Effect of UV wavelength, temperature and photocatalyst on the removal of PAHs from industrial soil with photodegradation applications

ABSTRACT

The aim of the present study was to evaluate the effectiveness of UV-based processes to the removal of PAHs from soils with and without photocatalyst. PAH removal experiments were conducted in a specially designed UV photochamber. The effects of various factors, namely temperature, light wavelength (UVA, UVC), TiO₂ dose on the removal of PAHs were examined. Furthermore, evaporation ratios of PAHs during UV applications were determined with polyurethane foam (PUF) samples. Temperature increase positively affected PAH removal process. The total 12 (∑₁₂) PAH content reduced by 86–90% in the soil samples during UV applications. With the use of UVA rays, higher ∑₁₂ PAH removal was enhanced when compared to UVC rays. It was thought that in the existence of UVC rays, other aromatic compounds or other PAHs in soil converted to targeted PAHs with photodegradation. The amounts of evaporated PAHs from soil were increased with increasing of temperature and more than 90% of PAHs in the air consisted of 3–4 ring compounds. It was found that TiO₂ provided an increase in removal ratios and ∑₁₂ PAHs removal ratios changed between 87% and 94%. Furthermore, the amount of PAH migrated to the air decreased during this application. During UVA-TiO₂ and UVC-TiO₂ applications, at 30°C, evaporated average ∑₁₂ PAH amounts were 2.91 ng/m³ and 6.59 ng/m³, respectively.

GRAPHICAL ABSTRACT

KEYWORDS:

• Soil
• PAH
• UV
• photocatalyctic degradation
• evaporation

Acknowledgments

We would like to thank Betül Sena SAGLAM and Tugba CELEBİOGLU for their selfless laboratory work.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This study was supported by the Scientific and Technological Research Council of Turkey (TÜBİTAK), project number [114Y833].