Photocatalytic degradation of industrial acrylonitrile wastewater by F–S–Bi–TiO2 catalyst of ultrafne nanoparticles dispersed with ­SiO2 under natural sunlight

Strategies for acrylonitrile industrial wastewater photodegradation with F-S-Bi-TiO2/SiO2 ultrafine nanoparticles under natural or simulated sunlight irradiation

Like Comment
Read the Paper

Acrylonitrile is considered as a significant industrial chemical, originated by the direct oxidation of propylene with ammonia. It is extensively used for the preparation of synthetic rubber & resin, plastic and acrylic fiber. Various types of organic pollutants are formed during the production of acrylonitrile which has definitely induced serious impact on environmental and public health. Owing to its low bioavailability, high toxicity and mingled composition, acrylonitrile production wastewater has been directed as one type of refractory organic wastewater. Therefore, it is necessary to develop a safe and efficient technology for the treatment of acrylonitrile wastewater.

Various methods have been reported for the treatment of acrylonitrile wastewater, among those methods photocatalysis acquired much attention over the past decade. Since, photocatalytic reaction under sunlight irradiation is more energy-advantageous, and a lot of researchers have made vast efforts to realize the industrialization of photocatalytic treatment of industrial wastewater under sunlight. However, there were few successful reports under sunlight because of the complexity of industrial wastewater. Thus, photocatalytic treatment of industrial wastewater under sunlight was a great challenge for the researchers.

In our previous study, PhD Dandan Pang1,2 found that the high photocatalytic activity of F-doped TiO2 with degradation ratio 65.9% was attributed to the increase in the number and strength of surface acid sites. It was explained that F-doping led to the creation of surface oxygen vacancies, or the increase of Ti3+ state. The high photocatalytic activity provides a favorable guarantee for the degradation of acrylonitrile industrial wastewater, due to the complexity of industrial wastewater. Recently, highly active photocatalyst with degradation ratio 81.9%, having certain anti-ionic interfering function, of F, S and Bi doped TiO2/SiO2 (F-S-Bi-TiO2/SiO2) ultrafine nanoparticles was used for the first time to degrade the organic pollutants in acrylonitrile industrial wastewater under natural sunlight. UV-Vis analysis revealed addition of F, S and Bi led to the expansion of TiO2 response in the visible region and hence the efficient separation of charge carrier. Because SiO2 makes the catalyst have ultrafine crystal characteristics, the time for electrons to transfer from the inside to the surface becomes shorter, thereby accelerating the generation of active radicals, which ultimately leads to an increase in photocatalytic efficiency. The photocatalytic potential of as prepared catalyst to degrade acrylonitrile wastewater under simulated and natural sunlight irradiation was investigated. CODCr in wastewater decreased from 88.36 mgL-1 to 7.20 mgL-1 via 14 h irradiation of simulated sunlight and achieved regulation discharge by 6 h under natural sunlight, illuminating our photocatalyst effectiveness for refractory industrial wastewater treatment.

More details of this work could be found here: https://doi.org/10.1038/s41598-020-69012-z

References

  1. Pang, D. D.,Wang, Y. T., Ma,  D. & Ouyang, F. Fluorine promoted and silica supported TiO2 for photocatalytic decomposition of acrylonitrile under simulant solar light irradiation. Chem. Eng. J. 258, 43–50 (2014).
  2. Pang,D. D., Qiu, L., Zhu, R. S., Ouyang, F. Silica supported SO42-/TiO2 for photocatalytic decomposition of acrylonitrile under simulant solar light irradiation. Chem. Eng. J. 270, 590–596 (2015).

Feng Ouyang

Professor, Harbin Institute of Technology (Shenzhen)