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

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 chlor-ide-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 mole-cules of crude glycerol components, and probably the formation of copper-glycerol com-plexes 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.