Effect of pH, Anions and Acids on the Extraction of Zinc (II) from Aqueous media using Acetylacetone Solutions of Sulphamethoxazole

Abstract

The challenge of heavy metal contaminations have been remediated to a certain level by the application of several methods of their extractions from aqueous media. Solvent extraction of zinc (II) ions from buffered aqueous solutions into acetylacetone solution of sulphamethoxazole as a function of pH and concentration of anionic substances and certain mineral acids were investigated in this work. The aqueous medium was prepared by dissolving 1.0995g of ZnSO4.7H2O in 250 ml volumetric flask to form 1000mg/L solution. 50mg/L working concentration was prepared from the 1000mg/L by dilution method. The organic phase is 0.5 M Sulfamethoxazole solution prepared by dissolving 12.664g of the salt in 100 ml acetylacetone. 2 ml each of aqueous and organic phases were taken with micro pipette and transferred into a set of 20 ml extraction bottle and the mixture was agitated mechanically for about 30 minutes. The mixture was allowed to settle and separate into two layers. 1 ml of the aqueous phase was taken, diluted and analysed for Zn (II) ions using atomic absorption spectrophotometer at a wavelength of 213.9. The results obtained on studying the effect of pH showed that Zn (II) ion was quantitatively extracted between pH of 7.0 to pH 8.0. The highest percentage extraction 85.37% was observed at pH 8.0 in acetylacetone solution of sulphamethoxazole. Increase in pH above 8.0 resulted in a steady decrease in the extraction of Zn (II). Studies on the effect of anions showed significant extractions which changes as the anions concentrations increased. All studies on mineral acids also showed significant extractions and increase in the concentrations of the acids affected the percentage extraction. Generally Zinc (II) ions can be extracted quantitatively in mild acids and anions concentrations when buffered from slightly acidic pH ranges of 6.0 to slightly alkaline pH values of 8.5.