Dyeing of Shoe Upper Leather with Extracted Dye from Acacia Nilotica Plant Bark-An Eco-Friendly Initiative

Document Type : Original Article


1 Department of Leather Engineering, Institute of Leather Engineering and Technology, University of Dhaka, Dhaka, Bangladesh

2 Department of Leather Products Engineering, Institute of Leather Engineering and Technology, University of Dhaka, Dhaka, Bangladesh



In recent years, the application of non-toxic and eco-friendly natural dyes for textile and leather coloration is getting interest among manufacturers and buyers due to the hazardous impact of conventional azo dyes. Natural dyes have extensive use in textiles, yet their application to leather is very limited. In this research, the prospect of using dye extracted from Acacia nilotica bark for dyeing of shoe upper leather was examined. Chrome-tanned goatskins were employed as raw material for dyeing with the extracted dye using drum dyeing method. The dyeing process was conducted with and without mordant, following pre-mordanting and post-mordanting techniques. Color analysis, various colorfastness tests, and determination of dye exhaustion rate were conducted to evaluate the dyeing quality. It was observed that the experimental dye imparted amber color to the leather that turned brown and gray upon mordanting with potash alum and ferrous sulfate, respectively. The dyed leather samples showed excellent colorfastness but moderate heat and light fastnesses. Mordanted dyed samples, especially the prr-mordanted dyed samples, possessed a better color intensity and more dye exhaustion rate. The leather samples dyed with extracted dye also increased the strength property of the leather and various color shades were produced by mordanting techniques. 


  1. J. Madhavi, J. Srilakshmi, M. V. R. Rao, K. R. S. S. Rao, Efficient leather dehairing by bacterial thermostable protease, Int. J. Bio-Sci. Bio-Technol., 3(2011), 11-26.
  2. S. Famielec, K. Wieczorek-Ciurowa, Waste from leather industry. Threats to the environment, Chem. Czas. Technic.,8(2011), 43-48.
  3. Z. Abajihad, Assessment of tannery solid waste management and characterization, A case of Ethio-Leather Industry Private Limited Company (EliCO), MSc thesis, Addis Ababa University, Ethiopia, 2012.
  4. E. Andrioli, M. Gutterres, Evaluation of waste management in tanneries, in Proceedings of the XXXIII IULTCS Congress, Novo-Hamburgo, Brazil, 2015, 180, 1-9.
  5. C. K. Ozkan, H. Ozgunay, Usage of starch in leather making, in Proceedings of the 6th International conference on advanced materials and systems, Bucharest, Romania, 2016, 495-500.
  6. A. D. Covington, Tanning chemistry: The science of leather, 1st Edition, RSC Publishing, Cambridge, UK, 2009, 370.
  7. S. S. Dutta, An introduction to the principals of leather manufacturing, 1st Edition, Indian Leather Technologists Association, Mercantiles Buildings, Lalbazar Street Calcutta-700001, India, 1990, 464-505.
  8. A. Ado, H. Yahaya, A. A. Kwalli, R. S. Abdulkadir, Dyeing of textiles with eco-friendly natural dyes: A review, Int. J. Environ. Monit. Prot., 5(2014), 76-81.
  9. V. Beghetto, A. Zancanaro, A. Scrivanti, U. Matteoli, G. Pozza, The leather industry: A chemistry insight Part I: an overview of the industrial process, Sci. Ca' Fosc., 2013, DOI: 10.7361/SciCF-448.
  10. S. Pervaiz, T. A. Mughal, M. Najeebullah, F. Z. Khan, Extraction of natural dye from Rosa damascena Miller.- A cost effective approach for leather industry, Int. J. Biosci., 8(2016), 83-92.
  11. R. Mansour, Natural dyes and pigments: Extraction and application, in: Handbook of renewable materials for coloration and finishing (M. Yusuf Ed.), Scrivener Publishing LLC, USA, 2018, 75-102.
  12. S. M. Etezad, M. Sadeghi-Kiakhani, Decolorization of malachite green by bacterial biodegradation, Prog. Color Colorants Coat.,14(2021), 79-87.
  13. J. Anadkumar, B. Mandal, Adsorption of chromium(VI) and rhodamine B by surface modified tannery waste: Kinetic, mechanistic and thermodynamic studies, J. Hazard. Mater., 186(2011), 1800-1896.
