The role of calcium in high pH excursions for reactivated GAC

Water contact pH experiments employing several reactivated granular activated carbons (GAC) showed that reactivated carbons exhibit pH excursions (i.e., pH > 8.5) when wetted. Moreover, when the water contact pH was predicted based on the log of the quantity of calcium that leached out of the GAC during the pH experiments, good agreement was obtained with the measured water contact pH for reactivated GACs that contained a range of calcium content, typically 0-1% wt. Ca.