# _Laasonia inermis_ as an Active Corrosion Inhibitor for Mild Steel in Hydrochloric Acid
###### Abstract  
Corrosion is a pervasive issue affecting metallic materials, with significant economic losses and safety risks in various industries. Mild steel, extensively used in construction and infrastructure, faces corrosion challenges, needing continuous research to effectively tackle them. Natural compounds, because of their eco-friendliness and corrosion inhibition potential, are attracting increasing interest for corrosion control. _Lawsonia inermis_ (LI), or henna, a plant native to North Africa and South Asia, has bioactive compounds exhibiting corrosion inhibitive properties. This study comprehensively explores _Lawsonia inermis_'s effectiveness as a corrosion inhibitor for mild steel, filling a gap in the existing research. Various concentrations of _Lawsonia inermis_ extract were tested in acidic solutions to evaluate corrosion inhibition. Experimental results indicate a significant reduction in the corrosion rate with increasing inhibitor concentration. Langmuir adsorption isothermal analyses reveal the adsorption mechanism as being an interplay between physisorption and weak chemisorption. Electrochemical measurements demonstrate _Lawsonia inermis_'s capability to alter both cathodic and anodic reactions, leading to improved corrosion resistance. Scanning electron microscopy reveals a more even surface morphology in the presence of the _Lawsonia inermis_, indicating corrosion inhibition. Gas chromatography-mass spectrometry (GC-MS) analyses identified organic compounds in _Lawsonia inermis_ extract responsible for corrosion inhibition. Overall, _Lawsonia inermis_ emerges as a promising corrosion inhibitor for mild steel, offering excellent inhibition efficiencies. This study sheds light on its adsorption behaviour and provides insights into its mechanism of action. These findings underscore _Lawsonia inermis_'s potential as a green corrosion inhibitor, paving the way for its practical application in industrial corrosion protection strategies. corrosion inhibitor; mild steel; _Lawsonia inermis_; GC-MS; electrochemical experiments; SEM; adsorption mechanism +
Footnote †: journal: Applied Sciences  
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Footnote †: journal: Applied Sciences  
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Footnote 0: _Lawsonia inermis_ are the authors of the _Lawsonia inermis_, which is a great  
there has been growing interest in exploring natural compounds as corrosion inhibitors because of their eco-friendly nature and potential effectiveness in inhibiting corrosion [2]. _Lawsonia internis_ (LI), commonly known as henna, is one such natural compound that has shown promise in corrosion inhibition studies [3]. This plant, native to North Africa and West and South Asia, produces bioactive compounds that exhibit inhibitory properties against metal corrosion. _Lawsonia internis_ is a plant species belonging to the Lythracee family. Indigenous to North Africa, West Asia, and South Asia, _Lawsonia internis_ has been traditionally used for its medicinal, cosmetic, and dyeing properties. The plant contains bioactive compounds, such as lawsone (2-hydroxy-1,4-naphthoquinone), tannins, flavonoids, and polysaccharides, which exhibit various biological activities, including antioxidant and antimicrobial properties [4]. Several studies have investigated the potential of _Lawsonia internis_ as a corrosion inhibitor for different metals and alloys, such as aluminium, copper, and carbon steel. A study by [PERSON] et al. [5] confirmed the corrosion inhibition of mild steel in well water in the presence of a _Lawsonia internis_ leaf extract, using weight loss, polarisation techniques, and AC impedance spectroscopy. Fourier-transform infrared (FTIR), scanning electron microscopy (SEM), and atomic force microscopy (AFM) investigations confirmed the presence of a protective iron-lawsone complex that was adsorbed on the metal surface. In addition, [PERSON] et al. [6] have explored the corrosion inhibition potential of henna for aluminium alloys in seawater.