Reversible electrokinetic adsorption barriers for the removal of atrazine and oxyfluorfen from spiked soils

Abstract

This study demonstrates the application of reversible electrokinetic adsorption barrier (REKAB) technology to soils spiked with low-solubility pollutants. A permeable reactive barrier (PRB) of granular activated carbon (GAC) was placed between the anode and cathode of an electrokinetic (EK) soil remediation bench-scale setup with the aim of enhancing the removal of two low-solubility herbicides (atrazine and oxyfluorfen) using a surfactant solution (sodium dodecyl sulfate) as the flushing fluid. This innovative study focused on evaluating the interaction between the EK system and the GAC-PRB, attempting to obtain insights into the primary mechanisms involved. The obtained results highlighted the successful treatment of atrazine and oxyfluorfen in contaminated soils. The results obtained from the tests after 15days of treatment were compared with those obtained using the more conventional electrokinetic soil flushing (EKSF) technology, and very important differences were observed. Although both technologies are efficient for removing the herbicides from soils, REKAB outperforms EKSF. After the 15-day treatment tests, only approximately 10% of atrazine and oxyfluorfen remained in the soil, and adsorption onto the GAC bed was an important removal mechanism (15-17% of herbicide retained). The evaporation loses in REKAB were lower than those obtained in EKSF (45-50% compared to 60-65%).

Techno-economic analysis of the scale-up process of electrochemically-assisted soil remediation

“…Table 1 presents the main features of all facilities and Figure 1 shows a plan view, a section and a picture of each EASR reactor. More detailed information about the setup and details of the instrumentation used can be found elsewhere (López-Vizcaíno et al, 2014a, b;López-Vizcaíno et al, 2016;López-Vizcaíno et al, 2017a, b;Vieira dos Santos et al, 2017).…”

“…develop simultaneously in the soil when it undergoes the application of an electric field. The smart coupling of all these mechanisms makes EASR a very versatile and efficient technology, which has been used for the decontamination of soils polluted with a great variety of compounds, including heavy metals (Ferrucci et al, 2016;Ottosen et al, 2001;Pamukcu et al, 2004;Pazos et al, 2008), polycyclic aromatic hydrocarbons (PAH) (Bocos et al, 2015;Hahladakis et al, 2014), polychlorinated biphenyls (PCB) (Gomes et al, 2015;Pedersen et al, 2017), pesticides and herbicides (Ribeiro et al, 2011;Ribeiro et al, 2005;Rodrigo et al, 2014;Vieira dos Santos et al, 2017), among many others. From a scientific point of view, such works have generated a great and very useful increase of the knowledge in the field.…”

Calcite buffer effects in electrokinetic remediation of clopyralid-polluted soils

“…Specifically, this technique is called electrokinetic remediation (EKR) when it is applied to contaminated soils with the aim of mobilizing polluting species to controlled extraction points [1][2][3][4]. The coupling of the above-mentioned transport mechanisms and the fact that, these treatments can be successfully applied in soils with low hydraulic permeability, where Darcy flow is very limited, makes EKR technology a very versatile technique and consequently, an efficient and competitive alternative for treating pollution events with different compounds such as heavy metals [5][6][7][8], PAH [9][10][11][12][13] or pesticides [14][15][16][17][18].…”

Enhanced electrokinetic remediation of polluted soils by anolyte pH conditioning

“…The involvement of several transport mechanisms makes possible to cover a wide range of applications. EKR has been applied in the treatment of soils contaminated with heavy metals (Ottosen et al, 2001;Mascia et al, 2007;Kim et al, 2009), PAH (Pazos et al, 2010;Hahladakis et al, 2014;Bocos et al, 2015) and pesticides (Ribeiro et al, 2005;Ribeiro et al, 2011;Rodrigo et al, 2014;Vieira dos Santos et al, 2016, 2017 obtaining good results.…”