1990 Volume 39 Issue 9 Pages 461-466
In our previous works, aluminium ion was found to serve as effective inhibitor for iron corrosion in water. However, the ion is partly hydrolyzed to form AlOH2+ ion, which cause the solution slightly acidic (pH=4.3). It follows that neutralization is inevitable for discharge. In order to overcome this defect, aluminium-ligand system was examined. Among many ligands investigated, oxalate and malonate were found to be suitable. Since these salts prevented the hydrolysis of aluminium ion as a result of the complex formation, the solution became neutral. Furthermore, the inhibitive effect was considerably enhanced as high as 97%. The mechanisms of these behaviour were also discussed based on the thermodynamic consideration.
