The sorption of iron(III) in ionic and colloidal states on iron(III) oxide deposited on a silica gel surface has been studied as a function of pH of aqueous solution by batch equilibrations. The behaviour of Fe3+ and colloidal Fe(III) on the sorbent column has also been investigated. Conditions for sorption of iron from aqueous solutions are given. The colloidal iron(III) can be quantitatively separated from Fe3+ on the sorbent column under given experimental conditions.
Authors:K. Venkatesan, N. Sasidharan, and P. Wattal
Laboratory experiments were performed on the sorption of cesium on gamma-irradiated silica-titania gel. The detrimental effects
of absorbed dose on the affinity of the sorbent towards cesium was discussed. Data obtained from sorption studies were fit
into heterogeneity based Freundlich isotherm. The empirical parameters, thus obtained were used to arrive at the site distribution
function. The potential of site distribution function in foreseeing, the reusability and long-term residence of radionuclides
in the sorbent has been highlighted.
Authors:H. Sepehrian, M. Ghannadi-Maragheh, S. Waqif-Husain, R. Yavari, and A. Khanchi
Five different samples of a new sorbent, modified mesoporous cerium(IV) silicate have been prepared with various mole ratios
of Si/Ce and Cetyltrimethylammonium bromide (CTMABr) as template. XRD, nitrogen sorption, SEM, IR, thermogravimetry and sorption
of radionuclides have been studied. Separation of Hg(II)-Th(IV), Hg(II)-Zr(IV) and Rb(I)-Zr(IV) have been developed on columns
of this novel sorbent.
The correlation between the distribution coefficients of phenols in liquid extraction systems and extractive-chromatographs
systems with modified sorbents has been studied in order to investigate the influence of extractant characteristics on the
extractive activity of modified sorbent. We have used polysorb C processed with hexyl, heptyl and octyl alcohols, esters,
i.e., TBP, triisobytylphosphate and tricresylphosphate, aromatic carbohydrates, i.e., foluene and andoxylene.
The effects of pH, ionic strength and concentration on the sorption of Th(IV) on alumina and silica were investigated and the sorption isotherms of Th(IV) on alumina and silica at different pH values were determined. It was found for both sorbents that the absorbability of silica is less than that of alumina. The relative sorption rate of silica is similar to that of alumina. The sorption edges are similar to each other, that the insensitivity of sorption to ionic strength is about the same. These similarities between the sorbents suggest that the speciation of Th(IV) in aqueous solutions plays a significant, but subtle role, in controlling the sorption process, because the charges of both sorbents are distinctly different. The mechanism of Th(IV) sorption on alumina is distinctly different from that of the sorptions of Cs+, Eu3+ and Yb3+ on alumina, and similar to that of the sorption of Co(II) on alumina.
Authors:S. Goheen, B. McVeety, T. Clauss, R. Lucke, M. Ligotke, J. Edwards, and J. Fruchter
Organic species from the headspace of one Hanford radioactive waste tank are described. Samples were collected either using a sorbent trap or a SUMMATM canister and were analyzed by gas chromatograph and mass spectrometry. The headspace contained several organic components, including alkanes, alkenes, ketones, aldehydes, organic nitriles, and chlorinated hydrocarbons. Sorbent trap samples were designed to collect only normal paraffin hydrocarbons (NPHs). A comparison of NPH data from sorbent traps and SUMMATM cans revealed results of 693 and 1320 mg/m3, NPH respectively. Significant differences were observed in NPH values when samples were collected at different times, or at different locations in the tank. These data suggest either the time of collection, or the position of the sampling device are important variables in the analysis of organic species from Hanford tanks.
Authors:T. Denisova, S. Grinenko, and L. Kuznetzova
stability of two-component organosilica sorbents – silico-polymethylsiloxanes
with the ratio of hydrophilic and hydrophobic components of 50:50 and 70:30
mass%, and their forms, modified by copper(II), was investigated using thermal
analysis (DTG, DTA, TG). The influence of the composition of modified organosilica
sorbents and copper(II) content on the endothermic (removal of adsorbed water)
and exothermic (decomposition by oxidation of methyl groups, possible hydration
of surface) peak temperatures and on mass loss is shown. It was found that
thermal stability of organosilica modified by copper(II) was lower than that
of initial sorbents and depends on the content of modifying component and
ratio of silanol and methylsilil groups in organosilica composition.
, acetonitrile, and solid sorbent for BPA extraction. The samples with BPA concentrations <MDL were in glass containers or cans that are void from any BPA lining like tin, gold plated, or steel plating. This indicated also that raw food (before canning
Authors:V. Baran, R. Caletka, M. Tympl, and V. Urbánek
Starting from the principles of sol-gel method, developed originally for the preparation of nuclear fuels in spherical form,
their application to the preparation of microspheres of various non-nuclear elements is presented. In addition to the preparative
conditions of the primarily hydroxidic spheres, their conversion into other insoluble compounds such as phosphates, ferrocyanides,
sulphides, etc. is described. These sol-gel products work very well as ion-exchangers; their sorption properties are quite
comparable to those of the common powder sorbents, the sphere from being their main beauty. Applicability of these sorbents
as well as their limitations are also discussed.