Ethanolic extract of waste spinach leaves for corrosion prevention of copper in 3.5 % NaCl

Corrosion is the natural deterioration of the metals due to their high and imbalanced energy. The corrosion causes significant loss of metals, which can lead to failure generating economic losses and safety threats for human. One of the most effectual approaches for corrosion control is coating of protective materials on metal surfaces. The coating isolates metals from surroundings and protects the base metal. Though inorganic coating materials can be used for the above-mentioned purpose, organic materials are preferred for corrosion protection due to their sustainability, effectiveness, low-cost, low to negligible toxicity, and easy availability. Organic materials derived from natural sources are good alternatives for the same. One of the similar organic materials (spinach leaves) has been investigated in this work for copper ' s (Cu) prevention in 3.5wt% NaCl solution. The waste spinach leaves (SL) obtained from house garbage have been extracted in ethanol and tested by spectroscopic techniques. The ethanol extract of spinach leaves (EESL) is found rich in biomolecules, which is good for its stacking strength on Cu. The EESL has been deposited on Cu by drop casting (DC) in layers (1-3). The coated Cu samples have been examined by open circuit potential (OCP), Tafel polarization curves (TPC), electrochemical impedance spectroscopy (EIS), and optical microscopy (OM). The corrosion tests (OCP, EIS, and TPC) have shown that EESL coatings effectively protect Cu in NaCl. It is noticed that the maximum corrosion protection (85%) has been offered by 3 layers of EESLcoated Cu. It has been analyzed that the efficient coverage of Cu surface by nobler EESL layers are responsible for this. This fact has also been disclosed by OM studies of Cu surfaces. Based on overall examination, a schematic corrosion protection mechanism has also been made and discussed. Future scope of the work is performing tests at industrial scale, purification of the extract, and experiments in different environmental conditions.