Hydrothermal Synthesizing Di-crystalline TiO2 and CNT-COCl/TiO2 Nanocomposites to Degrade Bisphenol A Irradiated with Visible Light - Effect of pH and PO43-

摘要

[[abstract]]Background: Bisphenol A (BPA) is widely used in its monomeric form in the manufacture of poly carbonate plastics, epoxy resins, and flame retardant. The visible photodegradation of BPA with di-crystalline TiO2 and CNT-COCl/TiO2 nanocomposites was investigated in this study.?Methods: The di-crystalline phases of nanocomposites were observed via preparing 1 mL HNO3 of 0.4-1.0 M for synthesis. The CNT-COCl/TiO2 nanocomposites were synthesized by doping acyl chloride- grafted CNTs onto titanium tetraisopropoxide followed by a hydrothermal method. The precursor ratio of CNT-COCl to Ti was set at 1/99 (w/w).?Results: Results showed distinguish increase in red-shift effect of characteristic wavelength at higher rutile crystalline phase. It addressed that a faster degradation rate of BPA was exhibited for di-crystalline nano-composites under visible irradiation compared to that for P25. Further, the BPA degradation rate was much higher in the photocatalytc system using di-crystalline TiO2 doped with CN-COCl. Both solution pH and addition of phosphate showed significant influences on the photo-activity of CNT-COCl/TiO2. The promotional effect caused by phosphate was ascribed to a proper charge separation and high amount of hydroxide radical formation. A degradation rate of 59.5 % was found for the synthesized CNTCOCl/ TiO2 with 50% rutile crystalline phase at pH 9.0 and 10-4 M PO43-.?Conclusion: A novel CNT-COCl/TiO2 photocatalyst was successfully synthesized and characterized. The titanium photocatalysts can be successfully excited by visible irradiation via adjusting the ratio of crystalline phase. Compare with peer carbon-doping TiO2, the CNT-COCl/TiO2 fabricated in this study has superior photocatalytic activity in visible light.