Comments on ＂Ion adsorption components in liquid/solid systems＂

Recently, Wu et al. （J Environ Sci 18（2006） 1167- 1175） published a paper entitled as above. In the paper, the authors proposed a plotting method for describing adsorption isotherms, where adsorption density （qe） was plotted against the ratio of equilibrium concentration/particle concentration （CdWo） rather than Ce as traditionally defined. The authors claimed that this plot can eliminate the ＂particle concentration effect＂ （i.e., adsorption isotherms decline with increasing particle concentration）, which may otherwise be inevasihle with traditionally defined adsorption isotherms. We think that their conclusion is conceptually flawed and the plot may cause substantial inconstancy problems in practice.