isolate (WPI) aggregates. Results show that the large aggregates breakdown kinetic constant is strongly reduced at >0.25 mol L −1 NaOH, but also at high protein concentrations. Moreover, large aggregates become increasingly stable for long times at ≥0.5 mol L −1 NaOH. The kinetic analysis predicts that large protein aggregates would be fully stable at 0.085–0.105 g WPI/g solution, explaining the dissolution threshold observed in macroscopic swelling studies.
研究领域:
食品科学
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生物化学
✓ 已验证
DOI
高影响因子
FOOD HYDROCOLLOIDS
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2020
·
IF 7.053
Hongjie Dai,Xueke Chen,Lin Peng,Liang Ma,Yi Sun,Lin Li,Qiang Wang,Yuhao Zhang
In this study, the interaction mechanism between rosmarinic acid (RA) and myosin and its effect on gel formation during the heating process at different NaCl concentrations were investigated. The results showed that the RA addition improved the strength, water retention and elastic modulus of myosin gel. During the gel formation, the head aggregation of myosin was weakened due to the enhanced hydrophobic interaction and hydrogen bonds between RA and myosin. As temperature increased, the partially oxidized RA could form covalent crosslinking with the sulfhydryl groups of myosin. The interaction between RA and myosin promoted the unfolding of myosin structure, resulting in the reduction of the α-helix content and the exposure of hydrophobic groups of myosin, which accelerated the gel formation of myosin during the heating process. Moreover, the medium-high NaCl concentration facilitated these non-covalent and covalent interactions, thereby improving the gel properties of myosin.
研究领域:
食品科学
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生物化学
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蛋白质化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS
·
2022
·
IF 4.383
Cheng Wang,Jiale Yu,Kai Feng,Huidong Guo,Lipeng Wang
In this study, natural clinoptilolite was treated with NaOH solutions of different concentrations under mild ambient conditions. The composition and structure of the as-prepared samples were characterized, and their performance was assessed in terms of the removal of the heavy metal ions Cd 2+ , Cu 2+ , and Cr 3+ from the aqueous solution. The results showed that the composition, structure, and capability of removal of heavy metal ions of the samples were significantly influenced by the NaOH concentrations. The crystal structure of clinoptilolite remained invariant under a relatively low NaOH concentration (≤0.5 M), began transforming into zeolite Na–P under a medium NaOH concentration (∼1.0 M), and then completely transformed into it under a high NaOH concentration (2.0–4.0 M). The samples treated with NaOH had lower SiO 2 /Al 2 O 3 ratios, and were superior to unmodified natural zeolite in removing the heavy metal ions. This method of treatment with relatively high concentrations of NaOH is a simple and effective way to transform natural clinoptilolite into the zeolite Na-P rich ion exchanger, which is suitable for removing heavy metal ions.
研究领域:
环境科学
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材料科学
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产品关联
DOI
高影响因子
NEW JOURNAL OF CHEMISTRY
·
2023
·Vol. 47
·期 16
·7722-7732
·
IF 3.3
Liran Tian,Xiangwei Song,Tianjiao Liu,Anfeng Li,Yang Ning,Xiuyi Hua,Deming Dong,Dapeng Liang
Based on the specific identification ability of aptamers towards a target, a combined UV-Visible with fluorescence detection method for acetamiprid was designed. In the absence of acetamiprid, AuNPs were uniformly distributed and had a good quenching ability for Rhodamine B's fluorescence at a higher NaCl concentration. In the presence of acetamiprid, a few AuNPs lost their protective effect and aggregated, meanwhile, the absorption peak of the UV-vis spectrum gradually redshifted from 520 nm to 680 nm. Additionally, the quenching effect of AuNPs on Rhodamine B was diminished when aggregation took place. Thus the presence of acetamiprid could be clearly determined using a UV-vis or fluorescence method. The combination of the two routes had a wider detection range and a detection limit as low as 0.0559 μM. This method was successfully used to determine acetamiprid in spiked lake water samples and would be a potential simple method for the determination of acetamiprid residues in natural water bodies.
