title: [Adsorption characteristics and mechanism of uranium on attapulgite].
abstract: The adsorption characteristics of uranium on attapulgite were investigated by conducting a series of batch adsorption experiments in this study. The influence of solution pH, initial uranium concentration and contact time was investigated. Scanning electron microscope (SEM) and X-ray diffraction (XRD) were used to characterize the surface structure of the attapulgite, Fourier transform infrared spectrometer (FTIR) were used to characterize the surface properties of the attapulgite before and after uranium adsorption, and to analyze the adsorption mechanism and adsorption kinetics of uranium on attapulgite. The experimental results showed that sorption of uranium on attapulgite was strongly dependent on pH, and the highest adsorption reached at pH = 5. The adsorption quantity increased with time, adsorption could achieve balance in 2 h. The adsorption isotherm equation conformed to the Langmuir isothermal adsorption model and adsorption process could be described by the two-order kinetics model. According to FTIR spectral, the absorbance of attapulgite decreased, which may result from R--OUO2+ or (R--O)2UO2 formed by the bond between uranium and R-OH of attapulgite in the high frequency area 3700-3000 cm(-1), and which uranium ion and magnesium ions may produce ion exchanges in the intermediate frequency area 1700-800 cm(-1). Adsorption mechanism of uranium on attapulgite was mainly ion exchange and complexation.
authors.affiliation: School of Environmental Science & Engineering, Guangzhou University, Guangzhou 510006, China. lj_brave@hotmail.com
authors.forename: Juan
authors.initials: J
authors.lastname: Liu
authors.forename: Di-yun
authors.initials: DY
authors.lastname: Chen
authors.forename: Jing
authors.initials: J
authors.lastname: Zhang
authors.forename: Gang
authors.initials: G
authors.lastname: Song
authors.forename: Ding-gui
authors.initials: DG
authors.lastname: Luo
mesh_terms: D000327:Adsorption; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D017616:Magnesium Compounds / Q000737:chemistry*; D017655:Silicon Compounds / Q000737:chemistry*; D012990:Soil Pollutants, Radioactive / Q000737:chemistry / Q000302:isolation & purification*; D014501:Uranium / Q000737:chemistry / Q000302:isolation & purification*
chemical_list: D017616:Magnesium Compounds; D017655:Silicon Compounds; D012990:Soil Pollutants, Radioactive; D014501:Uranium; C026325:attapulgite