Custom design approach of design of experiment as a tool for the optimisation of parameters for corrosion inhibition study of (+)-arabinogalactan on AISI 5140 steel

Biopolymers have become prevalent in industries to prevent acid corrosion because of their robust structure and biodegradability. The current research investigates the effectiveness of the biopolymer (+)-arabinogalactan (AG) in inhibiting corrosion on AISI 5140 steel in H₂SO₄ media, employing a novel approach to experimental design called the custom design of experiment (DoE). Temperature and medium concentration have the greatest effects on the response, according to p-value analysis. The highest inhibitory efficiency (IE) at 50 °C, 0.1 M H₂SO₄ concentration, and 0.1 g/L of AG is predicted to be 75.57%. Density functional theory-based computational investigations demonstrate the potential of AG as a corrosion inhibitor, with chemisorption being the primary mode of adsorption. AG's adsorption on the metal surface is further confirmed by scanning electron microscope and energy-dispersive X-ray studies. Thus, this study pioneers the application of custom DoE in investigating AG's corrosion inhibition properties on AISI 5140 steel in H₂SO₄ medium.