• Applied Science and Convergence Technology
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• v.25 no.6
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• pp.162-165
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• 2016

APhotocatalysis process uses ambient oxygen from air and irradiation, fundamentally UV light, to generate oxidation and reduction which can degrade almost all harmful organic and inorganic compounds to nontoxic substances. This study was focused on enhancement of photocatalytic activity which improves the photocatlytic efficiency with $TiO_2$ particle by mixing of certain amounts of Zn particles. We analyzed degradation of organic pollutant materials such as toluene and phenol with the mixed photocatalysis by using UV-visible spectrophotometer and obtained a result that photocatalytic activity is increased with increasing amount of Zn particle. Especially, in the case of $TiO_2$ (1 mmol) and Zn (0.1 mmol) mixture photocatalyst, we obtained at least 2 times higher photocatalytic activity compared with the commercially available $TiO_2$ photocatalyst (Degussa P-25), indicating that our mixed photocatalyts (Zn-doped $TiO_2$) is very effective of removing both organic dye and pollutants and the conversion rate of toluene is much faster than that of phenol.

• Journal of the Korean Society of Safety
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• v.19 no.1
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• pp.81-87
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• 2004

Composite particles using inorganic and organic chemicals were synthesized and the results of those reaction were compared to variation of temperature and agitation speed in presence of $CaCO_3$ which was adsorbed SDBS. Also the synthesises were optimized according to conversion rate of composite particles. In inorganic/organic core-shell composite particle polymerization, $CaCO_3$ adsorbed by 0.5wt% surfactant SDBS was prepared initially and then core $CaCO_3$ was encapsulated by sequential emulsion polymerization using MMA at the addition of APS 3.16${\times}$$10^{-3}$mol/L to minimize the coagulated PMMA particle itself during MMA shell polymerization. Encapsulated PMMA on $CaCO_3$ as inorganic/organic core-shell particles was verified by FT-IR and DSC analysis. It was found that the $CaCO_3$ was very well encapsulated by PMMA as shell. The surfaces were distinctly found as spindle shape and broad particle distribution after capsulation.

• Journal of Wetlands Research
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• v.9 no.3
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• pp.1-12
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• 2007

In this study, the correlation of organic content with particle size and type of sediment was found out.Particle size, stratigraphic section and organic content of sediments sampled from Dalpo wetland was analyzed. Dalpo wetland consists of three wetlands, and the area of Dalpo wetland is about $31,295m^2$. The particle size analyses for sampled sediments of 7 points (3 points in wetland A, 3 points in wetland B and 1 point in wetland C) were tested. As results of the particle size analyses, the sediment particle size becomes larger as to the edge of the wetland. It is revealed in order of wetland A > wetland C > wetland B. Borehole surveys with horizontal distance in the major and minor axes of wetland A, the major and minor axes of wetland B and the major axis of wetland C were accomplished. Clayey peat deposit is distributed at 10~90 cm depth below ground surface in the major axis of wetland A. The clayey peat deposit was the most thick at the center of wetland A that horizontal distance is 100 m. As the depth below ground surface of clayey peat deposit is less than 27 cm in the wetland B, we can infer that the life for the wetland B is being finished. Sediment composition of wetland C is simple because wetland C is small scale, and clayey peat deposit is distributed at 10~34 cm depth below ground surface. Sediment sampled by borehole survey in the Dalpo wetland was cut at interval of 10 cm, then organic content was analyzed. Organic content of wetland A sediment showed more than 40% until 70 cm depth below ground surface, also sediment of wetland B is similar to wetland A until 10 cm depth below ground surface, but is showed within 20 % above 30 cm depth below ground surface. Organic content of wetland B is showed the lowest as organic content near the ground surface is about 40%. All of the three wetlands, organic content is showed higher at clayey peat deposit near to ground surface. This is caused by finer particles of the clayey peat deposit, also organic materials were supplied from dead vegetation. Organic content of the Dalpo wetland showed in order of wetland A > wetland C > wetland B. This result is caused by thickness of clayey peat deposit in sediment. Through this study, it was verified that organic content of the Dalpo wetland sediment was dominated by particle size of sediment and vegetation of the upper part.

• Journal of Korean Society on Water Environment
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• v.20 no.6
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• pp.708-713
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• 2004

This study was performed to investigate the variations of hydrophilic and hydrophobic organic matter fractions in soluble organic matter according to livestock wastewater treatment by ionized gas and coagulation effect to these fractions after ionized gas contact. As a result of experiment, because of ionized gas contact, particle in the surface of livestock wastewater was more smaller and the result was consisted of particle size analysis and the amount of small size was increased. Also, we confirmed that organic matters in livestock wastewater by ionized gas contact were removed. The relation equation between ionized gas contact time(X) and $TCOD_{cr}$(Y) was shown as yscale(y)=3.748-0.431* xscale(X). That between ionized gas contact time(X) and $TCOD_{cr}$(Y) was yscale(y)=3.283-0.463* xscale(X). As respects the HPL(hydrophilic matter)and HPO(hydrophobic matter) fractions of raw in livestock wastewater treatment plant, HPL fraction was 53.2% and HPO fraction was 46.8%. But, HPO fraction according to ionized gas treatment was increased at 30min and after that time, HPL fraction was increased. Also, when we performed coagulation process after ionized gas treatment of raw wastewater, the removal efficiency of organic matter was the highest at 30min of ionized gas treatment because of the variation of HPL and HPO fractions in organic matter by ionized gas. In coagulation process following after ionized gas process, HPO was removed more effective than HPL.

