The Effect of Surface Pretreatment with Polymaleic Acid, Phosphoric Acid, or Oxalic Acid on the Dissolution Kinetics of Calcium Carbonate in Aqueous Acid

The kinetics of calcite dissolution in aqueous acidic solution following various surface treatments was investigated using the channel flow cell method with microdisk electrode detection. Pretreatment of calcite with solutions of polymaleic acid, phosphoric acid, or oxalic acid for up to 24 h is shown to provide protective coatings over the calcite, which substantially reduces further acid attack on the surface. Quantitatively each pretreatment was found to lead to a rate constant for proton-induced calcite dissolution of as low as 0.003 cm s−1, an order of magnitude less than that observed for untreated calcite, 0.035 cm s−1at 21°C.