Studies on Collagen Structure using X-Ray Scattering on a Closed-Loop Leather Process

Abstract

Waste management in leather processing is crucial in limiting the excess use of hazardous materials that lead to environmental pollution and health concerns. A closed-loop approach was developed to recycle the spent solutions from leather processing to reduce waste in the effluent. The structural changes of collagen that accompany such processing are yet to be studied and is crucial in understanding the closed-loop process and its subsequent leather properties. In this study, we analysed the collagen structure at different processing stages across the closed-loop approach using synchrotron small-angle X-ray scattering. An increased filling effect in the collagen matrix was observed and attributed to the residual organic component and chromium species in recycled spent solutions. A high uptake of chromium was also observed from the increased scattering intensity from leathers treated with recycled chrome solution, indicating its efficient use. Additionally, the changes in scattering intensity from keratin and lipids indicated an effective unhairing process. Such findings on collagen structure changes will support the development of more environmentally and economically sustainable processing methods to benefit the leather industry.