  14. A. Haji, Dyeing of cotton fabric with natural dyes improved by mordants and plasma treatment, Prog. Color Colorants Coat., 12(2019), 191-201.
  15. M. Hosseinnezhad, K. Gharanjig, R. Jafari, H. Imani, Green dyeing of woolen yarns with weld and madder natural dyes in the presences of biomordant, Prog. Color Colorants Coat., 14(2021), 35-45. 
  16. N. Ashrafi, K. Gharanjig, M. Hosseinnezhad, M. K. Mehrizi, H. Imani, N. Razani, Dyeing properties and color fabrics using natural dye and mordant, Prog. Color Colorants Coat., 11(2018), 79-83.
  17. A. El Sikaily, A. Khaled, A. El Nemr, Textile dyes xenobiotic and their harmful effect, in: Non-conventional textile waste water treatment (A. El Nemr Ed.), Nova Science Publishers Inc., New York, USA, 2012, 31-64.  
  18. Z. Aksu, N. K. Kılıc¸, S. Ertu˘grul, G. D¨onmez, Inhibitory effects of chromium(VI) and remazol black B on chromium(VI) and dyestuff removals by Trametes versicolor, Enzyme Micob. Technol., 40(2007), 1167-1174.
  19. A. K. Samanta, A. Konar, Dyeing of textiles with natural dyes, in: Natural dyes (E. A. Kumbasar Ed.), IntechOpen, Croatia, 2011, 29-56.
  20. A. K. Samanta, P. Agarwal, Application of natural dyes on textiles, Indian J. Fibre Text. Res., 34(2009), 384-399.
  21. S. U. Islam, M. Shahid, F. Mohammad, Perspectives for natural product based agents derived from industrial plants in textile applications-A review, J. Clean. Prod., 57(2013), 2-18.
  22. S. Pervaiz, T. A. Mughal, F. Z. Khan, M. Najeebullah, Floral dyes: An opportunity for Punjab leather industry to promote sustainable fashion development, Int. J. Res. Adv. Tech., 4(2016), 34-39.
  23. S. F. Harlapur, S. F. Harlapur, H. P. Nagaswarupa, Marigold: Eco-friendly natural dye for fabrics, Mater. Today: Proc., 5(2018), 22350–22354.
  24. L. J. Rather, S. U. Islam, M. Azam, M. Sabbir, M. N. Bukhari, M. Shahid, M. A. Khan, Q. M. R. Haque, F. Mohammad, Antimicrobial and fluorescence finishing of woolen yarn with Terminalia arjuna natural dye as an ecofriendly substitute to synthetic antibacterial agents, RSC Adv., 6(2016), 39080-39094.
  25. M. Shahid, S. U. Islam, F. Mohammad, Recent advancements in natural dye applications: a review, J. Clean. Prod., 53(2013), 310-331.
  26. S. Pervaiz, T. A. Mughal, F. Z. Khan, Leather dyeing with plants dyes: A review, J. Biodiv. Environ. Sci., 9(2016), 455-464.
  27. W. F. Fuck, A. Brandelli, M. Gutterres, Special review paper: Leather dyeing with biodyes from filamentous fungi, J. Am. Leather Chem. As., 113(2018), 299-310.
  28. N. R. Singh, M. K. Jhariya, A. Raj, Tree crop interaction in agroforestry system, Read. Shelf, 10(2013), 15–16.
  29. C. B. Pandey, D. K. Sharma, Residual effect of nitrogen on rice productivity following tree removal of Acacia nilotica in a traditional agroforestry system in central India, Agr. Ecosyst. Environ., 96(2003), 133–139.
  30. P. R. Bhushette, U. S. Annapure, Comparative research of Acacia nilotica exudate gum and acacia gum, Int. J. Biol. Macromol., 102(2017), 266–271.
  31. L. J. Rather, S. U. Islam, F. Mohammad (2015), Acacia nilotica (L.): A review of its traditional uses, phytochemistry, and pharmacology, Sustain. Chem. Pharm., 2(2015), 12–30.
  32. Anonymous author, Medicinal plant of Bangladesh, www.assignmentpoint.com/ science/ zoology/medicinal-plant-of-bangladesh.html, Accessed online on May 27, 2020.
  33. D. Cardon, Dyes and Tannins, 3rd Edition, PROTA Foundation/Buckhuys Publishers/CTA, Wageningen, Netherlands, 2005, 19-25.
