title: In situ removal of copper from sediments by a galvanic cell.
abstract: This study dealt with in situ removal of copper from sediments through an electrokinetic (EK) process driven by a galvanic cell. Iron (Fe) and carbon (C) were placed separately and connected with a conductive wire. Polluted sediments were put between them and water was filled above the sediments. The galvanic cell was thus formed due to the different electrode potentials of Fe and C. The cell could remove the pollutants in the sediments by electromigration and/or electroosmosis. Results showed that a weak voltage less than 1V was formed by the galvanic cell. The voltage decreased with the increase of time. A slight increase of sediment pH from the anode (Fe) to the cathode (C) was observed. The presence of supernatant water inhibited the variation of sediment pH because H(+) and OH(-) could diffuse into the water. The removal of copper was affected by the sediment pH and the distribution of electrolyte in sediment and supernatant water. Lower pH led to higher removal efficiency. More electrolyte in the sediment and/or less electrolyte in the supernatant water favored the removal of copper. The major removal mechanism was proposed on the basis of the desorption of copper from sediment to pore solution and the subsequent electromigration of copper from the anode to the cathode. The diffusion of copper from sediment to supernatant water was negligible.
authors: Environmental Science Research Institute, Huazhong University of Science and Technology, Wuhan 430074, PR China.
authors: Songhu
authors: S
authors: Yuan
authors: Chan
authors: C
authors: Wu
authors: Jinzhong
authors: J
authors: Wan
authors: Xiaohua
authors: X
authors: Lu
mesh_terms: D003300:Copper / Q000302:isolation & purification*; D017753:Ecosystem; D019015:Geologic Sediments / Q000032:analysis*; D006863:Hydrogen-Ion Concentration; D007202:Indicators and Reagents; D007220:Industrial Waste; D007501:Iron / Q000302:isolation & purification; D007700:Kinetics; D017942:Nitric Acid; D012722:Sewage
chemical_list: D007202:Indicators and Reagents; D007220:Industrial Waste; D012722:Sewage; D017942:Nitric Acid; D003300:Copper; D007501:Iron