Photocatalytic Degradation of Bisphenol A by TiO2 Mineralized Using a Polystyrene-Peptide Template

Biomineralization is an environment-friendly strategy for producing inorganic materials, where nitrogen-doped particles of controlled size can be synthesized. A peptide-mediated biomineralization was investigated to produce TiO2 particles with enhanced photocatalytic activity. The heptapeptide, HKKPSKS, verified previously as exhibiting TiO2 mineralizing activity, was immobilized on the surface of functionalized polystyrene (PS) bead through N-ethyl-N-(3-dimethylamino-propyl) carbodiimide hydrochloride-N-hydroxy-succinimide (EDC-NHS) coupling, so that it acted as the nucleus to trigger TiO2 precipitation on its surface in ambient condition. During the calcination of PS-peptide-TiO2, the PS-peptide template both allowed the formation of porous-structured particles, and generated nitrogen-doped crystalline mixed phase (anatase/rutile) TiO2. More than 86 % of bisphenol A (BPA) was decomposed in the presence of optimally calcined TiO2 under visible light in 2 h, whereas commercial P25 catalyst degraded 48 % of BPA. After five cycles of repeated reactions for BPA degradation, the photocatalytic activity of TiO2 decreased by less than 10 %.