The dissolution of calcite in aqueous polymaleic acid PMA solution at around pH

4 The dissolution of calcite in aqueous polymaleic acid (PMA) solution at around pH 3 

The dramatic inhibitory effect of even trace amounts of PMA on the precipitation of calcium carbonate has long been recognised [249] and it has thus found considerable commercial application as an inhibitor of the formation of scale in hard water systems [251]. However, the mechanism by which this species inhibits the precipitation reaction remains unclear. Furthermore, to our knowledge, there have been no kinetic or morphological studies on the effect of polymaleic acid on the dissolution process. 

In this section, we report results on the dissolution of calcite in PMA using the channel electrode technique. Dissolution experiments were carried out with unbuffered polymaleic acid solutions using the channel elec- 

Potassium chloride (0.5 M) served as supporting electrolyte. Specifically, a solution of 0.885 g l-1 in PMA gave rise to a solution of pH 2.70, suggesting that the average composition of such solutions can be represented in the form 

CO3 released according to eqn. (xxxiv) will then undergo rapid reaction with H+ in solution 

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