Recycling of collagen from solid tannery waste and prospective utilization as adhesives

This study explores the innovative potential of recycled collagen derived from tannery waste for high-performance adhesive formulations. The leather industry generates significant amounts of solid waste, primarily from chromium-tanned leather, which poses substantial environmental challenges. Recent advancements in recycling techniques have opened new avenues for repurposing this waste, particularly through collagen extraction, which comprises about 30-35% of tannery residues. This research systematically reviews the methods and applications of collagen extraction, highlighting the material's versatility and environmental benefits when used as a bio-adhesive. The review identifies key challenges such as low water resistance, shear strength, and adhesiveness in collagen-based adhesives compared to synthetic counterparts. However, innovative solutions are emerging, including incorporating silane coupling agents and cross-linking technologies that significantly improve adhesive water resistance and mechanical properties. Economic analyses further support using tannery waste-derived collagen in adhesive production, aligning with global sustainability goals and reducing reliance on petrochemical-based adhesives. Despite these advancements, transitioning from laboratory research to commercial applications remains a significant challenge. Current studies primarily focus on small-scale experiments, with limited pilot-scale studies available. Nonetheless, the potential for collagen-based adhesives to replace harmful chemicals in industrial applications is promising, especially in sectors requiring biodegradable and non-toxic materials. This review concludes that while significant progress has been made, further research is necessary to overcome existing limitations and fully realize the commercial potential of collagen-based adhesives derived from tannery waste.