REGULARIZED LEAST-SQUARES METHODS FOR THE CALCULATION OF DISCRETE AND CONTINUOUS AFFINITY DISTRIBUTIONS FOR HETEROGENEOUS SORBENTS

From experimental isotherms, we calculate discrete and continuous affinity distribution functions for environmental sorbents. The calculation of such distributions is an ill-posed problem, which, if approached by classical solution schemes, leads to serious numerical problems and instabilities. The application of regularization methods circumvents these difficulties and provides a substantial stabilization of the resulting distributions. We show that, without additional information about the affinity distribution, it is generally impossible to recover the true affinity distribution from realistic experimental data. As this information is usually not available, such data analysis remains a fitting exercise, which may however have an enormous practical value. The stability of the resulting distributions offers novel possibilities for comparison of sorption properties of environmental materials.