caa a22 4500 378851322 CHVBK 20180305123324.0 cr unu---uuuuu 161128e20030901xx s 000 0 eng 10.1524/ract.91.9.513.20000 doi (NATIONALLICENCE)gruyter-10.1524/ract.91.9.513.20000 On the study of Th(IV)-humic acid interactions by competition sorption studies with silica and determination of global interaction constants [Elektronische Daten] [Pascal Reiller, Valérie Moulin, Florence Casanova, Christian Dautel] The influence of humic acids (HA) on the retention of thorium (IV) onto the surface of silica colloids is investigated. Thorium is considered as an analogue of tetravalent actinides (U, Np, Pu), except for the fact that it has no f electrons. Silica (SiO2) is chosen as a model surface because it is a component of many minerals and because of its weak HA sorption properties. Retention experiments are performed by batch procedure at constant ionic strength (I = 0.1M NaClO4), at various pH (2 to 9) and HA concentrations (1-100mg/L). The sorption of Th(IV) onto colloidal amorphous silica is characterised using a surface complexation model. The ternary system (i.e. HA-Th-Silica) clearly shows the influence of HA on Th(IV) retention. This can lead to a strong reduction of the amount of Th(IV) sorbed onto silica in the presence of HA compared to silica colloids without HA, due to a predominant part of thorium present in solution as humic complexes. In a pH range where no organic coating onto silica occurs, there is a competitive reaction between Th(IV) sorption onto the silica surface and onto HA reactive functional groups. In this case, Schubert´s method is applied to obtain a global interaction constant for the Th(IV)-HA system. The large interaction constant values indicate a strong affinity of HA for Th(IV). © 2003 Oldenbourg Wissenschaftsverlag GmbH Laboratory techniques, experiments nationallicence Analytical chemistry nationallicence Inorganic chemistry nationallicence Reiller Pascal aut Moulin Valérie aut Casanova Florence aut Dautel Christian aut Radiochimica Acta/International journal for chemical aspects of nuclear science and technology Oldenbourg Wissenschaftsverlag GmbH 91/9/2003(2003-09-01), 513-524 0033-8230 91:9/2003<513 2003 91 ract https://doi.org/10.1524/ract.91.9.513.20000 text/html Onlinezugriff via DOI 1 research article jats NATIONALLICENCE 856 40 https://doi.org/10.1524/ract.91.9.513.20000 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Reiller Pascal aut NATIONALLICENCE 700 1- Moulin Valérie aut NATIONALLICENCE 700 1- Casanova Florence aut NATIONALLICENCE 700 1- Dautel Christian aut NATIONALLICENCE 773 0- Radiochimica Acta/International journal for chemical aspects of nuclear science and technology Oldenbourg Wissenschaftsverlag GmbH 91/9/2003(2003-09-01), 513-524 0033-8230 91:9/2003<513 2003 91 ract CC0 http://creativecommons.org/publicdomain/zero/1.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-gruyter