A novel use of solid waste extract from tea factory as corrosion inhibitor in acidic media on boiler quality steel

Abstract

Solid waste from a tea factory was used to prepare environment-friendly, inexpensive “green corrosion inhibitor”. The solid tea waste extract (STWE) was prepared from the solid waste by the conventional extraction method and characterized by liquid chromatography–mass spectroscopy (LC–MS). The inhibition performance of this synthesized STWE was evaluated in 1 (M) HCl on boiler quality (BQ) steel. Their efficiency of inhibition was assessed by electrochemical techniques, namely the potentiodynamic polarization test (PDP), electrochemical impedance spectroscopy (EIS). The results depict that the increase in the concentration of STWE increases the inhibition efficiency of the extract. Various models were fitted to explore the type of adsorption, and among them, Langmuir was found fitted best. The free energy ΔGads° was calculated as -17.76 KJmol−1 from adsorption isotherm and, revealed physisorption of STWE on the BQ surface. The inhibitive strength or effectiveness of inhibitor molecules was assessed based on donor-acceptor capabilities between the molecules and the metallic surface. This capability was evaluated with the help of quantum chemical calculations based on density functional theory.