Acidic surfactant solutions for tributylphosphate removal in nuclear fuel reprocessing plants: A formulation study

The removal of tributylphosphate (TBP), an organic solvent widely used as a complexing agent for uranium and plutonium in nuclear plants, was investigated to understand and adapt the mechanisms involved in TBP detachment and solubilization in acidic surfactant solutions. Two well-known degreasing mechanisms, roll-up and emulsification, should be combined for maximum effect. These mechanisms were characterized with a CCD camera to measure contact angles between a solid substrate and a liquid drop. We measured the contact angles of a TBP drop deposited on a stainless steel plate immersed in an acidic surfactant solution, and quantified the amount of TBP solubilized in the micelles by turbidity measurements. Preliminary results of micelle size characterization by dynamic light scattering are presented. We formulated new acidic surfactant solutions associating two industrial surfactants, Pluronic P123 and Rewopal X1207L, with improvement factors in various fields (total organic matter content, oil detachment and solubilization efficiency, emulsion stability, etc.).