作者: Hang, T.; Nash, C. A.; Aleman, S. E.
来源出版物: SEPARATION SCIENCE AND TECHNOLOGY 卷: 48 期: 14 页: 2090-2098 出版年: SEP 22 2013
摘要: The spherical Resorcinol-Formaldehyde and hypothetical spherical SuperLig (R) 644 ion-exchange resins are evaluated for cesium removal from radioactive waste solutions. Modeling results show that spherical SuperLig (R) 644 reduces column cycling by 50% for high-potassium solutions. Spherical Resorcinol Formaldehyde performs equally well for the lowest-potassium wastes. Less cycling reduces nitric acid usage during resin elution and sodium addition during resin regeneration, thereby significantly decreasing life-cycle operational costs. A model assessment of the mechanism behind cesium bleed is also conducted. When a resin bed is eluted, a relatively small amount of cesium remains within resin particles. Cesium can bleed into an otherwise decontaminated product in the next loading cycle. The bleed mechanism is shown to be fully isotherm-controlled vs. mass transfer controlled. Knowledge of residual post-elution cesium level and resin isotherm can be utilized to predict rate of cesium bleed in a mostly non-loaded column. Overall, this work demonstrates the versatility of the ion-exchange modeling to study the effects of resin characteristics on processing cycles, rates, and cold chemical consumption. This evaluation justifies further development of a spherical form of the SuperLig (R) 644 resin.
作者: Dwivedi, Charu; Kumar, Amar; Singh, Krishan Kant; 等.
来源出版物: JOURNAL OF APPLIED POLYMER SCIENCE 卷: 129 期: 1 页: 152-160 DOI: 10.1002/app.38707 出版年: JUL 5 2013
摘要:A novel synthetic method for the preparation of different sorbentpolymer composite beads has been developed under simple laboratory conditions. Copper hexacyanoferrate was synthesized, and its composite beads of required size were synthesized by phase-inversion technique, using polyethersulfone as the polymer matrix. Suitable size and mechanical stability, along with their spherical shape, make these composite beads most appropriate for column operation. The efficiency of these composite beads was tested for the removal of cesium, using radioanalytical techniques, in batch conditions. The effect of pH, the initial metal ion concentration, and contact time was also investigated. The synthesized beads perform best in the pH range 59. Different sorption isotherm models were applied to the experimental data. Equilibrium data are represented well by the Langmuir isotherm equation, with a monolayer sorption capacity of 1.56 mg g1 for the swollen beads. Kinetic modeling analysis, by fitting the data in the pseudo first-order, pseudo second-order, and intraparticle diffusion equations, shows that the pseudo second-order equation is the most appropriate model for the description of sorption of cesium ions onto the composite beads. The process mechanism is found to be complex, consisting of both intraparticle diffusion and film diffusion.
作者: Leng, Yuxiao; Ye, Gang; Xu, Jian; 等.
来源出版物: JOURNAL OF SOL-GEL SCIENCE AND TECHNOLOGY 卷: 66 期: 3 页: 413-421 DOI: 10.1007/s10971-013-3025-6 出版年: JUN 2013
摘要:In this article, a new class of silica gel adsorbent functionalized with macrocyclic receptors was developed for cesium recognition. A calixcrown molecule, with strong affinity to cesium cation, was decorated precisely at the 1,3-alternate benzene rings with reactive amino substituents, followed by the anchoring to the silica matrix to obtain a high functionalization degree. Structural characterization of the monomers and the organosilicas was carried out by H-1/C-13 NMR, Si-29/C-13 solid-state NMR, and FT-IR spectra. Besides, XPS survey, BET, TGA and ESEM were employed to investigate the surface property, thermal stability and micro-morphology of the organosilicas. Due to the host-guest interaction between the calixcrown receptor and cesium cation, efficient separation of cesium in the presence of competing alkali metals including sodium and potassium was realized. Mechanism regarding the recognition effect was discussed. The calixcrown-grafted organosilica material possesses the potential to be applied for the separation of cesium in radioactive liquid waste.
作者: Kubota, T.; Fukutani, S.; Ohta, T.; 等.
