Understanding Eco-Friendly Anticorrosion Prospect on Steel-Reinforcement in NaCl-Immersed Concrete from Biochemical Characterization of Irvingia Gabonensis Leaf

Abstract

Different characterization techniques were employed for understanding anticorrosion prospect of Irvingia gabonensis leaf-extract on steel-reinforcement. FTIR spectroscopy showed that this leaf-extract is constituted of N-, SO O-, Hg-containing heteroatoms having π-electron ligands that usually exhibit affinity for steel-rebar Fe constituent. AAS indicates Irvingia gabonensis leaf inorganic composition includes Ni, Cu, Cd, Fe, but neither Pb nor Cr, and with the low/non-toxic heavy metal levels supporting the natural-plant's eco-friendliness. Phytochemical-screening showed that the leaf-extract is rich in glycosides (known for steel corrosion-protection in NaCl) and in saponnins, with traces of flavonoids, stenoids and terpenoids. Anticorrosion prospect investigation, via the leaf-extract admixture in 3.5% NaCl-immersed steel-reinforced concretes, showed that corrosion-inhibition performance increased with increasing leaf-extract concentrations. By statistical modeling of the electrochemical/corrosion test-data, the lower Irvingia gabonensis leaf-extract concentrations aggravated corrosion, indicating insufficient admixture usage, while the higher concentrations exhibited η > 80% corrosioninhibition efficiencies, suggesting sufficient bio-constituent combinations for corrosion-mitigation.

Cymbopogon citratusand NaNO2Behaviours in 3.5% NaCl-Immersed Steel-Reinforced Concrete: Implications for Eco-Friendly Corrosion Inhibitor Applications for Steel in Concrete

“…As it was explained in [50], which rather involves H 2 SO 4 , it is worth noting that C. citratus leaf-extract shares some of these indicated biochemical constituents in common with other plant-extracts that had inhibited chloride-induced corrosion of steel in concrete in studies [26,85]. These ecofriendly and biocompatible phytoconstituents would have been capable of preferential interaction with the reinforcingsteel metal, which could have exhibited chloride attack prevention activity in a more multifaceted mechanisms than that obtainable from the NaNO 2 chemical.…”

“…The problem with corrosion inhibiting admixture usage depends on the fact that admixture substances that have been known to be effective in inhibiting chloride-induced reinforcing-steel corrosion in concrete include compounds of nitrites and of chromates [26,28,30,35,36]. The challenges from using these substances are that they are environmentally hazardous due to their toxicity and lethality to living beings/organs, even as they also exhibit ability to cause hereditarily inheritable health conditions [15,[37][38][39].…”

“…Among these techniques, the use of corrosion inhibitors attracts much preference due to its economically lower cost, labour saving, and ease of applications, all combined with its relative effectiveness at mitigating corrosion of steel embedded in concrete [20,[26][27][28][29][30]. Applications of corrosion inhibitors can take the form of admixture into freshly cast concrete or it can be applied unto the surface of already cast concrete structures as migratory corrosion inhibitors (MCIs) [31][32][33].…”