Zeolite versus other tanning systems: A life cycle and end-of-life perspective

This study evaluates zeolite-based tanning systems as sustainable alternatives to conventional methods from both life cycle and end-of-life perspectives. Zeolite formulations combined with masking agents, hydrotropic substances, and vegetable tanning compounds were tested for biodegradability, compostability, and environmental impact. Results show that zeolite-tanned leathers achieved biodegradability rates above 94 % and complete compostability within 10–28 days, outperforming glutaraldehyde (54 %) and chromium tanning (6 %). Hydrolysable tannins such as tara enhanced compostability, whereas condensed tannins (mimosa) inhibited degradation. Life cycle assessment showed zeolite systems reduced global warming potential by 54 %, ecotoxicity by 76 %, and carcinogenic toxicity by 98 % compared with chrome tanning, while also eliminating heavy metal contamination in compost. These results highlight the importance of holistic evaluation of tanning chemistries, where environmental trade-offs extend beyond carbon footprint to include toxicity, land use, and circularity. Overall, zeolite-based tanning stands out as a viable pathway for large-scale, chrome-free leather production aligned with sustainable development and circular economy principles.