Corrosion inhibition of aluminium alloy in NaCl solution by glycerol from biodiesel production

Abstract It was evaluated the potential of using crude glycerol, a by-product of biodiesel production from vegetable oil, as a «green» corrosion inhibitor for aluminum alloys in the neutral chloride-containing medium. It was found that it has inhibitory properties and efficiently protects aluminum alloys from corrosion in 0.1% NaCl solution; the degree of protection was up to 79%. The protective action of crude glycerol increases with increasing its concentration to 2.5 g/l. Impedance modulus of aluminum alloy increases in inhibited corrosion solution. The mechanism of corrosion inhibition is the physical and partially chemical adsorption of molecules of crude glycerol components, and probably the formation of copper-glycerol complexes on the metal surface. The adsorption of the studied inhibitor is described by the Frumkin isotherm. Energy dispersive x-ray analysis confirmed the formation of an organic protective layer on the metal surface.