Biochar was prepared from corn ( Zea mays) stalks and impregnated with sulfuric acid. The biomass was impregnated for 24 h with a 50% solution of H2SO4 with impregnation ratios 1:2 (B 1:2) and 1:3 p/v (B 1:3); then, it was carbonized in a muffle furnace at 520°C for 30 min with a 10°C per min ramp. The adsorption capacity to remove anions (nitrate, sulfate, and phosphate) in an aqueous solution was evaluated by varying the temperature. The adsorption mechanism was studied by determining the thermodynamic parameters: Gibbs free energy (ΔGº), enthalpy (ΔHº) and entropy (ΔSº) standard. The biochars were characterized by Scanning Electron Microscopy-Energy Dispersive X-Ray Spectroscopy (SEM-EDS) analysis and were found to exhibit a heterogeneous surface and porous nature, with C, O, S, and Si. The experiments in the batch system showed the best performance of B 1: 2 in the removal of the three anions occurred at 303 K, while B 1: 3 had the best performance at 298 K. From the thermodynamic parameters, it was found that the removal processes are endothermic, their mechanism is by chemisorption. It is concluded that synthesized biochar is an excellent alternative to removing nutrient anions present in the solution.