sorption onto edge sites (XOH0.5-) was modeled with a 1pK-basic Stern approach; cation sorption onto permanently charged face sites (X-) described by 3 models: Gaines-Thomas equation (GT), basic Stern (BS), extended basic Stern (BS ext) (see article for fitted parameters and constants of the face sites, log K only valid in combination with these values)
here: BS/BS, same log K value for BS/BS ext