Electrochemical Insights into 2,2-Dithio Bisbenzothiazole as a Sustainable Corrosion Inhibitor for Mild Steel in Low pH Medium
The corrosion of mild steel, a commonly used material in various industries, is a significant concern, particularly in acidic environments such as those containing hydrochloric acid. To address this, the 2,2-Dithio Bisbenzothiazole derivative has emerged as a promising sustainable corrosion inhibitor. In this study, the electrochemical and computational behavior of DBBT was investigated as a potential eco-friendly solution for controlling MS corrosion in 1 M HCl medium.
Experimental Methods and Findings
To evaluate the effectiveness of DBBT as a corrosion inhibitor, a variety of experimental techniques were employed, including gravimetric analysis, potentiodynamic polarization electrochemical impedance spectroscopy, and surface analysis through scanning electron microscopy and atomic force microscopy. The studies were carried out at 298 K with varying concentrations of DBBT, specifically at 800 ppm, under acidic conditions.
The results revealed an impressive inhibition efficiency of 97.71%, positioning DBBT as a highly effective and environmentally friendly alternative to traditional corrosion inhibitors. Electrochemical impedance spectroscopy further supported these findings, showing an increase in polarization resistance and a decrease in double-layer capacitance as the concentration of DBBT was increased. These changes confirmed that DBBT was effective in protecting the MS surface from corrosion.
The Langmuir adsorption isotherm provided the best fit for the experimental data, indicating that the inhibitor molecules adsorbed onto the metal surface in a monolayer formation. Furthermore, Gibbs free energy values indicated a combination of both physical and chemical adsorption processes, which enhance DBBT's ability to reduce corrosion.
Theoretical Analysis: Molecular Insights
Theoretical analysis was conducted using Density Functional Theory and Molecular Dynamics simulations to gain a deeper understanding of DBBT's inhibitive properties. The results from these computational approaches were consistent with the experimental data, supporting the claim that DBBT interacts strongly with the MS surface and effectively prevents corrosion. These insights correlate the molecular structure of DBBT with its corrosion inhibition efficiency, highlighting its ability to donate electrons via its heteroatoms (S and N) and π-electrons, crucial factors in its action as a corrosion inhibitor.
Mechanism of Corrosion Inhibition
The mechanism behind DBBT's corrosion inhibition properties can be attributed to the formation of a protective layer on the MS surface. This protective layer hinders the interaction of the metal with aggressive ions in the acidic solution, significantly slowing down the oxidation process. The presence of a disulfide bridge in the DBBT structure enhances its adsorption capabilities, ensuring that the inhibitor remains firmly attached to the steel surface. This creates a barrier that shields the metal from corrosive attack.
Experimental Validation: Surface Analysis
Surface analysis conducted through SEM and AFM provided visual confirmation of the protective layer formed by DBBT on the MS surface. The images showed a smoother surface with fewer signs of corrosion compared to untreated MS samples. Contact angle measurements further indicated that DBBT's adsorption led to changes in the surface properties, making it more hydrophobic and resistant to corrosion.
Environmental and Economic Benefits
In addition to its technical effectiveness, DBBT stands out as a non-toxic, cost-effective, and environmentally friendly solution for corrosion inhibition. Traditional corrosion inhibitors often contain harmful substances that can pose significant environmental and health risks. In contrast, DBBT offers a safer alternative, with its low toxicity and green chemistry profile making it suitable for industrial applications seeking to reduce their ecological footprint.
Conclusion and Future Applications
The study presents DBBT as a highly effective and sustainable corrosion inhibitor for mild steel in low pH environments, such as those found in industrial applications. With its high inhibition efficiency, physicochemical interaction with metal surfaces, and eco-friendly profile, DBBT could serve as a viable alternative to conventional corrosion inhibitors in industries such as petrochemical, marine, and construction. Future research may explore the scalability of DBBT for large-scale applications and its use in combination with other corrosion protection strategies.
This work paves the way for developing green corrosion inhibitors that are not only effective in protecting materials but also contribute to sustainability efforts across various industrial sectors.
