Document Type

Thesis - Open Access

Award Date

1977

Degree Name

Master of Science (MS)

Department

Chemistry

Abstract

The use of salicylic, thiosalicycle, and phthalic acids as chelating agents for the extraction of Cr(III) from aqueous solution was investigated. Normal butanol was selected as a solvent due to its relatively low solubility in the aqueous phase. Heating of the metal-ligand mixture was necessary to accelerate complex formation. The efficiency of the extraction process was found to be dependent upon pH, heating duration, and the choice of buffer systems. The % extraction was reduced using some buffer systems due to the formation of non-extractable complexes with chromium. A potassium hydrogen phthalate buffer system was found to yield the highest % extraction. The extraction efficiency is enhanced by using NaCl as a salting-out agent. Optimum extraction conditions using the phthalate buffer are pH 3.0, 35 minutes healing, and 6.7 grams NaCl per 25 ml of aqueous phase. Under these conditions 97.3% extraction efficiency was obtained. Extraction efficiencies were calculated after analysis of sample by atomic absorption spectroscopy. The composition of the extracted species was investigated by use of the mole ratio method and u.v.-visible spectroscopy. The ligand to metal ratio was found to be 2:1 yielding a complex of the formula Cr(L)(HL).

Library of Congress Subject Headings

Chromium

Ligands

Extraction (Chemistry)

Format

application/pdf

Number of Pages

66

Publisher

South Dakota State University

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