• Resources Recycling
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• v.25 no.1
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• pp.48-59
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• 2016

The earth has been warming due to $CO_2$ gas emissions from fossil fuel cars and a ship. So the hydrogen fuel cell vehicle(FCV) using hydrogen as a fossil fuel alternative energy is in the spotlight. Hyundai Motor Company of Korea and a car companies of the US, Japan, Germany is developing a FCV a competitive. Obtained hydrogen as a by-product of the coke plant, oil refineries, chemical plants of steel mill, coal is reacted with steam at high temperatures, methane gas, manufacture of high purity hydrogen Methane Steam Reforming and hydrogen detachable reforming method using the Pressure Swing Adsorption or Membrane Reforming technical or decomposition of water to produce electricity. Hydrogen is the electronic industry, metal and chemical industries, which are used as rocket fuel, etc. are used in factories, hospitals, home of the fuel Ene.Farm system or FCV. And a method of storing hydrogen is to store liquid hydrogen and a method for compressing normal hydrogen to the hydrogen container, by storing the latest hydride or Organic chemical hydride method is used to carry the hydrogen station. Korea is currently 13 hydrogen stations in place and in operation, plans to install a further 43 places.

• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.7
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• pp.858-863
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• 2020

We experimented with the particle-settling velocity and CHCl3 absorption efficiency of seven activated-carbon and analyzed seven heavy metal contents by elution for application to the field treatment of sunken HNS on the marine seabed. The mean particle-settling velocity was in the range 0.5-8 cm/s, except when the 8-20 mesh was used. The larger the HNS particle, the faster the particle-settling velocity was, and the CHCl3 absorption efficiency increased considerably owing to the larger surface area. In addition, the elution test results showed that the total Zn and As contents in >100-meshed activated carbon was higher than the contents criteria for the standard for water-treatment agents, and Cr, Zn, and As were released at higher concentrations than those released by other activated-carbon groups. Taken together, the CHCl3 absorption efficiency, settling velocity, and elution test results suggested that the 20-60, 20-40, and 2mm&down mesh activated-carbon adsorbents could be applied to the field treatment of HNSs and that the minimum required amount for field treatment were 0.82, 0.90, and 1.28 ton/㎘, respectively, as calculated based on the HNS-adsorption-capacity priority.

• Applied Chemistry for Engineering
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• v.33 no.6
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• pp.600-605
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• 2022

In this study, nitrogen oxide (NO_x) removal experiments were performed using a graphene based ceramic filter coated with a V₂O₅-WO₃-TiO₂ catalyst. Graphene oxide (GO) was prepared by Hummer's method using graphite, and the reduced graphene oxide was produced by reducing with hydrazine (N₂H₄). Vanadium (V), Tungsten (W), and Titanium (Ti) were coated by the sol-gel method, and then a metal oxide-supported filter was prepared through a calcination process at 350 ℃. A NO_x removal efficiency test was performed for the catalytic ceramic filters with UV light in a humid condition. When graphene oxide (GO) and reduced graphene oxide (rGO) were present on the filter, the NOx removal efficiency was superior to that of the conventional ceramic filter. Most likely, this is due to an improvement in the adsorption properties of NOx molecules on graphene coated surfaces. As the concentration of graphene increased, higher NO_x removal efficiency was confirmed.

• Ecology and Resilient Infrastructure
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• v.10 no.3
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• pp.64-72
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• 2023

Biopolymer is a versatile material used in food processing, medicine, construction, and soil reinforcement. 𝛽-glucan is one of the biopolymers that improves the soil water content and ion adsorption in a drought or toxic metal contaminated land for plant survival. We analyzed drought stress damage reduction in sweet potatoes (Ipomoea batatas L. cv. Sodammi) by measuring the growth and major protein expression and activity under 𝛽-glucan soil amendment. The result showed that sweet potato leaf length and width were not affected by drought stress for 14 days, but sweet potatoes grown in 𝛽-glucan-amended soil showed an effect in preventing wilting caused by drought in phenotypic changes. Under drought stress, sweet potato leaves did not show any changes in electrolyte leakage, but the relative water content was higher in sweet potatoes grown in 𝛽-glucan-amended soil than in normal soil. 𝛽-glucan soil amendment increased the expression of plasma membrane (PM) H⁺-ATPase, but it decreased the aquaporin PIP2 (plasma membrane intrinsic protein 2) in sweet potatoes under drought stress. Moreover, water maintenance affected the PM H⁺-ATPase activity, which contributed to tolerance under drought stress. These results indicate that 𝛽-glucan soil amendment improves the soil water content during drought and affects the water supply in sweet potatoes. Consequently, 𝛽-glucan is a potential material for maintaining soil water contents, and analysis of the major PM proteins is one of the indicators for evaluating the biopolymer effect on plant survival under drought stress.

