Performance of molecularly imprinted photocatalysts based on fly-ash cenospheres for selective photodegradation of single and ternary antibiotics solution

TiO2, as a steady and inexpensive photocatalysis, is widely applied for removal of organic pollutants. However, the poor selectivity of TiO2 is not conducive to remove high toxic pollutants from mixed solution in the presence of other pollutants. By using tetracycline (TC) as the molecular template and POPD/TiO2/fly-ash cenospheres as the supporter, molecularly imprinted photocatalyst (MIP) possessed the specific recognition ability toward TC was synthesized via the surface imprinting technology and the photo-induced method. This as-prepared MIP possessed hollow spherical structure, the average diameter was ranged from 90 mu m to 140 mu M. Moreover, the photocatalytic activity of MIP was evaluated by degrading 20 mg/L TC solution under the visible light irradiation, and the photodegradation rate could reach 77%. In addition, MIP showed the strong ability to selective recognition and photodegradation of TC in the ternary solution containing TC, oxytetracycline (OTC) and ciprofloxacin (CIP), and the coefficient of selectivity (k(selectivity)) of degradation of TC relative to OTC and CIP was 1.67 and 1.25, respectively. The photodegradation mechanism of TC was also discussed through the mass spectrum (MS), the results indicated that TC was degraded step by step and finally decomposed to CO2, H2O and other gaseous components. (C) 2013 Elsevier B.V. All rights reserved.