Non-polar Medium Enables Efficient Chrome Tanning

Abstract

Converting raw hides and skins into leather through chrometanning in water medium creates huge environmental burden bycontaminating the precious water resource on the one hand anddischarging more chromium on the other. Here, a non-polargreen solvent, heptane, alternate to water has been evaluated forchrome tanning employing both pickle-based and pickle-lessmethod. The preceding (pre-tanning) and succeeding (posttanning)processes were water mediated for comparison. Theresults show that the color and other organoleptic properties ofboth wet blue and crust leathers are comparable to conventionalleathers. The strength and structural properties of experimentalcrust leathers are comparable to that of control leathers. Themain benefits in switching over to heptane medium areimproved exhaustion of chromium during both pickle-basedand pickle-less chrome tanning, better chromium distributionand recycling ability. The process also helps in reducing thechemical oxygen demand, biological oxygen demand and totalsolids levels in the composite liquor significantly.