This research aimed to enhance the column bioleaching recovery of uranium ore by Acidithiobacillus ferrooxidans.Seven factors were examined for their significance on bioleaching using a Plackett-Burman factorial desig...This research aimed to enhance the column bioleaching recovery of uranium ore by Acidithiobacillus ferrooxidans.Seven factors were examined for their significance on bioleaching using a Plackett-Burman factorial design.Four significant variables([Fe2+]initial,pH,aeration rate and inoculation percent)were selected for the optimization studies.The effect of these variables on uranium bioleaching was studied using a central composite design(CCD).The optimal values of the variables for the maximum uranium bioleaching recovery(90.27±0.98)%were as follows:[Fe2+]initial=2.89g/L,aeration rate420mL/min,pH1.45and inoculation6%(v/v).[Fe2+]initial was found to be the most effective parameter.The maximum uranium recovery from the predicted models was92.01%.This value was in agreement with the actual experimental value.The analysis of bioleaching residue of uranium ore under optimum conditions confirmed the formation of K-jarosite on the surface of minerals.By using optimal conditions,uranium bioleaching recovery is increased at column and jarosite precipitation is minimized.The kinetic model showed that uranium recovery has a direct relation with ferric ion concentration.展开更多
In the present work, uranium concentrations were measured in twenty surface soil samples forselected regions in AI-Anbargovernorate using fission track etch technique, CR-39 track detector was used for registration of...In the present work, uranium concentrations were measured in twenty surface soil samples forselected regions in AI-Anbargovernorate using fission track etch technique, CR-39 track detector was used for registration of induced fission tracks. The results show that, the uranium concentrations ranged from 4.61 ppm, 56.93 Bq/kg （AL-Falluja AL-Jolan District） to 1.81 ppm 22.35 Bq/kg （Anah）with an average 3.42±0.79 ppm, 41.76±9.04 Bq/kg. The present results have shown that the uranium concentrations in the studied surface soil samples were less than the allowed limit 11.7 ppm recommended by UNSCEAR, 1993.展开更多
Uranium extraction from seawater is of strategic significance for nuclear power generation.Amidoximebased functional adsorbents play indispensable roles in the recovery of seawater uranium with high efficiency.Neverth...Uranium extraction from seawater is of strategic significance for nuclear power generation.Amidoximebased functional adsorbents play indispensable roles in the recovery of seawater uranium with high efficiency.Nevertheless,balancing the adsorption capacity and selectivity is challenging in the presence of complicated interfering ions especially vanadium.Herein,a polyarylether-based covalent organic framework functionalized with open-chain amidoxime(COF-HHTF-AO)was synthesized with remarkable chemical stability and excellent crystallinity.Impressively,the adsorption capacity of COF-HHTF-AO towards uranium in natural seawater reached up to 5.12 mg/g,which is 1.61 times higher than that for vanadium.Detailed computational calculations revealed that the higher selectivity for uranium over vanadium originated from the specific bonding nature and coordination pattern with amidoxime.Combining enhanced adsorption capacity,excellent selectivity and ultrahigh stability,COF-HHTF-AO serves as a promising adsorbent for uranium extraction from the natural seawater.展开更多
基金the Tarbiat Modares University & Nuclear Science and Technology Research Institute for their financial support
文摘This research aimed to enhance the column bioleaching recovery of uranium ore by Acidithiobacillus ferrooxidans.Seven factors were examined for their significance on bioleaching using a Plackett-Burman factorial design.Four significant variables([Fe2+]initial,pH,aeration rate and inoculation percent)were selected for the optimization studies.The effect of these variables on uranium bioleaching was studied using a central composite design(CCD).The optimal values of the variables for the maximum uranium bioleaching recovery(90.27±0.98)%were as follows:[Fe2+]initial=2.89g/L,aeration rate420mL/min,pH1.45and inoculation6%(v/v).[Fe2+]initial was found to be the most effective parameter.The maximum uranium recovery from the predicted models was92.01%.This value was in agreement with the actual experimental value.The analysis of bioleaching residue of uranium ore under optimum conditions confirmed the formation of K-jarosite on the surface of minerals.By using optimal conditions,uranium bioleaching recovery is increased at column and jarosite precipitation is minimized.The kinetic model showed that uranium recovery has a direct relation with ferric ion concentration.
文摘In the present work, uranium concentrations were measured in twenty surface soil samples forselected regions in AI-Anbargovernorate using fission track etch technique, CR-39 track detector was used for registration of induced fission tracks. The results show that, the uranium concentrations ranged from 4.61 ppm, 56.93 Bq/kg （AL-Falluja AL-Jolan District） to 1.81 ppm 22.35 Bq/kg （Anah）with an average 3.42±0.79 ppm, 41.76±9.04 Bq/kg. The present results have shown that the uranium concentrations in the studied surface soil samples were less than the allowed limit 11.7 ppm recommended by UNSCEAR, 1993.
基金supported by the Science Challenge Project(TZ2016004)the National Natural Key Research and Development Program of China(2018YFC1900105 and 2017YFA0207002)Beijing Outstanding Young Scientist Program。
文摘Uranium extraction from seawater is of strategic significance for nuclear power generation.Amidoximebased functional adsorbents play indispensable roles in the recovery of seawater uranium with high efficiency.Nevertheless,balancing the adsorption capacity and selectivity is challenging in the presence of complicated interfering ions especially vanadium.Herein,a polyarylether-based covalent organic framework functionalized with open-chain amidoxime(COF-HHTF-AO)was synthesized with remarkable chemical stability and excellent crystallinity.Impressively,the adsorption capacity of COF-HHTF-AO towards uranium in natural seawater reached up to 5.12 mg/g,which is 1.61 times higher than that for vanadium.Detailed computational calculations revealed that the higher selectivity for uranium over vanadium originated from the specific bonding nature and coordination pattern with amidoxime.Combining enhanced adsorption capacity,excellent selectivity and ultrahigh stability,COF-HHTF-AO serves as a promising adsorbent for uranium extraction from the natural seawater.
