Journal of Liaoning Petrochemical University
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The Effect of Precipitators on the Texture Properties and CO Catalytic Oxidation Performance of CuO/CeO 2 Catalysts
Dongbei YU, Xue LI, Xinyu YANG, Caishun ZHANG, Jiao HAN, Honghao WANG, Lei ZHANG, Zhixian GAO
Abstract80)   HTML5)    PDF (839KB)(85)      

Catalysts CuCe?OH and CuCe?CO3 were prepared by hydrothermal method using KOH and K2CO3 as precipitating agents. The catalyst was characterized by XRD, BET, H2?TPR and TG?DTA, and its CO catalytic oxidation performance was evaluated by a fixed bed reactor. The results show that the type of precipitator not only has a great influence on the texture properties of the catalyst, but also determines whether the CuCe catalyst without heterocrystalline phase can be successfully prepared. The specific surface areas of CuCe?OH and CuCe?CO3 catalysts were 96.5 m2/g and 17.3 m2/g, respectively. Under the evaluation conditions of 60 000 mL/(g·h), CO volume fraction of 0.6%, O2 volume fraction of 1.5%, Ar volume fraction of 97.9%, CuCe?OH catalyst showed good catalytic activity, and CO conversion reached 99.0% at 140 ℃.

2023, 43 (6): 48-53. DOI: 10.12422/j.issn.1672-6952.2023.06.008
Determination of Flavonoids From Codonopsis Pilosula With Spectrophotometer
WANG Qing-ming, ZHANG Jin-sheng, LI Li-hua, XUE Li-min
Abstract410)      PDF (195KB)(294)      
Flavonoids were extracted from codonopsis pilosula with microwave-assisted method, and its content was determined by spectrophotograpy. Two methods with NaNO2-Al(NO3)3 or AlCl3 as the chromogenic agent were performed and the precision, stability, reproducibility and recovery ratio of the two methods were studied. The results show that the AlCl3 colorimetric determination of flavonoids in codonopsis pilosula was simple, convenient, accurate and reliable as compared with the NaNO2-Al(NO3)3 colorimetric determination method.
2010, 30 (4): 4-07. DOI: 10.3696/j.issn.1672-6952.2010.04.002
Determination of Flavonoids From Codonopsis Pilosula by Microwave-Assisted Extraction and Spectrophotometer
WANG Qing-ming, ZHANG Jin-sheng, LI Li-hua, XUE Li-min
Abstract499)      PDF (209KB)(228)      
 
Flavonoids were extracted from Codonopsis pilosula by microwave-assisted extraction and its contents were determined by spectrophotometer. The extraction rate of flavonoids were investigated by single factor experiment included alcohol volume fraction, ratio of material to liquid, extraction temperature, and extraction time. The best conditions for procedure were as follows: extracting time is 15 min, extracting temperature is 85 ℃, the volume fraction of ethanol is 70%,  and material to liquid ratio is 1∶30. Under the optimal conditions, the amount of flavonoids in codonopsis pilosula was 2.87%, RSD=0.878%(n=5), and their recovery is between 99%~102%.
2010, 30 (2): 8-10. DOI: 10.3696/j.issn.1672-6952.2010.02.003