scholarly journals Separation of Radionuclides from a Rare Earth-Containing Solution by Zeolite Adsorption

Minerals ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 20
Author(s):  
Deniz Talan ◽  
Qingqing Huang
Keyword(s):  
Rare Earth ◽  
Rare Earths ◽  
Contact Time ◽  
Separation Efficiency ◽  
Ph Value ◽  
Solid Phase ◽  
Separation Performance ◽  
Solution Ph ◽  
Zeolite Sample ◽  
Alternative Sources

The increasing industrial demand for rare earths requires new or alternative sources to be found. Within this context, there have been studies validating the technical feasibility of coal and coal byproducts as alternative sources for rare earth elements. Nonetheless, radioactive materials, such as thorium and uranium, are frequently seen in the rare earths’ mineralization, and causes environmental and health concerns. Consequently, there exists an urgent need to remove these radionuclides in order to produce high purity rare earths to diversify the supply chain, as well as maintain an environmentally-favorable extraction process for the surroundings. In this study, an experimental design was generated to examine the effect of zeolite particle size, feed solution pH, zeolite amount, and contact time of solid and aqueous phases on the removal of thorium and uranium from the solution. The best separation performance was achieved using 2.50 g of 12-µm zeolite sample at a pH value of 3 with a contact time of 2 h. Under these conditions, the adsorption recovery of rare earths, thorium, and uranium into the solid phase was found to be 20.43 wt%, 99.20 wt%, and 89.60 wt%, respectively. The Freundlich adsorption isotherm was determined to be the best-fit model, and the adsorption mechanism of rare earths and thorium was identified as multilayer physisorption. Further, the separation efficiency was assessed using the response surface methodology based on the development of a statistically significant model.

Effects of Rare Earths and Yttrium on Striated Muscle and the Neuromuscular Junction

1972 ◽  
Vol 50 (6) ◽  
pp. 603-611 ◽  
Author(s):  
John M. Bowen
Keyword(s):  
Rare Earth ◽  
Rare Earths ◽  
Time Course ◽  
Striated Muscle ◽  
Ringer Solution ◽  
Solution Ph ◽  
Rare Earth Ion ◽  
End Plate ◽  
Trivalent Rare Earth ◽  
Frog Sartorius

Effects of several rare earths and yttrium on isolated frog sartorius muscles were investigated. Lanthanum (La), praseodymium, neodymium (Nd), samarium, gadolinium, dysprosium, erbium, thulium, ytterbium, and yttrium (Y) inhibited twitch tension of indirectly stimulated preparations. Concentrations required to reduce twitch tension to 50% of control tension in 15 min ranged between 0.52 mM and 1.10 mM (Ringer solution; pH 6.0). Similar concentrations (La, Nd, and Y) also inhibited twitch tension of directly stimulated, curarized preparations. A relationship between effect on twitch tension and atomic number was not found. La (0.3 mM) and Y (0.3 mM) reduced the amplitude, but did not appear to alter the time course, of extracellularly recorded end-plate potentials (E.P.P.'s). Amplitudes of intracellularly recorded E.P.P.'s were reduced by La (0.0125–0.05 mM) and Y (0.0125 and 0.025 mM). Effect on quantal contents of E.P.P.'s indicated that the principal action of both agents was an inhibition of transmitter release. La (0.025 and 0.05 mM) and Y (0.05 mM) significantly increased the frequency of miniature end-plate potentials. It is concluded that the prejunctional membrane does not differentiate significantly between the action of the trivalent rare earth ion lanthanum and the action of the trivalent rare-earth-like ion yttrium.

Dry beneficiation of +0.5mm-5.6mm South African coal using an air dense medium fluidization bed

2021 ◽  
Author(s):  
Elmarie Sunette Diedericks ◽  
Marco Le Roux ◽  
Quentin Peter Campbell
Keyword(s):  
Particle Size ◽  
Fluidized Bed ◽  
Separation Efficiency ◽  
Solid Phase ◽  
Poor Performance ◽  
Operating Conditions ◽  
High Mass ◽  
Dense Medium ◽  
Separation Performance ◽  
Coal Particles

