Fabrication of porous carbon microspheres with numerous spherical microstructures directly from waste Camellia oleifera shells and their application in sustained-release of 5-fluorouracil

Porous carbon microspheres with numerous spherical microstructures were successfully fabricated directly from waste Camellia oleifera shells by hydrothermal carbonization combined with annealing treatment and potassium hydroxide chemical activation technique in the assistance of phloroglucinol. Numerous aromatic carbon microspheres were constructed after hydrothermal carbonization due to the structure-directing effect of phloroglucinol. The spherical microstructures remain intact after suffering from potassium hydroxide chemical activation because the aromatic carbon framework was further graphitized by annealing treatment. The mesoporous carbon microspheres were successfully obtained from microporous carbon microspheres through the secondary potassium hydroxide chemical activation. As valuable porous materials, the as-prepared microporous and mesoporous carbon microspheres were successfully applied to the sustained-release of anticancer drug 5-fluorouracil. The as-prepared microporous and mesoporous carbon microspheres showed some obvious advantages such as low-cost, high-capacity, and strong biological affinity compared with traditional drug sustained-release agent.