Janus hollow polymeric hairy microspheres as efficient adsorbents and catalyst scaffolds

Polymeric hairy microspheres with a Janus hollow structure were prepared via cationic polymerization using SiO2 nanoparticles as interface protection cores and sacrificial templates. Sulfonic acid groups (–SO3H) were introduced onto the surface of the microspheres by sulfonation and facilitated the further loading of titania. The Janus hollow polymeric hairy microspheres (HSPHS) could be applied as efficient adsorbents to remove both hydrophilic dye rhodamine B (RB) and hydrophobic dye dimethyl yellow (DMY) from the surrounding solution, and the results showed that >98% of RB or/and DMY could be removed within several minutes. The maximum adsorption amount on the Janus HSPHS was 3.48 and 0.14 mol g−1 for RB and DMY, respectively. In addition, the HSPHS can also serve as catalyst scaffolds to load anatase titania for the photocatalytic degradation of RB. Janus hollow microspheres coated with anatase titania (HSPHS@TiO2-An) demonstrated a remarkable photocatalytic efficiency and recyclability. High photocatalytic activity was observed for HSPHS@TiO2-An and the catalytic efficiency remained with almost no loss of the photocatalytic activity even after five catalytic cycles. Thus, the Janus hollow polymeric hairy microspheres have promising applications in water treatment as efficient adsorbents and catalyst scaffolds.