Cysteine as an Alternative Eco-Friendly Corrosion Inhibitor for Absorption-Based Carbon Capture Plants

Abstract

Inorganic corrosion inhibitors are commonly applied to mitigate severe corrosion in absorption-based carbon capture plants. They are, however, not environmentally friendly, posing a health risk, harming the environment, and making chemical handling and disposal costly. Therefore, this study evaluated the corrosion inhibition performance of an amino acid, namely cysteine, with the aim of providing an eco-friendly alternative to the commercial inorganic corrosion inhibitors. Electrochemical and weight loss corrosion measurements showed that cysteine was effective in protecting carbon steel at all process operating conditions. At 80 °C, a 500 ppm cysteine could provide up to 83% and 99% inhibition efficiency under static and dynamic flow conditions, respectively. Its inhibition efficiency could be improved when the cysteine concentration, solution temperature, and flow condition were altered. Cysteine was an anodic corrosion inhibitor and underwent spontaneous, endothermic, and combined physical and chemical adsorption that followed the Langmuir adsorption isotherm model. The quantum chemical analysis indicated that cysteine had a high reactivity with metal surfaces due to its low energy gap and high dipole moment. The EDX analysis revealed a significant sulphur content on the metal substrate, indicating that cysteine’s mercapto group played an integral role in forming an effective adsorption layer on the metal interface.

Inhibition Effect of Triphenylmethane Dyes for the Corrosion of Carbon Steel in CO2-Saturated NaCl Corrosion Medium

“…As the temperature increases, the inhibitory effect of the corrosion inhibitor gradually weakens (as shown in Figure 4 ). Both the cathodic and anodic current densities are observed to decrease after the addition of the corrosion inhibitor, which indicates that the adsorption of the inhibitor film on the surface hinders both the cathodic and anodic processes [ 31 ]. Table 3 lists the inhibition efficiencies of the studied dyes and other dyes reported in the literature.…”

“…adsorption of the inhibitor film on the surface hinders both the cathodic and anodic processes [31]. Table 3 lists the inhibition efficiencies of the studied dyes and other dyes reported in the literature.…”

New Inhibitor Based on Hydrolyzed Keratin Peptides for Stainless Steel Corrosion in Physiological Serum: An Electrochemical and Thermodynamic Study

“…The standard Gibbs free energy of adsorption ( ) was determined using Equation (29) [ 32 , 42 , 48 , 55 ]. where R is the universal constant of gases (8.31 J mol −1 K −1 ), T is the temperature and 55.5 is the value of the molar concentration of water in the solution.…”

“…The standard Gibbs free energy of adsorption (∆G o ads ) was determined using Equation (29) [32,42,48,55].…”

The Inhibition Action of Some Brij-Type Nonionic Surfactants on the Corrosion of OLC 45 in Various Aggressive Environments

“…The efficacy of these inhibitors can be evidenced by the area covered, which is influenced by the molecule’s geometrical form, electron-donating/retro (back)-donation functional groups, steric elements, aromatic character, and planarity of construction, etc. In recent years, the progress of new friendly organic substances (surfactants, plants extract, polymers) with anticorrosion properties that have ecological, biodegradable, cheap, and healthy characteristics for active materials represents a large domain of exploration in the area of anticorrosion protection [ 39 , 40 , 41 , 42 , 43 , 44 ]. Surfactants are organic inhibitor molecules which contain hydrocarbonate chains of diversified lengths and these variations of the attached alkyl chains can determine a notable impact on the hydrophobicity of a corrosion inhibitor [ 45 , 46 , 47 , 48 ].…”