AbstractThe adsorption isotherms of the three main types of surfactant have been plotted against various pH's and temperatures. It has thus been possible to propose new ways of insuring adsorption and determining the importance of the ionic links and hydrophobic interactions involved in the various‐medium conditions considered. The presentations by Lauginuir and Freundlich have permitted to develop the adsorption equations corresponding to each case. Finally, the isotherm plotting in a series of low concentrations has permitted to predict the maximum volume of an effluent purified per kilogram of substrate, in the case of the concentrations frequently found in the waste water