• Economic and Environmental Geology
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• v.54 no.6
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• pp.709-716
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• 2021

In this study, an adsorbent prepared by natural drying of iron hydroxide-based sludge collected from settling basin at a mine drainage treatment facility located in Gangneung, Gangwon-do was used to remove fluoride in an artificial fluoride solution and mine drainage, and the adsorption characteristics of the adsorbent were investigated. As a result of analyzing the chemical composition, mineralogical properties, and specific surface area of the adsorbent used in the experiment, iron oxide (Fe₂O₃) occupies 79.2 wt.% as the main constituent, and a peak related to calcite (CaCO₃) in the crystal structure analysis was analyzed. It was also identified that an irregular surface and a specific surface area of 216.78 m²·g^-1. In the indoor batch-type experiment, the effect of changes in reaction time, pH, initial fluoride concentration and temperature on the change in adsorption amount was analyzed. The adsorption of fluoride showed an adsorption amount of 3.85 mg·g^-1 16 hours after the start of the reaction, and the increase rate of the adsorption amount gradually decreased. Also, as the pH increased, the amount of fluoride adsorption decreased, and in particular, the amount of fluoride adsorption decreased rapidly around pH 5.5, the point of zero charge at which the surface charge of the adsorbent changes. Meanwhile, the results of the isotherm adsorption experiment were applied to the Langmuir and Freundlich isotherm adsorption models to infer the fluoride adsorption mechanism of the used adsorbent. To understand the thermodynamic properties of the adsorbent using the Van't Hoff equation, thermodynamic constants 𝚫H° and 𝚫G° were calculated using the adsorption amount information obtained by increasing the temperature from 25℃ to 65℃ to determine the adsorption characteristics of the adsorbent. Finally, the adsorbent was applied to the mine drainage having a fluoride concentration of about 12.8 mg·L^-1, and the fluoride removal rate was about 50%.

• Journal of the Korean Society of Costume
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• v.35
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• pp.45-66
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• 1997

This thesis is a study on the kaftan styles iin Asia. The purpose of he study was to examine the origin o the kaftan concentrating on the history and cultural backgrounds of nomads in he Western Central and North Eastern Asia. Secondly for more thorough study and expla-nation on how these kaftans contributed to East-West trade along the silk road. wall paintings and miniature illuminations along Oasis roads persia and Saracen period were compared, Also real kaftans were compared and analyzed the characteristics of Western (Turkey palestine) Central(Kazakistan Uz-bekistan Tadzhistan Qyrgyztan Turkmenistan) and the North Eastern Asian(Mongol) area. Thirdly an attempt has been made to provide the North Eastern Asian(Mongol) area. Thirdly an attempt has been made to provide the style classifications according to their peculiarities of the various kaftans as well as how kaftan gave important influences on custumes of different religious sects. The kaftan is a long coat-like garment with front openings fastened with long sash having an extra long sleeves which were worn by middle and high class nomadics throughout the West Central and North Eastern Asia This type of kaftans were a basic clothing for nomadics since they were constantly moving fromone to another areas on their horse back riding. They also wore tight trousers with boots. Kaftans seem to be originated from nomads of Steppe around B.C. 800 On B. C 400 west asian areas such as Solokha Kul-oba Kulogan had pictures sculptues on vases showing kaftans of half coat type length with front opening tied with band. Also the materials used were the products of animals such as wool or felt with animal designs showing Scythian nomads. In the North Eastern Asia Hsiung-Nu were active in Kazakha North Altai and Mongol The Clothing and fabrics exfavated near Noin-ula Pazyrik showed many samples of kaftan with trousers with other interment be-longings with a corpse around B.C 300 to A. D 100 when trades along the silk roads were proven by many historians Kaftans excavated in this area wore red front opening silk materials which suggesting settling down of nomads. in he central Asia Dol-gull near Altai mountain area were mainly miners who later had many trades with Persia and Bizantine. After Dol-gull Bezeklik temple Samarkant Kizil cow Budda sculture wall paintings of Astana tomb showed typical kaftan of this re-gion. These were both hip covered length as well as long coat with narrow sleeves. Es-pecially they had different color band fron the main kaftan with grogeously and splendously designed silk. In perusia during A. D 1400 to 1600 minia-ture illumination showed kaftan as a high class symbol more than clothing purpose. They had best quality silk with extra long sleeves draping and had a layers of kaftans one on top of anther as a symbol of wealth These Kaftans with different colors and designs were even more beautiful with their effective combinations and contrast of colors. On the other hand the lower class common people and servants wore simple kaftan with the front part of the kaftan were slipped into the belt in order to be more active and con-venient to work, The real kaftans discovered at Topkapi Saray palace of Turkey from A. D 1300 to 1900 were also compared. These kaftans were very numerous in numbers as well as designs The materials and designs used were also vari-ous such as Chinese to Italian silk. The shaped and pattern itself were not much different from the previous nomad's Kaftans. The Palestian kaftans remained were from the beginning of 19th and 20th century. Since this area is hot and dry desert they used black and navy blue colors mostly in order to exclude the sun lights. The patterns used were similar to Nomads and Bedouin with cross stiches and patch work decorations. In the central Asia they had similar life style and natural environmental cnditions with Turkish tribe which resulted in similar kaftan styles as nomads. Mongols conserved basic patterns of kaftan since Cinggis Khan with deep folding in order to keep warm. At last the kaftans studided in this thesis were classified in to four such as half coat long coat jacket and vest style. A pattern used in the Central Asia were zigzag and ani-mal design whereas in the West Asia were floral plant arabesk and circle pattern. As I discussed previously kaftan styles of nomads in the Asia maintained its basic pat-tern throughout the history except slight changes in color gusset sleeve shapes. These slight changes were made according to the need to adapt the need of environmental natu-ral conditions, The reason for aboriginality of kaftan in Asia was its simplicity and con-venience Most interesting fact is that for all these years Mongols are still wearing kaftan in their life ensuring us that they art the preserves of old kaftan. Since this thesis dealt enormous Asian regions I had a limitation of not being able to cover the Far Esatern asian areas such as Korea China and Japan how these kaftans were influenced in their clothing history as well as Eastern and Western culture. This topic along with the studies on materials and designs of patterns of kaftan will be another research project in the future.

