Boron-doped Titanium Dioxide Nanofibers For The Adsorption And Photodegradation Of Dyes

Approximately one million tons of dyes are synthesized worldwide every year.A large amount of colored industrial wastewater will be produced during their synthesis and utilization process.These hardly biodegraded dyes remain in the environment for a long time,harmful to ecosystem and human health.Ti O₂photocatalysts are widely used due to their good stability and non-toxicity.However,Ti O₂only gives response in the Ultraviolet region,accounting for only 4%of the solar energy.Doing Ti O₂with other element is a common technique to extend its light absorption region and enhance its photocatalytic performance.We prepared sodium titanate nanofibers and hydrogen titanate nanofibers by hydrothermal method and ion exchange,respectively.On this basis,boron-doped titanium dioxide nanofibers were easily obtained by thoroughly grinding hydrogen titanate with Na BH₄,followed by calcination.We found that the boron-doped titanium dioxide nanofibers obtained from different calcination temperatures possessed different crystal phases and boron probably located at interstitials of Ti O₂.Boron doping could also reduce the zeta potential of Ti O₂.The results from UV-Vis and PL spectra showed that boron-doped titanium dioxide could absorb visible-light and achieved high separation efficiency of photo-induced electron-hole pairs.Utilizing methylene blue as a model dye,we investigated the influence of temperature,p H and light wavelength on its adsorption and photodegradation over B-doped titanium dioxide（B-Ti O₂）.The results showed that temperature has negligible effect on the adsorption performance of B-Ti O₂.B-Ti O₂was applicable to a wide p H range（p H>4）for the adsorption and photodegradation of methylene blue and could restore its adsorption capability via self-cleaning by light irradiation.In addition,the adsorption performance of B-Ti O₂on different types of organic dyes was investigated.Compared with undoped Ti O₂,B-Ti O₂showed excellent adsorption performance on those cationic dyes in the absence of carboxylic acid or sulfonic acid groups in the main structure and N⁺connected with non-aromatic groups.