es034554o_si_002.ppt (49.5 kB)
Natural Leathers from Natural Materials: Progressing toward a New Arena in Leather Processing
presentation
posted on 2004-02-01, 00:00 authored by Subramani Saravanabhavan, Palanisamy Thanikaivelan, Jonnalagadda Raghava Rao, Balachandran Unni Nair, Thirumalachari RamasamiGlobally, the leather industry is currently undergoing
radical transformation due to pollution and discharge
legislations. Thus, the leather industry is pressurized to
look for cleaner options for processing the raw hides and
skins. Conventional methods of pre-tanning, tanning and
post-tanning processes are known to contribute more than
98% of the total pollution load from the leather processing.
The conventional method of the tanning process involves
the “do−undo” principle. Furthermore, the conventional
methods employed in leather processing subject the skin/hide to a wide variation in pH (2.8−13.0). This results in
the emission of huge amounts of pollution loads such as
BOD, COD, TDS, TS, sulfates, chlorides and chromium. In the
approach illustrated here, the hair and flesh removal as
well as fiber opening have been achieved using biocatalysts
at pH 8.0, pickle-free natural tanning employing vegetable
tannins, and post-tanning using environmentally friendly
chemicals. Hence, this process involves dehairing, fiber
opening, and pickle-free natural tanning followed by
ecofriendly post-tanning. It has been found that the extent
of hair removal and opening up of fiber bundles is
comparable to that of conventionally processed leathers.
This has been substantiated through scanning electron
microscopic analysis and softness measurements.
Performance of the leathers is shown to be on par with
conventionally chrome-tanned leathers through physical and
hand evaluation. The process also exhibits zero metal
(chromium) discharge and significant reduction in BOD,
COD, TDS, and TS loads by 83, 69, 96, and 96%, respectively.
Furthermore, the developed process seems to be
economically viable.