Nanocellulose–Carbonized Lignin Films for Enhanced Tetracycline Removal

The development of sustainable and efficient adsorbent materials for tetracycline hydrochloride (TCH) removal is of great importance for wastewater treatment. Structural characterizations (XRD and FTIR) confirmed successful lignin carbonization and the abundance of oxygen-containing functional groups, while N2 physisorption revealed a phosphoric acid-induced hierarchical porous structure rich in mesopores to facilitate mass transfer. CL exhibited excellent tetracycline hydrochloride (TCH) adsorption, achieving a maximum capacity of 21.06 mg g−1 within 2 h. The adsorption data closely followed the pseudo-second-order kinetic model, indicating a predominantly chemisorption process. While nanocellulose enabled the fabrication of flexible, self-supporting films with well-dispersed CL, excessive loading deteriorated film integrity. An optimized 30 wt% CL content achieved the ideal balance between structural stability and adsorption performance, demonstrating that these sustainable films hold great potential for aquatic antibiotic remediation.