Improvement of glycerin removal from crude biodiesel through the application of a sulfonated polymeric adsorbent material

The proposal of suitable processes for glycerin removal from crude biodiesel is an important task for making the overall biodiesel production process environmentally friendly and economically viable. In this article, we propose a dry purification process for biodiesel treatment with different polymeric materials [chitosan, cellulose acetate, poly(vinyl alcohol) (PVA), and sulfonated PVA]. Except for pure PVA, all of the proposed materials were able to reduce the free glycerin content of crude biodiesel from 0.03 wt % to values lower than 0.02 wt %. When the PVA was sulfonated, the glycerin removal increased from 12 to 82% compared that of pure PVA. The glycerin content in the biodiesel sample treated with sulfonated PVA was 0.0055 wt %. Mid-IR spectrometric analysis showed that the sulfonation of PVA increased the band due to H-O-H stretching vibrations; this enabled greater hydrogen bonding between glycerol and the -SO3- groups of the sulfonated adsorbent. (C) 2017 Wiley Periodicals, Inc.