Sorption of U(VI) onto Layered Double Hydroxides of Mg and Al with β-Cyclodextrin from Aqueous Solutions

Theoretical Foundations of Chemical Engineering - The possibility of removing U(VI) from aqueous solutions using layered double hydroxides of Mg and Al, which contain β-cyclodextrin...     

Behavior of radioaerosols formed by evaporation of 137Cs131I and 137CsOH from the metal surface in an electrostatic field

The behavior of radioaerosols formed by condensation of supersaturated ¹³⁷Cs¹³¹I and/or ¹³⁷CsOH vapor in an electrostatic field was studied. Supersaturated ¹³⁷Cs¹³¹I and/or ¹³⁷CsOH vapor was generated by evaporation of salt crystals from a metal surface heated to high temperatures owing to ohmic resistance. By applying additional potential to the aerosol generator, it is possible to control the behavior of ¹³⁷Cs¹³¹I, ¹³⁷CsOH, or ¹³⁷Cs¹³¹I + ¹³⁷CsOH aerosols in an electrostatic field.     

Synthesis of sorbents based on coarsely dispersed silica gel, containing nanoparticles of Ag compounds, for localization of volatile radioactive iodine compounds from the water vapor-air medium

The paper deals with the synthesis and physicochemical properties of sorbents based on coarsely dispersed silica gel, containing 1, 2, 4, and 8 wt % nanoparticles of Ag compounds, intended for localization of volatile radioactive iodine compounds from the water vapor-air medium.     

Coprecipitation of 60Co with d element sulfides from aqueous solutions in the presence of EDTA

Coprecipitation of ⁶⁰Co microamounts from aqueous solutions with sulfides of d elements (Cu²⁺, Ni²⁺, Co²⁺) in the presence of 10^?2 M EDTA was studied. Under these conditions, the initial solution can be efficiently decontaminated from ⁶⁰Co by its coprecipitation with NiS. The degree of coprecipitation of ⁶⁰Co microamounts with NiS exceeds 95% at [Na₂S]: [Ni²⁺] = (5–10): 1.     

Gas-Phase Treatment of Dump Tailings from Metallurgical Plants in Nitrating Media to Enhance Nickel Extraction

Theoretical Foundations of Chemical Engineering - A new approach to the processing of the dump waste product stored in the tailings dumps of the nickel production enterprise Punda Gourda (Cuba) has...     

Sorption of Radioactive Iodine and Fluoride Ion on Hydroxyapatite from the Aqueous Phase

Sorption of the ¹³¹I^-, ¹³¹IO₃ ^-, and F^- ions on various samples of hydroxyapatite (HAP) from aqueous solutions was studied. The HAP samples were prepared by the following reactions: Ca(OH)₂ + H₃PO₄ HAP, CACl₂ + Na₃PO₄ + NaOH HAP, and Ca(NO₃)₂ + HAP seed + (NH₄)₂HPO₄ + NH₃ HAP. None of the HAP samples sorb ionic species of radioactive iodine from aqueous solutions. As for F^-, the best sorption properties are exhibited by the HAP sample prepared by the second reaction. The degree of recovery of fluoride ion with the HAP precipitate in 5 min, 4 h, and 5 days of the contact of the solid and liquid phases is 54, 66, and >95% of the initial F^- amount, respectively. The distribution factor K _d of the fluoride ion between the HAP solid phase and solution decreases with increasing V/m ratio and pH of the initial solution.     

Sorption of 85Sr, 137Cs, and 152Eu from solutions on mixed hexacyanoferrates of potassium and uranyl

Sorption of ⁸⁵Sr, ¹³⁷Cs, and ¹⁵²Eu from neutral and acidic solutions on mixed hexacyanoferrates of potassium and uranyl K₄(UO₂)₄[Fe(CN)₆]₃ · 4H₂O and K₂(UO₂)₅[Fe(CN)₆]₄ · 3H₂O is studied. The distribution coefficients of ⁸⁵Sr, ¹³⁷Cs, and ¹⁵²Eu between the solid phase of K₂(UO₂)₅[Fe(CN)₆]₄ · 3H₂O and the aqueous phase are determined to be 210±10, 3000±500, and 1100±250 ml g^?1, respectively, at a contacting time of 120 min. For solid K₄(UO₂)₄[Fe(CN)₆]₃ · 4H₂O, the respective values are 6670±900, 5600±300, and 3300±250 ml g^?1. The ⁸⁵Sr, ¹³⁷Cs, and ¹⁵²Eu distribution coefficients K _d between the solid K₄(UO₂)₄[Fe(CN)₆]₃ · 4H₂O and the aqueous phase decrease with decreasing pH.     

Sorption of U(VI) onto layered double hydroxides and oxides of Mg and Al,prepared using microwave radiation

Layered double hydroxides of Mg and Al, containing CО₃^2– ions in the interlayer space (LDH-Mg-Al-CО₃), and layered double oxides of Mg and Al (LDO-Mg-Al) were prepared using microwave radiation (MWR). The use of MWR allows not only acceleration of the synthesis of both LDH and LDO, but also preparation of compounds with high kinetic characteristics of the U(VI) sorption. The degree of U(VI) sorption (α) from 10^–2 M aqueous U(VI) solutions at a sorption time of 4 h and V/m = 50 mL g^–1 exceeds 99.0%. In sorption from more concentrated (10^–1 M) aqueous U(VI) solutions under similar conditions, α on all the samples does not exceed 37.5%.