Influence of Fe(III) Colloids on Np(V) Migration through Quartz-Packed Columns Journal Articles uri icon

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abstract

  • The influence on Np(V) migration behaviour through quartz-packed columns brought by the presence of Fe(III) real colloid was studied at pH 6.0 and 9.5. At pH 6.0, NpO2+ -which constituted the dominant species of Np(V) at this pH-proved to move faster in the presence than in the absence of Fe(III) real colloid. Moreover, whereas 25-30% of the supplied NpO2+ was found retained in the column in the absence of Fe(III) real colloid, the presence of this colloid induced about 95% of the NpO2+ to be recovered from the column. It is shown that change in the particle size distribution brought about by the formation of Fe(III) real colloid, and the consequent effect on the filtration of Np(V)-Fe(III) pseudocolloid, vitally influence the migration behaviour of the NpO2+ At pH 9.5, more than 50% of NpO2CO3- -the dominant Np(V) at this pH -remained uneluted in the column, whether or not Fe(III) real colloid was present. The filtration behaviour of NpO22CO3- -in the forms of Np(V)-Fe(III) and Np(V)-silica pseudocolloidsignificantly affects the migration behaviour of NpO2CO3-. At both pH 6.0 and 9.5, the first stage of contact with eluant was characterized by a small but distinct fraction of Np(V)-Fe(III) pseudocolloid that was eluted from the column faster than HTO, and the rate of Np(V)-Fe(III) pseudocolloid elution was higher at pH 9.5 than at pH 6.0. The rapid elution noted above of a fraction of Np(V)-Fe(III) pseudocolloid is con-sidered attributable to the formation of large pseudocolloid particles.

publication date

  • February 1994