Adsorption and Desorption of U(VI) on Functionalized Graphene Oxides: A Combined Experimental and Theoretical Study

The sorption of 152?154 Eu(III) on NKF-6 zeolite is investigated by batch technique under ambient conditions. The results indicate that the sorption of Eu(III) is affected by ionic strength at pH \8.0 and independent of ionic strength at pH[8.0. The sorption is dominated by ion exchange or outer-sphere surface complexation at low pH and by inner-sphere surface complexation at high pH. The thermodynamic parameters suggest that the sorption is an endothermic and spontaneous process. The results show that the NKF-6 zeolite is a suitable adsorbent for the preconcentration of Eu(III) from large volumes of nature aqueous solutions.

Section: Resultsmentioning

confidence: 99%

Investigation of the effect of pH, ionic strength, foreign ions, temperature, soil humic substances on the sorption of 152+154Eu(III) onto NKF-6 zeolite

Chen

2015

“…It is worth noting that the adsorption (light off) of U(VI) by the ZnO/ rectorite catalyst without visible light irradiation was also checked and approximately 24.5 % of U(VI) was adsorbed in the dark after 180 min. This result shows that the ZnO/ rectorite catalyst had a high adsorption capacity for U(VI), which is in favor of the photoreduction of U(VI) [25,26]. The photoreduction activity of the ZnO/rectorite sample was all much higher than that of the ZnO, which indicated that the as-prepared samples may combine the adsorbility of rectorite and the catalytic ability of ZnO together to remove U(VI) from its aqueous solutions efficiently.…”

Section: Photoreduction Of U(vi)mentioning

confidence: 87%

Adsorption and photocatalytic reduction activity of uranium(VI) on zinc oxide/rectorite composite enhanced with methanol as sacrificial organics

Guo

et al. 2016

In this work, zinc oxide/rectorite composites were synthesized by a sol-gel method. The methanol as sacrificial organics could be enhance the adsorption capability and photocatalytic reduction activity of U(VI) onto the zinc oxide/rectorite composites. In addition, the composite still showed the high photoreduction activity after four reaction cycles under visible light irradiation. On the basis of the experimental results and photoluminescence, the enhanced photoreduction activity could be attributed to charge-transfer-complex and the coupling effect of ZnO and rectorite in the composite.

“…For the presence of both surface complexes and surface (co)precipitates, it is very difficult to distinguish them on attapulgite surface. The surface (co)precipitates and inner-sphere surface complexes can be distinguished from the bond distances of Eu-O in the first coordination shell or the bond distances of Eu-O-Eu in the second coordination shell from the EXAFS analysis [47,48]. From the acid-base titration curve, the surface site concentration of attapulgite was calculated to be 2.425 9 10 -3 mol/g [20].…”

Section: Effect Of Ionic Strength and Phmentioning

confidence: 99%

Sorption and desorption properties of Eu(III) on attapulgite

Chen

2015

The sorption-desorption of Eu(III) on attapulgite was studied using batch technique. The sorption of Eu(III) on attapulgite was strongly dependent on pH and ionic strength at low pH, and independent of ionic strength at high pH. The interaction was dominated by outer-sphere surface complexation/ion exchange at low pH, and by inner-sphere surface complexation at high pH. The irreversible sorption-desorption curves also suggested the formation of strong surface complexes. The high sorption capacity of attapulgite suggested that the attapulgite is a suitable material for the efficient elimination of Eu(III) from aqueous solutions in nuclear wastewater management.