Solid-Phase Extraction of Chromium (VI) by Polyurethane Foam Treated with Hydrochloric Acid

Chromium exists widely in nature as both trivalent and hexavalent forms. Although, Cr(III) is an essential element for humans at trace levels, Cr(VI) has great toxicity and carcinogenicity at low concentrations. Cr(VI) is typically present in aqueous solutions, such as CrO42- anion. Polyurethane foam (PUF) was impregnated with hydrochroric acid (HCl-PUF) and then used to remove Cr(VI) from environmental water samples. However, Cr(VI) was not adsorbed on RN, Cr(VI) was adsorbed on HCl-PUF. In this study, the adsorption conditions of Cr(VI) on HCl-PUF were investigated, such as the adsorption time and the solution pH. Further, the deadsorption conditions of Cr(VI) from HCl-PUF were investigated, such as the kind of eluents and their concentrations. Cr(VI) was quantitatively adsorbed on HCl-PUF at a pH range 3.0-8.0 from aqueous solutions and their adsorption isotherms were fitted by the Freundlich equation. The Cr(VI) adsorbed on HCl-PUF as eluted with 3.0 mol dm(-3) nitric acid. The property of HCl-PUF was extended to the preconcentration and determination of trace amounts of Cr(VI) in water samples by Inductively Coupled Plasma Emission Spectrometry (ICP-AES).