CHELLOU, NesrineLAHRACHE, Fatima ZahraDAOUD, Mounir Encadreur2025-07-032025-07-032025https://dspace.univ-ghardaia.edu.dz/xmlui/handle/123456789/9570This study aimed to evaluate the efficiency of activated carbon (CAP), prepared from date palm stem, in removing Congo red (CR) dye from aqueous solutions. To achieve this, a Box-Behnken design (BBD) was applied to optimize operating conditions and study the effects of three key factors: sorbent dosage (X1), initial dye concentration (X2), and solution pH (X3). The physicochemical properties of the activated carbon showed a zero-charge (pHPZC) value of 10, and Bohm analysis indicated that the activated carbon surface contained a basic group. Kinetic analysis showed that the pseudo-second-order (PSO) model was the most appropriate for describing the adsorption process, with a high correlation coefficient (R2 = 0.99). The equilibrium data were applied to the Langmuir and Freundlich models, with the Langmuir model showing the best fit (R2 > 0.98), indicating monolayer adsorption on a homogeneous I surface. The maximum adsorption capacity was found to be 142.85 mg/g. Thermodynamic parameters indicated that the adsorption process was endothermic.indicated that the adsorption process was endothermic. Key words : Activated carbon, Adsorption,Red Congo,Box-Bennken design, isotherm.Charbon actif, Adsorption, Rouge Congo, Box-Behnken, isothermes d'adsorption.Thesis