Separation characteristics of glucose and maltooligosaccharides in grannular activated carbon beds

The adsorption and desorption behavior of maltooligosaccharides in granular activated carbon beds (GAC) was studied experimentally. Adsorption rates of larger molecules, such as maltopentaose and maltolieptaose, for a pitch coal-based activated carbon, F400, with a relatively uniform pore size distribution (32 - 550 Angstrom), were faster than those of smaller molecules. On the other hand, the adsorption rates of smaller molecules, such as glucose and maltose, for a coconut shell-based activated carbon, SLS103, which has a smaller pore size, in the range 32 - 47 A, were faster than those of larger molecules. With pH adjustment using acetic acid, both adsorbents adsorbed almost all of the saccharides, except for glucose, at pH greater than or equal to 4.1, but no saccharides were adsorbed at pH < 2.2. For 2.2 < pH < 4.1, the adsorption rate increases as both pH and molecule size increase. Acid treatment of the GAC increases the carboxyl group, but did not significantly affect the adsorption rate of the saccharides. For the desorption of the saccharides, the amount of ethanol in the solution was more important than the concentration. The TLC imaging densitometry method was applied for the quantitative determination of the sugar concentration in the maltooligosaccharides.