• Journal of Environmental Science International
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• v.29 no.4
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• pp.383-393
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• 2020

To increase electrolysis performance, the applicability of seawater to the iron-fed electro-Fenton process was considered. Three kinds of graphite electrodes (activated carbon fiber-ACF, carbon felt, graphite) and dimensionally stable anode (DSA) electrode were used to select a cathode having excellent hydrogen peroxide generation and organic decomposition ability. The concentration of hydrogen peroxide produced by ACF was 11.2 mg/L and those of DSA, graphite, and carbon felt cathodes were 12.9 ~ 13.9 mg/L. In consideration of durability, the DSA electrode was selected as the cathode. The optimum current density was found to be 0.11 A/㎠, the optimal Fe²⁺ dose was 10 mg/L, and the optimal ratio of Fe²⁺ dose and hydrogen peroxide was determined to be 1:1. The optimum air supply for hydrogen peroxide production and Rhodamine B (RhB) degradation was determined to be 1 L/min. The electro-Fenton process of adding iron salt to the electrolysis reaction may be shown to be more advantageous for RhB degradation than when using iron electrode to produce hydrogen peroxide and iron ion, or electro-Fenton reaction with DSA electrode after generating iron ions using an iron electrode.

• Microbiology and Biotechnology Letters
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• v.17 no.5
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• pp.407-411
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• 1989

Extracellular neutral pretense of Streptomyces rimosus producing oxytetracycline was purified by ammonium sulfate fractionation, DEAE Sephadex A-50 chromatography and Sephadex G-100 gel filteration, and was showed single band on the cathodic gel electrophoresis. The optimum pH and temperature of the enzyme were pH 8.0 and 6$0^{\circ}C$, respectively. The enzyme was activated about 80% in the presence of Co$^{2+}$ ion, and strongly inhibited by Hg$^{2+}$, Fe$^{2+}$ and chelatig agent, EDTA. Molecular weight of the enzyme was estimated to be 12, 000. The Km value of the enzyme of casein as a substrate was 2.7$\times$10$^{-4}$M.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.13 no.6
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• pp.545-550
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• 2000

In order to synthesize Ba-ferrite particles by molten salt method KCl and NaCl were added to basic composition to 50% by weight. X was varied from 0.0 to 1.0 to control the magnetic properties in $BaFe_{12-2x}$/ $Co_{x}$ / $Ti_{x}$ / $O_{19}$ and 1 mol% of $SiO_2$was added to control the aspect ratio of hexagonal platelets. And the effects of reaction temperatures were examined by varying the temperature from 85$0^{\circ}C$ to 120$0^{\circ}C$ with 5$0^{\circ}C$ intervals. Eutectic composition of NaCl and KCl lowered the crystallizing temperature of Ba-ferrite in molten salts than using KCl and NaCl separatly. The morphology of resulting Ba-ferrite particles was clearly hexagonal-shaped plates. $H_{c}$ and $M_{r}$ were decreased when F $e^{3+}$ was substitued with $Co^{2+}$ and $Ti^{4+}$ from x=0 to x=1.0 in $BaFe_{12-2x}$/ $Co_{x}$ / $Ti_{x}$ / $O_{19}$ . Adding 1mol% $SiO_2$in molten salt method increased the size but shortened c-axis of the hexagonal ferrites and this result is an opposite phenomenon compared with the result in solid-statge reaction.n.ion.n.

• Journal of Korea Ship Safrty Technology Authority
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• s.21
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• pp.66-77
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• 2006

Stainless steel has been stably used closed by passivity oxidation films(Cr₂O₃) is made by neutral atmospheric environment. However, passivity oxidaton films of the surface of stainless steel occasionally comes to be destroyed in seawater which is influenced by an environment having galogen ion like Cl‾, then, localization corrosion comes to occur Stainless steel 304 for shaft system material of the small-size FRP fishing boat on seawater environments made an experiment on simulation of sacrifical anode(Al, Zn). Through these experiment and study, following results have been obtained ; According to the field inspection and corrosion simulation, the corrosion on the 2nd class stainless steel shaft(STS304) in FRP fishing boat has been verified to occur by crevice corrosion and galvanic corrosion etc., According to the comparison and analysis of Stainless steel 304 was severely corroded, but, protected shaft specimen was not totallay corroded. This result is assumed to be made by the facts that anodic reaction, Fe → fe²+＋ 2e¯, has been restricted by the cathodic protection current of sacrificial anode material.

• Journal of the Korea Organic Resources Recycling Association
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• v.9 no.2
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• pp.45-51
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• 2001

Mackban-stone effectively removed heavy metals, such as Fe, Cu, Cd, and Zn, with best removal of Fe and Cu. And the removal of heavy merals related with ion exchange of Ca. Mackban-stone is also an efficient deodorant of hydrogen sulfide and ammonia and inhibited the growth of E coli. The degradation rare of 4-nitropheno1 by Nocardioides sp. PNP101 and 2,4-dinitrophenol by Strain CJ1 and Rhodococcus sp. DNP 505 are increased by Mackbane-srone.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2005.11a
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• pp.232-233
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• 2005

