The Role of pH, Electrodes, Surfactants, and Electrolytes in Electrokinetic Remediation of Contaminated Soil

Abstract

Electrokinetic remediation has, in recent years, shown great potential in remediating polluted environments. The technology can efficiently remove heavy metals, chlorophenols, polychlorinated biphenyls, phenols, trichloroethane, benzene, toluene, ethylbenzene, and xylene (BTEX) compounds and entire petroleum hydrocarbons. Electrokinetic remediation makes use of electrolysis, electroosmosis, electrophoresis, diffusion, and electromigration as the five fundamental processes in achieving decontamination of polluted environments. These five processes depend on pH swings, voltage, electrodes, and electrolytes used in the electrochemical system. To apply this technology at the field scale, it is necessary to pursue the design of effective processes with low environmental impact to meet global sustainability standards. It is, therefore, imperative to understand the roles of the fundamental processes and their interactions in achieving effective and sustainable electrokinetic remediation in order to identify cleaner alternative solutions. This paper presents an overview of different processes involved in electrokinetic remediation with a focus on the effect of pH, electrodes, surfactants, and electrolytes that are applied in the remediation of contaminated soil and how these can be combined with cleaner technologies or alternative additives to achieve sustainable electrokinetic remediation. The electrokinetic phenomenon is described, followed by an evaluation of the impact of pH, surfactants, voltage, electrodes, and electrolytes in achieving effective and sustainable remediation.

An electrokinetic-biocementation study for clay stabilisation using carbonic anhydrase-producing bacteria

“…This increase and decrease in electrolyte pH could be attributed to anions and cations moving from the electrode chamber into the soil chamber and back into the chambers. This phenomenon causes the pH in both chambers to increase and decrease depending on the present ions in the soil (Gidudu and Chirwa 2022 ; Mena et al 2016 ). Compared to other cases investigated, the nutrients only did not have drastic zigzag changes due to the limited amounts of ions involved compared to bioaugmentation, biostimulation, and cementing solution which contained calcium acetate.…”

Enhancing Soil Health: Nanotechnologies for Effective Remediation and Sustainable Development

“…When the electricity is applied, one end of the electrode will turn to anode and the other will turn to cathode, placed in between the contaminated soil. Advantage of using electrokinetic method to remediate contaminate soil is its capability to remove many types of contaminants from the soil by just applying electric current and this method can also be applied in clay medium [17]. This remediation method can be performed at the site, making the remediation cost to be lower.…”

Multifaceted Assessment of Porous Silica Nanocomposites: Unraveling Physical, Structural, and Biological Transformations Induced by Microwave Field Modification

“…Hence, an exponential function (Equation ( 4)) and the pseudo-first-order model (Equation ( 5)) were investigated as the most reliable to analyze the comparative time of silver release from the tested samples (Figure 8) [43,[46][47][48]. q(t) = q e 1 − e −k 1 t (5) where q e -the number of ions after equilibrium of adsorption (µg/L); q(t)-the number of desorbed ions at time t (µg/L); k 1 -pseudo-first rate constant (1/h). A comparative analysis of the two proposed models unveiled slight discrepancies in the values of silver ions released into the solution (Table 11).…”

“…Here, broadly defined water and soil serve as reservoirs for these compounds [ 4 ]. Heavy metal contamination also diminishes soil fertility, with conventional remediation methods incurring substantial costs and often causing secondary environmental contamination [ 4 , 5 ]. Furthermore, an excess of environmental metals corresponds to increased bioaccumulation in living organisms and consequently affects the nervous, digestive, and reproductive systems [ 6 ].…”