EFFECT OF ADSORBENT PARTICLE-SIZE AND TEMPERATURE ON WATER-ETHANOL SEPARATION BY STARCHY AND CELLULOSIC SUBSTRATES

Inverse gas chromatography was used to study the adsorption of water a nd ethanol on two starchy (cornmeal and wheatflour) and one cellulosic (wheat straw) substrate, in the temperature range 50-90 degrees C, Th ree particle size fractions of each substrate were investigated -180-2 50 mu m. 160-180 mu m and 125-160 mu m. denoted, respectively, by: 60- 80 mesh, 80-100 mesh and 100-120 mesh. Values for the separation facto r and for thermodynamic parameters. such as Gibbs free energy and enth alpy of adsorption. were calculated from the chromatographic retention data. The results showed that water was adsorbed more strongly than e thanol on all substrates, at all temperatures. In addition, it was fou nd that lower temperatures were more favourable for the adsorption of both solutes. There was no significant difference between values of se paration capacity of the three fractions of wheat straw. In contrast, the separation capacities of starchy materials with smaller particle s izes, i.e. 80-100 mesh and 100-120 mesh, were greater. The 100-120 mes h wheatflour fraction exhibited the highest separation at all temperat ures.