Obtención de un catalizador de óxido de cinc a partir de pilas C-Zn usadas para la elaboración de biodiesel con aceite vegetal reciclado

Abstract

In the present research work supported zinc oxide catalyst was made out of spent Zn-C batteries in order to elaborate biodiesel with recycled vegetable oil. To carry out this process recollection of batteries were made first at the company ETAPA EP, after they were dismantled and their components were separated (zinc, manganese oxide and carbon rod). The zinc casing had a hydrolysis process that consisted of acid lixiviation, purification, crystallization and calcination; resulting in a zinc oxide catalyst out of this process. The carbon rod was treated with nitric acid. Then the catalyst was impregnated in the rod by solvent evaporation. After, recycled vegetable oil had a treatment also obtained from ETAPA EP; which consisted of filtering, washing and drying. In order to obtain biodiesel treated vegetable oil and ethanol was used in a molar ratio of (6:1), the reaction took at 230ºC for 1 hour with constant agitation. The zinc oxide was used as a catalyst in 5% W/W both supported and unsupported. Catalyst was characterized by UV-Visible spectrophotometer, which measured the particle size. Zinc oxide purity was determined by an atomic absorption spectrophotometer resulting in 98.49%. In addition, yield of the catalyst production was 56%. Likewise, BET (Brunauer, Emmett y Teller) analysis has been done in order to know the superficial area and pore size of the carbon rod, obtaining 1.927 m2/g and 0.7894 cm3/g respectively. In biodiesel samples, calorific power, water quantity, viscosity, density and yield were determinate. Having as results 37 553 J/g, 0.005%, 4.1887 mm2/s, 0.8916 g/cm3 and 70.908% respectively. All of those results are within in the range given by the regulations INEN 2482, ASTM B 100 and EN 590. It is worth to say that blank did not meet the aforementioned parameters by the regulations, additionally its yield was of 5%. The research showed that a high purity catalyst was obtained and the process can be optimized to improve the yield. The catalyst doesn´t need size reduction because the pores´ support are in macro scale. A better result was obtained at density, viscosity and reaction yield when a supported catalyst was used, but not so with calorific power. Biodiesel yield was higher compared with other authors that used the same catalyst