High photocatalytic and adsorptive performance of anatase-covered titanate nanotubes prepared by wet chemical reaction

Abstract

Anatase-covered titanate nanotubes (TiNTs) with high photocatalytic and adsorptive performance characteristics were prepared through wet chemical reaction. TEM and XRD analysis revealed that the morphology and composition of the modified TiNTs were directly related to the ambient pH and temperature conditions of the reaction. Lower pH and higher temperature tended to enhance the transition from titanate to anatase; moreover, the transition process involved an in situ rearrangement of the primary structural unit [TiO6]. The photocatalytic performance of modified TiNTs depended on the amount of TiO2 transformed from titanate, whereas the adsorptive property was primarily determined by the tubular titanate structure. TiNTs modified under optimal conditions of pH 2 and 120°C (TiNTs-120-2) not only exhibited high photocatalytic degradation rate for methyl orange (0.568×10−2min−1), but also possessed a considerable capacity for adsorption of methylene blue (195.31mg/g). Based on their excellent photocatalysis and adsorption properties, TiNTs-120-2 could simultaneously remove methyl orange, methylene blue, Pb2+, and phenol initially present in a compound pollution system, and the materials could be efficiently reused after a simple further treatment. In addition, TiNT-120-2 is well suited to sedimentation, and so has strong potential for application as an easily separable and recoverable material.