• Membrane Journal
• /
• v.26 no.2
• /
• pp.116-125
• /
• 2016

This study described a synthesis of MF having a arsenic removal characteristics and the fundamental research was performed about the simultaneous removal system of both As(III) and As(V) ions with the composite nanofiber membrane (PMF) based on PVdF and MF materials for the water-treatment application. From the TEM analysis, the shape and structure of MF materials was investigated. The mechanical strength, pore-size, contact angle and water-flux analysis for the PMF was performed to investigate the possibility of utilizing as a water treatment membrane. From these results, the PMF11 showed the highest value of mechanical strength ($232.7kgf/cm^2$) and the pore-diameter of composite membrane was reduced by introducing the MF materials. In particular, their pore diameter decreased with an increase of iron oxide composition ratio. The water flux value of PMF was improved about 10 to 60% compared with that of neat PVdF nanofiber membranes. From the arsenic removal characterization of prepared MF materials and PMF, it was shown the simultaneous removal characteristics of both As(III) and (V) ions, and the MF01, in particular, showed the highest adsorption-removal rate of 93% As(III) and 68% As(V), respectively. From these results, prepared MF materials and PMF have shown a great potential to be utilized for the fundamental study to improve the functionality of water treatment membrane.

• The Journal of the Petrological Society of Korea
• /
• v.22 no.1
• /
• pp.63-70
• /
• 2013

We report an easy and efficient method for separating zircon grains using a gold pan and disposable sieve together with the tap water. Samples powdered to less than $230{\mu}m$ in grain size are placed on the water-filled pan tilted at about $10^{\circ}$. The outflowing water flooded with low-density particles is screened by a ${\sim}70{\mu}m$ sieve. The most efficient rate of water outflow is estimated to be 0.1 L/sec, when the distance between the tap and the surface of water-filled pan is kept at 20-25 cm. After 20-30 minutes of water outflow, heavy mineral fractions are ready for zircon collection using a hand magnet (and heavy liquid when necessary) or simply hand-picking. This procedure is most likely applicable for the separation of other heavy minerals including monazite.

• Resources Recycling
• /
• v.30 no.5
• /
• pp.57-66
• /
• 2021

In this study, we attempted to separate and recover Cu from low-grade copper ore by a hydrometallurgical process. The leaching sample obtained after crushing and sieving by 0.355 mm of low-grade copper ore contained 1.5% Cu, 4.7% Fe, 1.0% Mn, and 0.3% Zn. The Cu in the oxide ore was very well leached into sulfuric acid and 97% Cu leaching efficiency was achieved at 80℃ and 3 M sulfuric acid (H₂SO₄). From the leaching solution, Cu was separated by solvent extraction from Fe, Mn, and Zn using LIX984N. The separation tendency between Cu and other metals was confirmed through the distribution ratio and separation factor. By plotting the McCabe-Thiele Diagram, the optimum condition for recovering Cu is 5 vol.% LIX984N, 2-stage counter-current solvent extraction, and an O/A ratio of 0.5. Using this method, 99% of the Cu was extracted and a CuSO₄ solution was finally obtained that contained 1.6 g/L Cu after the stripping process using 2 M H₂SO₄.

• Analytical Science and Technology
• /
• v.20 no.6
• /
• pp.496-501
• /
• 2007

The 242.795 nm on ICP-AES for the gold analysis was the most sensitive wavelength which was also interfered severely by the spectra of other metal ions such as manganese, chromium, cobalt, and iron. In order to analyze the gold in ore, the gold must be separated from the interfering ions. The best solvent for separation of gold in ore solution was 10 % n-hexane contained MIBK mixed solvent. The gold recovery was 97.5 % from mixed metal solution contained about 2 M $HNO_3$ and 0.5 M HCl.

• Resources Recycling
• /
• v.30 no.6
• /
• pp.28-35
• /
• 2021

An experiment was conducted to separate or recover Co and Ni using Cyanex 301 from process by-products and waste resources containing Co and Ni. To separate and recover Co and Ni from simulated leaching solutions, 10 v/v% Cyanex 301 was used as an extractant in this study; Li was not extracted. At equilibrium pH 1.5 and a phase ratio (A/O) of 1.0, 0.44% of Mg and 11.57% of Mn were extracted, and more than 99% of Co and Ni were extracted. McCabe-Thiele diagram analysis confirmed that more than 99.9% of Co and Ni could be extracted simultaneously through two-stage extraction with an extraction phase ratio (A/O) of 2. It was possible to extract Mg and Mn simultaneously through the scrubbing process. In the scrubbing process, more than 99% of Mg and 87% of Mn were scrubbed using 0.05 M of H₂SO₄, and 99.9% of Mg and more than 80% of Mn were scrubbed using 0.05 M of HCl. In the stripping process, 93% of Co and 5% of Ni were stripped selectively by 3.0 M of H₂SO₄. However, when 8.0 M of HCl was used as a stripping solution, more than 99.9% of Co and more than 90% of Ni were stripped simultaneously.

