EVALUATION OF PHYSICOCHEMICAL INTERACTIONS IN CROSS-FLOW FILTRATION IN THE PARTICULAR CASE OF MINERAL MEMBRANES AND SUGAR REMELTS

This study is part of a research program on the fouling of inorganic m embranes in cross-flow filtration. The aim of our work was to determin e the physico-chemical characteristics of powders used in manufacturin g inorganic membranes in cross-flow filtration as well as those of whi te and raw cane sugar remelts, in order to study interactions between them. First, we determined the surface bulk density for three powders (alpha-Al2O3, ZrO2, TiO2) by the electrophoretic mobility measurement at various pH and the surface tension using the capillary rise method. All the methods were applied to unmanufactured and heated powders (50 0 degrees C; one hour duration). At the same time, we evaluated the en ergy characteristics of the white and raw cane sugar remelts by measur ement of the contact angle with various pure liquids. It was clear tha t heat treatment had an influence on the surface properties of powders and on the isoelectric point of alpha-Al2O3 Heating led to the increa se in the acid-base character and, as a result, to the increase in the interactions between these particles and the treated solution. Theref ore, the increase in the acid character of alpha-Al2O3 by heating caus ed an increase in interaction with the white and raw sugar remelts (wh ich had a Lewis-base character).This study analyzed the interactions i n a membrane. Further studies may help in the choice of the membrane a nd the treated solution. This paper presents the preliminary results o f our program. (C) 1997 Elsevier Science B.V.