Abstract

The leather industry is facing a serious problem with water pollution. To eliminate pollution by tanneries’ wastewater, carbon dioxide supercritical fluid (SCF-CO2) was put forward to substitute for water as leather making medium. The results showed that chrome tanning in SCF-CO2 medium is an effective new clean method for leather making. In order to achieve a leather with good qualities, the parameters of chrome tanning in SCF-CO2 medium should be controlled so that the chrome tanning temperature is up to 31°C, the initial pHv alue of the sample was 3.0-3.5 and it was tanned for 2 hours. The tanning procedure could be shortened to 2 hours compared to a traditional time of approximately 20 hours. SCF-CO2 medium has the ability to open up collagen fibres, and it plays a role in the penetration of chrome tanning agents into skin and their fixation to collagen. This research reveals the potential of chrome tanning by using much less water than current technology.

Abbreviations

SCF-CO2: carbon dioxide supercritical fluid; Pc: Critical pressure; Tc: Critical temperature; Ts: Shrinkage temperature