A theoretical approach to the corrosion inhibition of iron (110) in HCl activation by environmental benign four amino acids: MC simulation and DFT studies
Umme Habeeba, Narasimha Raghavendra
Abstract
In order to get a comprehensive understanding of the corrosion behaviour of mild steel (110) with alanine, arginine, cysteine, and tyrosine in gas and aqueous phases, a systematic theoretical study using MC simulation was conducted in the current investigation. Stronger interfacial spontaneous adsorption of amino acid molecules across the Fe (110) surface in the investigated environment is made possible by the more negative adsorption energy values found in the MC simulation. Effectively repelling the corrosive particles from the substrate and delaying their aggregation are the capabilities of four amino acids. The results of the MC simulation also show that, in order to stop corrosion, amino acid molecules replace any other ions or solvent water that had previously been adsorbed on the metal surface. The trend of tyrosine > cysteine > alanine > arginine is shown by the protection capacity derived from the MC simulation. Furthermore, the DFT studies demonstrate that, charge transfer takes place within the molecule based on the calculated E-HOMO and E-LUMO energies. When adsorbed onto a metal surface, heteroatoms like nitrogen, oxygen, and sulphur in an amino acid structure provide the stronger inhibition. The decreased HOMO-LUMO gap, indicating improved electronic contact with the Fe (1 1 0) surface. A greater reactivity and potential for electron transfer are suggested by the EHOMO and ELUMO values (EHOMO -19.71 eV for alanine, -16.83 for cysteine, -10.73 for arginine and -16.80 for tyrosine) and (ELUMO EHOMO -10.81 eV for alanine, --9.34 for cysteine, -2.69 for arginine and -9.06 for tyrosine) which are advantageous for adsorption onto the Fe (1 1 0) surface. Current study finds that, alanine, arginine, cysteine and tyrosine were emerging as a novel and effective and sustainable corrosion resistance agent for acid pickling and cleaning procedures. These outcomes may lead to the development of more and large-scale green inhibitors and a better understanding of their mechanisms for eco-friendly industrial processes.