Within the framework of sustainable development and the circular economy, it is essential to utilize natural materials derived from agricultural waste as adsorbents. The objective of this study is to investigate the removal capacities of nitrates and phosphates using biosorbents derived from cocoa shells and rubber tree residues, in order to identify the most suitable biosorbent for each type of pollutant.The optimal conditions for biosorbent preparation were determined using experimental design methodology. Throughout the study, including the Plackett–Burman design (PBD), the removal efficiency of nitrates and phosphates was used as the sole response indicator to evaluate material performance.The results showed that cocoa shells were more effective for phosphate removal, whereas rubber-based materials exhibited better performance for nitrate adsorption. This difference is attributed to the physicochemical properties of the ions and the surface characteristics of the biosorbents.
