Seeds powder of Foeniculum vulgare (FVES) was used to prepare a novel adsorbent, the new adsorbent was characterized and its ability to eliminate potassium permanganate (KMnO 4 ) was examined. The impact of KMnO 4 concentration, adsorbent dose, contact temperature, contact time, and solution pH on the adsorption performance was also investigated. The experimental data of this adsorption was analyzed by different kinetic and isotherm models. As Constants of thermodynamic ΔG°, ΔH°, and ΔS° have been also evaluated. Surface area, pore volume, and pore size of the FVESP adsorbent were determined as 0.6806 m 2 .g -1 , 0.00215 cm 3 .g -1 , and 522.063 Å, as pH ZPC of Ox- FVESP was stated to be 7.2. The R 2 values obtained from applying different isotherm and kinetic models (0.999 and 0.996) showed that the adsorption performance of KMnO 4 follows the Langmuir and Pseudo 2 nd order models. Furthermore, high adsorption capacities of 1111.11, 1250.00, and 1428.57 (mg/g) were achieved at three temperatures that were used in this study. Constants of thermodynamic ΔG°, ΔH°, and ΔS° values indicate chemical and spontaneous adsorption at the adsorbent surface.