• International Journal of Safety
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• v.11 no.1
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• pp.15-18
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• 2012

Because of development of printing technology, toner cartridge particle becomes smaller and more dangerous. And sometimes we had incidents with dust explosion of toner cartridge particle at recycling facilities in Japan. Therefore we studied on hazard of toner particle relating with dust explosion. We found that toner particle is so dangerous compared with most organic solids, even though it does not belong to hazardous materials in the UN regulation and the Japanese Fire Service Law.

• Journal of the Korean Graphic Arts Communication Society
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• v.14 no.2
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• pp.81-99
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• 1996

The characteristics of printing inks are affected, to a greater or lesser extent, by the size and distribution of the pigment particles in the dispersion. Color strength, transparency and gloss increase with a decrease in particle size of pigments and with an increase in surface area of pigments. On the contrary, opacity and lightfastness tend to increases with an increase in particle size of pigments and with a decrease in surface are and particle size if pigments on the physical properties of printing ink which made up vehicles for sheet fed and organic pigment Lake Red C(C.I Pigment Red 53:1) that different surface area and particle size.

• Journal of Environmental Health Sciences
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• v.20 no.4
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• pp.45-52
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• 1994

This study was performed to investigate the contents of six heavy metals (Cd, Cr, Cu, Ni, Pb and Zn) with respect to the particle sizes and depths in sediment collected at nine sites of the lower Kumho river. The mean Cd, Cr, Cu, Ni, Pb and Zn contents in sediment of all sites ranged from 1.59~5.32 mg/kg, 17.4~301.7 mg/kg, 23.2~399.9 mg/kg, 9.48~116.8 mg/kg, 31.1~294.1 mg/kg and 74.2~964.3 mg/kg, respectively. The highest heavy metal contents was generally found to be Zn and lowest was Cd. The mean contents of heavy metal by particle sizes (1.0~0.5, 0.5~ 0.25, <0.25 mm)was the highest in particle sizes less than 0.25 mm, but the coefficients of variation was lowest in particle sizes less than 0.25 mm. Mean contents and coefficient of variation by depths (0~5 cm, 5~10 cm, 10~15 cm) were generally found to be higher in the upper parts of sediment than in the lower parts of sediment. Organic substances were found to be higher as the particle sizes become more small. Moreover, contents of heavy metal increased with the amounts of organic substances in sediment.

• Journal of Korean Society for Atmospheric Environment
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• v.21 no.6
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• pp.639-647
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• 2005

A single particle analytical technique, named low-Z particle electron probe X-ray microanalysis (EPMA), was applied to characterize samples collected at a subway station and ambient samples in Seoul. According to their chemical composition, many distinctive particle types were identified. For samples collected at the subway station platform, the major chemical species are carbon-rich, organic, aluminosilicates (AlSi), AlSi/C, AlSi/$CaCO_{3},\;CaCO_{3},\;SiO_{2},\;and\;Fe_{2}O_{3}$. For outdoor samples, carbon-rich, organic, AlSi, $CaCO_{3},\;SiO_{2},\;NaNO_{3},\;(Na,Mg)NO_{3},\;Na(CO_{3},NO_{3},SO_{4}),\;and\;(NH_{4})_2SO_4$, are abundantly encountered. Samples collected at the subway station show very high contents of $Fe_{2}O_{3}$, both in coarse and fine fractions, which come from brake block, subway train wheel, electric contact materials, etc. It is demonstrated that the single-particle characterization using this low-Z particle EPMA technique provided detailed information on various types of chemical species in indoor and outdoor samples.

• Journal of Korean Society for Atmospheric Environment
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• v.20 no.6
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• pp.823-832
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• 2004

Atmospheric aerosol particles collected in Seoul on four single days, each in every seasons of 2001, were characterized and classified on the basis of their chemical species using low-Z particle electron probe X-ray microanalysis (low-Z particle EPMA). Low-Z particle EPMA technique can analyze both the size and the chemical species of individual aerosol particles of micrometer size and provide detailed information on the size distribution of each chemical species. The major chemical species observed in Seoul aerosol were aluminosilicate, silicon dioxide, calcium carbonate, organic, carbon-rich, marine originated, and ammonium sulfate particles, etc. The soil originated species, such as aluminosilicate, silicon dioxide, and calcium carbonate were the most popular in the coarse fraction, meanwhile, carbonaceous and ammonium sulfate were the dominant species found in the fine fraction. Marine originated species such as sodium nitrate was frequently encountered, up to 30% of the analyzed aerosol particles.

• Journal of Korean Society of Water and Wastewater
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• v.20 no.5
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• pp.719-726
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• 2006

Adsorption isotherms and kinetics for taste and odor (T&O) compounds and natural organic matters (NOMs) were performed to evaluate the impacts of activated carbon particle size on coagulation and adsorption. Adsorption capacities for iodine, T&O compounds, and NOM of all the activated carbons under #325 mesh were more excellent than those of virgin activated carbons. Small activated carbon particles were more rapidly adsorbed low molecular weight T&O compounds in the water, while those were slowly adsorbed high molecular weight NOM. When the activated carbon and alum were added simultaneously, the adsorption capacity for organics was better than alum was added alone.