Abstract
Direct application of the kinetic spectrophotometric methods for determination of trace levels of vanadium(V) to waste waters may be unreliable. This may be attributed to the problems of interferences of various cations which are common pollutants in many kinds of industrial waste water samples in Cairo. The oxidation of gallic acid by ammonium persulphate, catalysed by vanadium(V) was chosen for our study. The interfering effects of cations that often accompany vanadium in waste waters such as Cr3+, Co2+ Cu2+, Fe3+, Ni2+, Sr2+, Pb2+ and Cd2+ ions on the net absorbance given by 4 mug l(-1) of vanadium(V) solution were studied. The minimum concentrations of citric acid, EDTA, ascorbic acid, and oxalic acid as leveling off agents required to level off interfering effects due to the aforementioned cations in the kinetic determination of vanadium(V) were 30, 40, 50 and 100 mug ml(-1), respectively. Satisfactory agreement was achieved by comparing the analytical results for wastewater samples, obtained by ICP-AES using the standard addition method and the proposed method. Significantly high recoveries (97-102%) were obtained for the analysed samples with Sr of less than 2%, indicating the high accuracy and precision of the proposed method.