  34. S. Adeel, F. U. Rehman, R. Hanif, M. Zuber, E. U. Haq, M. Muneer, Ecofriendly dyeing of UV-irradiated cotton using extracts of Acacia nilotica bark (kikar) as source of quercetin, Asian J. Chem., 26(2014), 830-834.
  35. M. T. Ali, S. T. Haque, M. L. Kabir, S. Rana, M. E. Haque, A comparative research of in vitro antimicrobial, antioxidant and cytotoxic activity of Albizia lebbeck and Acacia nilotica stem bark, Bull. Fac. Pharm., Cairo Univ., 56(2018), 34–38.
  36. T. N. Rao, Riyazuddin, P. Babji, N. Ahmad, R. A. Khan, I. Hassan, S. A. Shahzad, F. M. Husain, Green synthesis and structural classification of Acacia nilotica mediated-silver doped titanium oxide (Ag/TiO2) spherical nanoparticles: Assessment of its antimicrobial and anticancer activity, Saudi J. Biol. Sci., 26(2019), 1385-1391.
  37. Z. Shah, S. Hassan, K. Shaheen, S. A. Khan, T. Gul, Y. Anwar, M. M. Al-Shaeri, M. Khan, R. Khan, M. A. Haleem, H. Suo, Synthesis of AgNPs coated with secondary metabolites of Acacia nilotica: An efficient antimicrobial and detoxification agent for environmental toxic organic pollutants, Mater. Sci. Eng.: C, 112 (2020), 110829.
  38. N. Roozbeh, L. Darvish, Acacia nilotica: New plant for help in pelvic organ prolapse, J. Menopausal Med., 22(2016), 129-130.
  39. H. A. Bachaya, Z. Iqbal, M. N. Khan, Z. U. Sindhu, A. Jabbar, Anthelmintic activity of Ziziphus nummularia (Bark) and Acacia nilotica (Fruit) against Trichostrongylid nematodes of sheep, J. Ethnopharmacol., 123(2009), 325-329.
  40. A. Salimi, J. Pourahmed, Role of natural compounds in prevention and treatment of chronic lymphocytic leukemia, In: Polyphenols: Prevention and treatment of human disease (R. R. Watson, V. R. Preedy, S. Zibadi Eds.), 2nd Edition, Elsevier, 2018, 195-203.
  41. S. MaganLal, S. Sharma, V. Gupta, Removal of Cr(III) by activated Acacia nilotica leaf powder, Euro. Chem. Bull., 2(2013), 144-148. 
  42. P. Thilagavathy, T. Santhi, Sorption of toxic Cr(VI) from aqueous solutions by using treated Acacia nilotica leaf as adsorbent: Single and binary system, Bio Resour., 8(2013), 1813-1830.
  43. T. Santhi, A. L. Prasad, S. Manonmani, A comparative research of microwave and chemically treated Acacia nilotica  leaf as an ecofriendly adsorbent for the removal of rhodamine B dye from aqueous solution, Arab. J. Chem., 7(2014), 494-503.
  44. R. Thenmozhi, T. Santhi, Characterization of activated Acacia niloticaseed pods for adsorption of Nickel from aqueous solution, Int. J. Environ. Sci. Technol., 12(2014), 1677- 1686.
  45. S. Waseem, M. I. Din, S. Nasir, A. Rasool, Evaluation of  Acacia nilotica  as a non-conventional low cost bio sorbent for the elimination of Pb(II) and Cd(II) ions from aqueous solutions, Arab. J. Chem., 7(2014), 1091-1098.
  46. P. Thilagavathy, T. Santhi, Kinetics, Isotherms and equilibrium research of Co(II) adsorption from single and binary aqueous solutions by  Acacia nilotica  leaf carbon, Chin. J. Chem. Eng., 22(2014), 1193-1198.
  47. N. G. Telkapalliwar, V. M. Shivankar, Adsorption of zinc onto microwave assisted carbonized Acacia nilotica bark, Mater. Today: Proc., 5(2018), 22694–22705.
  48. R. Khaid, Z. Aslam, A. Abbas, W. Ahmad, N. Ramzan, R. Sawabkeh, Adsorptive potential of Acacia nilotica  based adsorbent for chromium (VI) from an aqueous phase, Chin. J. Chem. Eng., 26(2018), 614-622.
