Extraction and Characterization of Potassium Chloride from Banana Peels for Potential Application as a Sustainable Fertilizer

Abstract

With growing interest in sustainable and affordable fertilizer alternatives, agricultural waste has gained considerable attention as a potential source for nutrient recovery. This study investigated the extraction and characterization of potassium chloride (KCl) from banana peels, a readily available agricultural waste material. Banana peels were dried, ground, ashed, subjected to acid digestion, concentrated, filtered, and processed for the recovery of KCl. The extraction process yielded 1.21 g of KCl from 4 kg of banana peels, with a reported recovery of 77.1%. The extracted KCl was characterized using physical and chemical tests, including solubility, pH, flame, cobalt nitrite, perchloric acid, tartaric acid, and melting-point tests. The extracted salt exhibited a white crystalline appearance, high water solubility, and a neutral pH. A characteristic lilac flame and confirmatory chemical tests indicated the presence of potassium ions. Fourier-transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) analyses were further used to characterize the extracted material, while flame photometry was employed to determine potassium concentration. The findings demonstrate the potential of banana peels as a source of recoverable potassium compounds and support their further investigation for sustainable fertilizer applications and agricultural waste valorization.