Use of residual clay recovered as adsorvent medium of frying oil for production of biodiesel

Abstract

In order for the oils to achieve the desired sensory quality, they undergo refining steps. Clarification is one of these steps, where clarifying clays are used in which natural undesired pigments adhere to the oil, making it visually more attractive to consumers. The problem is the incorrect disposal given to these clays wich are disposed of in landfills causing damage to the environment. Similarly, waste frying oils cause problems when disposed of in sinks and drains, compromising groundwater. Thus, a solution to this drawback would be the production of biodiesel, since it is produced through oils and fats, even in a state of deterioration provided that the physicochemical quality standards are met. The objectives of this work were to thermally activate the residual clay, to purify the residual oil in this recovered clay and to produce via biodegradable residual oil and purified oil biodiesel. All physicochemical analyzes were performed according to official methodologies and the near infrared (NIR) spectra were treated by Principal Component Analysis (PCA). Physicochemical analyzes were performed after thermal activation of the clay. Results were obtained of humidity of 1.07%, acidity of 0.16 g oleic acid.100g^-1 and peroxides 19.01 meq.kg^-1. For the insoluble in ether, no significant values were obtained, besides the difference between the recovered residual clay and virgin clay by the NIR technique. With the results, the acidity values in the purified oil and residual oil remained within the standards, stipulated by the National Health Surveillance Agency (Anvisa), but the peroxide index above the recommend values, showing that the oil was deteriorating. It is concluded that thermally activating the clay from the industrial process together with the residual oil is a good alternative for its reuse, as it contributes to the fact that this material is not lost and possibly incorrectly discarded and halso has advantages over the production of biofuel by acid transesterification.