Durable sodium alginate hydrogel with hard-soft interpenetrating networks and directed electron flow: Toward pan-regional photo-Fenton-like catalysis for persistent antibiotic degradation

Achieving a balance between catalytic efficiency and structural durability remains a key challenge in heterogeneous photo-Fenton-like systems. Herein, we report a robust sodium alginate hydrogel (ACCN) with hard–soft dual interpenetrating networks, constructed by incorporating Cu@MoS 2 nanosheets and carbon dots-modified cellulose nanofibrils (CNF@CDs). This structural design enables pan-regional photo-Fenton-like catalysis via structural optimization and directed electron transport, thereby ensuring sustained ciprofloxacin (CIP) degradation. Three key features synergistically enhance both catalytic performance and material integrity: (1) a dual interpenetrating network comprising Cu 2+ -crosslinked sodium alginate (SA, soft phase) and hydrogen-bonded CNF@CDs (rigid phase), which reinforces mechanical strength and prevents Cu@MoS 2 leaching; (2) the SA/CNF@CDs network exhibits an ultrahigh CIP adsorption capacity, which spatially concentrates pollutants and accelerates reaction kinetics; and (3) CNF@CDs facilitates electron transfer from Cu@MoS 2 to Cu 2+ crosslinking sites, promoting pan-regional Cu 2+ /Cu + redox cycling. This spatial–electronic integration endows ACCN with a CIP degradation rate constant of 0.0426 min −1 —7.5-fold higher than that of Cu@MoS 2 . Furthermore, ACCN demonstrates excellent durability and reusability, maintaining over 95 % catalytic activity after 10 cycles, with Mo leaching below 8 ppb. This work provides a sustainable strategy for integrating structural and electronic modulation to enable high-efficiency, durable antibiotic wastewater treatment.