Activation of Natural Zeolite as Water Adsorbent for Mixed-Adsorption Drying

Abstract

Mixed-adsorption drying with material using zeolite is an option to improve product quality and energy efficiency of drying seeds. In this case, zeolite and seeds are mixed and fluidized by warm air as drying medium. The air will desorb water from seed, and at the same time, zeolite will adsorb vapor from air. Thus, the driving force of drying can be kept high. However, in Indonesia, the zeolite with high adsorption capacity is hardly found in market. This research studied the activation of natural zeolite using two different methods: by heating at 200-400oC, and adding NaOH 0.5-2.0 N. Results showed that the adsorbing capacity of zeolite activated by 1.0 N NaOH is 0.170 gr water/gr dry zeolite. While, by heating at 300oC for 3 hours, is 0.140 gr water loaded/gr dry zeolite. With the performance, zeolite can be used for drying application. Keywords: zeolite, fluidized, adsorption, drying, activation