Experimental and computational investigation of waste pineapple crown for mild steel corrosion inhibition in salty water

초록

A waste natural material (WNM) is investigated in this work to determine effectiveness to prevent mild steel (MS) corrosion in 0.5 M NaCl. The pineapple crown (PC) is extracted into water, and 50-400 mg L-1 of its aqueous extract (AEPC) is directly mixed in NaCl solutions to investigate the inhibition effects. The biomolecules in AEPC have been tested by UV-vis (UVS) and FTIR spectroscopy (IRS). The MS's corrosion, with various amounts of AEPC, has been investigated by open circuit potential (OCP), Tafel polarization curves (TP), and electrochemical impedance spectroscopy (EIS). The results have confirmed that AEPC significantly protects MS in NaCl, and the best performance is obtained for 300 mg L-1 of AEPC (91%). The surface pictures, clicked field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM), show that AEPC has effectively protected MS in NaCl. To get more insights, quantum chemical calculations like density functional theory (DFT) and molecular dynamics (MD) simulations are also explored. Based on the overall investigation, mechanism for corrosion prevention has also been proposed. The adsorption of AEPC MS is suggested to be responsible for lowering the corrosion rate.

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