Chrome-free leather processing based on amine pendant metal-organic frameworks and dialdehyde with enhanced dye...

Area of Science:

• Materials Science
• Sustainable Chemistry
• Textile and Leather Technology

Background:

• Tanning industry faces stringent regulations on chromium salts and dye-rich effluent.
• Need for eco-friendly alternatives to conventional chrome tanning processes.
• Metal-organic frameworks (MOFs) offer tunable properties for material applications.

Purpose of the Study:

• To develop a sustainable leather processing system using amine pendant MOF (UiO-66-NH2) and glyoxal.
• To evaluate the performance of MOF-glyoxal treated leather compared to conventional chrome-tanned leather.
• To investigate the mechanism of interaction and wastewater treatability of the proposed method.

Main Methods:

• Leather treatment with amine pendant MOF (UiO-66-NH2) and glyoxal.
• Evaluation of shrinkage temperature, MOF exhaustion, and dye adsorption.
• Assessment of dye fastness (rubbing, perspiration) and wastewater characteristics (BOD5/COD ratio).
• Mechanism studies using X-ray photoelectron spectroscopy (XPS).

Main Results:

• 8% MOF and 6% glyoxal treatment increased shrinkage temperature to 89°C with 84.3% MOF exhaustion.
• Dye adsorption improved from 74.3% to 91.8%, with enhanced dye fastness and washability.
• XPS revealed collagen-MOF interactions via amino acid linkages.
• Wastewater BOD5/COD ratio of 0.36 indicated better treatability.

Conclusions:

• The combination of amine pendant MOFs and dialdehyde is a promising strategy for chrome-free leather production.
• This sustainable approach yields robust leather with excellent functional properties and improved environmental performance.
• The developed method addresses regulatory challenges and offers a viable alternative to traditional tanning.