Mehdi Hatami

Photocatalytic degradation of Reactive Orange 16 (RO16) was investigated using immobilized TiO2 nanoparticles on polyester support in exposure of UV irradiation in recirculated tubular photoreactors. Utilization of the polyester as a support has several advantages, such as low price, remarkable surface area, flexibility, and durability. Moreover, the prepared TiO2/polyester was successfully applied for the photocatalytic degradation of RO16 in aqueous media for several times without any discernible diminution in its activity. Applied TiO2 nanoparticles were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). Experimental results indicate that the degradation rate of RO16 follows pseudo-first-order kinetics. With nonlinear regression, a model was developed for prediction of pseudofirst-order rate constants (kapp) as a function of operational parameters, including temperature (295–328K), flow rate (5–15 L$min- 1 ), and initial concentration of RO16 (5–25 mg$L- 1 ) as kapp ¼ 2:20ðexp ½ 7427=RTÞ (FR) 0:5034½0:112=ð1 þ 0:112[RO16]0Þ: Calculated data from the model are in good agreement with the experimental results. Electrical energies per order (EEO) were estimated from the calculated and experimental data show that EEO depends on the operational parameters, considerably. To monitor the mineralization of RO16, chemical oxygen demand (COD) measurements were carried out during the UV/TiO2 process. COD measurement results indicated that all organic substances were completely mineralized after 5 h of UV irradiation.