Photocatalytic performance of TiO2 impregnated polyester for the degradation of Reactive Green 12: Implications of the surface pretreatment and the microstructure

In the present work, we investigate the degradation of recalcitrant industrial textile dye (Reactive green 12) in aqueous solution by TiO2 impregnated polyester at room temperature. The TiO2 loading on polyester was optimized using different polyester pretreatments (plasma surface activation and UV-C photons). The applied surface pretreatments led to slightly different microstructure, crystalline sizes and photocatalytic activities. Both catalyst tests showed no photocatalytic activity for Radio-Frequency plasma (from now as "RF-plasma") pretreated polyester under visible light and a lower activity compared to UVC-pretreated-impregnated-fabrics under UV light. This was attributed to the TiO2 aggregation on the surface of RF-plasma activated polyester. However, the photocatalytic performance of UV-C activated catalyst was investigated studying the optimal reaction conditions such as pollutant initial concentration, applied light (UV or Visible), catalyst loading and the presence of hydrogen peroxide at different concentrations. Under optimized operating conditions, namely catalyst dose of 5.18 and an initial dye concentration of 2 mg/L, the removal of Reactive green 12 reached 100% under UV light and 87.14% under visible light within 120 min. Moreover, the presence of hydrogen peroxide showed a positive impact on the degradation, since the time needed for total dye decreased to 80 min under UV light irradiation for a [H2O2] to RG 12 ratio in the range 20-30. The kinetic results showed that the removal of this recalcitrant dye nearly followed a Langmuir-Hinshelwood (L-H) model with a regression coefficient (R-2) value of 0.926. The catalyst activity was found to be stable for more than five reuse cycles. (C) 2017 Elsevier B.V. All rights reserved.