  49. N. Rani, A. Gupta, A. K. Yadav, Removal of Cr (VI) from aqueous solutions by Acacia nilotica bark, Environ. Technol., 27(2006), 597-602.
  50. A. Ali, N. Akhtar, B. A. Khan, M. S. Khan, A. Rasul, S. U. Zaman, N. Khalid, K. Waseem, T. Mahmood, L. Ali, Acacia nilotica: A plant of multipurpose medicinal uses, J. Med. Plant. Res., 6(2012), 1492-1496.
  51. T. B. Gupta, D. H. Lataye, Adsorption of indigo carmine dye onto Acacia nilotica (Babool) sawdust activated carbon, J. Hazard. Toxic Radioact. Waste, 21(2017), 1-13.
  52. M. H. Abella, A. E. Musa, S. B. Ali, Sunt bark (Acacia nilotica) powder combination tanning for manufacture of upper leather, Int. J. Eng. App. Sci., 5(2018), 83-88.
  53. A. C. Adiguzel-Zengin, G. Zengin, C. K. Ozkan, U. Dandar, E. Kilic, Characterization and application of Acacia nilotica L. as an alternative vegetable tanning agent for leather processing, Fresenius Env. Bull., 26(2017), 7319-7326.
  54. A. E. Musa, G. A. Gasmelseed, Application of Acacia nilotica spp nilotica pods (Garad) powder as alternative vegetable retanning material, J. Forest Prod. Ind., 3(2014), 112-117.
  55. A. I. Nasr, H. Mueller, M. M. Abdelsalam, A. H. Azzam, C. Jungandreas, W. Poppitz, Evaluation of potential application for sunt pod extracts (Acacia nilotica) in leather tanning, J. Am. Leather Chem. As., 112(2017), 23-32.
  56. M. H. Alhaji, M. S. Abdullahi, E. N. Oparah, H. Bitrus, A. R. H. Rigit, Production of tannins from Acacia nilotica pods for the leather manufacturing industry- extractions, characterization, and optimization using design of experiment, Bio Resour., 15(2020), 2212-2226.
  57. S. Saxena, A. S. M. Raja, Natural dyes: Sources, chemistry, application and sustainability issues, in: Roadmap to sustainable textiles and clothing (S. S. Muthu Ed.), Textile science and clothing technology, Springer, Singapore, 2014, 37-80.
  58. L. J. Rather, S. U. Islam, F. Mohammad, Research on the Application of Acacia nilotica natural dye to wool using Fluorescence and FT-IR spectroscopy, Fibers Polym., 16(2015), 1497-1505.
  59. K. H. Shen, S. H. Hung, L. T. Yin, C. S. Huang, C. H. Chao, C. L. Liu, Y. W. Shih, Acacetin, a flavonoid, inhibits the invasion and migration of human prostate cancer DU145 cells via inactivation of the p38 MAPK signaling pathway, Mol. Cell. Biochem., 333(2010), 279-291.
  60. X. Wang, H. Perumalsamy, H. W. Kwon, Y. E. Na, Y. J. Ahn, Effects and possible mechanisms of action of acacetin on the behavior and eye morphology of  Drosophila models of Alzheimer’s disease, Sci. Rep., 5(2015), 16127, doi: 10.1038/srep16127
  61. A.V. A. David, R. Arulmoli, S. Parasuraman, Overviews of biological importance of quercetin: A bioactive flavonoid, Pharmacogn. Rev., 10(2016), 84-89.
  62. M. B. Kasiri, S. Safapour, Natural dyes and antimicrobials for textiles, in: Green materials for energy, products and depollution (E. Lichtfouse, J. Schwarzbauer, D. Roberts Eds.), Environmental chemistry for a sustainable world 3, Springer Science+Business Media Dordrecht, New York, USA, 2013, 229-286.
  63. K. H. Prabhu, A.S. Bhute, Plant based natural dyes and mordnats: A review, J. Nat. Prod. Plant Resour., 2(2012), 649-664.
  64. Saakshy, M. Agarwal, Ajendra, R. K. Jain, A. K. Sharma, Acacia arabica-A source of natural dye for handmade paper making, Int. J. Eng. Res. Tech., 12(2013), 2237-2245.
