Citric Acid → Citric acid, lanthanum(3+) salt(1:1)

Participants

Reaction Conditions

Reaction Steps

A sodium citrate solution was formed by dissolving 59 g citric acid in 500 ml water and then adding 37 g sodium hydroxide dissolved in 50 ml water. The temperature increased from 20 to 50° C. 113 g lanthanum chloride heptahydrate dissolved in 200 ml of warm water was then mixed into the sodium citrate solution and resulted in the formation of a dense gelatinous floc or gel of lanthanum citrate. While the solubility of the citrate was not measured, it was inferred to be about 0.01 g/l. Such a gel is clearly not suited for addition to the filter as it is likely to raise the pressure drop excessively. Nor is it suitable for addition to the bulk of the pool water because it would be unsightly and disperse slowly.

Provenance & Evidence