来源出版物: JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY 卷: 296 期: 2 页: 981-984 DOI: 10.1007/s10967-012-2068-4 出版年: MAY 2013
摘要:Cs-134, Sr-85, and I-131 were produced by neutron irradiation of CsCl, SrCl2, and K2TeO3, respectively, using the Kyoto University Reactor. These radioactive nuclides were added to river water and seawater to prepare artificially contaminated samples, and the removal of these nuclides using bentonite, zeolite, and activated carbon was then investigated. In the river water samples, Cs-134 and Sr-85 were successfully removed using bentonite and zeolite, and I-131 was removed using activated carbon. In the seawater samples, Cs-134 was removed using bentonite and zeolite, whereas Sr-85 and I-131 were hardly removed at all by these adsorbents.
作者: Shelkovnikova, L. A.; Kargov, S. I.; Gavlina, O. T.; 等.
来源出版物: RUSSIAN JOURNAL OF PHYSICAL CHEMISTRY A 卷: 87 期: 1 页: 125-128 DOI: 10.1134/S0036024413010251 出版年: JAN 2013
摘要:We compare the ion exchange selectivity of phenol-type sorbents based on phenol formaldehyde resins, products of condensation of diatomic phenols with formaldehyde, and crosslinked polymer based on C-phenylresorcinarene resin, for cesium and rubidium ions. It is shown that phenol formaldehyde sorbents are the ones most selective. The interaction of alkali metal cations with the anion of calixarene is investigated via quantum-chemical modeling. It is shown that the selectivity toward cesium and rubidium ions in ion exchangers of the phenolic type is not due to specific interactions of ions with phenolic groups.
作者: Yang Li-Xin; Wu Sai-Xiang; Liu Xiao-Li; 等.
来源出版物: CHEMICAL JOURNAL OF CHINESE UNIVERSITIES-CHINESE 卷: 34 期: 1 页: 55-60 DOI: 10.7503/cjcu20120171 出版年: JAN 10 2013
摘要: Aiming at salt lake brine with a high ratio of magnesium/lithium, extracting lithium was researched via the extractant tributyl phosphate (TBP) as well as the co-extraction reagent NaClO4, and the effects of temperature, solution pH value, phase ratio, ClO4- amount and other factors on Li+ extraction rate have been investigated in detail. The optimum operating conditions of a single extraction from brine are the following: the extraction time of 10 min, temperature of 25 degrees C, V-o/V-w = 2. 0, n(ClO4-)/n(Li+) = 2.0 and pH value in a range of 5-8. Under these conditions, the highest extraction rate for Li+ and Mg2+ was 65. 41% and 13. 31%, respectively, and the Li/Mg separation coefficient reached 12. 32. Reversed phase extraction was carried out with water in V-w/V-o =1. 0 and 50 degrees C, the stripping rate of Li+ reached 81. 52%, and the mass ratio of Mg/Li decreased from 45. 61 to 8. 45. The extraction process of Li+ and Mg2+ presented exothermic effect, metal ions extracted into the organic phase had no effect on the chemical shifts of H in TBP, but made the IR stretching vibration frequencies of P = O double bond shift to 1264 cm(-1) from 1280 cm(-1). The composition of extracted complex of Li+ was close to 2LiClO(4) center dot 5TBP determined by the slope method at 25 degrees C, and Li2CO3 was prepared by the strip liquor after demagnesium deeply.
作者: Du, Juan; Chen, Zhen; Wu, Yu-Long; 等.
来源出版物: TURKISH JOURNAL OF CHEMISTRY 卷: 37 期: 2 页: 228-238 DOI: 10.3906/kim-1204-21 出版年: 2013
摘要:The crystal transformation process of magnesium carbonate hydrate by the reaction of magnesium sulfate (MgSO4) with ammonium carbonate [(NH4)(2)CO3] was investigated. MgSO4 is one of the main magnesium resources of the Lop Nur salt lake in the Xinjiang Autonomous Region of China. Magnesium carbonate hydrates with different chemical compositions were prepared. The transformation process of the 2 crystals, MgSO4 and (NH4)(2)CO3, was analyzed by Raman spectroscopy, and the associated changes in crystal morphology were observed by scanning electron microscopy. The needle-like MgCO3 center dot 3H(2)O transformed into sheet-like 4MgCO(3)center dot Mg(OH)(2)center dot 4H(2)O when the temperature was increased from 323 K to 333 K. The changes in the relative contents of these 2 crystals during the transformation process were analyzed by thermoanalysis. The crystal transformation process is discussed from the viewpoint of the crystal plane and growth unit changes.
