Investigation of African mangosteen leaves extract as an environment-friendly inhibitor for low carbon steel in 0.5 M H2SO4

Abstract

The African mangosteen plant species comprises a variety of bioactive molecules. In the following research, phytochemicals have been screened with Shinoda test, Benedict's test, etc., for ethanolic African mangosteen leaves extract (AMLE). The inhibition efficacy of AMLE for low carbon steel corrosion in 0.5 M H2SO4 was assessed by mass-loss, polarization, and electrochemical impedance spectroscopic (EIS) approach. Corrosion studies were performed for various inhibitor concentrations and differing temperatures. The inhibition performance of AMLE on low carbon steel rises with concentration rise. Potentiodynamic polarization results revealed that AMLE bind to the surface of low carbon steel, as they hinder corrosion spots from the bulk media, and the maximum inhibition performance (ηw) was 96.14% for 1.5 g/L concentration. Electrochemical impedance spectroscopy (EIS), the maximum inhibition performance (ηw) was 95.57% attributed to AMLE adsorption on the low carbon steel surface. Findings reported from electrochemical and chemical research are well in agreement. The AMLE inhibition activity is stated by the adsorption process on low carbon steel and complies with Langmuir isotherm. The values of ΔGadso were estimated to be between −30.27 to −33.06 kJ mol−1, indicating that the inhibition effect is exothermic and spontaneous. Furthermore, the determined thermodynamic parameters suggest that the adsorption process is intuitive. Scanning electron microscope (SEM), Fourier-transform infrared (FT-IR) spectroscopy, and atomic force microscopic technique (AFM) were employed to examine the surface analysis of the low carbon steel samples.