Progress of human civilization, overpopulation and the use of new technologies release heavy metals into the environment and led to water and soil pollution. Water and soil pollution with heavy metals is usually caused by metal working, plastics-making, mining and chemical fertilizers application. To remove heavy metals from contaminated water, various techniques such as chemical precipitation, ion exchange, reverse osmosis, filtration and sorption are used. Sorption is one of the most convenient and economical methods, used for the removal of heavy metals from aquatic environments. Biochar has just been used to remove heavy metals from aqueous solutions as a sorbent. Biochar is a coal produced from plant biomasses and agricultural wastes during pyrolysis process (slow burning organic matter with the lack of oxygen). In this study, biochars were made from the pyrolysis of palm tree residues at a temperature of 200, 400 and 600 ° C. The prepared biochars were then used to remove Ni from aqueous solutions. Given the importance of pH in the physicochemical behavior of Ni in aqueous solutions, sorption isotherm tests were conducted at pH=5 and 7 as well. To investigate equilibrium time, sorption kinetic experiments were carried out at a Ni concentration of 10 and 100 mg/L. The results showed that the biochars prepared at 200 °C and 600 °C had more Ni sorption rates. The equilibration time was about 5 and 48 h for Ni concentrations of 10 and 100 mg/L, respectively. Sorption rate was reduced but sorption capacity was increased with increasing concentration of Ni in solution.. Power function and parabolic diffusion models were the best equations fitted to the kinetic data. Langmuir and Freundlich isotherms described sorption of Ni on the sorbents very well. According to the Langmuir model predictions, the biochar produced at 600°C has the highest and the raw residues the lowest capacity to sorb Ni from the solution and the biochars produced at 200°C and 400°C were intermediate in this respect. By reducing the pH to 5 both the capacity and affinity of the sorbents for Ni were decreased. Overall, under the experimental conditions applied in this study, the biochar prepared at 600 ° C showed the highest efficiency for Ni removal from aqueous solution. Keywords : Heavy Metals, Biochar, Biosorption, Nickel, Pyrolysis