ADSORPTION OF THORIUM AND PROTACTINIUM ONTO DIFFERENT PARTICLE TYPES: EXPERIMENTAL FINDINGS

Abstract

Here we present the results of experiments investigating the adsorption of Protactinium and Thorium onto different particle types in natural seawater. Particle types studied were smectite as a representative of clay, biogenic opal from a cleaned diatom culture, manganese dioxide precipitate, and calcium carbonate. The particles were added to three different types of natural seawater (0.5 mg/L) which were first 0.2 μm-filtered, and the distribution of Pa and Th between dissolved and particulate phase (>0.2 μm) was monitored for 4 to 5 d at increasing time intervals. The tracers applied were the β-emitters 233Pa and 234Th. The measurement technique via β-counting for both nuclides in the same sample is reported here for the first time.