  65. A. Farooq, M. A. Ashraf, A. Rasheed, J. U. Khan, F. Irshad, Development of a novel method for natural dyeing of cotton fabrics using ultrasonic radiations and acacia bark, J. Nat. Fibers, 15(2018), 680-686.
  66. L. J. Rather, S. Akhter, R. A. Padder, Q. P. Hassan, M. Hussain, M. A. Khan, F. Mohammad, Colorful and semi durable antioxidant finish of woolen yarn with tannin rich extract of Acacia nilotica natural dye, Dyes Pigm., 139(2017), 812-219.
  67. D. Jamadar, K. J. Sannapapamma, Acacia nilotica Pods: A natural dye source for textile colouration, Int. J. Curr. Microbiol. App. Sci., 7(2018), 602-612.
  68. B. H. Patel, B. J. Agarwal, H. M. Patel, Dyeing of nylon with Acacia Arabica willd bark extract, Text. Asia, 33(2002), 34- 42.
  69. F. F. Yildirim, A. Yavas, O. Avinc, Printing with sustainable natural dyes and pigments, in: Sustainable textiles: Production, processing, manufacturing & chemistry (S. S. Muthu and M. A. Gardetti Eds.), Sustainable textiles, clothing design and repurposing, Springer International Publishing, Switzerland, 2020, 5.
  70. P. S. Vankar, V. Tiwari, R. Shankar, Commercial dyeing with aqueous extract of Acacia catechu (Katha) using ecofriendly mordants, Asian Text. J., 11(2002), 60-61
  71. S. Pant, M. Gahlot, Dyeing of leather with natural dyes extracted from Acacia catechu, Asian Dyer, 9(2012), 54-59
  72. E. Önem, M. M. Mutlu, S. Gunay, H. Azeri, Natural dyestuff extraction from onion (Allium Cepa) Skin and utilization for leather dyeing, Tekst. Mühen., 9(2012), 1-8.
  73. B. H. Patel, New approach for the application of natural dye in modern textile dye houses, Bangladesh Text. Tod.,6(2013), 14-21.
  74. Determination of Moisture, Official Methods of Analysis: Society of Leather Technologists and Chemists, TheCharllesworth Group, Huddersfield, UK, SLC-113, 1996.
  75. Approximate determination of the solubility of leather dyes, Official Methods of Analysis, International Union of Leather Technologists and Chemists Societies, IUF-201, 1966.
  76. Stability to acid of dye solutions, Official Methods of Analysis, International Union of Leather Technologists and Chemists Societies, IUF-203, 1966.
  77. Stability to hardness of dye solutions, Official Methods of Analysis, International Union of Leather Technologists and Chemists Societies, IUF-205, 1972.
  78. Fastness to acid of dye solutions, Official Methods of Analysis, International Union of Leather Technologists and Chemists Societies, IUF-202, 1966.
  79. Colorfastness to water spotting, Official Methods of Analysis, International Union of Leather Technologists and Chemists Societies, IUF-420, 1998.
  80. Colorfastness of small samples to solvents, Official Methods of Analysis, International Union of Leather Technologists and Chemists Societies, IUF-434, 2009.
  81. B. Bitlisli, A. Adıgüzel Zengin, G. Yeldiyar, G. Kairanbekov, E. Küçükakın, Upper leathers in shoe manufacturing, J. Ind. Technol. Eng., 2(2013), 37-41.
  82. L. J. Rather, S. U. Islam, M. Shabbir, M. N. Bukhari, M. Shahid, M. A. Khan, F. Mohammad, Ecological dyeing of woolen yarn with Adhatoda vasica natural dye in the presence of biomordants as an alternative copartner to metal mordants, J. Environ. Chem. Eng., 4(2016), 3041-3049
  83. M. T. Uddin, M. A. Razzaq, A. H. Quadery, M. J. Chowdhury, A. Mizan, M. M. Raihan, F. Ahmad, Extraction of dye from natural source (LAC) & its application on leather, Am. Sci. Res. J. Eng. Technol. Sci., 34(2017), 1-7.
  84. P. Velmurugan, J. Shim, S. K. Seo, B. T. Oh, Extraction of natural dye from Coreopsis tinctoria flower petals for leather dyeing − An eco-friendly approach, Fibers Polym., 17(2016), 1875-1883.
