ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Comparative evaluation of the anti-corrosion efficacy of ethanol extracts of Mangifera indica, Psidium guajava, and Carica papaya on mild steel in water-in-diesel emulsion

Chukwuemeka Fortunatus Nnadozie, Chiamaka Prisca Onuoha, and Eze Christopher Akanazu

Department Chemistry, Federal University of Technology, Owerri, Nigeria

E-mail: chukwuemeka.nnadozie@futo.edu.ng

Received: 15 July 2025  Accepted: 17 September 2025

Abstract:

The mitigation effects of Mangifera indica, Psidium guajava, and Carica papaya on mild steel were studied in water-in-diesel emulsion (WiDE) with different concentrations (0.1–0.5 g/L) of the plant extracts for 1344 h. The stability tests indicated that WiDE with 10% water content and 5% surfactant dosage exhibited the highest stability, showing minimal phase separation after 33 h. The corrosion inhibition results demonstrated that Mangifera indica leaf extract exhibited the highest inhibition efficiency (IE) (91.28% at 0.5 g/L), followed by Psidium guajava (87.78%) and Carica papaya (85.71%). Additionally, the extracts reduced the average surface roughness by 72.48%, 49.61%, and 48.17%, respectively. FT-IR confirmed the interaction of the extract’s bioactive components with the mild steel surface, demonstrating the creation of a protective barrier. These findings highlight the potential of eco-friendly, plant-based inhibitors to mitigate corrosion in WiDE systems, enhancing the durability of engine components and supporting the broader adoption of WiDE as a low-emission fuel technology.

Keywords: Water-in-diesel emulsion (WiDE); Stability; Corrosion; Mangifera indica; Psidium guajava; Carica papaya

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-025-04392-y

Chemical Papers 80 (1) 309–319 (2026)