Technical feasibility for bar soaps elaboration from residual cooking oil

Abstract

This article presents the main results to determine if it is technically feasible or not the use of residual cooking oil for the formulation of a bar soap, as an alternative to reduce or minimize the impacts to the environment due to its inadequate final disposal in soils and water bodies. The bar soap was formulated using the next ingredients: waste cooking oil from a restaurant, sodium hydroxide, distilled water and fragrance. The technical feasibility in making bar soap was determined based on the basis of the similarity of the physicochemical properties of pH, electrical conductivity, surface tension, density and COD of soapy water respect to the conventional bar soap, evaluated at through the Student's t-distribution. The range obtained of the results of pH are from 7,05 to 9,13 units, the electrical conductivity from 32,5 to 182,5 μS/cm, density from 0,99 to 1,04 g/mL, the surface tension from 27,88 to 37,39 dyne/cm and for the COD from 300 to 2 800 mg/L. The obtained graphs present similar trends, whose data were corroborated by Student's t-distribution. The formulation and elaboration of bar soap is technically feasible, since there is no significant difference between the evaluated physicochemical properties of soapy water, being an option for environmental sanitation. The final product was a yellow soap, with a pleasant characteristic door, which when applied to the skin during
hand washing, leaves the skin clean, soft and moisturized, without dryness, which contributes to the health benefit of people.