Ball milling synthesis of Fe₃O₄ nanoparticles-functionalized porous boron nitride with enhanced cationic dye removal...

Enhancement of the adsorption performance and recyclability of adsorbents is a crucial aspect of water treatment. Herein, we used one-dimensional porous boron nitride (PBN) as a carrier to load Fe₃O₄ nanoparticles for the preparation of Fe₃O₄ nanoparticles-functionalized porous boron nitride (Fe₃O₄/PBN) via a ball milling method. The high-energy ball milling promoted the creation of a negatively charged PBN surface and facilitated the uniform distribution of Fe₃O₄ nanoparticles on the surface of PBN. The adsorption performance of Fe₃O₄/PBN toward cationic dyes could be significantly improved while no enhancement was observed for anionic dyes. The great adsorption performance of Fe₃O₄/PBN is due to its surface functional groups and surface defects formed in the ball milling process. Moreover, the strong interaction force between Fe₃O₄/PBN and cationic dyes promotes rapid initial adsorption due to their negatively charged surface. Magnetic measurements demonstrated that Fe₃O₄/PBN is superparamagnetic. The composites with low loadings of Fe₃O₄ nanoparticles could be quickly separated from the aqueous solution under a low applied magnetic field, improving their recyclability. This work highlights the role of ball milling in improving the adsorption performance of Fe₃O₄/PBN and greatly promotes the practical application of Fe₃O₄/PBN in the field of environmental purification.