EXAFS studies of co-precipitation and adsorption reactions of Tc

Adsorption and co-precipitation reactions may be a simple way of removing [TcO4]- from aqueous solution. The effectiveness of a range of potential and adsorbents precipitants has been evaluated and some are capable of near-quantitative (>98%) removal of [TcO4]- from solution. X-ray absorption near edge structure (XANES) has been used to determine Tc oxidation states and extended X-ray absorption fine structure spectroscopy (EXAFS) has been used to identify the local environment of Tc. The absorption edge position has been determined using [PPh4] [TcO4], TcS2 and Tc2S7 as model compounds, and is diagnostic of Tc oxidation state. (authors)