Enhanced adsorption performance of PPy/TiO2 prepared on surface of TiO2 without calcination

Abstract

The PPy/TiO2 composites were synthesized by polymerizing pyrrole monomer on the surface of TiO2 calcined at different temperatures. The results of Fourier Transform Infrared spectroscopy, X-ray diffraction, Temperature programmed desorption, X-ray photoelectron spectroscopy and Zeta potential showed that the type and amount of the active groups on TiO2 surface decreased with the increase of calcination temperature, leading to a significant decline in its adsorption capacity for Acid Red G (ARG) and Methylene Blue (MB). This also had a significant influence on the physicochemical property and adsorption performance of PPy/TiO2. The prepared PPy/TiO2 composite exhibited an enhanced adsorption capacity for ARG and MB. The adsorption ability of PPy/TiO2 was the strongest when TiO2 was not calcined and gradually decreased with the increase of the calcination temperature of TiO2. The PPy/TiO2 composite without calcination was chosen to investigate its adsorption performance. The results showed that the adsorption behaviors of ARG and MB on PPy/TiO2 were described by the pseudo-second-order and Langmuir isotherm models with the maximum adsorption amount of 424.75 and 439.61 mg/g for ARG and MB, respectively. Finally, the surface chemical properties of TiO2 seriously affected the adsorption performance of PPy/TiO2. The PPy/TiO2 composite could possess excellent adsorption performance when the selected TiO2 contained more hydroxyl and carboxyl groups.