Determination of Cr (VI) in Dark-colored Leathers Adsorbability of Active Carbon for Cr (VI)

摘要

It is well known that sexivalent chromium ion (Cr (VI)) may do great harm to human health and the environment. To detect and control the amount of Cr (VI) contained in leathers is of great significance in both theory research and practical application. Absorption spectrophotometer, which has been being widely used in the detection of Cr (VI) nowadays, is apt to be interfered by colors of dyestuff in the extraction mixture and the corresponding results are not exact as a result. In this paper, the relationship between the pH of the mixture and the Cr (VI) quantity adsorbed by active carbon was discussed. The results indicate that little or even no Cr (VI) might be absorbed by active carbon when the pH of the mixture is higher than 11.0. A precise method for detecting the Cr (VI) amount in deep colored leather sample may be found accordingly. Therefore, before the amount of Cr (VI) in the mixture is detected, the pH of the mixture should be adjusted to a value that is higher than 11.0. And then, active carbon is used to de-color the solution repeatedly until the dyestuff is adsorbed thoroughly. The amount of Cr (VI) in the extraction mixture may be detected precisely and without any interruption of dyestuffs.