Azeotrope ethanol-water mixture dehydration using water adsorbent synthesized from spent bleaching clay

Spent bleaching clay (SBC), waste gathered from palm oil refinery, is normally discarded at landfills. In this study, water adsorbent was synthesized from regenerated SBC to dehydrate azeotrope ethanol-water mixture. The SBC was converted into water adsorbent using modified fusion technique at the best variables combinations i.e. temperature of fusion of 550°C, temperature of aging of 80°C, aging time of 3 days, water addition of 65% wt, added KOH of 56% wt and added alumina of 80 g/100 g material mass. The synthesized water adsorbent was characterized using XRD, FESEM-EDX and porosity analyzer. The synthesized water adsorbent was used to purify azeotrope mixture of ethanol-water in a simple adsorption apparatus to produce dehydrated ethanol. XRD analysis showed that the water adsorbent cannot be considered as zeolite A. It was believed that the porous water adsorbent consisted of several phases of zeolites such as zeolite A, MFI plus amorphous phase based on SEM images. In terms of breakthrough time, the water adsorbent performance was 66.0% of the commercial water adsorbent. Results showed that the Yoon & Nelson model can be used to simulate the experimental dehydration data. In conclusion, this study showed that low cost water adsorbent can be produced from spent bleaching clay using modified fusion technique and was able to produce dry ethanol (>99% weight) as alternative fuel in petrol driven engine and fuel cell.