• Economic and Environmental Geology
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• v.33 no.5
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• pp.379-389
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• 2000

This study was focused on the investigation for the heavy metal contamination of soils derived from Yoecheon Industrial Complex in Chonnam Province. Total 201 soil samples including farmland, paddy, forest and playground soils were collected, extracted by 0.1N HCl and analyzed for Cd, Cu, Cr, Fe, Mn and Zn using AAS. Most pH values in soils were weak acidic ranges of 4-6, while some of them were over 8.0. Concentrations of Cd, Cu, Fe and Zn in the soils tend to be relatively high around the Au-Ag mine area, railroad stations and oil station, however, those of Cr, Mn and Pb show high at the northside of Pohang Steel Co (POSCO). Cadmium-Zn couples, and Cd-Zn and Zn-Cr couples have relatively good correlations in the farmland soils and paddy soils, respectively. Concentrations of Cd, Fe and Zn with depth tend to be higher in the top soils than in the bottom soils, but those of Cu and Pb do not show regular variations with depth.

• Proceedings of the KSEEG Conference
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• 2003.04a
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• pp.76-79
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• 2003

국내의 토양오염 공정시험방법에서는 Zn, Ni 추출시 산분해법에 가까운 방법을 사용하는 반면, Cd, Cu, Pb, $Cr^{6+}$ 추출시 0.1N HCl용액으로 산처리하여 1시간을 진탕한 후 이를 필터로 여과하여 분석용액을 추출하는 용출법을 사용하고 있다(환경부, 2001). 시료내에는 완충 물질이 존재하기 때문에 용출법 사용시 초기 pH 인 1(0.1N HCl)이 유지되지 않아 완충능력이 높은 토양의 경우 현재 국내 공정법상의 용출법이 중금속 오염정도를 추정하는데 적절치 않을 수 있다. (중략)

• Clean Technology
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• v.19 no.2
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• pp.165-172
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• 2013

In this study, the hydrogen chloride removal using K-based dry sorbents ($K_2CO_3/Al_2O_3$, KEPRI, Korea) was studied with varying the pressure in a fixed bed reactor (15 cm tall bed with 0.5 cm I.d.). Working temperature was $400^{\circ}C$ and feed gas concentration was 750 ppm (HCl vol%, $N_2$ balance). The chloride sorption capacity of sorbent increases with increasing pressure (1, 5, 10, 15 and 20 bar). Also, after forming KCl crystal by reaction with $K_2CO_3$ and HCl, owing to the strong bonding energy, sorbent regeneration was practically impossible. Its optical, physical and chemical characterizations were evaluated by SEM, EDAX, BET, TGA and XRD. At $400^{\circ}C$ and 20 bar condition, working condition for the dehalogenation process after gasification, K-based dry sorbent showed high HCl sorption capacity and HCl/$N_2$ separation performances comparing with Ca-based and Mg-based dry sorbents.

• Journal of the Korean Society of Tobacco Science
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• v.18 no.1
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• pp.85-91
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• 1996

Commercially available activated carbon was treated with 0.2N NaOH/0.1N HCl to decrease the ash contents and to analyze the effect of demineralization. We have studied their properties and adsorptivity to solvents such as benzene, acetone, toluene and carbon tetrachloride, ammonia and also aldehydes of cigarette smoke. By demineralization with NaOH/HCl, surface area and pore volume were increased up to 10 - 20% according to developement of micro-pore and pH of activated carbon was also changed from 10.2 to 6.3. Surface acidity of the activated carbon treated with chemicals increased slightly. The chemical treatment led to small increase in adsorptioil properties of solvents, ammonia and aldehydes of cigarette smoke, but content of chlorine and sulfur in activated carbon were reduced. As the results of smoking test, charcoal taste caused by the activated carbon was reduced significantly by the treatment with NaOH/HCl.

• The Korean Journal of Mycology
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• v.23 no.1 s.72
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• pp.53-60
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• 1995

Nutritional requirements for the growth of Flammulina velutipes were studied. Mannitol, glutamic acid and ammonium nitrate were chosen for the maximum mycelial growth when various carbon and nitrogen sources tested. Optimum C : N ratio for the mycelial growth was 20 : 1. Potassium dihydrogen phosphate was selected among the phosphate sources. Magnesium sulphate and thiamine HCl stimulate mycelial growth. Final compositions of optimized chemically defined medium were 1.5% mannitol, 0.082% $NH_4NO_3$, 0.312% glutamic acid, 0.25% $KH_2PO_4$, 0.06% $MgSO_4{\cdot}7H_2O\;and\;0.3\;{\mu}g/l$ thiamin HCl. This medium not only support mycelial growth but also induce fruit body formation.

• Journal of Korean Society of Forest Science
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• v.90 no.1
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• pp.64-73
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• 2001

