INFLUENCE OF CARBONATE TYPE ON TRANSPORT CHARACTERISTICS OF SiC-BASED CERAMIC MEMBRANES

Background. Ceramic membranes have recently attracted particular attention due to their thermal and chemical resistance, ability to be used in aggressive environments, and long service life. Among ceramic membranes, silicon carbide membranes deserve special attention due to their high strength. However, the high cost of such membranes and the controllability of porous characteristics, which significantly affect the transportation characteristics, remain an unresolved problem. Therefore, it is extremely important to investigate ways to reduce the annealing temperature of SiC membranes and control their porosity. Objective. The aim of this work is to determine the effect of the type of carbonate on the physicochemical properties and transport characteristics of ceramic membranes based on silicon carbide. The ceramic membranes were obtained by pressing, to which borax (to reduce the annealing temperature) and carbonates (as a pore forming agent) were added. Methods. Method of pressing and sintering with different composition of carbonates. Analysis of the obtained ceramic membranes by the diffraction method and scanning electron microscopy. Results. It has been shown that the addition of sodium carbonate results in the formation of a new phase, sodium aluminosilicate, while no new phases were detected when ammonium bicarbonate was used. The morphology of the synthesized ceramic membranes has a granular structure characterized by pores ranging in size from 13 to 21 μm and a specific surface area of 1.5–1.9 m3/g. The investigated transport characteristics of ceramic membranes indicate that the use of ammonium bicarbonate allows to obtain a ceramic membrane with a sufficiently high throughput, which can be recommended for use in the field of microfiltration. Conclusions. Ammonium bicarbonate is a more promising pore-forming additive for ceramic membranes based on silicon carbide. Further research will focus on studying the effect of the defoamer content on the transport and mechanical properties of ceramic membranes.