Scholarlink

<p>The present study investigates <i>Leonotis leonurus</i> leaf extract (LL-LE) as a green corrosion inhibitor for mild steel in 1.0&#xa0;M HCl medium. The corrosion inhibition performance was evaluated at different inhibitor concentrations (2–10%) and temperatures (303–333&#xa0;K) using weight loss measurements, linear polarization resistance (LPR), Tafel polarization, and electrochemical impedance spectroscopy (EIS). Preliminary phytochemical screening confirmed the presence of bioactive constituents such as alkaloids, flavonoids, tannins, saponins, glycosides, carotenoids, and phenolic compounds containing active heteroatomic sites. Bode plot analysis further supported the inhibition effect, showing an increase in impedance from 0.3167 Ω to 1.5680 Ω at 10% LL-LE, along with a phase angle rise from 31.10° to 65.78°, indicating enhanced surface coverage and protective film formation. The results show that the inhibition efficiency increases with increasing LL-LE concentration, while a decrease in efficiency is observed with rising temperature, indicating partial desorption of the protective film from the metal surface. Adsorption studies revealed that the inhibition process follows the Langmuir and Temkin isotherms, with high adsorption equilibrium constants and negative ΔG°ads values, confirming a spontaneous, predominantly physisorption-controlled mechanism. Spectroscopic analyses (FT-IR and UV–Vis) verified the interaction between phytochemical constituents and the metal surface. Surface characterization using SEM, AFM, and contact angle measurements confirmed corrosion-induced wettability changes, where the polished mild steel exhibited a contact angle of 145.4°, which drastically decreased to 38.1° after 2&#xa0;h immersion in 1.0&#xa0;M HCl, indicating severe surface degradation and increased hydrophilicity. The combined electrochemical, adsorption, and surface analyses demonstrate that LL-LE acts as an effective, eco-friendly corrosion inhibitor by blocking active metal sites through adsorption, highlighting its potential for sustainable industrial and environmental corrosion protection applications.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Electrochemical Study of Leonotis Leonurus Extract as Eco-friendly Corrosion Inhibitor

  • 期刊论文

  • 发表日期：

    2026年3月30日

查看全文
  • A. Samsathbegum,
  • H. Mohamed Kasim Sheit,
  • K. S. Mohan,
  • M. Varusai Mohamed,
  • P. Srinivasan,
  • M. Muthu Krishnan

摘要

The present study investigates Leonotis leonurus leaf extract (LL-LE) as a green corrosion inhibitor for mild steel in 1.0 M HCl medium. The corrosion inhibition performance was evaluated at different inhibitor concentrations (2–10%) and temperatures (303–333 K) using weight loss measurements, linear polarization resistance (LPR), Tafel polarization, and electrochemical impedance spectroscopy (EIS). Preliminary phytochemical screening confirmed the presence of bioactive constituents such as alkaloids, flavonoids, tannins, saponins, glycosides, carotenoids, and phenolic compounds containing active heteroatomic sites. Bode plot analysis further supported the inhibition effect, showing an increase in impedance from 0.3167 Ω to 1.5680 Ω at 10% LL-LE, along with a phase angle rise from 31.10° to 65.78°, indicating enhanced surface coverage and protective film formation. The results show that the inhibition efficiency increases with increasing LL-LE concentration, while a decrease in efficiency is observed with rising temperature, indicating partial desorption of the protective film from the metal surface. Adsorption studies revealed that the inhibition process follows the Langmuir and Temkin isotherms, with high adsorption equilibrium constants and negative ΔG°ads values, confirming a spontaneous, predominantly physisorption-controlled mechanism. Spectroscopic analyses (FT-IR and UV–Vis) verified the interaction between phytochemical constituents and the metal surface. Surface characterization using SEM, AFM, and contact angle measurements confirmed corrosion-induced wettability changes, where the polished mild steel exhibited a contact angle of 145.4°, which drastically decreased to 38.1° after 2 h immersion in 1.0 M HCl, indicating severe surface degradation and increased hydrophilicity. The combined electrochemical, adsorption, and surface analyses demonstrate that LL-LE acts as an effective, eco-friendly corrosion inhibitor by blocking active metal sites through adsorption, highlighting its potential for sustainable industrial and environmental corrosion protection applications.