Utilization of Fly Ash as Ceramic Support Mixture for the Synthesis of Zeolite Pervaporation Membrane

Abstract

s. Ethanol purification is a key problem during fuel grade bioethanol production. Conventional distillation cannot be used any more after the ethanol concentration has reached azeotrophic condition (~95 wt.%). In this case pervaporation (PV) is recognized as one of the promising alternative purification technologies. The performance of pervaporation is significantly influenced by the membrane material used. This paper utilizes fly ash, a solid waste from coal combustion of thermal power plant, to prepare porous support pervaporation membranes. The support was prepared from a mixture of fly ash, kaolin and alumina. The support membrane was then coated by crytallization of hydrophilic zeolite. The results show that the the performance of support material was influenced by the preparation temperature and fly ash content. The addition of fly ash and the increase in alumina concentration would raise the mechanical strength of the membrane but the more the fly ash used the harder the support to be molded. An optimum fly ash content in support layer was found to be ~50 wt.% of the mixture. The higher calcination temperature the better the resulting support layer. Zeolite crystallization on the support layer was influenced by crytallization temperature, zeolite solution concentration, and crystallization time.