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

From experimental isotherms, we calculate discrete and continuous affi nity distribution functions for environmental sorbents. The calculatio n 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 res ulting distributions. We show that, without additional information abo ut the affinity distribution, it is generally impossible to recover th e true affinity distribution from realistic experimental data. As this information is usually not available, such data analysis remains a fi tting exercise, which may however have an enormous practical value. Th e stability of the resulting distributions offers novel possibilities for comparison of sorption properties of environmental materials.