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. Graphical abstract: [Figure not available: see fulltext.]