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), TiO 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 (∑) PAH content reduced by 86-90% in the soil samples during UV applications. With the use of UVA rays, higher ∑ 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 TiO provided an increase in removal ratios and ∑ PAHs removal ratios changed between 87% and 94%. Furthermore, the amount of PAH migrated to the air decreased during this application. During UVA-TiO and UVC-TiO applications, at 30°C, evaporated average ∑ PAH amounts were 2.91 ng/m and 6.59 ng/m, respectively.

Highly Efficient Photocatalytic Remediation of Low Molecular Weight Polycyclic Aromatic Hydrocarbons (LMWPAHs) in Contaminated Soils

“…In addition, superoxide ionic radicals (O2 .-) are produced during the reaction between available electrons and O 2 present in the environment. These both radicals (OH) and (O2 .-) are highly reactive in nature and play the basic role in degradation of PAHs [13]. In our experiment radiation time, wavelength varied thus posing different affects.…”

“…After the absorption of UV radiation, the reactions occurs under the influence of tiO 2 producing a paired of negatively charged electrons along with positively charges holes [12]. During the process several radicals are created [13].…”

Impact of Titanium Dioxide (TiO2) Modification on Its Application to Pollution Treatment—A Review

“…The photocatalytic technology can completely mineralize the organic pollutants and remove the heavy metals in the soil. This technology also has the advantages of fast decomposition rate, no secondary pollution, and easy operation [252][253][254]. In recent years, photocatalysis has been widely used in organic soil remediation studies, including organic pesticides, aromatic organics, petroleum hydrocarbons, and heavy metals [255,256].…”

Impact of Polycyclic Aromatic Hydrocarbon Accumulation on Oyster Health

“…As such, they have become convenient proxies for all human activities that rely on fossil fuels. PAHs themselves are characterized by their low solubilities (Sangster, 1989) and are thus usually found adhering to small particles in either marine sediment (Vaezzadeh et al, 2019) or soil (Eker and Hatipoglu, 2019). Due to their semi-volatility, PAHs can be removed via evaporation or photooxidation (Karaca and Tasdemir, 2013;Eker and Hatipoglu, 2019), a process that could become problematic depending on the photoproducts.…”

“…PAHs themselves are characterized by their low solubilities (Sangster, 1989) and are thus usually found adhering to small particles in either marine sediment (Vaezzadeh et al, 2019) or soil (Eker and Hatipoglu, 2019). Due to their semi-volatility, PAHs can be removed via evaporation or photooxidation (Karaca and Tasdemir, 2013;Eker and Hatipoglu, 2019), a process that could become problematic depending on the photoproducts. In general, photooxidation of PAHs yields reactive molecules, such as aldehydes and aromatic ketones known as quinones (Ehrenhauser, 2011), which are highly toxic (reviewed by Lee, 2003) and reminiscent of the compounds created during PAH metabolism (reviewed by Ertl et al, 2016).…”