Evaluation of in situ catalysed hydrogen peroxide propagation (CHP) for phenanthrene and fluoranthene removals from soil and its associated impacts on soil functionality

Abstract

Extensive contamination of soils by highly recalcitrant contaminants such as polycyclic aromatic hydrocarbons (PAHs) is an environmental problem arising from rapid industrialisation. This work focusses on the remediation of soil contaminated with 3- and 4-aromatic ring PAHs (phenanthrene (PHE) and fluoranthene (FLUT)) through catalysed hydrogen peroxide propagation (CHP). In the present work, the operating parameters of the CHP treatment in packed soil column was optimised with central composite design (H2O2/soil 0.081, Fe(3+)/soil 0.024, sodium pyrophosphate (SP)/soil 0.024, pH of SP solution 7.73). The effect of contaminant aging on PAH removals was also investigated. Remarkable oxidative PAH removals were observed for the short aging and extended aging period (up to 86.73 and 70.61 % for PHE and FLUT, respectively). The impacts of CHP on soil biological, chemical and physical properties were studied for both spiked and aged soils. Overall, the soil functionality analyses after the proposed operating condition demonstrated that the values for soil respiration, electrical conductivity, pH and iron precipitation fell within acceptable limits, indicating the compatibility of the CHP process with land restoration.

The influence of sunlight and oxidative treatment on measured PAH concentrations in biochar

“…Lowering of PAH concentrations would be expected to occur through the actions of the oxidizing agents (e.g., hydroxyl radical) introduced either directly or via photooxidation processes (Ahmed et al 2014;Ricca and Bauschlicher 2000;Sabate et al 2001;Vela et al 2012;Venny et al 2012Venny et al , 2014, although the susceptibility of individual PAHs to reaction will vary (Flotron et al 2005). The hydroxyl radical mechanism generally begins with the addition of the hydroxyl radical across a carbon-carbon bond in the conjugated ring system of the PAH, followed by the loss of hydrogen to form an alcohol or ketone :…”

Fenton oxidation to remediate PAHs in contaminated soils: A critical review of major limitations and counter-strategies

“…SP > EDTA > OA > MA > SC (Venny et al, 2012b). Other studies by this research group have established the higher efficiency of SP during Fenton oxidation and its compatibility with biological treatment to promote PAH degradation (Venny et al, 2012c;Venny et al, 2014). Similarly, Jorfi et al (Jorfi et al, 2013) performed Fenton oxidation by employing iron nano-particles along with various CAs to remove pyrene in contaminated soil.…”

“…Venny and co-workers (2012c) demonstrated the strong compatibility of MF oxidation (Fe III + SP as chelating agent) with bioremediation (natural attenuation and biostimulation) for an efficient degradation of PAHs in column experiments simulating in-situ soil flushing. These authors, in another study in packed columns (Venny et al, 2014), described the impact of SP modified Fenton oxidation on soil functionality during remediation of PAHs in spiked and aged soils. Use of optimized operating parameters during MF oxidation (H 2 O 2 /soil=0.081, Fe III /soil=0.024, SP/soil=0.024, pH of SP solution=7.73) could make this treatment compatible with bioremediation and crop growth as the obtained values for pH, electrical conductivity, iron precipitation and soil respiration were within acceptable limits.…”

“…Prior to the field or in-situ applications, feasibility studies are generally conducted at batch scale to determine the extent and rate of PAH removal. However, few reports have investigated the Fenton oxidation under column dynamic conditions, which more closely mimic field conditions (Palmroth et al, 2006a;Laurent et al, 2012;Venny et al, 2012c;Lemaire et al, 2013b;Venny et al, 2014). Figure 1 shows the different experimental setups used to investigate Fenton oxidation in contaminated soils at laboratory scale.…”