Inhibition of Aluminium Corrosion in 1.0 M HCl by Caffeine: Experimental and DFT Studies

Abstract

Aluminium corrosion inhibition in 1.0 M hydrochloric acid solution by caffeine has been studied using mass loss technique and quantum chemical calculations based on DFT. The inhibition efficiency was found to increase with increasing concentration of caffeine but decreases with a rise in temperature. The molecule shows the highest inhibition efficiency of 74% at 10 −2 M for = 303 K. The experimental data were used to fit isotherms including Langmuir, Temkin, Freundlich, and El-Awady. The best fits were obtained with the Langmuir model and the kinetic-thermodynamic adsorption model of El-Awady. However, it was found that the adsorption parameters suit well with the isotherm of El-Awady which was chosen as the appropriate isotherm. To distinguish between physisorption and chemisorption, the Dubinin-Radushkevich adsorption model was used. The thermodynamic parameters governing the adsorption of caffeine onto aluminium and that of the metal dissolution were calculated and discussed. DFT study gave further insight into the mechanism of the inhibiting action of caffeine.

Alkaloids as green and environmental benign corrosion inhibitors: An overview

“…SEM, EDS and flurescence studies suggested the adsorption of the caffeine over the metallic surface. The inhibition effect of caffeine based compounds on copper [110][111][112][113], nickel [114], mild and carbon steel [115][116][117][118] and aluminum [119] corrosion in other electrolyte systems have also been reported in other studies. Besides the above reports, Mahmood reported the corrosion inhibition effect of theobromine, a purine based alkaloid on the corrosion on mild steel in acidic solution of HCl [119].…”

Corrosion Inhibition of Aluminium in Gas and Acid Media by Some Chalcone-Based N-(3-Aminopropyl)Imidazoles: TD-DFT-Based FMO, Conceptual DFT, QTAIM and EDA Studies

“…Quantum chemical calculations have been undertaken to evaluate the anticorrosion efficacy and modes of action of five chalcone-based imidazole ligands on aluminium in both gas phase and acidic aqueous medium. Computed values of the frontier molecular energy gaps in gas phase are in the range 3.574 eV and 4.444 eV, which are found to be lower than similar values in the literature, suggestive of very good adsorptive and inhibition capacity [5]. In order to model the inhibitor-aluminium interaction patterns, the geometries of inhibitor-aluminium complexes were fully optimized.…”

“…Upon adsorption on a metal surface, electrons are transferred from an organic inhibitor to vacant orbitals of a metal, leading to covalent and/or non-covalent interactions (closed shell interactions) between the metal and the inhibitor. Based on several studies [3] [4] [5], it has been found that the adsorption of organic inhibitors on metal surfaces is mainly dependent on physicochemical properties of the inhibitors, including: the type of functional groups present, the electron density at the donor atoms (typically S, N and O), the molecular size, the mode of adsorption, the formation of organo-metal complexes, and the estimated area of the inhibitor on the metallic surface (degree of surface coverage). Furthermore, the need to choose corrosion inhibitors that are nontoxic and eco-friendly cannot be underestimated.…”

Propriedades químico-quânticas utilizando o método TFD: uma ferramenta teórica aplicada no estudo de inibidores de corrosão

“…Recentemente, vários estudos foram publicados relatando a aplicação do índice de eletrofilicidade como descritor em análises de moléculas inibidoras de corrosão (Al-Fakih et al, 2019;Beda et al, 2017;Frau & Glossman-Mitnik, 2017). O cálculo destes descritores fornece informações que podem ajudar a obter mais informações sobre o sistema de corrosão, como o local mais provável para a adsorção do inibidor.…”