Recent advances in electrokinetic methods for soil remediation. A critical review of selected data for the period 2021-2022

Soil electrokinetics (SEK) emerged in the beginning of 1990 as a promising approach to remediate contaminated soils, as well as for dewatering, soil restoration, pollution prevention, geophysics, seed germination, sedimentation, and consolidation. Our previous review titled Comprehensive review of progress made in soil electrokinetic research during 1993-2020, Part I: Process design modifications with brief summaries of main output summarized the soil SEK process design modifications during 1993-2020 (& SIM; 28 years), in which approximately 125 designs/perspectives were discussed. During 1993-2020, SEK research was classified into three main approaches: horizontal (19 processes), vertical (11 processes), and mixed (7 processes), based on the position of the anodes and cathodes that control element movement. In the present review, we surveyed SEK design modifications during 2021-2022 to provide readers with an update on new SEK innovations incorporated with regular designs. Based on our search of six of the most popular research engines, most of the design modifications carried out in SEK were mainly focused on the horizontal process, and few studies focused on vertical design; however, no research has focused on the SEK mixed approach (combining horizontal and vertical processes). In 2021 and 2022, the SEK horizontal approach involved 13 processes. In the vertical process, a general study was conducted to investigate the electrical distribution and moisture migration of unsaturated clay under electroosmosis, in addition, two studies were focused on electro-osmosis with a vertical gradient and electrokinetic for chloride extraction. In 2021 and 2022, a variety of innovations (29 design modifications) will be introduced to maximize SEK performance, which may be utilized to increase SEK remediation efficiency.

Automated summary

Soil electrokinetics (SEK) is a method for remediation of contaminated soils, dewatering, soil restoration, pollution prevention, geophysics, seed germination, sedimentation, and consolidation. From 1993 to 2020, SEK research was classified into horizontal, vertical, and mixed approaches, with a focus on the horizontal process. In 2021 and 2022, new design modifications and innovations will be introduced to enhance SEK performance.