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

摘要

Problem statement: In this study we examined the precipitation of Zn(II) ion in water solutions of ZnSO_4.7H_2O (1.10~(-2) and 5.10~(-3) mol L~(-1)) with (2S)-2-aminobutanedioic acid (1.10~(-1)-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.