Immobilized carbon-doped TiO₂ in polyamide fibers for the degradation of methylene blue

The discharge of dyes in the textile industry leads to several hazardous effects on the environment. One of the most effective methods on treating dye-contaminated wastewater is photocatalytic degradation. TiO2 has been widely used as a photocatalyst for wastewater treatment. Since the light absorption of TiO2 is in the UV light range, however, doping of TiO2 with a non-metal or metal element is needed to improve its absorption in the visible light range. In this study, TiO2 photocatalyst was doped with carbon using sucrose as a carbon+e at ratios of 0.75:1 and 1:1. The surface area of TiO2 after doping with carbon improved to two times the TiO2 surface area. Additionally, the band gap energy of TiO2 was successfully reduced to 2.38 eV after doping with carbon. In order to avoid the secondary pollutant problems, the carbon-doped TiO2 was then immobilized with polyamide fibers at 1wt%, 2wt% and 3wt% to facilitate recollection of the photocatalyst. A photodegradation test was performed by degrading methylene blue under visible light irradiation using 70W halogen lamps with a total of 5 hours of time interval readings. The highest percentage degradation was recorded at 82.67% using immobilized 2wt% 1:1 carbon-doped TiO2 in polyamide fibers.