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 MIPRhB-PPy/TiO2 were successfully prepared by surface molecular imprinting technique with rhodamine B (RhB) as template molecule. The prepared MIPRhB-PPy/TiO2 coated with a thin imprinted layer could respond to visible light. The static and dynamic binding experiments revealed that MIPRhB-PPy/TiO2 possessed strong affinity, high adsorption capacity and fast adsorption rate for RhB. The selectivity experiments indicated that MIPRhB-PPy/TiO2 had excellent recognition selectivity for RhB. Selective photocatalytic degradation experiments indicated that the apparent rate constant (k) for the photodegradation of RhB over MIPRhB-PPy/TiO2 is 0.0158 min–1, being 3.6 times of that over non-imprinted nanocomposites NIPRhB-PPy/TiO2 (0.0044 min–1). Compared with the NIPRhB-PPy/TiO2, MIPRhB-PPy/TiO2 showed higher photocatalytic selectivity toward RhB under visible light, which was attributed the introduction of the imprinted cavities on the surface of MIPRhB-PPy/TiO2. Moreover, MIPRhB-PPy/TiO2 exhibited high reusability and stability. The results indicate that molecularly imprinted nanocomposites MIPRhB-PPy/TiO2 have a promising perspective in industrial wastewater treatment.

Keywords

• Nanocomposites
• Photodegradation
• Selectivity
• Molecular imprinting
• Rhodamine B