The positive value of DH (14.167 kJ/mol) at the studied temperature ranges of 30, 40 and 50 C explained that the adsorption is endothermic in nature with chemisorption process. But this phenomenon does not fulfill the criteria of chemisorptions definition. According to the Faust and Aly, the enthalpy change due to chemisorption < 84 kJ/mol is considered as physical adsorption. Therefore, in this study, bentazon adsorption onto the SFHAC was likely to be physisorption. The positive value of DS showed the SFHAC affinity to the bentazon and described increased randomness at the solid-solution interfaces during the adsorption process