Separation of biodiesel and glycerol using a combined process of ultrafiltration polymeric membrane followed by adsorption on passion fruit seed meal

Biodiesel is a biofuel that contributes to a more sustainable world, aligning with the Sustainable Development Goals. However, its purification traditionally relies on wet washing, a process that generates large volumes of effluents and results in the loss of emulsified biodiesel. To address these issues, this study aimed to evaluate the efficiency of a combined and sequential process using polymeric membranes and adsorption with passion fruit seed meal for glycerol removal, offering an alternative to conventional wet washing. First, the reaction mixture, containing 10% acidified water, was fed into a dead-end module with polymeric membranes and ultrafiltered using a regenerated cellulose membrane (30 kDa) under agitation. The resulting permeate was treated with 40 g L-1 of biosorbent at 45 degrees C for 90 min. The results showed that the membrane separation mechanism was promoted by increasing the size of the agglomerate, allowing the efficient retention of glycerol and producing a biodiesel-rich permeate. The final free glycerol content obtained after the combined process was 0.008%, with a total glycerol removal efficiency of 99.98%. The combined process using membrane filtration and adsorption with passion fruit seed meal proved an effective and sustainable alternative to traditional wet washing for biodiesel purification.