Microwave assisted decomposition of Tri-butyl phosphate in aqueous effluent-streams

Abstract

An investigation into the microwave assisted remediation of organic containing aqueous solutions has been conducted. Tri-n-butyl phosphate (TBP), the nuclear thel reprocessing solvent, and its diluents, are known to be responsible for the formation of interfacial deposits (cruds) in the alkali solvent wash stage of the Purex process for reprocessing spent nuclear fuel.

The presence of cruds in the process is managed by regular wash out and the collected cruds are separated from aqueous washings and stored.

Chemical oxidation of the cruds is one way of destroying them. This project explored microwave assisted oxidation, using TBP as a simple simulant for the crud. Low concentration TBP streams were circulated through an activated carbon loaded glass reaction vessel. The vessel was then subject to microwave radiation applied in short pulses.

Studies were performed to assess the variation in reaction parameters using two oxidants; air and hydrogen peroxide. The analytical techniques used to assess the extent of decomposition were ion chromatography and UV-V is spectroscopy. Results showed TBP was found to decompose to orthophosphate ions in solution and to di-butyl phosphoric acid (HDBP).