Photodegradation of phenanthrene in the presence of humic substances and hydrogen peroxide

Abstract

The photodegradation of phenanthrene in water was investigated for a variety of reaction conditions employing various fulvic acids (FAs) as photosensitizers and hydrogen peroxide as oxidant. All experiments were conducted by using artificial sunlight from Suntest apparatus (Hanau, Germany) as light source. The relative rates of phenanthrene photodegradation for the different experimental conditions were computed. Fulvic acids of different origins influenced the rate of sunlight-induced photodegradation of phenanthrene in different ways. Hydrogen peroxide vigorously enhanced the photodegradation rate of phenanthrene. The photoproducts identified were oxygenated products of aromatic ring, such as 9,10,-phenanthrenquinone, a group of hydroxyphenanthrene with hydroxyl at different position (1,3,4, and 9), 2,2'-biphenyldicarbonic acid, 2,2'-biphenyldialdehyde and 2-phenylbenzaldehyde. It can be consumed that the phenanthrene photodegraded via free radical mechanism.

Photochemical degradation of PAHs in estuarine surface water: effects of DOM, salinity, and suspended particulate matter

“…As the most photodegradable PAH, the photodegradation rate constant of BaP in deionized water was higher than that of Phe and BeP by a factor of 4.2 and 6.3, respectively. According to previous studies, the average value of the half-life for the photodegradation of Phe scaled to the natural sunlight photon flux is 11 ± 9 h (Zepp and Schlotzhauer 1979;Wang et al 1995;Bertilsson and Widenfalk 2002;Fasnacht and Blough 2002;Jacobs et al 2008;de Bruyn et al 2012), and the half-life for the photodegradation of BaP is much shorter, ranging between 0.69 and 6.4167 h (Mill et al 1981;Sanches et al 2011). The results of our experiments coincided well with the literature range.…”

Amelioration of the Photo-Induced Toxicity of Polycyclic Aromatic Hydrocarbons by a Commercial Humic Acid

“…Production of these reactive oxygen species by both commercial (Steinberg et al, 1992) and natural Wang et al, 1995) humics can oxidize a variety of organic pollutants, including PAHs. Therefore, HA photosensitization may not only photooxidize PAHs to more toxic forms (e.g., Greenberg et al, 1993), but it is also likely that the reactive oxygen species themselves could exert negative biological impacts even without PAHs present.…”

“…; Cooper et al, 1989;Hoigne´et al, 1989;. Production of these reactive oxygen species by both commercial (Steinberg et al, 1992) and natural Wang et al, 1995) humic substances is known to drive photooxidation of organic contaminants. Similar to PAHs, photosensitization of humic acids (HAs) thus may also induce direct negative biological effects.…”

Photocatalytic degradation of polycyclic aromatic hydrocarbons on soil surfaces using TiO2 under UV light

“…Humic acids (HAs) are complex organic molecules produced by the decomposition of plant and animals remained in soil, they can either enhance [29][30][31][32] or inhibit photolysis [33][34][35]. The influence of HA on the photocatalytic degradation of PAHs in the presence of TiO 2 on soil surfaces was investigated herein.…”