标题: Highly selective lithium recovery from brine using a lambda-MnO2-Ag battery
作者: Lee, Jaehan; Yu, Seung-Ho; Kim, Choonsoo; 等.
来源出版物: PHYSICAL CHEMISTRY CHEMICAL PHYSICS 卷: 15 期: 20 页: 7690-7695 DOI: 10.1039/c3cp50919b 出版年: 2013
摘要:The demand for lithium has greatly increased with the rapid development of rechargeable batteries. Currently, the main lithium resource is brine lakes, but the conventional lithium recovery process is time consuming, inefficient, and environmentally harmful. Rechargeable batteries have been recently used for lithium recovery, and consist of lithium iron phosphate as a cathode. These batteries feature promising selectivity between lithium and sodium, but they suffer from severe interference from coexisting magnesium ions, an essential component of brine, which has prompted further study. This study reports on a highly selective and energy-efficient lithium recovery system using a rechargeable battery that consists of a lambda-MnO2 positive electrode and a chloride-capturing negative electrode. This system can be used to recover lithium from brine even in the presence of magnesium ions as well as other dissolved cations. In addition, lithium recovery from simulated brine is successfully demonstrated, consuming 1.0 W h per 1 mole of lithium recovered, using water similar to that from the artificial brine, which contains various cations (mole ratio: Na/Li approximate to 15.7, K/Li approximate to 2.2, Mg/Li approximate to 1.9).
作者: Zhao, Zhongwei; Si, Xiufen; Liu, Xuheng; 等.
来源出版物: HYDROMETALLURGY 卷: 133 页: 75-83 DOI: 10.1016/j.hydromet.2012.11.013 出版年: FEB 2013
摘要:The challenge for lithium extraction from brine has been the separation of Mg and Li. Because they are located in diagonal positions within the periodic table, they exhibit many chemical similarities. But since Mg2+ has a high charge density and is easily hydrated, we explored a new separation method from an electrochemical perspective using LiFePO4/FePO4 as electrode materials. Through CV tests and technical experiments in a different electrolyte, this approach was verified. Our results show that lithium exhibits good reversibility in LiFePO4/FePO4 structures, and the redox peak separation is 0.592 V while that of Mg2+ is 1.403 V, indicating its more serious polarization. Technical studies using a voltage of 1.0 V show that, in pure lithium solution, the inserted capacity of lithium can reach 41.26 mg . (1 g LiFePO4)(-1), which is 93.78% of its theoretical value (44 mg), and the subsequent extracted capacity can attain 38.93 mg (1 g LiFePO4)(-1), which is 94.3% of its inserted capacity. But the extracted capacity of Mg2+ from a solution containing magnesium is only 5.5 mg. (1 g LiFePO4)(-1). Furthermore, the experimental data at different voltages prove that a lower voltage is beneficial for separating Mg and Li, and this method also works well in brine since the Mg/Li ratio can be reduced to 0.45 from 60. All these results indicate that this method, while simple, is quite promising for separating Mg and Li from a high Mg/Li ratio brine.
作者: 余疆江; 郑绵平; 伍倩
作者: Yu Jiangjiang; Zheng Mianping; Wu Qian
来源出版物: 化工进展 卷: 32 期: 1 页: 13-21 文献号: 1000-6613(2013)32:1<13:FLYHTL>2.0.TX;2-F 出版年: 2013
来源出版物: Chemical Industry and Engineering Progress 卷: 32 期: 1 页: 13-21 文献号: 1000-6613(2013)32:1<13:FLYHTL>2.0.TX;2-F 出版年: 2013