• Methanol and water extracts of coconut coir dust inhibited mild steel corrosion in H2SO4.
  • The adsorption of ME and WE follow Temkin and Freundlich isotherm models, respectively.
  • The extracts behave as a mixed-type inhibitor but under cathodic control.
  • Results from all the methods are in reasonable agreement.
  • ME is a better inhibitor than WE of coconut coir dust.


Corrosion inhibition of mild steel in H2SO4 by water and methanol extracts of coconut coir dust was studied using chemical and electrochemical techniques. It was found that the extracts inhibited the acid induced corrosion of mild steel. The inhibition efficiency increased with increase in extracts concentration but decreased with increase in temperature. Methanol extract was found to be a better inhibitor. The adsorption of the extracts’ components onto the mild steel surface follow Temkin and Freundlich adsorption isotherms for methanol and water extracts respectively. Polarization studies show that the extracts act as mixed typed inhibitor but under cathodic control.