Ceramic membranes (Al2O3/TiO2) used for separation glycerol from biodiesel using response surface methodology

The separation of glycerol from biodiesel in accordance with ASTM standards is critical. Conventional separation technology has not proven to be effective. Membrane technology is a viable and environmental friendly method of separating impurities from biodiesel. In this study, application of three different sizes ceramic membranes for separating glycerol from biodiesel is evaluated. The impact of process parameters such as average pore size, pressure and ethanol concentration on glycerol separation is evaluated using design expert software. The main aim of the present study is to address the separation and optimization of free glycerol from biodiesel using response surface methodology in combination with central composite design. Three pore-sized ceramic membranes (0.1, 0.2, and 0.3 µm) were used in this study to achieve complete retention of free glycerol from biodiesel. Response surface methodology was used to optimize process parameters such as average pore size, pressure, and ethanol concentration. At a pore size of 0.2 µm, 3 bar pressure, and 10% wt. ethanol concentrations, 99.8 percent glycerol retention was obtained under optimal conditions. The free glycerol was separated from the biodiesel in compliance with international standards.