Nonequilibrium sorption of dimethylphthalate - Compatibility of batch and column techniques

This study reconciles an apparent inconsistency between the dimethylphthalate (DMP) batch and column data reported in the literature. Some researchers found that retardation coefficients obtained by fitting a linear two-stage model to column data were about 50% smaller than those calculated from the distribution coefficient of a 14-d isotherm. In this study, sorption parameters were derived independently by fitting a linear and a nonlinear two-stage model simultaneously to the 3- and 14-d isotherms as well as to a sorption rate study reported by others. With the sorption parameters and the dispersion coefficient obtained from a tritium tracer experiment, the column data were adequately predicted. A major part of the differences in the retardation coefficients observed in other research could be related to experimental difficulties in detecting the tailing of nonequilibrium breakthrough curves.