Abstarct: In this study, pine cone as a very low-cost agricultural waste were modified using polyaniline and characterized by FT-IR (Fourier transform infrared spectroscopy), field emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD) techniques. The application of the modified adsorbent for the removal of chromium (VI) ions from aqueous solutions was then investigated. The effects of experimental parameters such as initial pH, contact time, adsorbent dose, chromium (VI) solution concentration and temperature on adsorption efficiency were investigated. Exprimental data were fitted by four different isotherm models including Langmuir, Frondelich, Dubinin-Radushkich, and Tamkin. baxsed on the obtained results, the process of surface adsorption follows the Langmuir isotherm. The adsorbent maximum capacity of 89.29 mg.g-1 was obtained at 298 K. Three adsorption kinetic models include pseudo-first order, pseudo-second order and intra-particle diffusion were used to analyse experimental data. The second-order model showed a better descxription of the laboratory data. Also, thermodynamic parameters such as ΔH, ΔS and ΔG were also examined, describing the exothermic and spontaneity process associated with increasing entheropy at the absorbent surface/solution interface. Also Absorbent recovery studies were performed to evaluate the reconstruction of the adsorption process. The removal efficiency of the adsorbent reduced only 13 percent in five subsequent cycles.