Electrospray Preparation of Robust Aramid Nanofiber Microbead Adsorbents for Wastewater Treatment

Adsorption is one of the promising techniques for effectively removing dyes from wastewater due to its low cost and high efficiency. However, most reported adsorbents still suffer from low adsorption capacity and stability under harsh conditions, which severely limit their practical application. Herein, we report a novel method to prepare robust aramid nanofiber (ANF) microbead adsorbents using electrospraying technology and solvent replacement method. The structure of the ANF microbeads can be easily manipulated by changing the coagulation baths, thus achieving fabricated ANF microbeads with a uniform and highly porous microstructure. The as-prepared ANF microbeads show high removal efficiency toward methylene blue (MB) with a maximum adsorption capacity of up to 267 mg/g, which can be attributed to the strong π–π stacking, hydrogen bonding, and electrostatic attraction between MB and the microbeads. Moreover, ANF microbeads show outstanding stability within a wide pH range (from 2 to 12) with an MB removal efficiency over 90% even after five adsorption–desorption cycles at pH = 12. Additionally, the ANF microbeads can maintain their structure integrity after the adsorption process and can be easily separated from the solution by static sedimentation because of their robust structure. This work provides a new strategy to design robust microbeads with excellent adsorption performance and stability, demonstrating their great potential in various environmental engineering applications.