Synthesis of polypyrrole‐modified TiO2 composite adsorbent and its adsorption performance on acid Red G

The adsorption–desorption characteristics of Acid Red G (ARG) on the polypyrrole‐modified TiO2 (PPy/TiO2) composite as a novel adsorbent was investigated. PPy/TiO2 was synthesized via the in‐situ polymerization of pyrrole monomer in the prepared TiO2 sol solution. Results from X‐ray diffraction and Fourier transform infrared spectra indicated the formation of the PPy/TiO2 composite. The adsorption experiments showed that the modification of PPy substantially improved the adsorption and regeneration abilities of PPy/TiO2. The adsorption equilibrium was achieved in a short time of 20 min, and the adsorption kinetics followed the pseudo‐second‐order model. The Langmuir adsorption isotherm was found for PPy/TiO2, with the maximum adsorption capacity of 179.21 mg/g. The regeneration experiments showed that PPy/TiO2 could be successfully regenerated by simple alkali‐acid treatment. The adsorption efficiency of the regenerated PPy/TiO2 adsorbent for ARG was still greater than 90% after regeneration for 10 times. Additionally, the adsorption efficiency of PPy/TiO2 for the ARG effluent was still higher than 78% after adsorption–desorption for four times. It is expected that the PPy/TiO2 composite can be considered as a stable adsorbent for the removal of dye.