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Dyes constitute major wastes from textile, dye manufacturing, pulp and paper industries. Some amounts of these dyes are transferred into water systems. In this research, Clay–Corn cob–FeCl3 composite (adsorbent) was prepared from clay, corn cob, FeCl3 and lime. The adsorbent was used for the effective removal of Congo red from aqueous solutions. The adsorbent was characterised using Fourier Transform Infrared Spectroscopy, Scanning Electron Microscopy and Nitrogen adsorption/desorption isotherm. Effects of pH, contact time, initial concentration of Congo red and temperature on the adsorption capacities were investigated using batch adsorption experiment. The optimum pH of 2 and equilibrium time of 1 h were observed for the adsorption process. The pseudo–second order model was the best model for description of the kinetic data out of four models (pseudo first order, pseudo second order, Elovich and intra-particle diffusion). The equilibrium data was evaluated using Langmuir, Freundlich and Temkin models. The Freundlich model gave the best fit of the equilibrium data. The maximum adsorption capacity calculated from the Langmuir model was 1000.00 mg/g. Thermodynamic parameters such as standard Gibbs free energy, standard enthalpy and standard entropy were evaluated. Congo red adsorption from aqueous solutions was spontaneous and exothermic. It showed that adsorbent prepared and used in this study was efficient for removal of Congo red from aqueous solutions. The adsorbent can be used for treatment of industrial effluents.  
keywords: Congo red, Adsorption, Equilibrium, Kinetics, Freundlich, Pseudo–second order model