Stainless steel has been stably used closed by passivity oxidation films($Cr_2O_3$) is made by neutral atmospheric environment. However, passivity oxidation films of the surface of stainless steel occasionally comes to be destroyed in seawater which is influenced by an environment having halogen ion like $Cl^-$, then, localization corrosion comes to occur. Stainless steel 304 for shaft system material of the small-size FRP fishing boat on seawater environments made an experiment on simulation of sacrifical anode(Al, Zn). Through these experiment and study, following results have been obtained ; According to the field inspection and corrosion simulation, the corrosion on the 2nd class stainless steel shaft(STS 304) in FRP fishing boat has been verified to occur by crevice corrosion and galvanic corrosion etc.. According to the comparison and analysis of Stainless steel 304 shaft materials after simulation leaving unprotected and applying cathodic protection, unprotected shaft specimen of stainless steel 304 was severely corroded, but, protected shaft specimen was not totally corroded. This result is assumed to be made by the facts that anodic reaction, $Fe{\rightarrow}Fe^{2+}$ + $2e^-$, has been restricted by the cathodic protection current of sacrificial anode material.

• Korean Journal of Ecology and Environment
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• v.40 no.4
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• pp.537-545
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• 2007

The heavy metal removal capacity of filamentous green alga Cladophora sp. cultured together with wet-mixed solidified soil (loess) was tested. A Cladophora sp. was cultured for 5d, with added Chu No. 10 medium, in stream water contaminated by high concentration of heavy metals from a closed mine effluent. Heavy metal ion concentrations of the medium and in algal tissue were measured every day during the experiment. Dissolved metals (Al, Cd, Cu, Fe, Mn, Zn) in medium were rapidly removed (over 90% elimination) within 1-2d when alga and loess were added. Dissolved heavy metals dropped by only 10% when algae were cultured without loess. The Cladophora sp. accumulated much more heavy metals when cultured with loess than when the alga was cultured alone. Cladophora sp. exhibited a maximum uptake capacity for Al ($17,000{\mu}g^{-1}$ algal dry weight). The metal bioremoval capacities of the algae were in the order Al, Fe, Cu, Mn, Zn and Cd. The heavy metal removal capacity of Cladophora sp. showed significant increases when wet-mixed solidified soil was added to culture media.

• Journal of Sensor Science and Technology
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• v.23 no.1
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• pp.58-65
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• 2014

We developed a low-cost automatic diagnosis system for water quality in cooling towers to measure the concentrations of key ingredients such as $Ca^{2+}$, $Cl^-$, $PO{_4}^{3-}$, and $Fe^{2+}$. $Ca^{2+}$, and $Cl^-$ are the main factors that cause the generation of scale, corrosion, and sludge in water pipes. $PO{_4}^{3-}$ prevents corrosion, sludge and scale by inhibiting the ions (i.e., $Ca^{2+}$, $Cl^-$) from sticking to the pipes. $Fe^{2+}$ is an indicator of pipe corrosion. The proposed system consists of a microprocessor, a specimen container and heater, a precision pump, relays and valves, LED optical sources, and photo detectors. It automatically collects water samples and carries out pretreatment for determining the concentration of each chemical, and then estimates the concentration of each ion using low-cost LED optical sources and detectors. Experimental results showed that the accuracy of the proposed system is sufficiently high for water quality diagnosis and management of cooling towers, demonstrating the possibility of the proposed system's wide usage in real environments.

• Journal of the Korean Chemical Society
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• v.12 no.3
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• pp.121-127
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• 1968

In the oligomerization of p-aminophenol under the catalytic action of the metallic complexes, the effects of the ligands are studied. When the initial velocity of $O_2$ uptake at pH 8 using Fe(Ⅲ) as the central metal and N-hydroxylethylethylenediaminetriacetic acid (HEDTA), ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepentaacetic acid (DTPA), 1,2-cyclohexanediaminetetraacetic acid(CyDTA) as the ligands respectively are compared, the velocities are as the following order: HEDTA > EDTA > DTPA > CyDTA. Further when the effect of the ligands, nitrilotriacetic acid (NTA), HEDTA, EDTA, and DTPA, on the yields of oligomers are compared, the result shows as the following order: NTA > HEDTA > EDTA > DTPA. These are nearly reverse order of the stability constants of the complexes. In order to determine the composition of the mixed complexes at the initial step, the method of continuous variation is used, and it is found that the composition ratio of Fe-EDTA complex to monomer in the mixed complexes is one at pH 5-8 range. It is also found that at pH 9 or in the more alkaline range, side reactions occur to form water soluble dimer of quinone type and the catalytic action of the metallic complex markedly decreases on account of the hydrolysis of the central metal by the $OH^-$ ion.

• Analytical Science and Technology
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• v.11 no.3
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• pp.174-178
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• 1998

A chelating resin was prepared by the reaction of formaldehyde and resorcinol. It possesses high adsorption selectivity for transition metal ions such as Pb(II) and Ni(II). The adsorption and desorption yields of Pb(II), Ni(II), Co(II), Fe(II) and Zn(II) were determined using batch method. The significant characteristics of the chelating resin is the exchange processes between its hydrogen and metal ions. The mechanism of metal adsorption and desorption seems to be the competing protonation and complexation reaction of the functional group of the resin. This resin was applied to the rapid concentration of trace amounts of these metal ions and to the separation of Pb(II) from other metal ions in bulk solution.