A bio-driven lime and pickle free tanning paves way for greener garment leather production

Conventional methods employed in leather processing subject the skin or hide to a wide variety of chemicals. This contributes to an increase in COD, TDS, chlorides, sulfates and other mineral salts in tannery effluent. A process sequence has now been explored viz., enzymatic dehairing, enzymatic fiber opening, and pickle-free chrome tanning for tanning red hair sheepskins, which limits the use of unsafe chemicals. A process for dehairing at pH 8.0 has been achieved by employmig a commercial enzyme. A novel opening up system has been established again using enzymes. A pickle-basification free chrome tanning has been adopted to tan the enzyme treated matrices. Using the above said strategy, garment leathers have been made from wet-salted sheepskins. This leads to substantial decrease in chemical consumption from 442 to 38 kg for tanning one metric ton raw skins. Performances of leathers are on a par with conventionally opened up leathers, which is substantiated through physical and hand evaluation. This has also been verified through scanning electron microscopic analysis and softness measurements. The process also enjoys reduction in COD and TS loads on the environment by 84%. This process has also been proved to be economically viable, when compared with conventional process. Thus, the bio-driven pickle-free chrome tanning process leads to the manufacture of garment leathers with a cleaner environment.