Generally potassium in the soil can be remained as water soluble, exchangeable, and available types, respectively. Theses types of potassiums are also known to keep their kinetic relationships to each other. The Purpose on this research was to investigate types and relationships of potassium in the soil, and the characteristics of potassium supply in different forest soils. The results could be summarized as follows; 1. The amounts of available potassium in A and B horizon soils by continuous leaching with 0.01N-HCl were as follows : for A Horizon soils, pohang(Gray brown forest soils), Changsung (Brown forest soils), and Youngwol(Dark red forest soils) were ranged from 0.2me/l00g to 0.8me/100g, Taean(Red and Yellow forest soils) was 0.1-0.6me/100g, Kapyung(Brown forest soils) was 0.2-0.4me/100g. For the B layer, Youngwol was 0.1-0.5me/100g, Pohang, Taean, Kapyung were 0.1-0.4me/100g, Changsung was 0.1-0.3me/100g, respectivly. 2. Of ten times-pulse leaching with 0.01N-HCl for A layer soil, more 80% of total available potassium leaching were recovered by the second pulse as leachate for Pohang, Changsung, Youngwol, while similar amounts of potassium in the leachate were obtained with the third pulse leaching for Kapyung, Taean, respectively, On the other hand, the 80 % release of available potassium from the B layer soil was obtained by the second pulse leaching for all areas investigated. 3. For the relationships between soluble potassium and exchangeable potassium, the exchangeable potassium was increased while the soluble potassium was not changed significantly in B layer. And both soluble potassium and exchangeable potassium in A layer were similar. For the relationship between exchangeable potassium and available potassium in both A and B layers, the amounts of available potassium increased by 1.2 to 1.5 times as the exchangeable potassium increased. 4. For distribution of all types of potassium throughout locations investigated, the types of potassium were in the decreasing orders of available, exchangeable, and soluble. 5. The simplified method for an analysis of all types of potassium by sequential leaching with 0.01N-HCl should be developed not only with respect to time-saving and efficiency but also verification of the relationship between available potassium and tree growth.

• Analytical Science and Technology
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• v.12 no.4
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• pp.306-311
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• 1999

Changes of silk protein compositions of average molecular weight (Mw) and free amino acid composition to different solubility conditions were studied by SDS-polyacrylamide electropholesis, gel permeation chromatography (GPC), and free amino acid analysis method. We can not detected average molecular weight distribution of different hydrochloric acid (HCl) conditions as SDS-polyacrylamide method, but as using GPC method, molecular weight distribution of 2N-HCl, 1N-HCl and 0.5N-HCl (3 hrs at $110^{\circ}C$ treated) are confirmed Mw 800, 1,500 and 3,700, respectively. The average molecular weight of calcium chroride and calcium chloride-enzyme treated samples are shown Mw 46,800 and 12,500, respectively. The degree of hydrolysis and the composition of the free amino acid in the fibroin hydrolysates effected significantly composition of free amino acids of the fibroin powder. The increase of the degree of hydrolysis and ratio of free amino acids and oligopeptides were found to be directly related to the concentration of hydrochloric acid and treatment of enzyme, resulting in the increase of water solubility.

• Korean Journal of Environmental Agriculture
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• v.18 no.2
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• pp.109-115
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• 1999

Lead and cadmium were analyzed with different pretreatemnt methods. Paddy soil and wastewater sludge samples were used and the result was compared each other. Pretreatment method affected the concentration obtained from samples significantly. Large difference was illustrated between the results. The concentration by 0.1N HCl extraction method, an official analytical method for soil and solid wastes, was far lower than those by the EPA3050B and mixed-acid digestion methods. The reason might be that metals associated with organics and silicates are not easily extracted by 0.1N HCl, while digestion methods using strong acids and high temperature dissolved all the elements in the samples. It implies that pretreatment method should be specified in addition to concentration on the report of metal analysis for environmental samples. Acid digestion methods are not necessarily good because the concentration obtained does not represent the natural condition which is our concern in many cases. The 0.1N HCl extraction method does not fully represent the natural condition either. The metals associated with organics will be extracted eventually as organics decompose with time. Therefore, proper pretreatment and analytical methods should be developed for specific purpose, and their standardization is recommended.

• Journal of Electrochemical Science and Technology
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• v.11 no.2
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• pp.117-131
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• 2020

The adsorption of N-[(E)-Pyridin-2-ylmethylidene] aniline, a Schiff base, on to mild steel surface in 1M HCl and 0.5 M H₂SO₄ solutions and the consequent corrosion protection were studied employing weight loss method, electrochemical impedance spectroscopy and potentiodynamic polarization measurements. DFT calculations were performed to investigate its interaction with the metal surface at the atomic level to understand its inhibition mechanism. The adsorption process is well described by the Langmuir isotherm. The thermodynamic parameters indicated that the adsorption is spontaneous and the interaction of the inhibitor at the mild steel surface is mainly through physisorption. The R_a values obtained in AFM studies for the uninhibited and inhibited sample in HCl media respectively are 0.756 and 0.559 ㎛, and that in H₂SO₄ media are 0.411 and 0.406 ㎛. The lesser roughness values of the inhibited sample shows the adsorption of the molecules onto the mild surface. The inhibition efficiencies were found to improve with concentration of the inhibitor and the maximum efficiency was observed at 400ppm in all the investigation methods adopted. The inhibitor was found to exhibit a higher efficiency in HCl media (95.7%) than in H₂SO₄ (92.8%). The theoretical and experimental results are found to be in good agreement.

• YAKHAK HOEJI
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• v.34 no.3
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• pp.192-198
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• 1990

Three sugar glass dispersions of sulfamerazine were prepared using dextrose, galactose and sucrose as the carriers, with the ratio of the drug to the carrier was 1:9. The chemical stability of sulfamerazine in the glass dispersion system was studied using TLC. TLC revealed no additional spot and there was good correspondence with the Sulfamerazine itself. While time required to dissolve 50%($T_{50%}$) of sulfamerazine powder was 390 min that of dextrose glass dispersion system was 1.5 min. and galactose system was 4.0 min. in distilled water. 23) $T_{50%}$ of physical mixture with dextrose, galactose and sucrose were 26.4 min., 26.5 min., and 26.0 min. respectively in distilled water. $T_{50%}$ of control was 54 min. and those of all of the glass dispersion systems were within 1 min. in 0.1N HCl. The dissolution rates of sulfamerazine from sugar glass dispersion system in distilled water was greater than that in 0.1N HCl.