Abstract The separation performance of solid phase bed material, at various particle size ranges, in an air dense medium fluidized bed (ADMFB), were evaluated during this study. The coal particles were separated into +0.5mm-1mm, +1mm-2mm, +2mm-2.8mm, +2.8mm-4mm, +4mm-4.75mm and +4.75mm-5.6mm particle size ranges and fed to the fluidized bed in these fractions. Along with the six coal particle size ranges, three dense media to coal ratios and the addition of vibration was tested to identify the best operating conditions. Adequate results were obtained for larger particle size ranges down to and including +2.0mm-2.8mm coal particles, after which the separation performance decreased significantly. Density stratification was irregular and not obvious for coal particles below 2.0mm and maintaining a consistent fluidization state also proved to be challenging, especially when dense medium was added. The coal particles separated vertically along the bed height because of differences in particle and bed density, while particle size proved to have a notable influence on the degree of separation. An air fluidization velocity of between 1.1 to 1.4Umf was shown as the best performing velocity, which yielded the maximum ash differential between the top and bottom layers of the bed for all the particle size ranges tested. For +2.0mm-5.6mm coal particles, low cumulative ash yields were obtained at high mass yields, however the ash yields increased for -2mm coal. Vibration and dense medium have, in some cases, enhanced the separation efficiency of the ADMFB. The -2.0mm particles experienced stronger particle-particle interactions as well as elevated levels of bubbling and back mixing than that of the +2.0mm particles, which explains the poor performance of the small particle sizes.

Solid-Phase Extraction Method for Preconcentration/Separation of Zinc Ion in Tap Water and Human Urine Using Organo-Bentonite Modified by Dithizone

2011 ◽  
Vol 230-232 ◽  
pp. 892-895
Author(s):  
Dong Zhang ◽  
Yan Li Zhang
Keyword(s):  
Human Urine ◽  
Contact Time ◽  
Ph Value ◽  
Solid Phase ◽  
Tap Water ◽  
Absorption Spectrometry ◽  
Zinc Ion ◽  
Good Tolerance ◽  
Flame Atomic Absorption ◽  
Experimental Parameters

A new method was proposed for the preconcentration/separation of zinc at trace levels using a modified organo-bentonite with dithizone (D-O-bentonite) and determined by flame atomic absorption spectrometry (FAAS). The influences of some experimental parameters including pH of the sample solution, contact time, and volume of eluent have been investigated. The influences of some matrix elements were also examined. The results show that the zinc ion could be adsorbed on the D-O-bentonite. The adsorbed quantitively was affected by the pH value of medium and contact time. In the medium of pH 4-5, the contact time was 20 min, and capacity of adsorption was 32.0 mg·g-1. The zinc adsorbed on the sorbent could be completely eluated by using 0.5 mol·L-1 HNO3. The method has a good tolerance to matrix interference. The detection limit of the method for zinc ion was 0.013 µg·L-1. The method was successfully applied to the pre-concentration/separation of zinc ion in the tap water and human urine with satisfactory results.

Removal of Low Concentration Chromium (III) from Aqueous Solution with 4 Microbial Biosorbents

2012 ◽  
Vol 610-613 ◽  
pp. 1863-1870
Author(s):  
Xin Li ◽  
Yong Liang Sun ◽  
Lin Zhou ◽  
Ju Fang Wang ◽  
Wen Jian Li
Keyword(s):  
Contact Time ◽  
Mass Concentration ◽  
Ph Value ◽  
National Standard ◽  
Batch Experiments ◽  
Solution Ph ◽  
Low Concentration ◽  
Ft Ir ◽  
Biomass Dosage ◽  
Optimal Ph

The low concentration Chromium (Ⅲ) adsorption was studied by 4 biosorbents (TP, XB, MY and TQ), which were isolated from Chrome-tanned leather construction section sludge. Batch experiments were carried out to investigate the effect of contact time, solution pH, biomass dosage, initial concentration of copper and temperature on biosorption efficiency. The experiment results showed that the concentration of chromium (Ⅲ) could meet the national standard (≤1.5mg/L) after treatment. The optimal pH value, mass concentration and temperature of biosorption was 4.0, 0.5g/L and 30°C, respectively. When the biosorbent were treated by [ NaOH ]= 0.3 mol/L, absorption capacitie was increased by 34.54%、23.21%、17.86% and 38.96% respectively. And from the results of SEM (Scanning electron microscope) and FT-IR (Fourier Transform infrared spectroscopy), the structure and functional groups of biosorbents was changed after the biosorption.

scholarly journals Study on the removal of high contents of ammonium from piggery wastewater by clinoptilolite and the corresponding mechanisms

