Abstract

A major contributor to the pollution from the tanning industry is conventional unhairing using sodium sulphide and lime. In this study, an attempt has been made to develop a lime-free unhairing process using sodium silicate as a hair immunization agent. The parameters of the unhairing process have also been optimized evaluating qualitative indexes of the hide during processes and the leather obtained as well. It was established that hair removal quality and chemical and strength properties of the experimental leathers are comparable to those of control leathers. A significant reduction in chemical oxygen demand (COD), biochemical oxygen demand and total Kjeldahl nitrogen were obtained in comparison with the comparative data for the conventional unhairing with hair burning.