Photocatalytic Degradation Of Cationic Dyes

The photocatalytic degradation of cationic dyes was investigated in this paper. Firstly,four different photocatalytic system of UV/H2O, UV/TiO2, UV/K2S2O8and UV/Na2S2O4were applied in photocatalytic degradation of Cationic Pink X-FG dyes.The effect of pH,photosensitizer concentration, temperature and time on degradation efficiency wereinvestigated.Further,photocatalytic degradation kinetics of the four different photocatalyticsystems were investigated.Then the dye of original solution and dye of residue in differentdegradation time were tracked by using infrared spectroscopy (FT-IR), high performanceliquid chromatography (HPLC), liquid chromatography-mass spectrometry (LC-MS),elemental analysis, nuclear magnetic resonance (1H-NMR) and other testing methods; anextracted component of dye degradation products was analyzed and it’s structure wassuggested. Finally, the four different photocatalytic systems were applied to commercialcationic dyes for photocatalytic degradation. In addition, an investigation of thephotocatalytic degradation of cationic dyes on dyed acrylic fiber was performed, as well asits effect parameters. The structure and properties of acrylic fiber faded by photocatalyticdegradation treatment was investigated by using Fourier transform infrared spectroscopy(FT-IR), X-ray powder diffraction (XRD), thermogravimetry (TG)-differential thermogravimetry(DTG)-differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and othertesting methods.The results show that the photocatalytic degradation of cationic dye pink X-FGsolution with UV/H2O, UV/TiO2, UV/K2S2O8and UV/Na2S2O4photocatalytic systemsresults good. Kinetic studies show that the dye photocatalytic degradation reaction is afirst-order reaction.The Cationic Pink X-FG dye was degraded in UV/H2O photocatalyticsystem with time, accompanying with a decrease of the solution pH, an increase of thedegradation products and a decline of the original dye component. The dye was degradedfor60min with UV/H2O photocatalytic system，one of the components in the degradationproducts might be C8H12O6. Commercial azo dyes were degraded more easily in UV/H2Oand UV/TiO2photocatalytic degradation systems, and good results were obtained for the methine dyes in UV/K2S2O8and UV/Na2S2O4photocatalytic degradation systems. Inaddition, results show that cationic dyes on acrylic fiber could be faded by photocatalyticdegradation. After Faded by different photocatalytic degradation systems, the crystallinityof acrylic fibers was increased, the influence of thermal decomposition properties ofacrylic fibers was relatively low, and no damage to the surface morphology of acrylic fiberwas observed.