• Journal of Korean Society on Water Environment
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• v.22 no.6
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• pp.1101-1106
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• 2006

Many BNR (Biological Nutrient Removal) plants have experienced a bulking problem, mainly due to the growth of filamentous organisms, particularly during the winter months. This study investigated the problem of bulking due to the growth of M. parvicella both at a full-scale municipal wastewater treatment plant and a pilot scale plant located in the C city. The full-scale facility was operated at a flow rate of $51,000m^3/d$, an F/M (Food-to-Microorganism) ratio of 0.12 kgBOD/kgMLVSS/d and an SRT (Solids Retention Time) higher than 25 days, respectively. This plant experienced bulking and foaming problems at low temperatures below $15^{\circ}C$ since it was retrofitted with the BNR system in 2003. The pilot plant employed had an identical process configuration as the full scale one and used the same wastewater source. It was operated at a flow rate of $3.8m^3/d$, temperatures between 10 to $25^{\circ}C$ and SRTs between 10 and 25 days. At full scale, the M. parvicella growth and SVI (Sludge Volume Index) patterns were studied in conjunction with temperature variations. At pilot scale, DO and SRT variations were also explored, in addition to the filamentous bacteria growth and SVI patterns. During the full-scale investigation, over a 3 year period, it was noted that the SVI was maintained within acceptable operational values (i.e. under 160) during the summer months. Moreover settling in the secondary clarifiers was good and was not affected by the presence of M. parvicella. In contrast, at low mean temperatures during winter, the SVI increased to over 300. Overall, as the temperature decreased, the predominance of M. parvicella became apparent. According to this study, M. parvicella growth could be controlled and SVI could drop under 160 by a change in operational conditions which involved an increase in DO concentration between 2 and 4 mg/L and a decrease in SRT to less than 20 days.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.1B
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• pp.51-60
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• 2006

Water quality improvement in mattress/filter system using porous material like slag from industrial activity and zeolite that has been studied for environment improvement and pollution abatement is very useful in polluted stagnant stream channel. Slag is consisted of CaO, $SiO_2$, $Al_2O_3$ and $Fe_2O_3$. Slag with large specific surface area of porosity has been used such as sludge settling and adsorptive materials. Because slag is porous, it can be used for purification filter. As slag is used as filled materials of mattress/filter system and the system has good advantages for the waste water treatment, water recycling, and the improvement of water quality at the same time and so on. Because zeolite has much advantage of cation exchange, adsorption, catalyst and dehydration characteristics, It is used for environment improvement of livestock farms, treatment of artificial sewage and waste water, improvement of drinking water quality, radioactive waste disposal and radioactive material pollution control. In this study, according to verifying effects of water quality improvement of fill materials by porosity that 38.6%, 45.8% and 49.8% respectively in the stagnant stream channel, water quality monitoring of inflow and outflow was conducted on pH, DO, BOD, COD, SS, T-N and T-P. Mattress/filter system was able to accelerate water quality improvement by biofilter as waste water flows through gap of mattress/filter fill materials and by contact catalysis, absorption, catabolism by biofilm. Mattress/filter system used slag and zeolite forms biofilm easily and accelerates adsorption of organic matter. As a result, mattress/filter system increases water self-purification and accelerates water quality improvement available for stream water clean-up.