An exploratory review on corrosion inhibitors derived from natural materials for low-carbon steel in acids: mechanistic insights, applications, challenges, and future strategies

Corrosion of carbon steel continues to be an important issue due to effects on the longevity and performance of metal structures and components. It is a big problem and becomes bigger when it is exposed in strong acids. Every year, huge money is spent on corrosion control. Out of various methods of control, the application of synthetic inhibitors for different type of metals in aggressive environments is very popular. Synthetic inhibitors are very efficient; however, their toxicity and price restrict their frequent exposure in public. Hence, inhibitors derived from green materials (GMs) or natural materials (NMs) have been preferred, now days. GMs and NMs are eco-friendly, cost-effective, efficient, and show no toxicity. NMs are equally competent to synthetic inhibitors and works similarly. However, a detailed investigation of their working mechanisms can offer a great help to persons working in this area for a better formulation of NMs for various purposes. This review investigates the papers published in this area since last 10 years, and tries to provide a complete and big view on working mechanisms of NMs for carbon steel in strong acid media. This review also discusses basics of corrosion, types, need of corrosion control, control methods, inhibitors, and basic working mechanisms. Furthermore, this review covers their application areas, drawbacks, and improvement for better performance. This review offers a great understanding of green inhibitors and their working mechanisms, which will be extremely beneficial for the researchers working in this area at basic as well as advanced levels.