Synthesis of molecularly imprinted polypyrrole/titanium dioxide nanocomposites and its selective photocatalytic degradation of rhodamine B under visible light irradiation

Abstract

Highly selective molecularly imprinted nanocomposites MIP RhB -PPy/TiO 2 were successfully prepared by surface molecular imprinting technique with rhodamine B (RhB) as template molecule. The prepared MIP RhB -PPy/TiO 2 coated with a thin imprinted layer could respond to visible light. The static and dynamic binding experiments revealed that MIP RhB -PPy/TiO 2 possessed strong affinity, high adsorption capacity and fast adsorption rate for RhB. The selectivity experiments indicated that MIP RhB -PPy/TiO 2 had excellent recognition selectivity for RhB. Selective photocatalytic degradation experiments indicated that the apparent rate constant (k) for the photodegradation of RhB over MIP RhB -PPy/TiO 2 is 0.0158 min -1 , being 3.6 times of that over non-imprinted nanocomposites NIP-PPy/TiO 2 (0.0044 min -1 ). Compared with the NIP-PPy/TiO 2 , MIP RhB -PPy/TiO 2 showed higher photocatalytic selectivity toward RhB under visible light, which was attributed the introduction of the imprinted cavities on the surface of MIP RhB -PPy/TiO 2 . Moreover, MIP RhB -PPy/TiO 2 exhibited high reusability and stability. The results indicate that molecularly imprinted nanocomposites MIP RhB -PPy/TiO 2 have a promising perspective in industrial wastewater treatment.