研究领域:
分析化学
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环境科学
·
纳米技术
✓ 已验证
产品关联
DOI
高影响因子
Toxics
·
2024
·Vol. 12
·期 11
·808
·
IF 3.9
Dongmei Yang,Jiale Huang,Fenli Min,Huixian Zhong,Jialu Ling,Qun Kang,Zhaohua Li,Lilian Wen
In this study, samples from the Yangtze River, Han River, and Liangzi Lake in Wuhan City were utilized to characterize the formation of disinfection by-products (DBPs) from chlorine-based disinfection residues in drinking water sources. The results indicated that the main DBPs in drinking water sources were trichloromethane (TCM) and trichloroacetic acid (TCAA). The generation of DBPs was significantly positively correlated with oxidative substances, aromatic compounds, pH, and ammonia nitrogen (NH 3 -N) content in the water. The concentration of TCAA increased from 0 to 2.45 ± 0.31 mg/L when the reaction time increased to 72 h. As the NaClO concentration increased from 5 mg/L to 15 mg/L, the concentrations of TCAA, TBM, and DCAN increased from 2.03 ± 0.04 mg/L, 0 mg/L, and 0 mg/L to 2.49 ± 0.34 mg/L, 0.21 ± 0.07 mg/L, and 0.10 ± 0.04 mg/L before decreasing to 1.75 ± 0.19 mg/L, 0.17 ± 0.07 mg/L, and 0.04 ± 0.05 mg/L, respectively. The orthogonal experimental results showed that Br − , NH 3 -N, and pH all had significant influences on the TCM generation, whereas temperature affected the formation of TCAA in the Han River. This work reveals the factors influencing the generation of DBPs from chlorine-based disinfection residues, offering a prevention and control method for DBPs in drinking water sources from a theoretical perspective.
研究领域:
环境科学
·
水处理
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公共卫生
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化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Cleaner Production
·
2023
·
IF 11.1
Shicheng Yuan,Hui Hu,Hao Huang,Zhongming Chen,Jiaxin Chen,Mi Zhang,Kunpeng Li,Ting Zhou,Ruibin Lv
Chlorobenzene (CB) is an important organic chemical material that is volatile and difficult to degrade, and has received much attention because of its strong ozone generation potential. An electrochemical-sodium peroxydisulfate (PDS) system was constructed and the oxidation reaction path of chlorobenzene in this system was analyzed. The effects of current density, PDS concentration, initial pH, CB blow-off gas ratio and temperature on the oxidation and mineralization rate of chlorobenzene in the system were investigated respectively. At a current density of 168 A/m 2 , a PDS concentration of 0.5 mol/L, an initial pH of 10, a CB blow-off gas ratio of 20% and a reaction temperature of 60 °C, the CB conversion and mineralization rates were able to reach more than 90%. The results of electron paramagnetic resonance (EPR) experiments using 5,5-dimethyl-1-pyrroline N-oxide (DMPO) and 2,2,6,6-tetramethyl-4-piperidone hydrochloride (TEMP) as spin trapping agents indicate the presence of ⦁OH, · S O 4 − and 1 O 2 in the system. The signal of · O 2 − was also captured after the quenching of ⦁OH, which further indicates the presence of 1 O 2 . And the results of active substance quenching experiments showed that the active species that mainly contributed to the oxidation of chlorobenzene included ⦁OH, · S O 4 − and 1 O 2 , and their contributions to the oxidation of chlorobenzene were 25.0%, 31.7% and 22.2%, respectively. The Liquid Chromatograph Mass Spectrometer (LC-MS) characterization results showed that the formation of chlorophenol and hydroquinone and their ring-opening reactions were the most critical processes in the oxidative decomposition of chlorobenzene, and the reaction pathways for the oxidation of chlorobenzene by ⦁OH, · S O 4 − and 1 O 2 were proposed by these characterization results.
研究领域:
环境科学
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化工工程
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分析化学
✓ 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）