الملخص

Abstract: This study includes calculation of the potential stickiness (S*) and apparent activation energy (AAE) by the adsorption process of some aromatic carboxylic acids using sand (clay) as a new adsorbent material. This clay was collected from dust storms coming to the city of Mosul. The obtained results showed that physical adsorption which is achieved by applying the modified Arrhenius equation through the values of (S *) and (AAE) which have low values and bear a negative charge is preferable Adsorption process occurs in two-step mechanism. The effect of the concentration of the acidic solution, temperature and the substituted groups SO3, NO2, OH, NH2 on the aromatic ring) was studied to clarify the nature of the association between organic carboxylic acid anions and inorganic metal oxides to form a complex surface model. The study concluded that the values of (S *) for all acids were less than one and they were more than the value of zero. Also, the values of (AAE) gave an indication that the adsorption process is exothermic and spontaneous. The presence of water molecules and (H+) ions in solution is very important to change the nature of the clay surface.