Abstract— Of all the materials used as adsorbents, activated charcoal is the most popular as it is excellent for reducing/eliminating a wide variety of contaminants. This capacity is mainly due to its structural characteristics that give it a large surface area. However, it has several disadvantages. The most important are that the adsorbent material is quite expensive as is its regeneration. For this reason, more economical absorbents have been sought, highlighting the study of adsorption phenomena in some types of biomass as adsorbents. Bioadsorption is considered a viable alternative to the physical-chemical methods currently used for the recovery or removal of heavy metals dissolved in liquid effluents. Its main attraction, from an industrial point of view, is its low cost due to the great abundance, easy to obtain and low price of the bioadsorbent material. Bioadsorption is very effective in treating metal concentrations below 100 mg/L, where the application of physical-chemical methods is neither technically nor economically feasible. One of these materials of interest is citrus peels, because, due to their abundance as a waste product of the food industries, they are hardly reused and currently have little economic value. However, these residues have a low adsorption capacity, so both physical and chemical modifications are required to increase their adsorption properties. This study compares the characteristics of orange and lemon peels undergoing a physical-chemical treatment with ultrasonic radiation assistance and the optimization of experimental conditions to obtain useful bioadsorbents in discontinuous processes (batch).