Batch adsorption of chromium metal ions from the aqueous solutions was studied using activated biochar material from Ziziphus jujube seed powder. Using the chemical synthesis technique, the adsorbent material was produced and activated by concentrated sulfuric acid. The characterization of the adsorbent material produced was performed through scanning electron microscopy and Fourier-transform infrared spectroscopy analyses, while the size of the pores was determined using Brunauer–Emmett–Teller isotherm analysis. Batch experiments were used to determine the best parameters for pH, contact duration, dose, ion concentration, temperature, and particle size. Adsorption isotherm studies were performed to verify the adsorption process, and kinetic experiments were performed to determine the nature of chromium ion absorption by the adsorbent. Thermodynamic tests confirmed that the adsorbent’s metal absorption is endothermic. 93.27% of chromium ions were desorbed from the wasted adsorbent using 0.3 N HCl. Using activated Ziziphus jujube biochar as an adsorbent, around 99.27% of the chromium ions were a