Release of chrome in leather production with less chrome tannage and less chrome retannage

Abstract

High chrome concentration in wastewater of traditional chrome tannage has attracted increasing attentions，and the distribution of chrome in wastewater in the processes of less chrome tanning and less chrome retanning has investigated. The results indicate that the residual chrome in chrome tanning and chrome retanning wastewater is still the main origin of chrome in effluent, but the decrease of chrome concentration in wastewater is found to be significant. It is interesting that the properties of leathers including shrinkage temperature and mechanical properties do not decrease sharply along with the decrease of chrome offer. This fact demonstrates that the chromes that effectively react with collagen have not been decreased although reducing the chrome offer. Therefore, the development of technologies of less chrome tannage and less chrome retannage that can reduce chrome offer might be an important direction in alleviation of chrome discharge in tannery.