2019 ◽  
Vol 17 (1) ◽  
pp. 1393-1402
Author(s):  
Liu Nan ◽  
Li Yingying ◽  
Li Jixiang ◽  
Ouyang Dujuan ◽  
Wang Wenjuan
Keyword(s):  
Contact Time ◽  
Adsorption Process ◽  
Ph Value ◽  
Optimal Conditions ◽  
Solution Ph ◽  
Piggery Wastewater ◽  
Column Study ◽  
Ammonium Removal ◽  
Ammonium Adsorption ◽  
Pseudo Second Order

AbstractIn this study, a clinoptilolite was applied to remove ammonium from piggery wastewater. The performance of ammonium removal and the correspondingly mechanisms were discussed. Under the optimal conditions of clinoptilolite dosage of 12 g/L, solution pH value of 8.3, shaking speed of 280 rpm and contact time of 55 min obtained by using response surface methodology (RSM), 19.7 mg of ammonium can be adsorbed onto 1 g of clinoptilolite, which was declined when metal cations were presented in the piggery wastewater. The ammonium adsorption process by the clinoptilolite can be well fitted by Langmuir isotherm with a spontaneous nature and pseudo–second–order kinetics model. Furthermore, column study showed that to some extent, the increased flow rate was beneficial to the removal of ammonium, and the ammonium adsorption capacity of clinoptilolite in column study was much higher than those in batch study.

scholarly journals Adsorption of rare earth elements using bio-based sorbents

2018 ◽  
Vol 245 ◽  
pp. 18001 ◽  
Author(s):  
Arina Kosheleva ◽  
Iryna Atamaniuk ◽  
Natalia Politaeva ◽  
Kerstin Kuchta
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Removal Efficiency ◽  
Permanent Magnets ◽  
Ph Value ◽  
Batch Adsorption ◽  
Freundlich Isotherms ◽  
Residual Biomass ◽  
Mixed Aqueous Solution ◽  
Alternative Sources

Rare earth elements (REEs) have recently received significant attention due to their irreplaceable industrial application for the number of crucial advanced technologies in production of permanent magnets, batteries, luminescence lamps, lasers and other electronic and electrical goods. These technologies have been strongly affecting present consumption of REEs as well as looking for alternative sources, that would guarantee their sufficient supply for the future demand. This study investigates one of the possible and widely employed techniques for the efficient and at the same time, environmentally friendly recovery of REEs by adsorption using bio-based adsorbents. Overall, three bio-sorbents with different composition (residual biomass originated from agriculture and bio-refineries) were examined to study removal efficiency of the 7 most commonly used REEs in mixed aqueous solution. Batch adsorption experiments were carried out at the room temperature, varying the pH value (pH=1,54; 4,24) and different initial concentration of REEs to determine optimum condition for their recovery. Results revealed that removal efficiency for most of the REEs was much higher at pH=4,24 and reached 70-100% for the minimal concentrations and 30-40 % at maximal initial concentrations respectively. Adsorbent containing residual biomass and chitosan showed to be the most effective bio-sorbent for recovery of most of the REEs. In order to describe and fit the obtained data Langmuir and Freundlich isotherms models were employed.

scholarly journals A Downhole Hydrocyclone for the Recovery of Natural Gas Hydrates and Desanding: The CFD Simulation of the Flow Field and Separation Performance

Energies ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 3257
Author(s):  
Shunzuo Qiu ◽  
Guorong Wang ◽  
Leizhen Wang ◽  
Xing Fang
Keyword(s):  
Flow Field ◽  
Removal Efficiency ◽  
Separation Efficiency ◽  
Solid Phase ◽  
Short Circuit ◽  
Tangential Velocity ◽  
Separation Performance ◽  
Volume Distribution ◽  
Recovery Efficiency ◽  
And Performance

The application of a hydrocyclone to recycle NGH and desand during NGH exploitation is a novel idea. The flow field and performance of this hydrocyclone is in the frontier of the research in this field and is unclear so far. This research aimed to reveal the flow field characteristics and performance of NGH downhole hydrocyclones. In this paper, flow field, solid phase particle volume distribution and separation efficiency were investigated according to the two objectives of NGH recovery efficiency and sand removal efficiency with different inlet velocities by computational fluid simulations (CFD)-FLUENT software. The results show that the short circuit flow contributed to the recovery of NGH. Axial velocity is a decisive factor in balancing the two objectives of NGH recovery efficiency and sand removal efficiency. In addition, the same as those in traditional hydrocyclones, the static pressure, tangential velocity and turbulence intensity play key roles in separation performance, hydrocyclone performance can be improved by increasing the inlet velocity. On the other hand, most separation efficiencies were greater than 80%, when the particle size was larger than 15 µm, and the differential pressure was less than 0.6 MPa. Therefore, all the above results confirm that hydrocyclone has good performance in NGH exploitation, and the basis of its structural design and optimization are provided.

