Modification of α‐Zirconium Phosphate Synthesis – Effects of Crystallinity and Acidity on Eu(III) and Am(III) Ion Exchange

Abstract

AbstractThe aim of an ongoing study is to develop ion exchange materials to be used in low pH in mineral acids for the uptake and separation of trivalent lanthanides and actinides. We present material development of α‐zirconium phosphate (ZrP), namely the effects of its crystallinity and acidity on other material properties and on Eu(III) and Am(III) trace ion exchange. One‐pot synthesis for three ZrP products having a time for (re)crystallization of 1 hour, 5 hours and 25 hours, is reported. Characterization techniques include X‐ray diffraction, solid‐state nuclear magnetic resonance, infrared spectroscopy, thermal analysis, electron microscopy, pKa1 determination, and 152Eu(III) and 241Am(III) ion exchange studies, i. e. distribution‐, selectivity‐ and metal binding coefficient determinations. As crystallinity and crystallite size increase, so do Eu(III) and Am(III) metal binding coefficients. The acidity and Eu(III) and Am(III) distribution‐ and selectivity coefficients increase in the reverse order. Findings are discussed with separation in mind. Promising separation factors (Eu:Am) of up to 90 were achieved in pH less than 1 in nitric acid.