We used a constant composition reactor, in which, calcite seed crystals were added to metastable, supersaturated solutions containing the organic acids. Crystallization began immediately upon seeding, and was accompanied by a drop in pH. The pH drop triggered addition of Ca2+ and CO32- titrants, maintaining constant chemical conditions in the reactor solutions. |
All experiments were run for 100 minutes under the following conditions:
Hydrophobic organic acids (humic acid + fulvic acid), isolated using XAD resins from surface waters in Water Conservation Areas 2A and 2B, were used in experiments and had the following characteristics: