title: Plutonium partitioning in three-phase systems with water, colloidal particles, and granites: new insights into distribution coefficients.
abstract: The traditional sorption experiments commonly treated the colloid-associated species of low-solubility contaminants as immobile species resulted from the centrifugation or ultrafiltration, and then solid/liquid distribution coefficients (Ks/d) were determined. This may lead to significantly underestimated mobility of the actinides in subsurface environments. Accordingly, we defined a new distribution coefficient (Ks/d+c) to more adequately describe the mobile characteristics of colloidal species. The results show that under alkaline aqueous conditions the traditional Ks/d was 2-3 orders of magnitude larger than the Ks/d+c involving the colloidal species of (239)Pu. The colloid/liquid distribution coefficients Kc/d≫0 (∼10(6)mL/g) revealed strong competition of the colloidal granite particles with the granite grains for Pu. The distribution percentages of Pu in the three-phase systems, depending on various conditions such as particle concentrations, Na(+) concentrations, pH and time, were determined. Moreover, we developed the thermodynamic and kinetic complexation models to explore the interaction of Pu with the particle surfaces.
authors.affiliation: Northwest Institute of Nuclear Technology, P.O. Box 69-14, Xi'an City, Shanxi Province 710024, PR China. Electronic address: xiejinchuan@hotmail.com.
authors.forename: Jinchuan
authors.initials: J
authors.lastname: Xie
authors.affiliation: Northwest Institute of Nuclear Technology, P.O. Box 69-14, Xi'an City, Shanxi Province 710024, PR China.
authors.forename: Jianfeng
authors.initials: J
authors.lastname: Lin
authors.affiliation: Northwest Institute of Nuclear Technology, P.O. Box 69-14, Xi'an City, Shanxi Province 710024, PR China.
authors.forename: Xiaohua
authors.initials: X
authors.lastname: Zhou
authors.affiliation: Northwest Institute of Nuclear Technology, P.O. Box 69-14, Xi'an City, Shanxi Province 710024, PR China.
authors.forename: Mei
authors.initials: M
authors.lastname: Li
authors.affiliation: Northwest Institute of Nuclear Technology, P.O. Box 69-14, Xi'an City, Shanxi Province 710024, PR China.
authors.forename: Guoqing
authors.initials: G
authors.lastname: Zhou
mesh_terms: D003102:Colloids / Q000032:analysis / Q000737:chemistry*; D007700:Kinetics; D008956:Models, Chemical; D011005:Plutonium / Q000032:analysis / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry*; D012995:Solubility; D014462:Ultrafiltration; D014867:Water / Q000737:chemistry*; D014875:Water Pollutants, Radioactive / Q000032:analysis / Q000737:chemistry
chemical_list: D003102:Colloids; D014875:Water Pollutants, Radioactive; C007886:granite; D014867:Water; D011005:Plutonium; D012822:Silicon Dioxide
keywords: Colloidal particle; Distribution coefficient; Granite; Plutonium; Sorption; Species