Corrosion Inhibition and Sustainable Waste Management: Evaluating the Potential of Expired Lopinavir-Ritonavir in Steel Protection

Abstract

This study investigated the potential of expired Lopinavir-Ritonavir (LPV-RTV) co-formulated antiretroviral drug, a pharmaceutical waste product, as a corrosion inhibitor for mild steel. The corrosion inhibition efficiency of expired LPV-RTV was evaluated through three complementary methods: weight loss, potentiodynamic polarization (PDP), and Scanning Electron Microscopy with Energy Dispersive X-ray Spectroscopy (SEM-EDX). The results demonstrated that expired LPV-RTV significantly enhanced the corrosion resistance of mild steel, achieving maximum inhibition efficiencies of 95.7% by weight loss and 93.0% by PDP. SEM-EDX analysis of the steel surfaces revealed the formation of a protective layer, further supporting the corrosion inhibition mechanism. These findings highlight the effectiveness of expired LPV-RTV as an efficient, eco-friendly corrosion inhibitor. The study also emphasizes the potential of utilizing expired pharmaceuticals for sustainable resource recovery, offering a viable solution for both pharmaceutical waste reduction and industrial corrosion control.