Comparison of batch completely mixed and column tests for the evaluation of phenol mobility in natural soils

This paper reports some results of an experimental work performed in order to evaluate the potential of different contact techniques for providing information on the adsorption capacity of a natural clay soil. Two different types of test were performed, one based on the widely applied completely mixed solid-liquid contact, the other on static column leaching. Five phenol concentrations ranging from 50 to 2000 mg l(-1) and three solid/liquid ratios (12.5%, 25%, and 37.5%) were adopted. After some considerations on the concepts of equilibrium and saturation, results of the two sets of tests were evaluated based on Langmuir's and Freundlich's models. They showed that the two contact techniques give comparable results, once consistent solid/liquid ratios are adopted.