RIGOROUS TREATMENT OF ADSORPTION DATA FOR MULTICOMPONENT PREDICTIONS

Three considerations in the rigorous treatment of adsorption data for multicomponent adsorption equilibria are discussed below: (1) choice o f pure-component model for the ideal adsorbed solution theory; (2) var iable sensitivity analysis for the choice of independent variable sets ; and (3) the error-in-variables method for binary interaction paramet ers. The O'Brien and Myers model gave better agreement with adsorption data than the Langmuir model for single components. However, in the p rediction of binary and ternary component adsorption equilibria, IAS t heory combined with the O'Brien and Myers model did not show any impro vement over the IAS theory with Langmuir model. Sensitivity analysis s howed that large sensitivities of dependent variables to independent v ariables can give large deviations in the prediction of binary compone nt adsorption. This motivated the use of the error-in-variables method , which was shown to be superior to conventional least-squares in calc ulating the Wilson binary parameters for the prediction of ternary com ponent equilibria with O2-N2-CO adsorption data on zeolite 10X. Smalle r deviations in the predictions of total amount of adsorption were fou nd from the parameters regressed by EVM, but the errors in the predict ion of mole fraction were not reduced significantly compared to the tr aditional least squares approach.