Controllable self-assembly of double polyphenol-metal-network: A universal gravel-like lignin catalysts for water purification.

Lignin has attracted wide attention in sustainable environment remediation, especially the polyphenol-metal-network (PMN) based on lignin that shows unique applicability. In this work, by self-assembly of double PMN formed by lignin, plant tannins (TA) and Fe ions, a universal gravel-like lignin catalysts were reported for cost-efficient water purification. A controllable self-assembly technique dependent in pH was developed, achieving the controllable synthesis of materials with highly uniformity. Driven by strong multiple intermolecular interactions and PMN mediated TA-Fe Fenton system, this bio-based material exhibited efficient interfacial capture (65.70 mg·g-1) and in-situ degradation performance (95.40 %), and removed ubiquitous dye contaminants through static and flowing operation. Benefiting from this, effective flowing purify platform that continuously purify large-scale dye-containing wastewater through flowthrough strategy was profiled, confirming the potential in real industrial system. The theoretical calculations including molecular dynamics simulation contributed to providing insightful comprehension for co-assembly of system and their intermolecular interaction with dye molecules. Additionally, this material also showed magnetic response ability, stable reusability performance, and extended preparation advantages. This work provided a facile strategy to develop advanced lignin-based double PMN derived materials to support water purification by utilizing solid-waste to repair liquid-waste.