Adsorption of selenite on goethites in NaCl and Na2SO4 solutions was p
erformed in a newly designed flow-through reaction chamber as well as
in a traditional batch system. Six goethites with different morphologi
es were used as adsorbents. For the experiments the goethite was place
d in the chamber prior to flushing with the salts. Introduction of the
NaCl and Na2SO4 solutions only, and in combination with selenite, res
ulted in different responses with respect to the pH. The pH changes we
re explained by means of anion-binding energies, with Cl- <SO42- <SeO3
2-. Neither the morphological characteristics of the adsorbents nor th
e electrolyte anion influenced the amount and the rate of selenite ads
orption. The mixing mode in the reactor chamber affected the selenite
adsorption density, as indicated by higher densities in the batch expe
riments.