# Removal of Heavy Metal Cd Element from Paddy Soil by Geo-Electrochemical Technology
###### Abstract
[[https://doi.org/10.3390/app13211685](https://doi.org/10.3390/app13211685)]([https://doi.org/10.3390/app13211685](https://doi.org/10.3390/app13211685))**  
**Citation:** [PERSON]. obstruction control [10]. Soil amendment includes chemical leaching [11], in situ passivation [12], plant enrichment [13; 14], and electrokinetic remediation [15; 16]. Electrokinetic remediation is an emerging in situ technology developed in recent years. It consists of inserting cathodes and anodes of an electric field into Cd-contaminated soil. The application of a direct current facilitates the directional migration of the Cd element toward electrodes due to electromigration, electro-osmotic flow, and electrophoresis in the electric field. Electromigration indicates the movement of charged ions and ionic complexes in soil solutions under the existence of an applied electric field, and it is the dominant transport mechanism for inorganic contaminants [17]. Electro-osmotic flow is the movement of the soil solution containing dissolved pollutant species through the pore system of the soil [18]. For soil heavy metal remediation, metal, or metal-containing species are usually positively charged and therefore migrate to the cathode through electromigration and electro-osmosis (electric attraction) [19]. Electrophoresis refers to the movement of charged particles or colloids under the application of an electric field. Compared with electromigration and electro-osmosis, electrophoresis has a negligible impact on inorganic matter transport in low-permeability soil systems, and thus it is not taken into account in the electrokinetic remediation process [17]. The Cd element is accumulated near the electrodes, and then the pollutants in the soil or electrolyte in the enrichment area are treated centrally to remove them [20]. The geo-electrochemical method is a low-voltage, self-powered, bipolar electrical extraction technology developed by the Hidden Ore Deposit Prediction Research Institute of the Guilin University of Technology. It is protected by independent intellectual property rights. Geo-electrochemical technology (GT) has yielded substantial results in exploring minerals for concealed ore deposits. Its working principle is also based on electrolysis, electromigration, electro-osmosis, electrophoresis, and other electric field actions to achieve directional migration and enrichment of heavy metal elements toward the cathode and anode. Therefore, it can be regarded as a kind of electrokinetic remediation technology. Geo-electrochemical technology uses lightweight and convenient equipment, is simple to use, has rapid and safe applications, and is environmentally friendly. In this study, the paddy soil and rice plants of the Quanzhou County Institute of Agricultural Science in the north of Guilin were selected as the study subjects. The study preliminarily investigated the removal efficiency of GT on heavy metal Cd elements in paddy soil. That included the distribution rule of heavy metal Cd in the paddy soil-rice system under the influence of an electric field to provide a theoretical basis and a new technical alternative for remediating Cd-contaminated paddy soil.