Comment on Zhou et al. Adsorption Behaviors of Lanthanum (III) and Yttrium (III) Ions on Gibbsite. Minerals 2023, 13, 1530

We compare trends in experimental observations reported by Zhou et al. to relevant results from numerous previously published studies. Based on these comparisons, we question the reliability of the gibbsite titration data and consider the cation uptake curves to be incomplete and questionable as well. The adsorption edges in Zhou et al. are too flat compared to the typical adsorption edges reported in hundreds of studies. Finally, we are convinced that trends of cation adsorption with NaNO3 content not only disagree with relevant, previously published results, but are even opposite to trends expected with increasing ionic strength, whenever such effects are observed. Finally, we discuss other inconsistencies in the experimental data.