Extraction and Characterization of Alkalis from Ashes of Selected Agro-Waste Peels: Toward Sustainable Alternatives for Industrial Base Applications

Abstract

Abstract: This study investigates the potential of selected agro-waste peels—banana, cassava, yam, groundnut, and soybean—as sustainable sources of industrial alkalis. The peels were oven-dried, combusted at 600 °C, and their ashes subjected to aqueous extraction to recover soluble alkalis. The resulting crude alkali solutions were analyzed using flame photometry and titrimetric methods to quantify potassium and sodium in both carbonate and hydroxide forms. Results showed that cassava and yam peels produced the highest yields of crude alkalis, with potassium carbonate being the most abundant compound across all samples. Groundnut and banana peels exhibited relatively higher concentrations of potassium and sodium hydroxides, making them suitable for applications requiring stronger base activity. Flame photometry confirmed potassium dominance in all samples, with K⁺ concentrations ranging from 42.8 to 61.2 mg/L and K⁺:Na⁺ ratios consistently above 1.4. The findings confirm that agro-waste peels are viable, low-cost alternatives to commercial base chemicals, with specific compositional profiles that can be aligned with targeted industrial uses such as soap production, water treatment, or biodiesel catalysis. This work supports the integration of biomass valorization into sustainable chemical sourcing strategies, especially in resource-constrained environments.