Comment on “The multi-mechanisms and interlayer configurations of metoprolol uptake on montmorillonite”

Thomas Thiebault (1, 2)

1 METIS - Milieux Environnementaux, Transferts et Interactions dans les hydrosystèmes et les Sols
2 EPHE - École Pratique des Hautes Études

In the work "the multi-mechanisms and interlayer configurations of metoprolol uptake on montmorillonite", published in Chemical Engineering Journal, montmorillonite are used as an an adsorbent for the uptake of metoprolol under various experimental conditions. The results are interesting but the authors has made a mistake when assessing the speciation of metoprolol. This β-blocker is mostly neutral rather than zwitterionic for pH values up to pKa1. This mistake may induce confusion and false conclusions for the readers of Chemical Engineering Journal unfamiliar with such organic contaminants, especially when assessing the impact of pH on the adsorption mechanisms of metoprolol onto clay minerals.

Keywords: Comment; Speciation; Metoprolol; Adsorption; Ion-dipole interaction

Domains: Continental interfaces, environment; Environmental and Society; Geochemistry; Organic chemistry

Thomas Thiebault. Comment on “The multi-mechanisms and interlayer configurations of metoprolol uptake on montmorillonite”. Chemical Engineering Journal, 2019, 371, pp.378-379. ⟨10.1016/j.cej.2019.04.059⟩. ⟨insu-02094825⟩