• Nuclear Engineering and Technology
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• v.53 no.10
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• pp.3352-3358
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• 2021

Aiming at selective adsorption and separation of Y(III) from the Y(III)-Sr(II) group in acid solution, a silica-based TODGA impregnated adsorbent [(TODGA+1-dodecanol)/SiO₂-P-F600] has been prepared. Batch adsorption experiments were conducted under the effect of contact time, acid concentration, solution temperature, and adsorption capacity etc. Chromatography recovery of more than 90% Y(III) was successfully achieved under elution with 0.01 M DTPA solution in nitric acid adsorption system, and 0.1 M HCl solution in hydrochloride adsorption system, respectively.

• Nuclear Engineering and Technology
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• v.54 no.4
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• pp.1471-1481
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• 2022

This paper aims to present a new method for obtaining an analytical solution for the Kaniadakis Doppler broadening (KDB) function. Also, in this work, we report the computational efficiencies of this solution compared with the numerical one. The solution of the differential equation achieved in this paper is free of approximations and is, consequently, a more robust methodology for obtaining an analytical representation of ψ_k. Moreover, the results show an improvement in efficiency using the analytical approximation, indicating that it may be helpful in different applications that require the calculation of the deformed Doppler broadening function.

• Korean Chemical Engineering Research
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• v.48 no.2
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• pp.157-163
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• 2010

A new etchant formulation was developed in this study to increase the shadow mask production rate, utilizing the $Fe(ClO_4)_3$ as an additive in the aqueous $FeCl_3$ solution. The shadow mask etch rate increased substantially with the increase of $Fe(ClO_4)_3$ concentration in the etchant. The etch rate difference between Ni and Invar steel was also reduced with the addition of $Fe{(ClO_4)_3}$ for most of the operating conditions, which was caused by the enhanced etch rate of both Ni and Fe by the new etchant. The increase in etch rate with the addition of $Fe(ClO_4)_3$ to aqueous ferric chloride solution was attributed to the superior electron transfer capability of $ClO^{4-}$ ion to that of $Cl^-$ ion.

• Journal of the Korean Ceramic Society
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• v.45 no.4
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• pp.226-231
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• 2008

The dense sintered bodies with >95% theoretical densities were successfully obtained from the $BaZrO_3,\;BaCeO_3,\;Ba(Zr_{0.7}Ce_{0.3})O_3$ solid solution, and core-shell structured $0.7BaZrO_3-0.3BaCeO_3$ composite powders prepared by sol-gel methods. The activation energy of $Ba(Zr_{0.7}Ce_{0.3})O_3$ solid solution calculated from the Arrhenius plot of the proton conductivities was similar to that of $BaZrO_3$. The activation energy of core-shell structured $0.7BaZrO_3-0.3BaCeO_3$ composite, however, was much lower than that of $BaZrO_3$ or $Ba(Zr_{0.7}Ce_{0.3})O_3$ solid solution, and was very similar to that $BaCeO_3$. These results could be assigned to the Ce-rich grain boundary which was clearly observed by EDX in core-shell structured $0.7BaZrO_3-0.3BaCeO_3$ composite.

• Journal of Sensor Science and Technology
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• v.24 no.6
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• pp.385-391
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• 2015

In this paper, we propose a new method to infiltrate $Fe_3O_4$-nanoparticles into a porous silicon film and a monitoring technique to detect packing density of nanoparticles within the film. Recently, research to use porous silicon as a drug carrier or a new functional sensor material by infiltrating $Fe_3O_4$-nanoparticles has been extensively performed. However, it is still necessary to enhance the packing density and to develop a monitoring technique to detect the packing density in real time. In this light, we forcibly injected a nanoparticle solution into a rugate-structured free-standing porous silicon (FPS) film by applying a pressure difference between the two sides of the film. We found that the packing density by the pressure-infiltration method proposed in this paper is enhanced, relative to that by the previous diffusion method. Moreover, a continuous shift in wavelength of the rugate reflectance peak measured from the film surface was observed while the nanoparticle solution was being injected. By exploiting this phenomenon, we could qualitatively monitor the packing density of $Fe_3O_4$-nanoparticles within the FPS film with the injection volume of the nanoparticle solution.

• Membrane Journal
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• v.30 no.2
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• pp.131-137
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• 2020

In this study, effect of inorganic particles on organic fouling was investigated by a laboratory-scaled pressurized membrane filtration. In order to cause organic fouling, sodium alginate (SA) was used as a feed solution. Regardless of the presence of inorganic SiO₂ particles, the complete pore blocking played an important role in determining the fouling rate during the initial period of membrane filtration. However, the formation of cake layer resulted in the membrane fouling more dominantly as filtration time progressed. In the presence of inorganic particles, both specific cake resistance and compressibility associated with the membrane fouling formed were relatively lower than that without SiO₂ particles. Membrane fouling was more severe at constant flux mode of filtration than that observed at constant pressure mode probably due to the concomitant increase of compressibility of fouling layer with transmembrane pressure (TMP). It was found that the presence of SA and SiO₂ particles in feed solution provided the synergistic effect on the hydraulic backwashing to reduce membrane fouling as compared to the SA solution alone without the inorganic particles.

