Carlos Andrés López Chun, Yocelyn Madeley Mite Leon, Jonathan Flavio Barco Acosta
The present study aimed to evaluate the heavy metal removal capacity, specifically lead (Pb²⁺), cadmium (Cd²⁺), and chromium (Cr⁶⁺), of three natural biosorbents of Ecuadorian agro-industrial origin: cocoa husk (Theobroma cacao L.), sugarcane bagasse (Saccharum officinarum L.), and banana fiber (Musa paradisiaca L.), in contaminated water samples collected from industrial and mining areas in the provinces of Pichincha, El Oro, and Morona Santiago. A quantitative approach was applied using a completely randomized factorial experimental design, evaluating pH (4, 6, and 8), contact time (30, 60, and 120 minutes), and biosorbent dosage (2, 5, and 10 g/L) as variables affecting removal efficiency. The results showed that cocoa husk achieved the highest removal efficiency for Pb²⁺ (94.3%) and Cd²⁺ (89.7%) at pH 6 and 60 minutes of contact time, with a dosage of 5 g/L, while banana fiber exhibited the highest adsorption capacity for Cr⁶⁺ (91.2%) at pH 4. The adsorption isotherm analysis indicated that the Langmuir model best described the process for all three biosorbents, with an R² greater than 0.97. It is concluded that the evaluated Ecuadorian agro-industrial residues show promising performance as biosorbents, along with environmental application potential that should be confirmed through economic and life cycle analysis, for the treatment of water contaminated with heavy metals. This represents a promising alternative for waste management and water decontamination in the Ecuadorian context.