Determination of Precipitation Limit of Zn(II) Ion with (2S)-2-Aminobutanedioic Acid

Problem statement: In this study we examined the precipitation of Zn(II) ion in water solutions of ZnSO₄.7H₂O (1.10^-2 and 5.10^-3 mol L^-1) with (2S)-2-aminobutanedioic acid (1.10^--1.10^-3 mol L^-1) in constant ionic strength of 0.6 mol L^-1 NaCl. We have determined the concentration region where we have found the clear solution and solid phase. The solid phase is analyzed by IR spectroscopy. Approach: From precipitation diagrams of zinc with (2S)-2-aminobutanedioic acid in ionic force 0.6 mol L^-1 NaCl, we have found that during decreasing the concentration (2S)-2-aminobutanedioic acid in case of constant concentration of Zn(II) the limit of precipitation is shifted to lower values of pH. Results: Also from precipitation diagrams we can see that when the concentration of zinc increases, in case of constant concentration of (2S)-2-aminobutanedioic acid the limit of precipitation will shift at lower values of pH. Conclusion: From the IR spectroscopic analysis we can conclude that Zn (II) ion has reacted with (2S)-2-aminobutanedioic acid.