• Journal of Applied Biological Chemistry
• /
• v.52 no.3
• /
• pp.109-115
• /
• 2009

The gene encoding a putative aspartate aminotransferase in Xanthomonas oryzae pv. oryzae (Xoo) was cloned using PCR technique. The gene was ligated with pET-21(a) vector containing His6 tag and expressed in E. coli BL21(DE3). Affinity purification of the recombinant aspartate aminotransferase with Ni-NTA resin resulted in one band by SDS-PAGE analysis. The purified enzyme showed a molecular weight of 43 kDa, as expected. The enzyme was the most active toward L-aspartate as an amino donor, indicating that the purified enzyme is one of aspartate aminotrans-ferases exist in Xoo. Optimal activity of the enzyme was observed at around pH 7.5 and stability was much higher at alkaline pH rather than acidic pH values. The enzyme was considerably activated by the presence of manganese ion, showing about 157% of control activity at 1.0 mM.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.24 no.8
• /
• pp.1071-1076
• /
• 2020

The importance of network separation is due to the use of the Internet with existing business PCs, resulting in an internal information leakage event, and an environment configured to allow servers to access the Internet, which causes service failures with malicious code. In order to overcome this problem, it is necessary to use network virtualization to separate networks and network interconnection systems. Therefore, in this study, the construction area was constructed into the network area for the Internet and the server farm area for the virtualization system, and then classified and constructed into the security system area and the data link system area between networks. In order to prove the excellence of the proposed method, a network separation construction study using network virtualization was conducted based on the basis of VM Density's conservative estimates of program loads and LOBs.

• Resources Recycling
• /
• v.15 no.6 s.74
• /
• pp.48-55
• /
• 2006

This study was carried out for establishing the physical recycling technique for commercializing process on household batteries. The procedure involves shape separator, crushing, magnetic separation, classification and eddy current separation in sequence. The separation capacity was 400-600 unit cell/hr with shape separation system. The impurities such as manganese and zinc in the magnetic product were below 0.1% respectively, the concentration of iron was above 99% in spent carbon zinc battery. Also non-magnetic products are composed of 22-30% En, 16-22% Mn, 1-3% Fe in the case oi spent zinc carbon battery. The amounts of other components such as carbon rod, plastics and separator were about 37-50%. From the eddy current separation of nonferrous products, the plate-type zinc components were separated up to 96% with 2,250-2,750 meter/min of the conveyor speed.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.25 no.1
• /
• pp.94-103
• /
• 1996

기능성 해조음료를 개발하기 위하여 미역, 톳 및 다시마를 저온하에서 마쇄, 원심분리, 한회여과를 거쳐 생해조 세포액을 얻었으며, 각 해조 생세포액의 성분 분석과 색차 측정 및 관능검사를 통하여 품질평한 결과 다음과 같았다. 원심분리 후 한외 여과에 의한 생세포액의 수율은 생해조에 대하여 6.8~56.5% 였으며, 톳과 미역의 수율은 높았으나 다시마는 수율이 낮았다. 해조액을 한회여과한 다음 동결건조한 시료의 회분 합량은 28~60%였으며, 조단백 함량은 12.7%~6.7%정도 였는데 미역과 톳은 다시마 보다 각 성분의 함량이 많았다. 알긴산과 chlrophyll 및 carotenoid 은 한회여과막에 의하여 대부분 제거되었으나 톳의 polyphenol은 30K 한외여과막에 의해서도 효과적으로 제거되지 않았다. 다시마와 톳 생세포액의 주요 아미노산은 glutamic acid와 aspartic acid 였으며, 미역의 경우는 alanine, aspartic acid, valine이었다. 해조 생세포액중의 무기 질은 칼륨의 함량이 특히 높았으며 양이온의 경우 나트륨, 마그네슘, 칼슘, 철, 아연, 망간, 구리순으로 함유 되어있었다. 음이온으로는 $Cl^{-}$,$SO_{4}^{2-}$,$HPO_{4}^{2-}$,$NO_{3}^{-}$의 함량이 높았으며, I와 Br의 함량은 다시마가 톳과 미역에 비하여 높았다.

• Resources Recycling
• /
• v.31 no.1
• /
• pp.12-20
• /
• 2022

The smelting reduction of spent lithium-ion batteries results in metallic alloys containing Co, Cu, Fe, Mn, Ni, and Si. A process to separate metal ions from the sulfuric acid leaching solution of these metallic alloys has been reported. In this process, ionic liquids are employed to separate Fe(III) and Cu(II). In this study, D2EHPA and Cyanex 301 were employed to replace these ionic liquids. Fe(III) and Cu(II) from the sulfate solution were sequentially extracted using 0.5 M D2EHPA with three stages of cross-current and 0.3 M Cyanex 301. The stripping of Fe(III) and Cu(II) from the loaded phases was performed using 50% (v/v) and 60% (v/v) aqua regia solutions, respectively. The mass balance results from this process indicated that the recovery and purity percentages of the metals were greater than 99%.