Recyclable 3D CMCS@COF aerogel with high performance adsorbent for dye wastewater treatment

With the accelerated industrialization, dye wastewater poses severe threats to the ecological environment and human health. In this study, sulfonated COF was synthesized via a solvothermal method, then crosslinked with CMCS, and the CMCS@COF composite aerogel with a 3D network structure was fabricated via freeze drying. The maximum adsorption capacities of the as prepared material for MG, MB and CV reach 2062.95, 510.96 and 1523.21 mg·g −1 , respectively. This performance is far superior to that of pure CMCS aerogel (228.16, 167.87 and 193.96 mg·g −1 , respectively), and also significantly higher than that of most reported COF based composite adsorbents. The adsorption process conforms to the Langmuir isotherm model and the pseudo second order kinetic model, indicating that the adsorption is monolayer chemisorption, and the mechanism involves the synergistic effects of electrostatic attraction, π-π stacking and hydrogen bonding. Compared to traditional powdered covalent organic framework materials, the developed aerogel exhibits excellent structural stability and convenient solid liquid separation capability, addressing engineering bottlenecks such as powder aggregation and difficult recovery. After five consecutive adsorption desorption cycles, no significant pore collapse was observed in the structure, demonstrating excellent regeneration performance. This strategy provides a technically feasible solution for the practical application of COF based adsorbents in dye wastewater treatment, achieving a balance between high adsorption capacity and operational recyclability.