Sorption of technetium and rhenium on natural sorbents under aerobic conditions

Activated carbon (AC) has a relatively high efficiency for retaining TcO 4 -compared to other materials. AC is used on a vast scale in gas and water purification, metal extraction, medicine and many other applications. The TcO 4 -adsorption mechanism on AC is not fully known, however there are assumptions of ion-exchange reaction between AC surface and TcO 4 -anions. Adsorption and anion competitive investigation have shown that perchlorate anions have most influence on TcO 4 -adsorption. Adsorption properties depend on standard absolute molar enthalpies of hydration. Anion competitiveness was investigated with five samples that were prepared in different ways (this was already published in previous article), we used several anions Cl -, Br -, ClO 4 -, CH 3 COO -, NO 3 -, HCOO -and SO 4 2-at different concentrations. In general, the adsorption of TcO 4 -is influenced mostly by ClO 4 -, what is explained by its similar structure with TcO 4 -; however the co-existence of Fe 3? cations in the AC structure decreases TcO 4 -adsorption.

Section: Introductionmentioning

confidence: 99%

Effect of competing anions on pertechnetate adsorption by activated carbon

Galamboš

Daňo

Víglašová

et al. 2015

“…Our results correlate well with literature data (Table 3). Vinsova et al [16] examined bentonite mixtures to remove pertechnetate ions. Bentonite-graphite and bentonite-FeSO 4 mixtures showed negligible sorption capacity, while bentonite showed less than 15%.…”

Section: Results Of Sorption Experimentsmentioning

confidence: 99%

“…The main clay mineral of bentonite is montmorillonite, which is a good sorbent because it has a large specific surface area and high cation exchange capacity. Shakira et al [15], Vinsova, [16] Jedináková-Křížová [17]; Jaisi [18]; Milutinović-Nikolić [19], Hamárová [20] dealt with modified clays, for example Vinsova et al [16] used mixtures of bentonite, bentonite activated carbon, iron powder, FeSO 4 and graphite to bind pertechnetate ions.…”

Section: Introductionmentioning

confidence: 99%

Sorption of pertechnetate anion by cation modified bentonites

Buzetzky

Kovács

Nagy

et al. 2019

Pertechnetate anion sorption was investigated on modified bentonites. Mn-, Cr-, Sn-bentonites were prepared by ion exchange process to sorb radioactive pertechnetate ions. In the case of Mn-, Cr-bentonite the sorb amount of metal ion was 70-90% of the cation exchange capacity of the bentonite which is expected. Interestingly in the case of Sn-bentonite this amount was 1.42 times higher than the cation exchange capacity. On Mn-bentonite the sorption was 35% at pH 5. The removal of pertechnetate ions was 100% on Cr-, Sn-bentonites and the significant sorption was achieved below 650 mV/SHE.

“…A number of raw and modified natural [9][10][11][12][13][14][15][16] as well as synthetic materials [17][18][19][20][21][22][23][24][25][26][27][28][29] have already been investigated as technetium and rhenium sorbents and extractants from aqueous solutions. Biomaterials and modified biomaterials were also studied for the removal of Re(VII) from waters [30][31][32].…”

Section: Introductionmentioning

confidence: 99%

Rhenium(VII) and technetium(VII) separation from aqueous solutions using a polyethylenimine–epichlorohydrin resin

Sarri

Μisaelides

Zamboulis

et al. 2015

The ReO 4 -and 99 TcO 4 -removal from aqueous solutions using a polyethylenimine-epichlorohydrin resin was investigated in absence and presence of background electrolyte (0.01 and 0.50 M NaCl). Re(VII) and Tc(VII) sorption isotherms were obtained for solutions with 2.3 B pH B 8.9 and concentration 0.21-26.9 mmol Re/L and 5 9 10 -3 -5 9 10 -2 mmol 99 Tc/L. The highest uptake for both elements (R d & 10 4 mL/g) was observed for solutions with pH B 4 and C NaCl B 0.01 M, hinting towards the existence of protonated groups contributing to the sorption of anions under acidic conditions and to the competition of Cl -. The sorption data were modeled using the Langmuir and Freundlich equations.