부산대학교 도서관

During the last few decades, the applications of ceramic membranes have been increased due to their excellent chemical, thermal and mechanical stability, and high separation efficiency. In the near future, the exploitation of natural ceramic materials and simple fabrication techniques could play a significant role for preparation of low cost membranes. Natural zeolites are very successful because of their unique physical-chemical characteristics such as an ion-exchange properties and selectivity in sorption. Ceramic multilayer micro-filtration membranes have been obtained on a porous support by dip coating of natural zeolite from the deposit Kralevo, Bulgaria, as the starting material. The preparation processes including zeolite powder sedimentation, semi-dry pressing, sintering of the support and the membranes, and dip coating of layers were systematically studied. The porous supports from natural zeolite were molded by semi-dry pressing in disks with diameter 30 mm and thickness 4 mm, and sintered at different temperatures from 80°C to 100°C. Water absorption, firing shrinkage, apparent density, apparent porosity, thermal expansion coefficient and mechanical bending strength of fired at different temperatures supports were determined by standard methods for ceramic materials. Phase composition of the ceramic support was established by XRD analysis. The interlayer and top layer of classified zeolite powders by dip coating on the zeolite support was obtained. Classification of zeolite powder was performed by sedimentation of the suspension with 1 mass % solid loading. The classified zeolite powders with different sedimentation time were tested with a photo sizing centrifugical particle analyzer. SEM studies of the membranes fired at different temperatures were carried out. [ABSTRACT FROM AUTHOR]