Anti-corrosion Properties of Piliostigma Thonningi Leave Extract-Transition Metal Nano Particle Composites on Mild Steel in 1.0m Hydrochloric Acid Solution
Ameh Ojochide Monday
Chahul Faith Habibat
Wuana Raymond Ahulle
Abstract
Ethanolic extract of Piliostigma thonningii was employed to synthesise silver and titanium nanoparticle composites. The particle sizes of the AgNPs and TiNPs were analysed and characterized via ultraviolet-visible spectroscopy, Fourier Transform Infrared spectroscopy, Scanning Electron Microscopy/Energy Dispersive X-ray and X-ray Diffraction. The result from the ultraviolet-spectroscopy showed a maximum absorption around (400-470 nm) for the AgNPs compared to TiNPs (270-350nm). The Fourier transformed infrared spectra showed maximum. Prominent peaks corresponded to C=C, N-H, O-H and C=O functionalities, these groups facilitated strong adsorption onto the mild steel surface through hydrogen bonding, metal-ligand coordination, and π-electron interactions, leading to the formation of a protective film with effective inhibition. The Scanning Electron Microscopy/Energy Dispersive X-ray analysis showed a progressive improvement in the surface morphology from the blank, PTE, PTE-AgNPs, and PTE-TiNPs samples. The PTE-nanoparticles composites, especially PTE-AgNPs, provided superior surface protection, confirming their effectiveness as corrosion inhibitors in 1.0 M solution. The X-ray Diffraction showed that the nanoparticles were around 38.62nm to 70.59nm in size, as derived from the Debye Scherrer equation d-0.89λ/βcosθ . The anticorrosion properties of the NPs for mild steel in 1.0 M HCl at 303-333K were studied using weight loss and electrochemical measurements. Both AgNPs and TiNPs were found to exhibit anti-corrosive properties against the dissolution of the steel coupons in the acidic electrolyte, with corrosion inhibitive effects found to be concentration and temperature dependent. The synthesized AgNPs displayed a higher inhibition efficiency (95.1%) at an optimum concentration of 0.10g/L compared with TiNPs (91.2%) and the plant extract (87.7 %). Potentiodynamic polarization results showed that the understudied nanoparticles behaved as mixed-type inhibitors, inhibiting the anodic dissolution of the mild steel and cathodic evolution of hydrogen gas. The plant-derived NPs adsorbed on the surface of mild steel via a physical adsorption mechanism as predicted by the Langmuir adsorption isotherm model.
References