Selective adsorption of fatty acid methyl esters onto a commercial molecular sieve or activated charcoal prepared from the <em>Acrocomia aculeata</em> cake remaining from press-extracting the fruit kernel oil

Abstract

Mixing light biodiesel at low concentrations (not exceeding 5% by volume) with mineral kerosene is thought to be an interesting alternative to aviation fossil fuels without the need for engine adjustments. From the environmental point of view, this addition would mean significantly minimizing the impacts of conventional fuel emissions. The adsorption of relatively short molecular chain (C8, C10 and C12) fatty acid methyl esters (FAME), constituents of the biodiesel produced from the macaúba oil, was investigated using two types of adsorbents: A commercial molecular sieve 13X and the activated charcoal prepared from the macaúba cake remaining after press-defatting the macaúba fruit kernel. The adsorption experiments were performed on a glass column filled with the adsorbent. The activated charcoal is more efficient than the molecular sieve for selectively adsorbing FAME with C8, C10 and C12 carbon chains. The process of separating shorter chains from biodiesel by adsorption was proven to be adequate and does not compromise the energy balance. This study indicates that the charcoal obtained from the macaúba cake remaining after extracting the oil might be suitable for the selective separation of fatty acid esters, which could potentially lead to the preparation of lighter biodiesel (of lower average molecular weight) than that produced from the crude oil.

Keywords

• biodiesel
• oil
• transesterification
• fatty acids
• adsorption
• activated charcoal