Fabrication, characterization and application of a reusable immobilized TiO_2-PANI photocatalyst plate for the removal of reactive red 4 dye

摘要

A method for immobilizing TiO_2 -PANI composite using ENR and PVC as adhesives was successfully developed. The immobilized system known as TiO_2/PANl/ENR/PVC plate was characterized by FTIR, Raman, diffuse reflectance UV-vis, photo luminescence spectroscopy and HRTEM. The optimum weight ratio for the TiO_2:PANI composite was 1:0.0035. The band gap energy of the optimum immobilized composite TiO_2/PANI/ENR/PVC (1:0035) was 2.86 eV where polyaniline (PANI) formed a core-shell coating of about 0.9 nm with a strong TiO_2-PANI interaction. Photo-etching of the immobilized TiO_2/PANI/ENR/PVC (1:0.0035) composite for 7h increased its surface area and improved its photocatalytic activity. TiO_2/PANI/ENR/PVC (1:0.0035)-7 h was visible light sensitive where 85% of 30 mg L~(-1) reactive red 4 (RR4) dye was decolorized after 60 min of irradiation. The immobilized TiO_2/PANI/ENR/PVC (1:0.0035)-7 h was reusable and its photocatalytic activity was sustainable with an average pseudo first order rate constant value of 0.103 ± 0.002 min~(-1). Adding PANI to the immobilized P25 TiO_2 has enhanced its photocatalytic activity throughout the entire ten recycled applications due to the increased BET surface area and lower e_(cb) and h~+ recombination.