Fouling of polymeric membranes during degumming of crude sunflower and soybean oil

Abstract

Membrane separation is an optional technology to replace the conventional degumming step during the processing of vegetable oils. In this work, the performance of an asymmetric membrane of polyvinylidenfluoride (PVDF) during the degumming of a crude vegetable oil/hexane mixture was investigated. Samples of soybean and sunflower oil were treated and the effect of oil source on membrane fouling was evaluated. The water and hexane membrane permeability were assessed by permeation experiments and their values were used to explain the membrane behavior. The degumming tests were performed in a stirred dead-end cell, at different temperatures and pressures. Retention of phospholipids (selectivity) was greater than 95% in the whole range of studied conditions (2 bar < Δ P < 6 bar; 30 °C < T < 50 °C). The results showed that degumming of sunflower oil produced a higher membrane fouling than degumming of soybean oil.