The characteristics of adsorption of pyrophosphate and citrate onto whewellite.

The adsorption of pyrophosphate and citrate to whewellite was measured by solution depletion. At pH 6.5, the concentration for one-half surface coverage CE(1/2) by pyrophosphate is 15 micrometer. The estimated maximum coverage is 37.5 mumoles per m2. The CE (1/2) for citrate is 4 micrometer, and the estimated maximum coverage is 6.42 mumoles per m2.