Abstract

Chrome commonly exists in two oxidation states: Cr(III) and Cr(VI). Cr(III) is considered helpful to health while Cr(VI) is highly toxic. Many reports have indicated the presence of Cr(VI) in some chrome tanned leathers. Various chemicals used in leather making and also storage conditions can affect the content of Cr(VI). In our experiments leather samples were treated with seven kinds of sulphited oil components and we determined the content of Cr(VI) after ultraviolet (UV) light exposure and heating. The results showed that the content of Cr(VI) was related to the iodine value of the oil. The higher the iodine value, the greater the content of Cr(VI). However, the levels are independent of the categories of fat-liquoring agents. The experiments have proved that vegetable catalpa oil had the strongest influence followed by fish oil. Tara extract was found to decrease the content of Cr(VI) in leather.