By combining Langmuir and Freundlich isotherms with mass balance of solutes between liquid solution and solid adsorbent phases, the removal efficiency or required adsorbent mass was successfully predicted using given sets of initial conditions. The validity of We have shown that even very small variation in the adsorp-tion isotherm might give rise to inflection points in the adsorptionisotherm that have a tremendous impact on the shape of the elu-tion profiles, see Fig. 3. The earlier in the adsorption isotherm thesevariations occur the larger the impact, but the impact decreasesrapidly with increasing adsorption isotherm mobile phase concen-tration. We have also shown that inflection points might be missedwhen using traditional experimental plateau methods for adsorption isotherm determination, such as Frontal Analysis (FA). Hereit should be noted that these traditional methods also have lessaccuracy at the lower concentration regions of the isotherm [17].Furthermore we have shown that it might not be possible to finda closed adsorption isotherm model that account for these inflec-tion points. We have therefore developed and validated a modifiedInverse Method (IM), which uses monotone piecewise interpola-tion instead of a fixed adsorption isotherm model, to solve theproblem of estimating adsorption isotherms where small variationsgive rise to inflection points. We demonstrated, both for a syntheticand