Preparation of porous alumina‑carbon composite fibers via coaxial electro-blown spinning for methylene blue adsorption study

The porous alumina‑carbon composite fibers (PACF) were innovatively prepared through the implementation of an coaxial electro-blown spinning (EBS) method in conjunction with carbonization process. This study pioneers a strategy where a carbon precursor core is encapsulated by an alumina precursor shell, co-incorporating PTFE as a porogen. This design yields a continuous porous carbon network within the alumina fiber, serving as a skeleton to ensure mechanical integrity and inhibit brittleness, while component diffusion enables surface carbon exposure for rapid adsorption. The optimal PACF (prepared at an inner-outer flow rate of 1:2, 3 °C/min, 800 °C) possesses a hierarchical pore structure, a high specific surface area (349 m 2 /g), and exhibits exceptional methylene blue adsorption performance (99% removal in 2.5 min) with excellent reusability (maintained a high adsorption efficiency of 95.5% even after five adsorption–desorption cycles). The superior adsorption performance of PACF originates from its hierarchical pore architecture formed by porous carbon and alumina, where carbon-derived micropores supply abundant adsorption sites and alumina-derived mesopores serve as efficient diffusion channels. This multiscale pore synergy reduces mass-transfer resistance and promotes methylene blue diffusion and accumulation within the fibers, enabling rapid and efficient adsorption. The synergistic effect between porous alumina and carbon endows the PACF with superior comprehensive performance, highlighting its potential for practical wastewater treatment applications.