• Applied Chemistry for Engineering
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• v.34 no.6
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• pp.612-618
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• 2023

Modern society spends more than 80% of its daily life indoors, emphasizing the need for attention to indoor air pollution due to the improvement in living standards. In this study, the performance and reaction characteristics of the Pt/TiO₂ catalysts prepared by liquid-phase reduction for the removal of formaldehyde (HCHO), one of the indoor air pollutants, at room temperature without the need for additional light or heat were investigated. As a result, it showed that catalysts prepared by the same method showed approximately 40~80% various activities depending on the type of TiO₂. XRD, BET, and XPS analyses were performed to investigate the particle size, crystal structure, specific surface area, and O/Ti molar ratio of the support material, and it revealed that the correlation between the properties and performance was insignificant. To explore the oxidation reaction pathway of formaldehyde (HCHO), in situ DRIFT analysis using carbon monoxide and H₂-TPR was perfomed. The results revealed that the performance was demonstrated by the oxidation state of the active metal and the adsorption-desorption characteristics of the adsorbate species.

• Journal of Korean Society of Environmental Engineers
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• v.37 no.7
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• pp.432-440
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• 2015

Biochar, a by-product from pyrolysis of biomass, is a promising option to mitigate climate change by increasing soil carbon sequestration. This material is also considered to have potential to remediate a soil with heavy metal pollution by increasing the soil's adsorptive capacity. This study conducted the assessment of two biochars considering the climate change mitigation potential and heavy metal removal capacity at the same time. Two kinds of biochars (BC_Ch, TW_Ch) were prepared by pyrolyzing the biomass of burcucumber (BC_Bm) and tea waste (TW_Bm). The soils polluted with Pb were mixed with biochars or biomass and incubated for 60 d. During the incubation, $CO_2$, $CH_4$, and $N_2O$ were regularly measured and the soil before and after incubation was analyzed for chemical and biological parameters including the acetate extractable Pb. The results showed that only the BC_Ch treatment significantly reduced the amount of Pb after 60 d incubation. During the incubation, the $CO_2$ and $N_2O$ emissions from the BC_Ch and TW_Ch were decreased by 24% and 34% compared to the BC_Bm and TW_Bm, respectively. The $CH_4$ emissions were not significantly affected by biochar treatments. We calculated the GWP considering the production of amendment materials, application to the soils, removal of Pb, and soil carbon storage. The BC_Ch treatment had the most negative value because it had the higher Pb adsorption and soil carbon sequestration. Our results imply that if we apply biochar made from burcucumber, we could expect the pollution reduction and climate change mitigation at the same time.

• Journal of the Korean Chemical Society
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• v.39 no.3
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• pp.163-175
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• 1995

Metal free phthalocyanine($H_2Pc$) partially doped with iodine, $H_2Pc(I)x$, has been made to improve photosensitizing efficiency of ZnO/$H_2Pc$. The content of iodine dopant level(x) for $H_2Pc(I)x$ upon $H_2Pc$ polymorphs was characterized as ${\chi}-H_2Pc(I)_{0.92}$ and ${\beta}-H_2Pc(I)_{0.96}$ by elemental analysis. Characterization of iodine-oxidized $H_2Pc$ were investigated by TGA (thermogravimetric analysis), UV-Vis, FT-IR, Raman and ESR (electron spin resonance) spectrum, and the adsorption properties of $H_2Pc(I)x$ on ZnO were characterized by means of Raman and ESR studies. TGA for $H_2Pc(I)x$ showed a complete loss of iodine at approximately 265$^{\circ}C$ and the Raman spectrum of $H_2Pc(I)x$ and ZnO/$H_2Pc(I)x$ at 514.5 nm showed characteristic $I_3^-$ patterns in the frequency region 90∼550 $cm^{-1}$. ZnO/$H_2Pc(I)x$ exhibited a very intense and narrow ESR signal at $g=2.0025{\pm}0.0005$ compared to $H_2Pc$/ZnO. Iodine doped ZnO/$H_2Pc(I)x$ showed a better photosensitivity compared to iodine undoped ZnO/$H_2Pc$. That is, the surface photovoltage of ${\chi}-H_2Pc(I)_{0.92}$/ZnO was approximately 31 times greater than that of ZnO/${\chi}-H_2Pc$ and ZnO/${\beta}-H_2Pc(I)_{0.96}$ was 5 times more efficient than ZnO/${\beta}-H_2Pc$ at 670 nm. And the dependence of photosensitizing effect upon $H_2Pc$ polymorphs was exhibited that the surface photovoltage of ZnO/${\chi}-H_2Pc(I)_{0.92}$ was approximately 5 times greater than ZnO/${\beta}-H_2Pc(I)_{0.96}$ at 670 nm. Therefore Iodine doping of H_2Pc$ resulted in increase in photoconductivity of $H_2Pc$ and photovoltaic effect of ZnO/$H_2Pc$ in the visible region.

