ISSN 1017-2548(Print)
ISSN 2234-8530(Online)
Volume 30, Number 5
JKCSEZ 30(5)
October 20, 1986 

Atomic absorption spectrophotometric (AAS) determination of hexavalent chromium [Cr(Ⅵ)] in a waste water was studied. Cr(Ⅵ) was extracted with p-xylene from the wastewater, in the way of ion pair formation with anion exchanger aliquat-336(tri-caprylmethyl ammonium chloride). 100ml waste water, after organic materials were extracted out with toluene, was acidified with conc. HCl adjusting the medium to pH 0.5 and 20ml of p-xylene containing 0.01M aliguat-336 was used to extract Cr(Ⅵ) from the acidified solution. The absorbance of chromium was measured with air-acetylene flame at 357.9nm. Standard addition method was used in the determining concentration of Cr(Ⅵ) extracted. No interference has been found in the extraction of Cr(Ⅵ) by the Al(Ⅲ), Fe(Ⅲ) and Cr(Ⅲ) ion presented. However, Fe(Ⅱ) decreased the absorbance of Cr(Ⅵ), due to the fact Fe(Ⅱ) reduces Cr(Ⅵ) to Cr(Ⅲ). The contained organic material was removed prior to extracting process, since it may reduced the absorbance of Cr(Ⅵ). The recovery of added Cr(Ⅵ) was over 96%, which seems to be promising and the relative standard deviation was 3.95%