REMOVAL OF CADMIUM FROM DILUTE-SOLUTIONS BY HYDROXYAPATITE .1. SORPTION STUDIES

The removal of toxic metals (such as cadmium) was investigated by usin g hydroxyapatite, an effective inorganic sorbent, at the ultrafine par ticle size range. In bench-scale experiments performed batchwise, the influence of the main sorption parameters were examined (i.e., solutio n pH, sorbent and cadmium concentrations, and temperature) and compari son was attempted between demineralized and tap water. Typical adsorpt ion isotherms of the Langmuir type were calculated; zeta-potential mea surements of the hydroxyapatite particles and the release of calcium ( during the process) were also examined and related to possible mechani sms occurring during the cadmium removal process.