Photocatalytic Decolorization of Acid Red 4 Azo Dye by Using Immobilized TiO2 Microparticle and Nanoparticle Catalysts

This research studied the synthesis of immobilized TiO2 microparticle and nanoparticle catalyst materials and evaluated its photocatalytic activity on the decolorization of Acid Red 4 (AR4) azo dye solution. TiO2 microparticles were immobilized on an acrylic plate, while TiO2 nanoparticles were immobilised on a glass plate. TiO2 nanoparticles were embedded in a nanofiber support layer to enhance photocatalytic performance, forming a nanofiber-nanoparticle composite on the glass plate. In the catalyst load 2.0 g/l, the performance of the photocatalytic layer of immobilized catalyst (k ′= 0.013/min) was better than that of the suspended catalyst (k′ = 0.008/min). Photocatalytic decolorization efficiency of TiO2 immobilized catalysts of nanoparticle sized reached 82.3% in irradiation time of 2 hours, which was higher than microparticle sized catalysts (77.8%). The technique of TiO2 nanofiber–nanoparticle composite showed improved photocatalytic kinetics (k’= 0.018/min) compared to a single layer of nanoparticle catalyst (k′= 0.015/min). Immobilized TiO2 catalysts remain effective with repeated use despite a slight decrease in processing efficiency.