Solvent extraction of chromium and copper using Schiff base derived from terephthaldialdehyde and 5-amino-2-methoxy-phenol

Abstract

Separation with solvent extraction of Cu2+ and Cr3+ from aqueous solution using [N,N′-p-phenylene bis (5-amino-2-methyoxy-phenol)] as the new extractant has been studied. The Schiff base was synthesized by reaction of terephthaldialdehyde and 5-amino-2-methoxy-phenol. Schiff base has been characterized by elemental analyses, mass and IR spectral data. The Schiff base has been studied by liquid–liquid extraction toward the metal ions (UO22+) and d-metal ions (Hg2+, Cu2+ and Cr3+) from aqueous phase to organic phase. The effect of chloroform and nitrobenzene as organic solvents on the metal chlorides extraction was investigated at 25 ± 0.1 °C by using flame atomic absorption. It observed that extraction percentages not effect with the change of diluents. It was found that the extraction efficiency of ligand for metals is in the order Cu2+ > Cr3+. The results show that metals ions of U3+ and Hg2+ are not extracted by Schiff base (E < 1%). The extractability and selectivity of cations was evaluated as a function of relationship between distribution ratios of metal and pH. Cu2+ showed the highest extractability and selectivity at pH 6.27. The effect of ionic strength and aqueous to organic phase on the extraction has been studied.

Keywords

• Synthesis of Schiff bases
• Extraction liquid–liquid
• Terephthaldialdehyde