Three famous isotherms, namely Langmuir, Freundlich and Temkin isotherms, Eqs. (4)–(6), were used to correlate experimen- tal equilibrium data for adsorption of CIP and NOR on prepared carbon at best conditions and different temperatures. The calculated constants of the three isotherm equations along with R2 values for both antibiotics are presented in Table 2. This table shows that the Langmuir isotherm represented by plot of Ce/qe versus Ce (Fig. 4) is of highest R2 values for both antibiotics at different temperatures. In other words, this result may be due to the homogeneous distribution of active sites on the surface of prepared carbon. Several authors [9,11] showed the successful application of Langmuir isotherm compared to Freundlich and Temkin isotherms to correlate experimental adsorption data of FQs antibiotics on activated carbons.