Removal of Strontium Ions from Aqueous Solution by Adsorption onto Sodium Trititanate Whisker

2011 ◽  
Vol 391-392 ◽  
pp. 1173-1178 ◽  
Author(s):  
Zu Lei Zhang ◽  
Lei Li
Keyword(s):  
Aqueous Solution ◽  
Solid Phase Extraction ◽  
Contact Time ◽  
Ph Value ◽  
Solid Phase ◽  
Maximum Adsorption Capacity ◽  
Phase Extraction ◽  
Flame Atomic Absorption ◽  
Relative Standard ◽  
Strontium Ions

Utilization of solid-phase extraction (SPE) to remove aqueous strontium ions by adsorption onto activated sodium trititanate whisker (STW) was investigated in this work under the conditions of various pH value, STW amount, shaken time and contact time by flame atomic absorption spectrometry (FAAS). The optimum conditions obtained were: pH value = 5.0, STW amount = 0.2 g, shaken time = 5 min and contact time of 3 h on the remove of 2 mg·L-1strontium(II). The adsorption of Sr(II) on activated STW follows pseudo-second order kinetics and the maximum adsorption capacity Q being 8.37 mg·g-1at 25°C. Finally, the detection limit (3σ) of 0.030 μg·mL-1with the relative standard deviation (RSD) for 1.0 μg·mL-1Sr(II) of 0.93 % (n=10) were obtained. Results showed that activated STW was a solid-phase extraction sorbent of efficient, low-cost, convenient adsorption of Sr(II) from aqueous solution and could be reused for five times with about 8.0%-9.0% regeneration loss.

Determination of Trace Bismuth in Urine and Tap Water Samples by Atomic Absorption Spectrometry after Solid-Phase Extraction

2011 ◽  
Vol 230-232 ◽  
pp. 884-887
Author(s):  
Dong Zhang
Keyword(s):  
Atomic Absorption Spectrometry ◽  
Atomic Absorption ◽  
Water Samples ◽  
Contact Time ◽  
Ph Value ◽  
Solid Phase ◽  
Tap Water ◽  
Absorption Spectrometry ◽  
Experimental Conditions

In this paper, a new method for the determination of bismuth in urine and tap water is described. The methodology combines determined using a hydride generation-atomic absorption spectrometry (HG-AAS) with pre-concentration of the bismuth on the modified organobentonite by dithizone (D-O-bentonite). Optimal experimental conditions for the adsorption and elution of the bismuth, including pH, contact time, eluent concentration, eluent volume and co-existing ions have been investigated. The result showed that the bismuth ion could be adsorbed on the D-O-bentonite. The adsorbed quantitive was affected by the pH value and contact time. In the medium of pH 5.0, the shaking time was 10 min, the adsorption capacity was 15.2 mg·g-1. The bismuth adsorbed on the modified organobentonite by dithizone could be completely eluated by using 2 mol·L-1 HNO3. The method has been applied to the pre-concentration/separation of bismuth in the human urine and tap water samples with satisfied results.

Improvement of Anti-Hydrolytic Property of AlN Powder Modified by the Rare-Earth Salts

2015 ◽  
Vol 816 ◽  
pp. 9-14 ◽  
Author(s):  
Yan Li ◽  
Mei Hui Song ◽  
Qian Yu ◽  
Xiao Chen Zhang
Keyword(s):  
Surface Modification ◽  
Rare Earth ◽  
Aluminum Nitride ◽  
Rare Earths ◽  
High Performance ◽  
Ph Value ◽  
Water Bath ◽  
Modifying Agent ◽  
Rare Earth Salts ◽  
Hydrolysis Of

In this article, the high-performance modified AlN powder was prepared, using Y(NO3)3·6H2O as the modifying agent, and characterizing by pH meter, TG , XRD and SEM. The results show that the Y2O3 coating was formed on the AlN surface, the pH value of aluminum nitride of treatment suspension solution maintains 7.75 in water bath for 100 hours. Therefore the conclusion is that surface modification with rare earths can effectively inhibit the hydrolysis of the AlN powder.

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