Waste to worth: a circular solution through lignin engineering

Abstract

The inefficient management of industrial waste threatens environmental sustainability, necessitating scalable resource recovery solutions. To address these challenges, we propose a novel and sustainable in situ one-step strategy for the simultaneous recovery and functionalization of lignin from industrial black liquor, using a sustainable organic acid system assisted by choline chloride. The functionalized lignin adsorbent material (FLAM) exhibited superior adsorption performance, effectively treating animal feedlot wastewater to recover ammonia. The ammonia enriched FLAM was subsequently repurposed as a slow-release fertilizer, enhancing plant growth and demonstrating a closed-loop pathway for waste valorization and nutrient recycling. Methylene blue was used as a model cationic compound to simulate the adsorption behavior and interactions. FLAM achieved a high adsorption capacity of 725.98 mg g⁻¹ across a broad pH range, significantly outperforming commercial kraft lignin. This sustainable approach advances circular economy principles by integrating remediation and resource recovery, offering a scalable, eco-friendly solution for environmental applications.