Adsorption capacity study of ethanol-water mixture for zeolite, activated carbon, and polyvinyl alcohol

Global energy issue is no longer a new topic. The expansion of energy production proven to show significant influence is the fossil fuel modification by blending it with liquid renewable fuel, such as bioethanol. Bioethanol must achieve fuel-grade standard to qualify as gasoline, one of the specification is to have moisture content of 1.0% v/v or less, as regulated by ASTM D4806. This parameter is a challenging one to achieve, because water-ethanol mixture will encounter the azeotrope phenomenon when the mixture undergoes a common distillation process and reach 95.6% v/v of ethanol. One of the dehydration method that use less energy is adsorption. One of the efficiency consideration of bioethanol dehydration with adsorption is its adsorption capacity. Adsorption capacity is influenced by the material of adsorbent, operational temperature and time. The material being tested in this research is poly vinyl alcohol (PVA), zeolite, and activated carbon. This research will analyze the dependency and influence of mixture's initial concentration and operational temperature condition towards the final concentration of ethanol and adsorption capacity utilizing a Langmuir model. The result of this study showed that the activated carbon has the highest parameter capacity, which is twice as much than zeolite and three times larger than PVA. Whereas the result of selectivity study between the three prove that zeolite has better selectivity.