Insight into the Anti-Corrosion Performance of Spinacia Oleracea Extracts as a Sustainable Corrosion Inhibitor for Copper in 1M Solution of Nitric Acid

Sustainable Energy & Environment Research Group (SEERG), Department of Chemical Engineering, Faculty of Engineering, Built Environment & Information Technology, University of Pretoria, Hatfield, 0028, Pretoria, South Africa.

^* Corresponding author: michael.daramola@up.ac.za

Abstract

Green corrosion inhibitors play a significant role in lowering the rate at which metal corrodes as well as the environmental effect of hazardous substances. Using electrochemical and gravimetric methods, Spinacia Oleracea extract was employed in this work as an environmentally friendly green inhibitor to minimize Cu dissolution in 1 M HNO₃. Activated parameters were identified and addressed, with varying inhibitor doses. The extract exhibits a corrosion inhibition efficacy of 98.9% at 500 ppm. Furthermore, its corrosion inhibition performance continuously stays above 90% even at higher temperatures. According to the Langmuir adsorption isotherms, the experimental results show that the adsorption process protects Cu from corrosion. Scanning electron microscopy was used to analyze the surface and show that a protective extract coating had precipitated on the Cu surface. Fourier transform infrared spectroscopy was used to examine the extract's interaction with copper. The application not only broadens the resource utilization of plant extracts but also brings an effective and innovative corrosion inhibitor to the field of environmentally friendly chemistry.