Estimation of Lead Sorption Based on Phosphorus Dissolution from Apatite

Abstract

 This study investigated the relationship between a apatite solubility and an amount and mechanisms of lead sorption using apatite samples, which have different cristalinities and impurities contents, to estimate the amount of the lead sorption onto the apatite from phosphorus extraction by a citric acid. The amount of the lead sorption increased linely with increases in an amount of calcium dissoleved from the apatite. It was considered that the sorption mechanism of lead were both precipitation of Pb-phosphate minerals like pyromorphite and surface complexations onto the apatite. The amounts of the lead sorption by surface complexations were almost equivalent even if the solubility of apatites was different, indicating that the increases in the solubility would only induce to the precipitation to increase the lead sorption. It was also confirmed that the maximum amount of lead sorption can be predicted from phosphorus extraction by 0.01M citric acid.