Electrophoretic characterization of thorium species in very dilute solutions containing humic acid

Abstract

Electrophoretic mobility of thorium was measured in aqueous solutions (HClO4+ NaClO4, I = 0.01) as a function of thorium concentration (≪ 10-7 - 10-5 M), pH (2 - 10) and solution composition (Aldrich humic acid, NaHCO3) using free-liquid electrophoresis. Results have shown that negatively charged thorium humate complexes can prevail at pH 2 - 10 even in solutions containing very low concentration of humic acid (0.1 - 1 mg/L) and medium concentration of carbonates (0.001 M). The mobilities determined can serve for analysis of formation of the humate complexes in aqueous solutions and natural or wastewaters.