Selective adsorption and degradation of rhodamine B with modified titanium dioxide photocatalyst

A new highly selective photocatalyst (RhB-MIP/TiO2) was successfully prepared by surface molecular imprinting technique using rhodamine B (RhB) as template molecule. The adsorption kinetics show RhB-MIP/TiO 2 possessed fast adsorption rate, and adsorption behavior followed the pseudo-second-order kinetics. The static binding experiments revealed RhB-MIP/TiO2 displayed strong affinity and high adsorption capacity for RhB. Moreover, the equilibrium adsorption rate of RhB-MIP/TiO2 for RhB can be well fitted by the Langmuir isotherm model. The thermodynamics parameters indicated that the binding system of RhB-MIP/TiO2 was endothermic and spontaneous. Compared with non-imprinted photocatalyst (NIP/TiO2), RhB-MIP/TiO2 exhibited excellent selectivity toward RhB, whose selectivity coefficient for RhB relative to rhodamine 6G (Rh6G) was 2.99. Selective photocatalytic degradation experiments indicated that the apparent rate constant for the photodegradation of RhB over RhB-MIP/TiO2 is 0.0212 min-1, being 216% of that over NIP/TiO2 (0.0098 min-1). Therefore, RhB-MIP/TiO 2 exhibited higher photocatalytic selectivity toward RhB. The prepared photocatalyst RhB-MIP/TiO2 has a promising perspective in industrial wastewater treatment. © 2014 Wiley Periodicals, Inc.