title: Desorption of copper and cadmium from soils enhanced by organic acids.
abstract: The adsorption/desorption behavior of copper and cadmium on soils was investigated in this study. The adsorption isotherm of copper and cadmium conformed to Langmuir equation better than Freundlich equation. The effect of ionic strength, pH, and organic acid, including ethylenediamine tetraacetic disodium acid salt (EDTA), citric acid, oxalic acid and tartaric acid, on the desorption of copper and cadmium was studied. The desorption of copper and cadmium increased with the increase of ionic strength, while the desorption decreased with the rise of pH. The desorption of copper and cadmium enhanced by organic acids was influenced by pH. EDTA showed excellent enhancement on the desorption of both copper and cadmium; citric acid demonstrated great enhancement on the desorption of copper but negligible enhancement on the desorption of cadmium; oxalic acid enhanced the desorption of copper only at pH around 6.4 and enhanced the desorption of cadmium in the pH range from 6.4 to 10.7; tartaric acid slightly enhanced the desorption of copper but negligibly enhanced the desorption of cadmium. The desorption mechanism in the presence of organic acids were explained as the competition of complexation, adsorption and precipitation. The net effect determined the desorption efficiency. This study provided guidance for the selection of organic acids to enhance the electrokinetic (EK) remediation of copper and cadmium from contaminated soils.
authors.affiliation: Environmental Science Research Institute, Huazhong University of Science and Technology, Wuhan 430074, PR China. yuansonghu622@hotmail.com
authors.forename: Songhu
authors.initials: S
authors.lastname: Yuan
authors.forename: Zhimin
authors.initials: Z
authors.lastname: Xi
authors.forename: Yi
authors.initials: Y
authors.lastname: Jiang
authors.forename: Jinzhong
authors.initials: J
authors.lastname: Wan
authors.forename: Chan
authors.initials: C
authors.lastname: Wu
authors.forename: Zhonghua
authors.initials: Z
authors.lastname: Zheng
authors.forename: Xiaohua
authors.initials: X
authors.lastname: Lu
mesh_terms: D000143:Acids / Q000737:chemistry*; D002104:Cadmium / Q000737:chemistry*; D019343:Citric Acid / Q000737:chemistry; D003300:Copper / Q000737:chemistry*; D004492:Edetic Acid / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D019216:Metals, Heavy / Q000737:chemistry; D019815:Oxalic Acid / Q000737:chemistry; D012987:Soil; D013644:Tartrates / Q000737:chemistry
chemical_list: D000143:Acids; D019216:Metals, Heavy; D012987:Soil; D013644:Tartrates; D002104:Cadmium; D019343:Citric Acid; D003300:Copper; D019815:Oxalic Acid; D004492:Edetic Acid; C029768:tartaric acid