کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
7808274 | 1501660 | 2018 | 16 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Study of temperature and irradiation influence on the physicochemical properties of Aspirin
ترجمه فارسی عنوان
بررسی اثر دما و اشعه بر خواص فیزیکوشیمیایی آسپیرین
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کلمات کلیدی
آسپرین درمان تجزیه و تحلیل حرارتی، کریستالی مرفولوژی، فوتوکاتالیست،
موضوعات مرتبط
مهندسی و علوم پایه
شیمی
شیمی آلی
چکیده انگلیسی
Pure Aspirin samples were treated with a wide spectrum of light (γ-ray, UV- lamp and sunlight) and 40â¯Â°C temperature at various time of exposure. The changes in the thermal degradation parameters, crystalline structure, morphology and purity due to radiation and temperature treatments of Aspirin were pursued by comparing their TGA, XRD, SEM and HPLC results. The non-isothermal thermogravimetric analysis curves (TG, DTG and DSC) at 10â¯Â°C minâ1 heating rate, under nitrogen flow and overheating range of 25-650â¯Â°C showed two degradation steps for the treated and untreated Aspirin samples. Accordingly, their thermal behavior and thermal stability were determined. Aspirin samples treated with 40â¯Â°C and UV-12â¯h were proven to be of the lowest thermal stability as their TDTG values (166.7 and 168.8â¯Â°C) were lower than that of the untreated sample (TDTGâ¯=â¯181â¯Â°C). The degradation kinetics parameters (i.e. activation energy, pre-exponential factor and order of reaction), life time prediction and thermodynamic parameters (ÎG*, ÎH* and ÎS*) were worked out using the Coats-Redfern (CR) expression and standard equations. The lowest activation energy (104.3â¯kJâ¯molâ1) associated with the highest degradation rate was observed for the UV-12â¯h treated Aspirin sample. Crystallinity percentage was estimated from XRD and DSC, whereas, morphology and purity changes due to treatments were detected by scanning electron microscopy (SEM) and HPLC. The significant change in crystallinity from the XRD results of the treated Aspirin samples occurred in the (32.2%-58.7%) range. The photocatalytic degradation of Aspirin samples before and after treatments was carried out using TiO2/sunlight system. The photocatalytic degradation of all samples followed pseudo first order kinetics and the shelf life, rate of reaction and efficiency of degradation were determined and discussed. The highest degradation percentage (â¼99%) and the associated lowest shelf life (4.3-5.8â¯min) were observed in the photocatalytic degradation of the 40â¯Â°C, UV-12â¯h, γ-ray-aqueous and sunlight treated samples.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Molecular Structure - Volume 1157, 5 April 2018, Pages 364-373
Journal: Journal of Molecular Structure - Volume 1157, 5 April 2018, Pages 364-373
نویسندگان
Hussein M. Al-Maydama, Adlia A. Abduljabbar, Maher A. Al-Maqtari, Khalid M. Naji,