Remediation of PAH-Contaminated Soil by Combining Surfactant Enhanced Soil Washing and Iron-Activated Persulfate Oxidation Process

Abstract

There is increasing concern regarding soils contaminated with polycyclic aromatic hydrocarbons (PAHs). In the present study, the remediation of soil spiked with PAHs was explored by the combination of soil washing with sodium dodecyl sulfate (SDS) and subsequent oxidation through persulfate (PS) activated by Fe2+, nanoscale zero-valent iron (nZVI), and SiO2-coated nZVI (SiO2/nZVI). Results demonstrated that the removal of phenanthrene (PHE), fluoranthene (FLU), and pyrene (PYR) by SDS is an efficient means for soil decontamination. At SDS concentration of 20 g/L, the removal efficiencies of PHE, PYR, and FLU were 37%, 40%, and 44%, respectively. For the degradation of PAHs and SDS in the soil washing effluents, the efficiencies of PS activated with SiO2/nZVI were not significantly different from those of PS activated with nZVI and Fe2+ (p > 0.05). In practice, SiO2/nZVI is more preferable due to the improved antioxidation and dispersibility. At the dosage of 2 g/L (in the amount of iron) of SiO2/nZVI, the removal efficiencies of PHE, FLU, PYR, and SDS within 30 min of treatment were 75%, 85%, 87%, and 34%, respectively. The degradation of SDS was much lower than those of PAHs, which facilitated the recycle of SDS. Our findings suggest that PS activated with SiO2/nZVI is a promising method for the treatment of soil washing effluents containing SDS and PAHs.

Remediation of soils contaminated by hydrophobic organic compounds: How to recover extracting agents from soil washing solutions?

“…Recently, a great attention has also been given to the development of AOPs based on persulfate activation, due to several inherent advantages of sulphate radicals such as (i) the convenience of storage and transportation of solid persulfate, (ii) the different way to activate persulfate (e.g. thermal or electrochemical processes, Fe 2+ ) and (iii) the longer lifetime of sulphate radicals compared to hydroxyl radicals [133][134][135][136][137].…”

“…Interestingly, a lower inhibitory effect was observed when using surfactants with bigger hydrated polar head, due to the reduction of surfactant adsorption at the surface of the catalyst [18,112]. Some other non-AOPs chemical oxidation processes have also been applied to the treatment of SW solution, particularly ozone, activated persulfate [135,136,161,162], and electrochemical processes using active electrodes that do not produce hydroxyl radicals [128,163]. Lower effectiveness for the removal of target pollutants has been reported because of the generation of weaker oxidant species [1].…”

Persistent organic compounds in the environment their impact on human health: A review

“…Manariotis et al, [56] have reported degradation of PAHs by the high frequency of ultrasound. Qiu et al, [57] during their studies found that PAHs can be removed from the soils by soil washing using sodium dodecyl sulfate (SDS) as the surfactant. Sodium dodecyl sulfate at the concentration of 20g/L can remove37-44% of PAHs.…”

Optimization of electro-kinetic process for remediation of soil contaminated with phenanthrene using response surface methodology

“…In a study conducted by Baneshi et al (2014) for the removal of phenanthrene and pyrene with the concentration of 100-300 mg/kg from the soil, using two plants Sorghum and Onobrychis sativa, the results obtained showed that after 120 days, the removal efficiency of PYR and PHE in soil significantly increased, that is, 74.1-73.84% of PYR and 85.02-85.2% of PHE were removed (Baneshi et al 2014). The results of the study performed by Qiu et al (2019) in the remediation of contaminated soil to PAH by surfactant (SDS) and ironactivated persulfate oxidation process showed that at SDS concentration of 20 g/L, the removal efficiencies of phenanthrene, fluoranthene, and pyrene reached 37%, 40%, and 44%, respectively. At the dosage of 2 g/L of SiO 2 /nZVI, PS solution (50 mM), and time of 30 min, the removal efficiencies of PHE, FLU, and PYR were 75%, 85%, and 87%, respectively (Qiu et al 2019).…”

“…The results of the study performed by Qiu et al (2019) in the remediation of contaminated soil to PAH by surfactant (SDS) and ironactivated persulfate oxidation process showed that at SDS concentration of 20 g/L, the removal efficiencies of phenanthrene, fluoranthene, and pyrene reached 37%, 40%, and 44%, respectively. At the dosage of 2 g/L of SiO 2 /nZVI, PS solution (50 mM), and time of 30 min, the removal efficiencies of PHE, FLU, and PYR were 75%, 85%, and 87%, respectively (Qiu et al 2019). In the other study done by Shin and Kim (2004), the removal of phenanthrene and diesel from sand with concentrations of 200 mg/kg and 20,000 mg/kg, by the surfactant (Tween 80) and rhamnolipid biosurfactant with the value CMC of 50 mg/L, was investigated.…”