Characterization and application of surface-molecular-imprinted-polymer modified TiO₂ nanotubes for removal of...

The removal of perfluorinated chemicals (PFCs) during wastewater reclamation is a great concern. However, the existing advanced treatment processes are inefficient for the removal of PFCs from secondary effluents of municipal wastewater treatment plants (WWTPs) because other coexistent pollutants with less environmental significance are removed simultaneously. Therefore, research on high-selectivity, low-cost removal methods is needed. The S-MIP-TiO₂ nanotube (NT) photocatalysts were fabricated, characterized and tested for removal of PFCs from wastewater for the first time. Scanning electron microscopy and Fourier transform infrared spectroscopy show that the TiO₂ NTs (average diameter 60 nm) were successfully imprinted with functional groups (i.e. carboxyl). The adsorption selectivity and photocatalytic activity of the S-MIP-TiO₂ NTs over perfluorooctanoic acid (PFOA) were improved compared with neat TiO₂ NTs and interestingly, were higher at low PFOA concentrations (10 to 100 ng/L, as normal PFC concentrations in secondary effluents) than at high concentrations (10 to 1,000 mg/L). With S-MIP-TiO₂ NTs used as photocatalysts, some representative PFCs were selectively and rapidly removed from secondary effluents of a municipal WWTP. S-MIP-TiO₂ NTs exhibited excellent regeneration performance. Thus, photocatalytic treatment using is promising for effective removal of PFCs from secondary effluents of municipal WWTPs.