Development of Ceramic Supports Derived from Low-Cost Raw Materials for Membrane Applications and its Optimization Based on Sintering Temperature

Abstract

In this work, a macroporous ceramic support was fabricated using inexpensive clays available in India by uniaxial compaction technique. Green ceramic supports were developed by mixing of kaolin, pyrophyllite, feldspar, ballclay, quartz, and calcium carbonate of desired composition with polyvinyl alcohol as a binder and were sintered at different temperatures (850°C, 900°C, 950°C, and 1000°C). The raw materials and sintered supports were characterized using thermogravimetric analysis, particle size distribution (PSD), X-ray diffraction, and scanning electron micrograph analysis. The effect of sintering temperature on porosity, mean pore size, pore size distribution, shrinkage, flexural strength, and pure water permeability was investigated. Chemical stability tests for the sintered supports were conducted with 20 wt% of H2SO4, HCl, and NaOH solutions and the supports showed good chemical resistance. The porosity of the sintered supports was in the range of 41–46%. It was observed that the average pore diameter and flexural strength of the supports increases with increase in sintering temperature. Based on these results, the support sintered at 950°C (porosity=44%, mechanical strength=28 MPa, and average pore diameter=1.01 μm) was considered as the optimum support for membrane applications. Solvent permeation studies were conducted for 950°C sintered support and the results confirmed that the support was hydrophobic in nature.