Application of eco-friendly products as corrosion inhibitors for metals in acid pickling processes – A review

Acid pickling is one of the industrial processes used for removal of scales. The main acids abundantly used in industries are HCl and H2SO4. One of the severe problems, in using these acids, is corrosion of metallic substrates. To overcome this problem, synthetic inhibitors have been used. On the other hand, most of these inhibitors are toxic. Eco-friendly inhibitors are suitable candidates for replacing synthetic inhibitors, because of their non-toxic nature, abundant sources and low cost. This paper discusses properties, mechanism of inhibition and efficiencies of eco-friendly inhibitors used in acidic media.