One potential method of recycling expired thiocolchicoside drug is to use an environmental corrosion inhibitor for carbon steel in HCl

Abstract

Abstract One of the problems facing our society today is managing hazardous waste. Expired pharmaceuticals are a type of waste that is not recycled in any way but is instead burned for disposal. These pharmaceutical drugs have been shown to have corrosion-inhibiting properties for various metals and corrosive solutions. The current study examined the corrosion tendency of 1040 carbon steel (1040CS) under acidic pH (1 M HCl) by using an unused, expired Thiocolchicoside (ETC) drug as a possible corrosion inhibitor was studied by using the weight loss (WL), electrochemical impedance spectroscopy (EIS), and potentiodynamic polarisation (PP) tests, and. It was observed that the increase in ETC doses led to the rise in corrosion IE (%) up to 93.3, 90.7, and 91.4%, as shown by EIS, PDP, and WL techniques, respectively. However, inhibition efficiency diminished with rising temperatures, declining from 91.83% at 298 K to 78.63% at 318 K (all at 400 ppm). The results obtained high Rct during electrochemical processes, which reduced Icorr and, in turn, the ETC molecule strong adsorption onto the 1040CS surface. The PP data showed that this ETC decreased the corrosion current density by a mixed-type mechanism. SEM, AFM, and FTIR surface studies demonstrated the development of a protective layer at the CS surface. DFT-based quantum chemical indices made further understanding of the inhibitory mechanism possible. Results gained for all techniques used are in good agreement.