• Korean journal of applied entomology
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• v.61 no.4
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• pp.669-673
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• 2022

To evaluate biological activity of honeydew honey produced by Apis mellifera L. in Korea, we measured antioxidant activity by using DPPH (1,1-diphenyl-2-picryl hydrazyl), ABTS [2,2-azobis(3-ethylbenzothiazoline-6-sulfonate)], FRAP (Ferric reducing antioxidant power), and total polyphenol content assays. Korean honeydew honey respectively scavenged 26% and 86% of DPPH and ABTS radicals at the highest concentration of 10 mg/mL. In the result of FRAP assay, Korean honeydew honey showed activity (126 µM of FRAP value) to reduce Fe³⁺ to Fe²⁺. Total polyphenol content was 73.41 mg GAE/kg. Korean honeydew honey exhibited excellent antioxidant activity due to having high radicals scavenging ability and reducing power of ferric ion as well as the presence of phenolic compounds. These findings suggest that Korean honeydew honey has great potential as a functional food material.

• Journal of the Korean GEO-environmental Society
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• v.10 no.5
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• pp.27-32
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• 2009

This study evaluates tripolyphosphate's ability to treat AMD (Acid Mine Drainage). Based on the batch test results for reaction between tripolyphosphate and AMD obtained from Munkyung coal mine, $4.7{\times}10^{-3}$ mole is the optimum dosage of tripolyphosphate for AMD treatment. $Ca^{2+}$ concentration is decreased from $16.4mg/{\ell}$ to $5.6mg/{\ell}$, in other words, the removal rate of $Ca^{2+}$ is 65.9%. $Fe^{3+}$ concentration is decreased from $3.7mg/{\ell}$ to $0.02mg/{\ell}$, that is, the removal rate of $Fe^{3+}$ is 99.5%. $SO{_4}^{2-}$ concentration ranges from $526.8mg/{\ell}$ to $566.5mg/{\ell}$, which shows no obvious decrease. After dosing up tripolyphosphate, $Na^+$ concentration in AMD ranges from $549.8mg/{\ell}$ to $599.3mg/{\ell}$ and orthophosphate concentration in AMD ranges from $6.82mg/{\ell}$ to $7.60mg/{\ell}$. It was found that the precipitate in the order of amount is Apatite${\gg}{\beta}$-tricalcium phosphate > $Fe(OH)_3$ from SEM, XRF, XRD analyses. Consequently, the treatment by tripolyphosphate is effective in pH buffering and in the removal of $Ca^{2+}$ and $Fe^{3+}$.

• Resources Recycling
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• v.6 no.3
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• pp.3-8
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• 1997

The EA.F. sleelmaking slag (slag that follow) of a cnmvany 1 Co.. containzd a simple substance of a metal, wustlte (FeO), magnetite (Fe,O,), gehlenite (CaAl,SiO,), monlicellite (CaMgSiO,), dc. To recovere a metal (Fe grade . t95%) in the slag, it is desirable that the particles of a metal are isolated from thc slag and madc for a liberated subslance. Then, the liberaled melal is easlly recoveled by a magnetic separation. If thc rcclarnalcd slag, the sizc of which ranges under 40 nun, have a mulli-stage crushing, the most of a metal in thc slag is simply isolaled as a liberated subslance. If the mad, lhat is a liberated subslance and a sphere, is recovered by a magnetic field intensity. the minimum intensity, at which a metal is attracted, is approximately IOOG and did no1 dcpcnd on the particle size of a metad in the same particles. TIe recovered material. that contdined a iron (Fe) over 95% is a metal which is crushed slag by l00G in the multi-stage. If the magnetic field intcns~ty increase, the recovery mcrcasc, but the concentration grade decrease Bewusc thc concentration eams more and more impurities, iron oxide and the coml~ound of alkali earth element. 'll~ercforc If the rccla~nated slag have the multi-stage crushing, the metal is almostly recovered in the crushed slag by lO0G on each particles. If the slag, used as a rcclamatian lhat is a amount of 350,000 tan from I Co., was undcr the multistage crushing and then separaled by 100gauss, it is possible to recova a metal approximately 2.500 Ion, lhat is 0.73% of n ~eclamated slag. in 304.7 mm particles and to recover 4.200 tan in 0.3-1.7 mm particles , that is 1.2% nf a rcclamated slag, in a year. Therefore, ihe told recoverable meld is 6,700 ton, that is 19% of a reclmated slag, in a year, too.

• Resources Recycling
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• v.32 no.1
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• pp.50-59
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• 2023

The amount of dust generated during the dissolution of scrap in an electric arc furnace is approximately 1.5% of the scrap metal input, and it is primarily collected in a bag filter. Electric arc furnace dust primarily consists of zinc and ion. The processing of zinc starts with its conversion into pellet form by the addition of a carbon-based reducing agent(coke, anthracite) and limestone (C/S control). These pellets then undergo reduction, volatilization, and re-oxidation in rotary kiln or RHF reactor to recover crude zinc oxide (60%w/w). Next, iron is discharged from the electric arc furnace dust as a solid called Fe clinker (secondary by-product of the Fe-base). Several methods are then used to treat the Fe clinker, which vary depending on the country, including landfilling and recycling (e.g., subbase course material, aggregate for concrete, Fe-source for cement manufacturing). However, landfilling has several drawbacks, including environmental pollution due to leaching, high landfill costs, and wastage of iron resources. To improve Fe recovery in the clinker, we pulverized it into optimal -sized particles and employed specific gravity and magnetic force selection methods to isolate this metal. A carbon-based reducing agent and a binding material were added to the separated coarse powder (>10㎛) to prepare briquette clinker. A small amount (1-3%w/w) of the briquette clinker was charged with the scrap in an electric arc furnace to evaluate its feasibility as an additives (carbonaceous material, heat-generating material, and Fe source).

