Processing of Leather Using Deep Eutectic Solvents

Andrew P Abbott,Omaymah Alaysuy,Andrew C Douglas,William R Wise,A Paula M Antunes,Jeffry Guthrie-Strachan

doi:10.1021/acssuschemeng.5b00226

Andrew P Abbott, Omaymah Alaysuy + Show 4 more

Open Access

https://doi.org/10.1021/acssuschemeng.5b00226

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Abstract

Processing of leather has an historical reputation as a chemically and energetically intensive process that produces large volumes of aqueous waste. Saline pollution combined with heavy-metal, dyes and acid and base streams make leather production an ecologically sensitive industry. The current study shows that a variety of deep eutectic solvents (DESs) may be used for the tanning, fatliquoring and dyeing of animal hides, being particularly useful for mineral (chromium) and vegetable tanning processes. The tanning agents are able to penetrate rapidly into the hide, driven by lyotropic swelling due to their high ionic strength. The samples are shown to have similar tanning agent content to the currently used aqueous chromium(III) sulfate solution; however, the waste metal content is shown to be significantly reduced. Incorporation of the DES Ethaline into the leather significantly alters the swelling properties of the leather increasing the flexibility and ductility of the material, therefore acting in the...

Highlights

The production of leather is an industry that dates back over 6000 years and elements of the process have changed relatively little in the past 100 years
The majority of the costs with the tanning process are associated with the chromium salt and the recovery from dilute aqueous solutions after processing
It can be seen that all three Deep Eutectic Solvents (DESs) yield samples with a chromium content that is comparable with aqueous chromium tanning

Summary

Introduction

The production of leather is an industry that dates back over 6000 years and elements of the process have changed relatively little in the past 100 years. The aqueous pre-treated bovine hide was washed in acidic buffer solution to give a pH = 4, at which the carbonyl groups on collagen should be largely anionic and this may help cationic chromium complexes bind.

Results

Conclusion