Production of Dye from Green and Brown Walnut Shells for Leather Coloration

Neslihan Doğan-Sağlamtimur,Tuğba Çivioğlu,Ruhsar Arabacıoğlu,Ersen Turaç

doi:10.21533/pen.v5i2.135

Abstract

Nowadays, it is observed that there is an increasing approach to the use of natural substances instead of synthetic ones. As the synthetic materials and products are more complex in comparison to natural substances, it will take a long time to complete their natural cycles and return to nature, thus, causing a lot of environmental pollution. Green and brown shells of walnuts that are not only valuable crops but also important components of the Mediterranean diet are by-products of the walnut production, having scarce use (especially green shell). Thus, using shells as a source of dye will increase the value of the walnut production, as well as offering utilization for a by-product, which is produced in large quantities. The purpose of this study is to produce dye from waste green and brown walnut shells, compare quality of these dyes and apply them separately in untreated leather. Before chemical processes, the walnut shells were chopped in a grinding mill. They were dried in an oven to eliminate the humidity and extracted in Soxhlet apparatus by using ethanol solution. Then, the ethanol solution was evaporated in controlled way and the produced dyes were mordanted by using potassium aluminium sulphate (PAS). The dyes were analysed by TLC and UV-Vis, whereas dyed leathers were analysed by colorfastness test. The present study showed that brown walnut shell dye having higher color values was better for yield, dye penetration and fastness properties compared to green walnut shell dye. Luminous effect was observed when these dyes were applied in leather. It is interesting, uncommon and economically valuable for leather industry. This study would be a positive step to meet the need of leather industry in Turkey and a good example for cleaner production.

Highlights

Nuts are important components of the Mediterranean diet
Still the use of natural dyes involves some disadvantages such as requirement of large amounts of plant material, limited success in dyeing synthetic materials, need for the use of mordants and poor light stability [11]. Overcoming these disadvantages, the aim of this study is to obtain natural dye from waste green and brown walnut (Juglans regia L.) shells for dye and leather industry.In this study, the leather coloration was performed by the dyes produced from green walnut shell (GWS) and brown walnut shell (BWS)
In this study, calculated Rf values of dyes produced from GWS and BWS were found to be 0.5625 and 0.6775

Summary

Introduction

Nuts are important components of the Mediterranean diet. Juglans regia Linn (Juglandaceae), which is known as the walnut, is a tall deciduous tree of about 20 meters-in-length [1]. Walnuts are widely distributed all over the world, and in Turkey, these species are common along the country. The walnut tree (Juglans regia L.) is its well-known member, constituting an important species of deciduous trees found primarily in temperate areas. It is cultivated commercially throughout southern Europe, northern Africa, eastern Asia, United States and western South America. In Turkey, walnut trees can be found all over the country, being the nuts very popular and largely consumed as part of the Mediterranean diet.

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