Antioxidant properties of natural extract during the leather finishing

When carrying out work on the manufacture of leather materials, a number of complex processes are performed. During these operations, many chemicals and additives are used that are harmful to the environment and dangerous to human health. The main goal of the leather industry is to replace chemicals with the most natural extracts. Natural extracts can be used as tanning materials, as well as in the process of finishing processes. The chemical composition of the natural extract prepared from walnut shells was determined using an LCMS-9030 mass spectrometer and a number of acids with antioxidant properties and flavone with coloring properties were found. Trivalent chrome tanning is widely used in the leather industry. After all, this type of tanning is one of the most suitable methods for production. Trivalent chromium free radicals present in the leather, under the influence of temperature, photoaging, humidity and the external environment, turn into hexavalent chromium. Hexavalent chromium causes life-threatening diseases such as carcinogenic, liver and kidney failure, and skin diseases. The antioxidants contained in natural extracts prevent the formation of hexavalent chromium. The amount of hexavalent chromium in leather trimmed with a natural extract made from walnut shells with antioxidant properties was determined by Shimadzu UV- 1601 PC UV-Visible equipment, in accordance with EN ISO 17075 standard. The amount of hexavalent chromium in the leather finished with natural walnut shell extract was significantly reduced than in the samples finished with chemical pigment, water and without finishing.

1. Yilmaz, S. Akça, Y. Saçlik, S. J. Int. Sci. Publ. 5 (2017):389–397.

2. Neeraj, M. and ets. Study on antioxidant activity of common dry fruits. Food and Chemical Toxicology 12, (2010): 3289-3500

3. Blomhoff, R. and ets. Health benefits of nuts: potential role of antioxidants. Br. J. Nutr 96, (2006): 52–60

4. Chen, W.Y., Li, G.Y.; Tanning Chemistry. Peking, China Light Industry Press (2011): 43-65

5. Yu, C.Z., Sun G.X., Guo S.W.; Exploration on the causes of Cr(VI) in leather. China Leather 31 (2002): 25-29

6. Wu, N., et al. The Retanning and Fatliquoring relating to Cr (VI) in Chrome Leather. Leather science and Engineering 22 (2012): 29-33

7. Gong, Y., Liu, X.L., Huang, L., et al. Stabilization of chromium: An alternative to make safe leathers. Journal of Hazardous Materials 179 (2010): 540-544

8. Yu, C.Z., Wang, R., Ma, X.Y., et al.; Antioxidant effect of phenolic compounds on unsaturated lipids preventing the oxidation of chromium(III). JSLTC 94 (2010): 33-38

9. Huang, J., Yang, G.Y., Li, H.J., et al.; Progress in mechanism studies of antioxidants. Chinese Journal of Nature 26 (2004): 74-78

10. Graf, D., Boehme, D. The influence of the relative humidity of air during storage on the formation lowering of Cr (VI) in chrome tanned leather. World Leather 13 (2000): 38

11. Yu, C.Z., Liu, P.J., Sun, G.X, et al. The influence of relative humidity on the level of Cr(VI) in chrome-tanned leather. JSLTC 89 (2005): 194-198

12. Yi, Z.J., et al. Integrated control of hexavalent chromium in leather. Leather and Chemical 26 (2009): 25-29

13. Chandra Babu, N.K., Venba, R., Gothi, G., et al. Elimination of hexavalent chromium in leather using reducing agents. JALCA100 (2005): 354-359

14. Ma, X.Y., Yang, X.P., Yu, C.Z., et al. Study on the control of hexavalent chromium in leather use antioxidants and reducing agents. West Leather 34(2012): 11-14

15. Su, J., et al. Modification of valonia extracts on prevention of chrome (VI). Leather science and Engineering 20 (2010): 28-33.