Membrane filtration in the sugar industry

This research work deals with possibilities of raw sugar juice purification by micro-, ultra-, and nanofiltration. Conditions that enable to reach such a juice purity for proceeding of crystallization without the prerequisite of the whole complex of purification techniques, which involve liming, carbonation, and filtration, were sought. Samples were treated with cross-how micro- and ultrafiltration on ceramic membranes having mean pore size 20 nm, 50 nm, and 100 nm. Increasing of juice purity and retention of almost 50 % of colour impurities by microfiltration is one of the most important results of this study. For nanofiltration tests, a special cross-flow testing cell with adjustable tangential speed of 0-3 m s(-1) has been designed. Several flat polymeric membranes have been tested. The aim was to find a membrane capable to reject the main part of the melassigenic elements as potassium and sodium ions, i.e. elements that increase amount of waste product (molasses) during sugar crystallization.