Saravanabhavan Subramani, Thanikaivelan Palanisamy, Rao Jonnalagadda Raghava, Nair Balachandran Unni, Ramasami Thirumalachari
Chemical Laboratory and Centre for Leather Apparels & Accessories Development, Central Leather Research Institute, Adyar, Chennai 600 020, India.
Environ Sci Technol. 2004 Feb 1;38(3):871-9. doi: 10.1021/es034554o.
Globally, 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.
在全球范围内，由于污染和排放法规，皮革行业目前正在经历根本性的变革。因此，皮革行业面临压力，需要寻找更清洁的生皮加工方法。已知传统的鞣前、鞣制和鞣后工艺产生的污染负荷占皮革加工总污染负荷的98%以上。传统的鞣制工艺采用“做- undo”原则。此外，皮革加工中使用的传统方法使皮肤/皮革的pH值在很大范围内变化（2.8 - 13.0）。这导致大量污染负荷的排放，如生化需氧量、化学需氧量、总溶解固体、总固体、硫酸盐、氯化物和铬。在这里阐述的方法中，使用生物催化剂在pH值8.0的条件下实现了脱毛和去肉以及纤维打开，采用植物鞣剂进行无浸酸天然鞣制，并使用环保化学品进行鞣后处理。因此，该工艺包括脱毛、纤维打开、无浸酸天然鞣制，随后进行环保型鞣后处理。已经发现，脱毛程度和纤维束打开程度与传统加工皮革相当。这已通过扫描电子显微镜分析和柔软度测量得到证实。通过物理和手感评估表明，该皮革的性能与传统铬鞣皮革相当。该工艺还实现了零金属（铬）排放，生化需氧量、化学需氧量、总溶解固体和总固体负荷分别显著降低了83%、69%、96%和96%。此外，所开发的工艺似乎在经济上可行。
