Dissolution behavior of metallic zinc in organic acid

Abstract

A series of experiments were conducted to examine the effect of citric acid on the dissolution of zerovalent zinc. Theeffects of citric acid concentration, the presence of anions and temperature were studied. The results have shown thatzinc dissolution registered a maximum of 34% with 0.5M citric acid after 270 min and that the nature of anionspresent with citric acid affected differently the dissolution rate. In fact, the presence of 2M nitrates with 0.5M citricacid dissolved totally zinc after 30min while 91.85% and 13.15% were dissolved in the presence of 2M chlorides andsulfates respectively after 270min. SEM analyses have shown that the morphology of the corroded surface dependedon the composition of the solution. The kinetic study has shown that zinc dissolution was controlled by the chemicalreaction in all cases and that the activation energy was 39.3 kJ $mol^{-1}$.