Synergistic Green Corrosion Inhibition of Mild Steel in Sulfuric Acid: Comparative Phytochemical and Gravimetric Evaluation of Cassia Occidentalis and Terminalia Superba

Suleman Aliyu. Abdulaziz M. Hassan; Yakubu Yahaya; Saifullahi Mustapha.

doi:10.56201/ijccp.vol.12.no5.2026.pg55.59

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Synergistic Green Corrosion Inhibition of Mild Steel in Sulfuric Acid: Comparative Phytochemical and Gravimetric Evaluation of Cassia Occidentalis and Terminalia Superba

Suleman Aliyu. Abdulaziz M. Hassan, Yakubu Yahaya and Saifullahi Mustapha.

Abstract

The escalating environmental hazards of synthetic corrosion inhibitors necessitate eco-friendly botanical alternatives. This study evaluates the individual and synergistic inhibition potentials of Cassia occidentalis (CO) and Terminalia superba (TS) leaf extracts on mild steel in 2M H2SO4. Phytochemical screening revealed distinct profiles; CO exhibited abundant flavonoids (18.18%) and phenols (9.65%), whereas TS contained moderate tannins (3.90%) and trace alkaloids (1.34%). Gravimetric weight loss measurements over 240 hours demonstrated severe corrosion in the uninhibited blank (20.04 mm/yr). The addition of CO and TS individually reduced corrosion rates to 1.25 mm/yr (93% efficiency) and 4.50 mm/yr (76% efficiency), respectively. Remarkably, a synergistic mixture of both extracts yielded optimal protection, achieving a corrosion rate of 0.41 mm/yr with 97% inhibition efficiency. The superior performance of CO is attributed to its high flavonoid content, facilitating strong chemisorption via electron donation to vacant metal d- orbitals. The synergistic mixture's exceptional efficiency suggests cooperative adsorption, where distinct phytochemical classes fill surface voids, creating a denser barrier. These findings establish the synergistic mixture as a highly potent, biodegradable alternative for mitigating acid-induced corrosion, aligning with global green chemistry initiatives and offering a scalable solution for industrial acid pickling.

Keywords

Green corrosion inhibitors; Mild steel; Cassia occidentalis; Terminalia superba; Phytochemical screening; Adsorption mechanism; Sulfuric acid.

References

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Synergistic Green Corrosion Inhibition of Mild Steel in Sulfuric Acid: Comparative Phytochemical and Gravimetric Evaluation of Cassia Occidentalis and Terminalia Superba

Abstract

Keywords

References

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