Surface Activity and Thermodynamic Assessment of Surfactants Derived from Oreochromis Niloticus Oil (Nile Tilapia Fish)

Surfactants were synthesized from Oreochromis niloticus (Nile Tilapia) oil via sulphonation and evaluated for surface-active and thermodynamic properties. The extracted oil had an acid value of 9.56 mg KOH/g, refractive index of 1.46, density of 1341 kg/m³, viscosity of 19.52 mPa.s, and lipid content of 18.20%. Fourier Transform Infrared Spectroscopy (FTIR) identified carboxylic acids and esters as major functional groups, while Gas Chromatography–Mass Spectrometry (GC-MS) detected oleic, palmitoleic, and decanoic acids among others. Three surfactants (NT-25, NT-30, NT-45) were obtained at sulphonation temperatures of 25°C, 30°C, and 45°C, respectively. They effectively reduced surface tension to 31.0, 36.0, and 44.0 mN/m, with critical micelle concentrations (CMC) of 2.86, 3.16, and 3.55 mmol/L, respectively. Wetting times ranged from 7.21 to 19.00 seconds, and foam stability reached 96% (NT-25), 95% (NT-30), and 96% (NT-45). NT-25 and NT-30 exhibited higher surface pressure at CMC (∠cmc), greater surface excess concentration (Γmax), and lower minimum surface area per molecule (A), enhancing their surface tension reduction compared to NT-45. These results suggest NT-25 and NT-30 possess excellent wetting and foam stability, making them promising for applications in soaps, detergents, and cosmetics.