Sorption of Uranium(VI) and Thorium(IV) by Jordanian Bentonite

Abstract

Puri�cation of raw bentonite was done to remove quartz. is includes mixing the raw bentonite with water and then centrifuge it at �50 rpm; this process is repeated until white puri�ed bentonite is obtained. �RD, �RF, FTIR, and SEM techniques will be used for the characterization of puri�ed bentonite. e sorption behavior of puri�ed Jordanian bentonite towards UO 2 2+and  4+ metal ions in aqueous solutions was studied by batch experiment as a function of pH, contact time, temperature, and column techniques at 25.0 ∘ C and pH = 3. e highest rate of metal ions uptake was observed aer 18 h of shaking, and the uptake has increased with increasing pH and reached a maximum at pH = 3. Bentonite has shown high metal ion uptake capacity toward uranium(VI) than thorium(IV). Sorption data were evaluated according to the pseudo-second-order reaction kinetic. Sorption isotherms were studied at temperatures 25.0 ∘ C, 35.0 ∘ C, and 45.0 ∘ C. e Langmuir, Freundlich, and Dubinin-Radushkevich (D-R) sorption models equations were applied and the proper constants were derived. It was found that the sorption process is enthalpy driven for uranium(VI) and thorium(IV). Recovery of uranium(VI) and thorium(IV) ions aer sorption was carried out by treatment of the loaded bentonite with different concentrations of HNO 3 1.0 M, 0.5 M, 0.1 M, and 0.01 M. e best percent recovery for uranium(VI) and thorium(IV) was obtained when 1.0 M HNO 3 was used.

Sorption of Heavy Metals on Clay Minerals and Oxides: A Review

“…The adsorption isotherms and kinetics commonly used are listed in Table 1. In addition, most of the adsorption of ions on clays and oxides are best described by Langmuir, Dubinin-Radushkevich and Freundlich isotherm models and Pseudo-secondorder kinetic model [47][48][49][50][51][52][53].…”

“…In the another study, bentonite was effectively used to remove thorium (IV) at pH 3, equilibration time of 18 h and 25°C and adsorption was fitted to Freundlich, Langmuir and Dubinin-Radushkevich isotherm models. Desorption experiment shows that thorium (IV) is best recovered with 1.0 M HNO 3 [49]. However, the use of bentonite for sorption of heavy metals has some negative effect.…”

Sorption Properties of a Bentonite Based Material for Removal of Uranium from Alum Shale Leachate

“…The latter study showed how U 6+ "preferred" to sorb to kaolinite and not to humic acid that was directly bound to a clay surface [30]. The upscaling of the removal of U 6+ by sorption, can be investigated in static or dynamic mode [10]. In the latter, binders are required to avoid permeability problems associated to flow rate (Q) in the columns.…”

“…Separation processes from liquid to solid are therefore getting relevance for the treatment of leachates from landfills or mining tails as significant amounts of water can be treated in order to reach legislation thresholds for discharges. , among them co-precipitation, membrane filtration and sorption [9][10][11].…”

“…Sorption processes represent a feasible alternative as well due to multiple regenerations of the sorbents with strong acids and use of natural abundant materials as apatites, clays and other silica-containing systems which have porosity and functional groups for physical/chemical binding of pollutants in solution [10][11][12]. In order to increase the efficiency of separation, it is necessary to create new types of sorbents, which have a maximum selectivity towards specific elements.…”