  85. Sampling, Official Methods of Analysis, Journal of the Society of Leather Technologists and Chemists, IUP-2, 2000.
  86. Conditioning, Acceptable Quality Standards in the Leather and Footwear Industry, Vienna: UNIDO, IUP-3, 1996.
  87. Colorfastness of leather to light, Official Methods of Analysis, International Union of Leather Technologists and Chemists Societies, IUF-401, 1972.
  88. Colorfastness of leather to heat, Official Methods of Analysis, Journal of the Society of Leather Technologists and Chemists, SATRA PM-49, 1996.
  89. Perspiration fastness of leather, Official Methods of Analysis, Journal of the Society of Leather Technologists and Chemists, BSEN ISO-105, 1996.
  90. Colorfastness to machine washing, Official Methods of Analysis, International Union of Leather Technologists and Chemists Societies, IUF-435, 1998.
  91. Color rub fastness of leather, Official Methods of Analysis, Journal of the Society of Leather Technologists and Chemists, SATRA PM-8, 1996.
  92. Gray scale for assessing change in color, Official Methods of Analysis, International Union of Leather Technologists and Chemists Societies, IUF-131, 1966.
  93. Measurement of tensile strength and percentage elongation, Official Methods of  Analysis,  Journal  of  the  Society  of  Leather  Technologists  and  Chemists,  IUP-6, 2000.
  94. Testing of leather, determination of the stitch tear resistance, German Institute for Standardization (Deutsches Institutfür Normung), DIN Method 53331, 1980.
  95. G. John, Possible defects in leather production: Definitions, causes, consequences, remedies and types of leather, 1st Edition, Gerhard John, Lampertheim, Germany, 1996, 135.
  96. A. Gürses, M. Açıkyıldız, K. Güneş, M. S. Gürses, Dyes and pigments, Springerbriefs in green chemistry for sustainability, Springer International Publishing, Cham, 2016, 31-45.
  97. A. Kechi, R. B. Chavan, R. Moeckel, Dye yield, color strength and dyeing properties of natural dyes extracted from Ethiopian dye plants, Text. Light Ind. Sci. Technol., 2(2013), 137-145.
  98. A. Konar, Studies on textile related properties and dye ability of jute and chemically modified jute textiles using selective synthetic and natural dyes, PhD thesis, Jadavpur University, India, 2011.
  99. S. D. Jain, A. Jain, S. Jain, N. Malviya, V. Jain, D. Kumar, Estimation of total phenolic, tannins, and flavonoid contents and antioxidant activity of Cedrus deodara heart wood extracts, Egypt. Pharm. J., 14(2015), 10-14.
  100. M. Ahmed, P. Khirstova, G. Icho, Comparative research of tannins of Acacia nilotica an indigenous tanning material in Sudan with Acacia mearnsii, Suranaree J. Sci. Technol., 12(2005), 1-7.
  101. I. E. H. Elgailani, C. Y. Ishak, Determination of tannins of the three common Acacia species of Sudan, Adv. Chem., 2014(2014), 192708, 1-5.
  102. H. Mahdi, K. Palmina, I. Glavtch, Characterization of Acacia nilotica as an indigenous tanning material of Sudan, J. Trop. For. Sci., 18(2006), 181-187.
  103. R. G. Chatwal, Synthetic dyes,3rd Revised Edition, Himalaya Publishing House, Mumbai, India, 2005, 5.1-5.22.
  104. A. T. Selvi, R. Aravindhan, B. Madhaban, S. J. Rao, Studies on the application of natural dye extract from Bixa orellana seeds for dyeing and finishing of leather, Ind. Crops Prod., 43(2013), 84-86.
  105. A. Kumar, P. K. Pareek, A. S. M. Raja, D. B. Shakyawar, Extraction from babool (Acacia nilotica) bark and efficacy of natural color on woollen yarn, Indian J. Small Ruminants, 21(2015), 92-95. 
  106. K. T. Sarkar, Theory and practice of leather manufacture, 1st Edition, Macmillan India Press, Madras, India, 1997, 341-365.
  107. S. Bordingnon, M. Gutterres, S. K. Velho, W. F. Fuck, A. V. Schor, M. Cooper, L. Bresolin, Novel natural dyes for eco-friendly leather articles, J. Asocia. Quím. Espanõl. Ind. Cuer., 63(2012), 93-99.
  108. S. S. Dutta, An introduction to the principles of physical testing of leather, 1st Edition, Indian Leather Technologists Association, Mercantiles Buildings, Lalbazar Street Calcutta-700001, India, 1999, 28-62.
