Electrostatic field and nano-adsorbent refining of fatty acid methyl esters

Abstract

Conventional crude fatty acid methyl ester (FAME) refining requires the use of expensive infrastructure, demands large water inputs, generates substantial amounts of waste, and is associated with substantial amounts of loss of FAME. In this study, electrostatic field (E-field) and nano-adsorbents were employed as novel tools in refining crude FAME. A reduction (37.6%) in soap content was immediately observed after treatment via E-field; however, total glyceride content remained unchanged. Soap content in crude FAME was further significantly reduced through the addition (<4 wt %) of nano-adsorbents (Al2O3, SiO2, and TiO2) in 6 min, with minimal agitation (≤600 rpm), and at ambient temperature. After adsorption, the spent Al2O3, SiO2, and TiO2 nano-adsorbents were successfully removed from FAME via E-field treatment, as observed by a reduction of 79.3 wt %, 75.4 wt % and 19.0 wt %, respectively. In addition, minimal FAME loss (0.66 wt %) was observed when using E-field treatment. Similarly, nano-adsorbent treatments were reported causing FAME loss of 0.45 wt %, 2.7 wt %, and 2.1 wt % for Al2O3, SiO2, and TiO2 nano-adsorbents, respectively. Furthermore, none of these treatments affected the FAME profile and, therefore, it is likely that exposure to the E-field did not affect FAME chemistry. The Al2O3 nano-adsorbent was successfully washed and reused for refining FAME. Altogether, crude FAME refining utilizing both E-field and nano-adsorbents treatment technologies offers distinct advantages as alternatives to conventional FAME refining methods.