• Microbiology and Biotechnology Letters
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• v.4 no.3
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• pp.91-97
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• 1976

During the course of studies on the production and utilization of thermostable ${\alpha}$-amylase from a thormophilic actinomycete species isolated from soil, partial characterization of the ${\alpha}$-amylase has been (arried out. The optimum pH for the dextrinogenic activity of the enzyme was found to be 6.5 and the maximum reaction rate was achieved at a temperature range of 55$^{\circ}$ to 65$^{\circ}C$. Calcium ion was recognized to have a slight effect in activating the enzyme, while heavy metal salts especially ferrous and cupric ions showed a remarkable inhibition effect. The enzyme was best protected iron thermal denaturation at pH 8.0 with tris-HCI buffer；inactivation was rapid at higher or lower pH values. Furthermore, its thermal stability was greatly increased by calcium ion, particulary at the final concentration of 1${\times}$10$\^$－2/ mole in the reaction mixture. The Km value for the ${\alpha}$-amylase was calculated to be 2.17${\times}$10$\^$－4/g per $m\ell$ and the energy of activation for the dextrinogenic reaction to be 12,000${\pm}$580 ㎈ per mole.

• Journal of the Korean Chemical Society
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• v.33 no.2
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• pp.208-214
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• 1989

A method for the simultaneous determination of copper and cobalt by spectrophotometry has been described. The procedure involves the co-extraction of Cu(Ⅱ) and Co(Ⅱ) from 0.3M HCl into methyl isobutyl ketone as the ion-pairs formed between their thiocyanate complexes and high molecular alkylamines such as Amberlite LA1, Alamine 336, and Aliquat 336. The extract shows the color development to have the maximum absorbances at two different wavelengths i.e., 480 nm for copper and 625 nm for cobalt. Since the spectra of the ion-pairs overlap each other, two simultaneous equations are used to obtain the concentrations from absorbances. Even small amount of Fe(Ⅲ) and Ni(Ⅱ) interferes with the determination of copper. The results of the analysis of samples are in good agreement with the results determined by separate methods within RSD 5.9%.

• Journal of the Korean Chemical Society
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• v.44 no.4
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• pp.322-327
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• 2000

A new absorption spectrometric method for the determination of the Cr$_2O_7^{2-}$ ionin acidic media has been developed. The new method is based on the oxidation-reduction reaction of the HCr$O_4^-$ ion with H$_2$O$_2$forming a deep blue CrO(O$_2$) $_2$ andis coupled with a technique of flow injection analysis(FIA). The new method provides a linear calibration curve which accurately follows the Beer's law over a wide range of the analytical concentrations(2.0 ${\times}$ $10^{-6}$M~8.0 ${\times}$ $10^{-3}$M) of K$_2$Cr$_2$O$_2$. The sensitivity of the new method is approximately two times greater than the current method and the effects of the interfering substances such as V, Co, Ni, Fe, and Mn are almost negligible except Cu.

• Applied Biological Chemistry
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• v.15 no.1
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• pp.27-33
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• 1972

The alkaline protease was isolated from the culture material of monascus sp. on wheat bran culture. The crude purification of this enzyme was extracted with distilled water and precipitated with ammonium sulfate of 0.5 saturation. And, the activity of this enzyme was determind very strongly by folin's colorimetric method. The optimal pH of this enzyme was ranging from pH 10 to 13 and the optimal temperature was $50^{\circ}C$. The pH stability was ranging from pH 5 to 12 and the enzyme activity was not inactivated by heat treatment in lower temperature than $40^{\circ}C$. The enzyme was protected from heat denature by the treatment of $Pb^#$, $Ba^#$, $Co^#$, $Zn^#$, and $Cu^#$, but was inactivated with $Hg^#$, $Fe^#$ strongly. Moreover, one of these metal ions, the cupper ion, has a strong protective activity on enzyme heat denature. And, it was not effected by treatment of EDTA.

• Journal of the Korean Society of Food Science and Nutrition
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• v.25 no.4
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• pp.701-707
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• 1996

Xylanase(EC. 3. 2. 1. 8) was purified approximately 10.2 fold from Aspergillus niger SFN-416 by a sequential process of ammonium sulfate fractionation, Sephadex G-100 gel filtration and DEAE-Sephacel ion exchange chromatography. Molecular weight of the enzyme was approximately 31,000 daltons. The optimum pH and temperature of the enzyme activity were 3.5 and $50^{\circ}C$ respectively. The enzyme activity was enhanced by $Fe^{2+}$ and $Mn^{2+}$, and inhibited by $Hg^{2+}$. The activity was decreased by addition of methanol, ethanol, isopropanol and 1-butanol at a concentration of 10%(v/v).

• Analytical Science and Technology
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• v.14 no.1
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• pp.59-63
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• 2001

A PVC membrane electrodes based on Fe(II)-dipyridyl-mefenamic acid ternary complex as ion exchanger were prepared using o-nitrophenyl octyl ether as a plasticizer. The 2,2'-dipyridyl, 4,4'-dipyridyl and 4,4'-dipyridyl-2,2'-dipyridyl were used as dipyridyl derivative ligand. The electrode dxhibits a fast stable and linear response for $10^{-5}-10^{-3}mol/L$ mefenamate with an anionic slope of -55.98, -49.47, -59.35mV/decade in pH 8.9 borate buffer solution respectively. Potentiometric selectivity measurements revealed negligible interferences from aromatic and aliphatic carboxylic acid salts.