Potassium Hydroxide in Plantain Peels ash and its Uses as a Source of Saponification

Abstract

The utilization of agricultural waste for value addition presents a significant opportunity for sustainable development in Sierra Leone. This study investigated the potential of plantain peel ash as a local, renewable source of potassium hydroxide (KOH) for saponification. The research aimed to scientifically validate this traditional practice by quantifying the alkali yield from both ripe and unripe plantain peels and demonstrating its efficacy in soap production. The methodology involved collecting, drying, and combusting separate batches of ripe and unripe plantain peels to produce ash. The alkali from each ash type was extracted into a leachate, and the KOH concentration was determined via acid-base titration with a standardized 0.2 M nitric acid solution. A combined alkali solution, mimicking realistic feedstock conditions, was then used to saponify palm oil to produce a final soap product. The study yielded two primary findings. First, a quantitative analysis confirmed that ripe plantain peels produce a significantly higher concentration of potassium hydroxide (12.376 g/dm³) compared to unripe peels (9.744 g/dm³), identifying the peel's stage of maturation as a critical factor for optimizing alkali yield. Second, the saponification trial using a combined-source alkali solution was successful, producing a quality soft soap with desirable characteristics, which validates the robustness of the method for practical, small-scale application where feedstock uniformity is not guaranteed. This research concludes that plantain peel ash is a viable and effective alternative to industrial alkali for soap making. It provides a scientific basis for an eco-friendly practice that supports the principles of a circular economy by converting agricultural waste into a valuable commodity. Key recommendations include the standardization of ash production, the development of low-cost methods for testing alkali strength, and the dissemination of best practices to local producers to foster economic empowerment and sustainable enterprise.