Experimental and theoretical approach to exploit the corrosion inhibition activity of 3-formyl chromone derivatives on mild steel in 1 m H ₂ SO ₄

Abstract

Abstract 3-Formyl chromone (3FC) derivatives, viz. 5-methoxy-3FC (5-Me-3FC), 6-hydroxy-3FC (6-OH-3FC), and 7-hydroxy-3FC (7-OH-3FC), were studied for the inhibition of mild steel corrosion in 1 m H 2 SO 4 at different temperatures and concentrations. The inhibition was studied using mass loss method, polarization technique, electrochemical impedance spectroscopy (EIS), scanning electron microscopy, and quantum chemical calculations. The results from mass loss, potentiodynamic polarization, and EIS showed that inhibition efficiency (IE) increased with gradual increments in concentration of 3FC derivatives. The polarization study revealed that these compounds act as mixed-type inhibitors and Langmuir adsorption isotherm is fitted well for adsorption behavior. The order of IE provided by all the three compounds is 7-OH-3FC≈6-OH-3FC>5-Me-3FC and lies in the range of 85%–95%. A proposed inhibition mechanism has been further described, including the support from all the experimental and theoretical techniques.