Журнал текстильной науки и техники

Selective Speciation of Cr(III) and Cr(VI) by Micro-emulsion Using UV-Vis. Spectrophotometry

Abstract

Mohammadi A, Doroodmand MM and Sadegh MMR

A novel UV-Vis. spectrophotometric detection system is introduced for speciation of Cr(III) and Cr(VI) via interaction with a new micro-emulsion generated between a sweet crude oil as nonpolar phase, H2O as polar phase and C2F4 (R22) gas as disperser. This micro-emulsion is selective for Cr detection and determination via observation of absorption peak at 578 nm wavelength. Determination of Cr is achieved under optimized conditions such as 3.0 mL of sweet crude oil/R22/water with mole fractions of 0.2, 0.2 and 0.6, respectively at 25°C and pH ~7.0. For Cr speciation, Cr(III) is detected via directly interaction with the synthesized micro-emulsion. Whereas Cr(VI) is detected via difference between total Cr and Cr(III) during reduction using 0.055 g of S2O32- as reducing agent. Relative standard deviation for at least 5 replicate analyses is 1.73%. Reliability of the method has also been evaluated via determination of Cr in some wastewater samples.