• Economic and Environmental Geology
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• v.40 no.3 s.184
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• pp.277-293
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• 2007

Seasonal and spatial variations in the concentrations of trace elements, pH and Eh were found in a creek watershed affected by mine drainage and leachate from several waste rock dumps within the As-Pb-rich Indae mine site. Because of mining activity dating back to about 40 years ago and rupture of the waste rock dumps, this creek was heavily contaminated. Due to the influx of leachate and mine drainage, the water quality of upstream reach in this creek was characterized by largest seasonal and spatial variations in concentrations of Zn(up to $5.830 mg/{\ell}$), Cu(up to $1.333 mg/{\ell}$), Cd(up to $0.031 mg/{\ell}$) and $SO_4^{2-}$(up to $173 mg/{\ell}$), relatively acidic pH values (3.8-5.1) and highly oxidized condition. The most abundant metals in the leachate samples were in order of Zn($0.045-13.909 mg/{\ell}$), Fe($0.017-8.730mg/{\ell}$), Cu($0.010-4.154mg/{\ell}$) and Cd($n.d.-0.077mg/{\ell}$), with low pH(3.1-6.1), and high $SO_4^{2-}$(up to $310 mg/{\ell}$). The mine drainage also contained high concentrations of Zn, Cu, Cd and $SO_4^{2-}$ and remained constantly near-neutral pH values(6.5-7.0) in all the year. While the leachate and mine drainage might not affect short-term fluctuations in flow, it may significantly influence the concentrations of chemicals in the stream. The abundance and chemistry of Fe-(oxy)hydroxide within this creek indicated that the Fe-(oxy)hydroxide formation could be responsible for some removal of trace elements from the creek waters. Spatial and seasonal variations along down-stream reach of this creek were caused largely by the influx of water from uncontaminated tributaries. In addition, the trace metal concentrations in this creek have been decreased nearly down to the background level at a short distance from the discharge points without any artificial treatments after hydrologic mixing in a tributary. The nonconservative(i.e. precipitation, adsorption, oxidation, dissolution etc.) and conservative(hydrologic mixing) reactions constituted an efficient mechanism of natural attenuation which reduces considerably the transference of trace elements to rivers.

• Analytical Science and Technology
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• v.29 no.3
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• pp.114-125
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• 2016

In this study, 165 wastewater discharge facilities in 10 business types were investigated with regard to 24 specific hazardous substances that included heavy metals, VOCs, CN, and phenol in the Gwangju city. Cu in the range from from 0.008 to 35.420 mg/L was detected in all business types and the detection rate was 46.8 %. Other heavy metals, such as Cd, As, Hg, Pb, and Cr⁺⁶ were detected as well. However, their detection rates ranged between 0.6 and 1.8 %. CN and phenol were detected in one and five facilities, respectively. 12 species of VOCs were detected: chloroform 80.6 % (0.42 to 81.60 μg/L), benzene 16.4 % (1.49 to 3.31 μg/L), trichloroethylene 11.5 % (1.78 to 6.02 μg/L), 1,1-dichloroethylene 10.3 % (1.23 to 5.89 μg/L), and dichloromethane 8.5 % (0.28 to 968.86 μg/L) in the detection rate order. The concentration of VOCs was detected in trace amounts, except for dichloromethane that exceeded the effluent quality standard in three business types, namely, metal manufacturing, food industry, and car washing facility. Chloroform was detected in all business types, where 24.88 μg/L were detected in the laundry business and 53.41 μg/L in the water supply business; the mean concentration of chloroform in these two business types was higher than elsewhere. Therefore, for the disposal of non-degradable specific hazardous substances in industrial wastewater, it is necessary to introduce physical and chemical processes, such as activated carbon adsorption, fenton oxidation, ozone treatment, as well as photocatalyst and the UV radiation.

• Journal of the Mineralogical Society of Korea
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• v.27 no.4
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• pp.301-310
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• 2014

To investigate the role of fault gauge in the behavior of heavy metals caused by the acid rock drainage in the area of pyrite-rich andesite, XRD, pH measurement, XRF, SEM-EDS, ICP, and sequential extraction method were used. Bed rock consists of quartz, pyrophyllite, pyrite, illite, and topaz, but the brown-colored fault gouge is composed of quartz, illite, chlorite, smectite, goethite, and cacoxenite. The mineral composition of bed rock suggests that it is heavily altered by hydrothermal activity. The concentrations of heavy metals in the bed rock are as follows, Zn > As > Cu > Pb > Cr > Ni > Cd, and those in fault gouge are As > Zn > Pb > Cr > Cu > Ni > Cd. The concentrations of the heavy metals in the fault gouge are generally higher than those in the bed rock, especially for Pb, As, and Cr, which were more than twice as those in the bed rock. It is believed that the difference in the amount of heavy metals between the bed rock and the fault gouge is mainly due to the existence of goethite which is the main mineral composition in the fault gouge and can play important role in sequestering these metals by coprecipitation and adsorption. The low pH, caused by oxidation of pyrite, also plays significant role in fixation of those metals. It is confirmed that the fractions of labile (step 1) and acid-soluble (step 2), which can be easily released into the environment, were higher in the bed rock. Those fractions were relatively low in fault gauge, suggesting that fault gauge can play important role as a sink of heavy metals to prevent those ones from being released in the area where the acid rock drainage can have an influence.