Enhanced Electroremediation of Metals from Dredged Marine Sediment under Periodic Voltage Using EDDS and Citric Acid

The electrokinetic remediation (EKR) method has been extensively considered for the removal of inorganic pollutants from contaminated dredged sediment. In addition, the use of chelating agents as electrolyte solutions has been beneficial in increasing the mobility of metals. This study investigated the metals' (Cd, Cr, Cu, Pb, and Zn) mobilities by assessing the effect of two environmentally friendly chelating agents, ethylenediaminedisuccinic acid (EDDS) and citric acid (CA), in enhancing the EKR efficiency under a periodic voltage gradient. The results showed that, for the same concentration (0.1 mol L-1), CA is more suitable for enhancing the removal of Cr (67.83%), Cu (59.77%), and Pb (32.05%) by chelating and desorbing them from the sediment matrix and concentrating them in the electrode compartments. EDDS provided efficiency to improve the Cd extraction percentage (45.87%), whereas CA and EDDS had comparable improvement removal impacts on Zn EKR (39.32% and 41.37%, respectively). From the comparison with previous results obtained with a continuous voltage, applying a periodic voltage gradient associated with a low concentration of chelating agents led to a promising result.

Automated summary

The effect of two environmentally friendly chelating agents, ethylenediaminedisuccinic acid (EDDS) and citric acid (CA), on the electrokinetic remediation (EKR) efficiency and metal mobilities were investigated. The results showed that CA was more suitable for enhancing the removal of Cr, Cu, and Pb, while EDDS provided efficiency to improve the Cd extraction percentage. Both CA and EDDS had comparable improvement impacts on Zn EKR. Applying a periodic voltage gradient with a low concentration of chelating agents led to a promising result compared to previous studies with continuous voltage.