Ultrasound-assisted extraction of corrosion inhibitor from plant and its application

Plant-derived extracts have emerged as a dynamic and promising class of corrosion inhibitors for metals, offering distinct advantages including cost-effectiveness, biodegradability, and biocompatibility. Conventional extraction techniques often require extended processing duration and elevated temperature, which can significantly diminish both the biological activity and corrosion inhibition efficiency of the obtained extracts. In addition, traditional extraction approaches frequently employ potentially hazardous organic solvents, presenting environmental concerns. Ultrasound-assisted extraction (UAE) represents a particularly effective methodology for obtaining plant corrosion inhibitors, demonstrating three principal benefits: reduced extraction time, decreased energy consumption and reagent requirements, and enhanced extraction efficiency, particularly for specific compound classes such as phenolic substances. Moreover, UAE enhances the bioavailability of active compounds and their subsequent interfacial interactions on metal surfaces. However, optimal UAE parameters must be carefully selected as they can vary considerably between different plant extracts. This work reviewed the extraction methods of plant corrosion inhibitors, UAE mechanism, the influence factors and applications of UAE, the future perspectives and challenges of UAE, and emphasized the integration of mechanistic studies with extraction parameter optimization to design next-generation, high-performance green corrosion inhibitors. Meanwhile, a forward-looking roadmap for future UAE research was proposed, which aimed to develop environmentally UAE technologies that operated under mild conditions (lower temperatures and shorter extraction times) to simultaneously enhance corrosion inhibitor performance and minimize ecological impact. This review offered insights and methodologies for the environmentally friendly and efficient extraction of plant corrosion inhibitors. • Ultrasound-assisted extraction is a promising method for obtaining plant corrosion inhibitors. • Various extraction methods for plant corrosion inhibitors were analyzed and summarized. • The utilization of plant corrosion inhibitors in metal anti-corrosion strategies were reviewed.