  109. C. Sendrea, C. Carsote, E. Badea, A. Adams, M. Niculescu, H. Iovu, Non-invasive characterization of collagenbased materials by NMR-Mouse and ATR-FTIR, U.P.B. Sci. Bull., Series B, 78(2016), 27-38.
  110. F. G.E. Nogueira, N. T. do Prado, L. C.A. Oliveira, A. R.R. Bastos, J. H. Lopes, J. G. de Carvalho, Incorporation of mineral phosphorus and potassium on leather waste (collagen): A new NcollagenPK-fertilizer with slow liberation, J. Hazard. Mater., 176(2010), 374-380.
  111. M. Mehta, R. Naffa, C. Maidment, G. Holmes, M. Waterland, Raman and ATR-FT-IR spectroscopy towards classification of wet blue bovine leather using ratiometric and chemometric analysis, J. Leather Sci. Eng., 2(2020), 1-15.
  112. F. D. M. Manavalan, M. Chellappa, R. Chellan, Detanning of chrome –ladden collagenous matrix for protein recovery from tannery solid waste, Br. J. App. Sci. Technol., 8(2015), 254-266.
  113. M. Yusuf, F. Mohammad, M. Sabbir, Eco-friendly and effective dyeing of wool with anthraquinone colorants extracted from Rubia cordifolia roots: Optimization, colorimetric and fastness assay, J. King Saud Univ. Sci., 29(2017), 137-144.
  114. A. A. Haroun, Evaluation of modified leather dyeing technique using black dyestuffs from the economical view, Dyes Pigm., 67(2005), 215-221.
  115. A. A. Haroun, H. F. Mansour, New approaches for the reactive dyeing of the retanned carbohydrate crust leather, Dyes Pigm., 76(2008), 213-219.
  116. A. Inayat, S. R. Khan, A. Waheed, F. Deeba, Applications of eco friendly natural dyes on leather using different modrants, Proc. Pakistan Acad. Sci., 47(2010), 131-135.
  117. B. Sangkyoung, Dyeing conditions and mordant effects on the cow leather dyed with lac powder, J. Fash. Bus., 17(2013), 140-148.
  118. A. K. Deb, M. A. A. Shaikh, M. Z. Sultan, M. I. H. Rafi, Application of lac dye in shoe upper leather dyeing, Rev. Piel. Înc., 17(2017), 97-106.
  119. V. Sivakumar, J. L. Anna, J. Vijayeeswarri, G. Swaminathan, Ultrasound assisted enhancement in natural dye extraction from beetroot for industrial applications and natural dyeing of leather, Ultrason. Sonochem., 16(2009), 782-789.
  120. S. Pervaiz, T. A. Mughal, F. Z. Khan, Green fashion colours: A potential value for Punjab leather industry to promote sustainable development, Pak. J. Contemp. Sci., 1(2016), 28-36.
  121. N. Teklay, A. Kechi, Optimization of leather dyeing using natural dye Extract, Int. J. Sci. Eng. Res., 6(2018), 136-141.
  122. A. Worku, Extraction and application of natural dye on tanned leather an eco-friendly approach, Int. Res. J. Eng. Technol., 5 (2018), 431-434.
  123. T. Berhanu, S. Ratnapandian, Extraction and optimization of natural dye from Hambo Hambo (Cassia singueana) plant used for coloration of tanned leather materials, Adv. Mater. Sci. Eng., 2017(2017), 7516409, https://doi.org/10.1155/2017/7516409.
  124. P. Velmurugan, S. Kamala-Kannan, V. Balachandar, P. Lakshmanaperumalsamy, J. C. Chae, B. T. Oh, Natural pigment extraction from five filamentous fungi for industrial applications and dyeing of leather, Carbohydr. Polym., 79(2010), 262-268.
  125. P. Velmurugan, J. C. Chae, P. Lakshmanaperumalsamy, B. S. Yun, K. J. Lee, B. T. Oh, Assessment of the dyeing properties of pigments from five fungi and anti-bacterial activity of dyed cotton fabric and leather, Color. Technol., 125(2009), 334-341.
  126. E. Önem, G. Gulumser, B. Ocak, Evaluation of natural dyeing of leather with Rubia tinctorum extract, Ekoloji, 20(2011), 81-87.