Biomass of Microalgae Chlorella sorokiniana as Green Corrosion Inhibitor for Mild Steel in HCl Solution
Gustavo Almeida de Oliveira, Viviane M. Teixeira, Jéssica Nogueira da Cunha, Matheus Rangel dos Santos, Victor Magno Paiva, Michelle Jakeline Cunha Rezende, Anita Ferreira do Valle, Eliane D’Elia
Abstract
Biomass of microalgae Chlorella sorokiniana was studied as a green inhibitor of corrosion of mild steel in 1 mol L −1 HCl solution. The investigation includes weight-loss experiments, potentiodynamic polarization curves, electrochemical impedance measurements and surface analysis by scanning electron microscopy. The use of 100 mg L −1 of the Chlorella sorokiniana biomass reached an inhibition efficiency of 94.6% after 24 h of immersion. The addition of the microalgae biomass did not change the apparent activation energy which characterizes adsorption by blocking, showing that the constituents form a protective film on the metallic surface of mild steel. The high molecular weight fraction isolated from the biomass showed an inhibition efficiency close to the total biomass, which suggests that proteins macromolecules are probably responsible for the inhibitory action observed by the microalgae biomass.