Nitrogen is a nutrient naturally present in wastewater. It is essential for the development of microorganisms, but at high contents can cause problems to the aquatic environment such as eutrophication of watercourses. The aim of this work was to produce an activated charcoal from the of ora-pro-nobis (Pereskia aculeata Miller) fibers in order to remove nitrogen in wastewater. Initially, 3.0 g of phosphoric acid (85%) were added to 1.0 g of ora-pro-nobis (OPN) fibers in a rate of 3:1 (acid: fiber) in crucibles of 50 ml. The samples were dried at 80 °C for 24 h. Then, the carbonization was carried out in a muffle at 500 °C for 30 min. Subsequently, the activated charcoal was washed with HCl solution (5 mol/L) and distilled water. The activated charcoals were dried at 105 °C for 24 h, triturated and sieved. The wastewaters used in this study were collected in Wastewater Treatment Station of Federal University of Lavras, during four consecutive weeks in July 2017. Batch adsorption experiments were conducted in stirred tanks (50 rpm) at 25 °C for 24 h, using 0.05 g of the adsorbent and 50 mL of the effluent solution. After, the supernatants were collected and filtered to remove the solids in suspension. The nitrogen content was determined by the Kjeldahl method. All experiments were done in triplicate. Results of nitrogen content found for the effluents before and after the adsorption processes were submitted to variance analysis and Tukey's test at 5% significance level. The adsorptive process employing the charcoals produced from OPN fibers significantly reduced (p<0.05) the nitrogen content of the effluents from 43.40% (v/v) to 20.90% (v/v). The results indicate that the carbon obtained from the OPN fiber can be used as adsorbent for the nitrogen removal in wastewater.