Application of polymeric solvent resistant nanofiltration membranes for biodiesel production

The potential of incorporating polymeric solvent resistant nanofiltration (SRNF) membranes for biodiesel separation processes was investigated. Eight types of commercial polymeric nanofiltration membranes (Solsep 030705, Solsep 030306F, Starmem 240, Starmem 120, Desal-DL, Desal-DK MPF-34 and MPF-44) were chosen and screened for their abilities to separate the methyl esters-rich effluent (biodiesel) from the mixture of the homogeneous catalyst, free glycerin and excess methanol after the transesterification process at various separation pressures and constant temperature. Scanning Electron Microscope (SEM) and Fourier Transform Infrared Spectroscopy (FTIR) were used to examine any changes to all the membranes studied. In order to enhance the SRNF membrane performance, the transesterification product properties was modified by reducing the alkalinity value. Results showed that for 3 membranes (Solsep 030705, Solsep 030306F, Starmem 240), the permeability of transesterification product after the alkalinity modification increased linearly to the operation pressures. The other 5 membranes namely Starmem 120, Desal-DL, Desal-DK, MPF-44, MPF-34 membranes gave dismal results. Out of the eight tested membranes, it was found that Solsep 030705 membrane gave the most promising result. Analysis of the used membranes showed minor differences on functional groups after the application.