Fabrication of chitin/graphene oxide composite sponges with higher bilirubin adsorption capacity

Chitin/graphene oxide (Ch/GO) composite sponges had been synthesized in 11 wt% NaOH/4 wt% urea aqueous solution by a simple method. The structure, thermal stability and mechanical properties of the composite sponges were investigated by scanning electron microscopy, Fourier-transform infrared spectroscopy, wide-angle X-ray diffraction, thermogravimetric analysis, and compressive strength measurements. The results revealed that chitin and GO were mixed homogeneously. Interestingly, the composite sponges showed meso-macroporous structure, which played an important role in improving their adsorption properties. Besides, thermal stability and mechanical properties were significantly improved compared with pure chitin sponges. Taking advantages of these fantastic characteristics, the maximum adsorption capacity of composite sponges for bilirubin was up to 422.9 mg/g under the optimized condition, which was not only significantly higher than the adsorption capacities of pure chitin sponges, but also superior to those of many reported adsorbents for removal of bilirubin. Furthermore, blood compatibility evaluations confirmed that this blended sponges had negligible hemolysis and coagulation. Therefore, this work provided a potential possibility to offer Ch/GO composite sponges for removal of bilirubin.