An ultrasonic-accelerated oxidation method for determining the oxidative stability of biodiesel

作者:Avila Orozco Francisco D; Sousa Antonio C; Domini Claudia E*; Ugulino Araujo Mario Cesar; Fernandez Band Beatriz S
来源:Ultrasonics Sonochemistry, 2013, 20(3): 820-825.
DOI:10.1016/j.ultsonch.2012.10.012

摘要

Biodiesel is considered an alternative energy because it is produced from fats and vegetable oils by means of transesteriflcation. Furthermore, it consists of fatty acid alkyl esters (FMS) which have a great influence on biodiesel fuel properties and in the storage lifetime of biodiesel itself. The biodiesel storage stability is directly related to the oxidative stability parameter (Induction Time - IT) which is determined by means of the Rancimat (R) method. This method uses condutimetric monitoring and induces the degradation of FAAS by heating the sample at a constant temperature. The European Committee for Standardization established a standard (EN 14214) to determine the oxidative stability of biodiesel, which requires it to reach a minimum induction period of 6 h as tested by Rancimat (R) method at 110 degrees C. In this research, we aimed at developing a fast and simple alternative method to determine the induction time (IT) based on the FAAS ultrasonic-accelerated oxidation. The sonodegradation of biodiesel samples was induced by means of an ultrasonic homogenizer fitted with an immersible horn at 480 Watts of power and 20 duty cycles. The UV-Vis spectrometry was used to monitor the FMS sonodegradation by measuring the absorbance at 270 nm every 2. Biodiesel samples from different feedstock were studied in this work. In all cases, IT was established as the inflection point of the absorbance versus time curve. The induction time values of all biodiesel samples determined using the proposed method was in accordance with those measured through the Rancimat (R) reference method by showing a R-2 = 0.998.

  • 出版日期2013-5