The effect of Spirulina sp. as green corrosion inhibitor on mild steel in 0.5M hydrochloric acid solution / Izzah Athirah Izandis

Large-scale and persistent corrosion harms the environment, our possessions, and our lives significantly while also costing money. Therefore, corrosion prevention needs more attention. Inorganic and synthetic metal corrosion inhibitors are used to stop and slow corrosion; however, they are hazardous. Green corrosion inhibitors, which are affordable and environmentally friendly, are quite likely to offer a solution to this issue. In this study, the potentiality of green microalgae (Spirulina sp.) to inhibit corrosion of mild steel was studied in acidic media, hydrochloric acid (HCl). Gravimetric method and thermodynamics analysis were used to study the performance of this green microalgae as corrosion inhibitor. Results revealed that used of 0.2 g/L of the Spirulina sp. reached maximum inhibition efficiency (IE%) and decreased in corrosion rate (CR). Interestingly, the rise in temperature has increased the value of IE% along with the corrosion rate. Furthermore, thermodynamic parameters of the adsorption process, such as activation energy (Ea), enthalpy (ΔH°), and entropy (ΔS°), were calculated, and these values showed a good interaction. The positive values of ΔH° and ΔS° proved that the reaction was endothermic and spontaneous. Thus, results from this study showed that these green microalgae were an attractive alternative to prevent corrosion as they showed great inhibition efficiency according to its optimum condition.