title: Adsorption and mobility of Cr(III)-organic acid complexes in soils.
abstract: The soluble Cr(III) is likely to be complexed with organic ligands in ligand-rich soil. Cr(VI) chemical reduction by organic acids and bioreduction by microorganisms can produce soluble Cr(III)-organic acids complexes. Thus, it is of great significance to investigate the absorption and mobility of Cr(III)-organic acid complexes in soils. In this study, Cr(III)-EDTA and Cr(III)-cit were prepared and purified, and then were examined for adsorption and mobility. The results demonstrated that Cr(III) was strongly bound to soil, while Cr(III)-organic acid complexes had no or slight interaction with soils since Cr(III)-EDTA and Cr(III)-cit complexes mainly existed as the forms of [Cr(III)-EDTA](-) and [Cr(III)-cit], respectively, under the tested conditions with initial pH 4.0-9.0. The adsorption of Cr(III) increased but that of Cr(III)-organic acid complexes decreased with the content of soil organic matter. Compared with Cr(III)-EDTA, the mobility of Cr(III)-cit in soil columns was reduced, due to the specific adsorption between soils and Cr(III)-cit which contained one free hydroxyl group.
authors.affiliation: College of Sciences, Nanjing Agricultural University, Nanjing 210095, PR China.
authors.forename: Xinhua
authors.initials: X
authors.lastname: Cao
authors.forename: Jing
authors.initials: J
authors.lastname: Guo
authors.forename: Jingdong
authors.initials: J
authors.lastname: Mao
authors.forename: Yeqing
authors.initials: Y
authors.lastname: Lan
mesh_terms: D000143:Acids / Q000737:chemistry*; D000327:Adsorption; D001673:Biodegradation, Environmental; D002244:Carbon / Q000737:chemistry*; D002623:Chemistry Techniques, Analytical / Q000379:methods*; D002857:Chromium / Q000737:chemistry; D004492:Edetic Acid / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D008024:Ligands; D009930:Organic Chemicals / Q000737:chemistry*; D012987:Soil; D012989:Soil Pollutants / Q000737:chemistry*
chemical_list: D000143:Acids; D008024:Ligands; D009930:Organic Chemicals; D012987:Soil; D012989:Soil Pollutants; D002857:Chromium; D002244:Carbon; D004492:Edetic Acid