Fenton’s reaction-based chemical oxidation in suboptimal conditions can lead to mobilization of oil hydrocarbons but also contribute to the total removal of volatile compounds

Abstract

Fenton’s reaction-based chemical oxidation is in principle a method that can be utilized for all organic fuel residues thus making it a potential all-purpose, multi-contaminant, in situ application for cases in which storage and distribution of different types of fuels have resulted in contamination of soil or groundwater. Since peroxide breakdown reactions are also expected to lead to a physical transport of the target compound, this secondary physical removal, or rebound concentrations related to it, is prone to be affected by the chemical properties of the target compound. Also, since soil conditions are seldom optimal for Fenton’s reaction, the balance between chemical oxidation and transport may vary. In this study, it was found that, with a high enough hydrogen peroxide concentration (5 M), methyl tert-butyl ether–spiked groundwater could be treated even under suboptimal conditions for chemical mineralization. In these cases, volatilization was not only contributing to the total removal but also leading to rebound effects similar to those associated with air sparging techniques. Likewise for diesel, temporal transport from soil to the aqueous phase was found to lead to false positives that outweighed the actual remediation effect through chemical mineralization.

In situ bioremediation of Fenton’s reaction–treated oil spill site, with a soil inoculum, slow release additives, and methyl-β-cyclodextrin

“…The mobilization of contaminant both within the soil and in the aqueous phase during chemical oxidation can be suggested to have been beneficial for subsequent biodegradation. The latter mechanism has been demonstrated by Talvenmäki et al (2019), whereas the total effect was now likely negatively affected by the clayey soil type. Regardless of the mobilization mechanism, the contaminant was thus transported to a location with enhanced oxygen and nutrient availability.…”

“…Non-water-saturated conditions were also required as otherwise infiltration of the peroxide may have been limited. Soil oxidant demand was tested as described in Talvenmäki et al (2019) as surpassing 800 mg KMnO 4 /100 g of soil even when visible organic material such as roots had been removed. However, as the majority of the contamination was suggested to appear within a small quantity of soil immediately below the tank, chemical oxidation was still considered an applicable method.…”

“…The efficiency of Fenton-based chemical oxidation may be compromised by radical reaction inhibition or scavenging by the organic material (Lindsey and Tarr 1999;Miller and Valentine 1999;Pham 2012) or low availability of the contaminant in NAPLs or adsorbed in to soil particles, especially in clayey soils (Sellers 1999;Villa et al 2010). Even if chemical oxidation is the target mechanism for contaminant removal, a secondary biological mechanism can contribute to the overall efficiency by increasing oxygen availability and contaminant bioavailability, especially if chemical mineralization itself has been insufficient (Talvenmäki et al 2019;Goi et al 2006).…”

Ferroptosis and its Role in Gastric Cancer

“…However, in cases of iron overload, excessive Fe 2+ is produced within the cell. The accumulation of intracellular Fe 2+ further leads to the production of Fe 3+ and ROS through the Fenton chemical reaction ( Talvenmäki et al, 2019 ). In addition, excess Fe 3+ can also be reduced to Fe 2+ through the Haber–Weiss reaction ( Kehrer, 2000 ).…”

“…In addition, excess Fe 3+ can also be reduced to Fe 2+ through the Haber–Weiss reaction ( Kehrer, 2000 ). Furthermore, under stress conditions, ferritin can self-degrade into Fe 2+ through iron autophagy ( Talvenmäki et al, 2019 ). Collectively, these processes can lead to ferroptosis, which in turn induces the formation of more ROS.…”