Nickel is a highly polluting heavy metal which, because of its toxicological effects, is a matter of great concern and the reason why the search for alternatives for its removal, being adsoption an applicative alternative for metal removal which is considered interesting due to its efficiency and low cost. In this way, the Ni (II) adsoption is proposed using two highly available waste materials in the Colombian Caribbean region: yam peels and oil palm pulp, both biomasses treated with citric acid. The experiments were carried out in batch system using nickel aqueous solution at a concentration of 100 ppm. The residual concentration of the solution was measured by atomic absorption spectroscopy, and it was found that the adsorption process is highly dependent of pH with an optimum value of 6. What is more, it was found that Ni (II) presents a quick sorption the first 50 minutes, and Elovich model showed the best fit. The maximum adsorption capacity according to Langmuir isotherm was 68.14, 47.93, 103.3 and 58.7 mg/g for unmodified chemically modified yam peels and oil palm pulp respectively showing a potential value of use of these biomaterials in the removal of Ni (II) present in aqueous solutions.