• Geomechanics and Engineering
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• v.32 no.3
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• pp.347-359
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• 2023

With the development of infrastructure, there is a critical shortage of filling materials all over the word. However, a large amount of silt accumulated in the lower reaches of the Yellow River is treated as waste every year, which will cause environmental pollution and waste of resources. Microbial induced calcium carbonate precipitation (MICP) technology, with the advantage of efficient, economical and environmentally friendly protection, is selected to solidify the abandoned Yellow River silt with poor mechanical properties into high-quality filling material in this paper. Based on unconfined compressive strength (UCS) test, determination of calcium carbonate (CaCO₃) content and scanning electron microscope (SEM) test, the effects of cementation solution concentration, treatment times and relative density on the solidification effect were studied. The results show that the loose silt particles can be effectively solidified together into filling material with excellent mechanical properties through MICP technology. The concentration of cementation solution have a significant impact on the solidification effect, and the reasonable concentration of cementation solution is 1.5 mol/L. With the increase of treatment times, the pores in the soil are filled with CaCO₃, and the UCS of the specimens after 10 times of treatment can reach 2.5 MPa with a relatively high CaCO₃ content of 26%. With the improvement of treatment degree, the influence of relative density on the UCS increases gradually. Microscopic analysis revealed that after MICP reinforcement, CaCO₃ adhered to the surface of soil particles and cemented with each other to form a dense structure.

• Resources Recycling
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• v.29 no.3
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• pp.61-74
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• 2020

This study was conducted to improve the recycling process of waste fluorescent lamp, and investigate the possibility of using the waste fluorescent lamp glass as a raw material for glass beads, the leaching method of rare earth from the waste phosphor powder, and the possibility of solvent extraction of rare earth from the rare earth leaching solution. The waste phosphor contained 28.9% yttrium oxide, 3.46% cerium oxide, 1.95% europium oxide, 1.76% terbium oxide, and 1.43% lanthanum oxide. As a result of the trial production of glass beads using waste fluorescent lamp glass, it was judged that the production yield and quality were excellent, so that waste fluorescent lamp glass could be used as a raw material for glass beads. The soda roasted waste phosphor was leached in water and thereby the aqueous solution was blown with CO₂ to drop the pH to about 7, Then, Al, Si and residual N₂CO₃ were dissolved, and NaAlCO₃(OH)₂ and SiO₂ were precipitated in the aqueous solution. In the solvent extraction of cyanex272-hydrochloric acid, cyanex272-sulfuric acid, D2EHPA-hydrochloric acid, D2EHPA-sulfuric acid, Ionquest290-hydrochloric acid, Ionquest290-sulfuric acid, p507-hydrochloric acid using xylene as a diluent, the extraction yield of Y, Eu, Ce, La, and Tb are close to 100%. However, in this conditions, the difference in extraction yield for each element, that is, selectivity is 16% or less.

• Resources Recycling
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• v.31 no.2
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• pp.56-62
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• 2022

This study investigated the water leaching behavior of vanadium in Na₂CO₃-roasted vanadium-bearing titaniferous magnetite (VTM) concentrate. The magnetic concentrate and Na₂CO₃, mixed in a mass ratio of 4:1, were roasted at 1050 ℃, kept for 3 h, and ground to a size of D₅₀ = 48.79 ㎛ using a rod mill. The effects of leaching temperature and pulp density on water leaching were then investigated. The results show that the vanadium leaching efficiency decreased to 90.4%, 88.2%, and 83.8% as the temperature increased to 25, 55, and 85 ℃, respectively, whereas it remained almost constant 90.4%, 87.0%, and 87.0% as the pulp density increased to 10, 50, and 100 w/v%, respectively. Based on the preliminary leaching results, multi-stage leaching was conducted with the experimental conditions of 25 ℃, 100 w/v%, 300 rpm, and 1 h. The vanadium concentration in the final leaching solution was determined as 16.20 g/L after four stages of leaching. Thus, a high-concentration sodium vanadate solution was prepared by multi-stage leaching.

• Journal of Environmental Science International
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• v.23 no.5
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• pp.887-893
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• 2014

In order to remove fluoride ions from aqueous solution, PVC-$Al(OH)_3$ beads were prepared by immobilizing $Al(OH)_3$ with polyvinyl chloride (PVC). The prepared PVC-$Al(OH)_3$ bead was characterized by using SEM, EDS and Zeta potential. Dependences of pH, contact time and initial fluoride concentration on the adsorption of fluoride ions were studied. The optimal pH was in the range of 4~10. The adsorption was rapid during the initial 12 hr, and equilibrium was attained within 72 hr. The adsorption rate of fluoride ions by PVC-$Al(OH)_3$ beads obeyed the pseudo-second-order kinetic model. The maximum adsorption capacity obtained from Langmuir isotherm model was found to be 62.68 mg/g.