Investigation on the adsorption mechanism of rice husk extract on steel surfaces: Experimental and theoretical

The drawbacks of traditional inhibitors have limited their application. The development of new inhibitors is of utmost urgency, and plant-based inhibitor has become the focus due to eco-friendly and effectiveness. The inhibition performance and mechanism of rice husk extract (RHE) on cold-rolled steel (CRS) in H 2 SO 4 were investigated by weight loss method, electrochemical test, surface characteristic and theoretical calculation. The findings reveal that RHE achieves a maximum inhibition efficiency of 91 % at 50 °C with 500 mg L -1 . As a cathodic-type inhibitor, RHE increases the charge transfer resistance ( R t ) after adsorption. The surface characterization of inhibited CRS surface, increase in surface tension and decrease in conductivity of the inhibited solution indicate that the RHE molecules are effectively adsorbed on CRS surface. The active components of RHE contain polar groups containing N and O, contributing to its excellent inhibition performance through a synergistic effect. The adsorption mechanism of RHE was deeply explored by classifying and screening the active components in RHE. Theoretical calculation further reveals that inhibitor molecules spontaneously and parallelly adsorb onto Fe(110) surface via active sites on O, N, and aromatic rings, thus theoretically confirming the inhibition properties of RHE.