Oxidation of activated carbon: application to vinegar decolorization.

This article reports studies on the feasibility of increasing the decoloring capacity of a granular activated carbon (GAC) by using oxidation with air at 350 degrees C to modify its surface activity and porosity. The GAC, obtained from olive stones, had a maximum decolorization capacity of 92% for doses of 20 g/l, while the maximum decolorization capacity of the modified granular activated carbon (MGAC) was about 96% at a dose of 10 g/l. The increase in decoloring capacity is thought to be due to an increase in mesopore area (from 129 to 340 m2/g) in the MGAC. The maximum decoloring values and the doses needed to attain them are very close to values obtained in previous studies using coconut shell powder-activated carbon (94 and 98% for red and white vinegar for a dose of 10 g/l, respectively).