Creating Rust-Proof Coatings from Plants for Steel

Jim Crocker
7th April, 2024

Creating Rust-Proof Coatings from Plants for Steel

Picture of the plants (a) Marjoram, (b) Yarrow, (c) Ribes rubrum, (d) Maurorum, (e) Wormwood.

Image adapted from: Pourmohseni et al. / CC BY (Source)

Key Findings

  • Researchers at Islamic Azad University found plant extracts can prevent metal corrosion
  • Marjoram extract was most effective, blocking up to 92% of corrosion in steel
  • These "green inhibitors" offer an eco-friendly alternative to toxic corrosion chemicals
In the ongoing quest to protect metals from corrosion, scientists have turned to nature for solutions. Corrosion is a natural process that deteriorates metals when exposed to aggressive environments, such as acid. It's a significant issue in industries that rely on metallic structures and components, leading to economic loss and potential safety hazards. Traditional corrosion inhibitors often contain toxic chemicals, prompting the search for greener alternatives. Researchers from the Islamic Azad University have conducted a study[1] exploring the potential of extracts from medicinal plants to prevent corrosion of mild steel in acidic conditions, specifically in a 1M hydrochloric acid (HCl) solution. This study builds on prior research that demonstrated the effectiveness of natural extracts in similar applications. For instance, an earlier study[2] found that an extract from the brown seaweed Sargassum muticum acted as a powerful inhibitor against carbon steel corrosion in an HCl medium. The current study delved into the efficacy of extracts from Yarrow, Wormwood, Maurorum, Marjoram, and Ribes rubrum (red currants). These plants were chosen for their rich array of phytochemicals, which have been recognized for their health benefits and therapeutic properties. Notably, red currants have been previously studied[3] for their ability to produce silver nanoparticles with strong antifungal and antibacterial properties, indicating the broad potential of plant extracts in various applications. The researchers used Fourier transform infrared spectroscopy (FT-IR) to characterize the plant extracts, identifying the specific organic compounds present. They then assessed the ability of these extracts to inhibit corrosion on mild steel electrodes immersed in the acidic solution using electrochemical techniques. Field emission scanning electron microscopy (FE-SEM) and Violet-visible (UV-Vis) spectroscopy were employed to examine the microstructure of the electrode surfaces and confirm the adsorption of the extracts. The results were promising. The extracts acted as "green inhibitors," with the effectiveness of corrosion prevention increasing with the amount of extract added to the solution. Marjoram extract emerged as the most potent, achieving up to 92% inhibition efficiency. It functioned as a mixed-type inhibitor, meaning it could reduce both the metal dissolution and the hydrogen gas evolution during the corrosion process. The study found that the Marjoram extract adhered to the Langmuir adsorption model, which describes how molecules distribute between the liquid phase and the solid surface. The adsorption of the extract's compounds onto the steel surface was further analyzed using density functional theory (DFT), a quantum mechanical modeling method. This analysis showed that the protonated (positively charged) organic compounds in the extract had a high affinity for the steel surface in the acidic environment. The findings of this study are significant as they not only provide an environmentally friendly alternative to synthetic corrosion inhibitors but also offer insight into the mechanisms by which plant extracts can protect metals. The use of natural extracts as corrosion inhibitors could have far-reaching implications for industries looking to reduce their environmental footprint while maintaining the integrity of their metal infrastructure. In conclusion, the investigation at the Islamic Azad University has not only highlighted the potential of certain medicinal plants as effective corrosion inhibitors but also reinforced the concept that natural substances can play a crucial role in industrial applications. By harnessing the power of these green inhibitors, we can protect valuable resources and move towards more sustainable practices in corrosion management.

EnvironmentSustainabilityPlant Science

References

Main Study

1) Preparation of corrosion inhibitor from natural plant for mild stil immersed in an acidic environmental: experimental and theoretical study.

Published 4th April, 2024

https://doi.org/10.1038/s41598-024-58637-z

Related Studies

2) Sargassum muticum extract based on alginate biopolymer as a new efficient biological corrosion inhibitor for carbon steel in hydrochloric acid pickling environment: Gravimetric, electrochemical and surface studies.

https://doi.org/10.1016/j.ijbiomac.2019.08.253

3) Sunlight-Mediated Green Synthesis of Silver Nanoparticles Using the Berries of Ribes rubrum (Red Currants): Characterisation and Evaluation of Their Antifungal and Antibacterial Activities.

https://doi.org/10.3390/molecules27072186


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