• Journal of the Korean Society of Environmental Restoration Technology
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• v.8 no.1
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• pp.45-51
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• 2005

Total phosphorus(TP) removal was examined in a surface-flow wetland constructed in April 2003 during its initial operating stage from June to November 2003. Its dimensions were 87mL by 14mW. It was a part of a four-wetland-cell treatment system constructed near the Kohung Estuarine Lake located in the southern part of Korea. Effluent from a night soil treatment plant was discharged into the wetland and purified effluent from the wetland was discharged into Sinyang Stream flowing into the Lake. Cattails(Typha angustifolia ) from natural wetlands were cut at about 40 cm height and transplanted into the wetland. An average of 25.0$m^3$/day of effluent flowed from the plant into the wetland. Water depth was maintained about 0.2m and hydraulic detention time was about 5.2 days. Average heights of the cattail stems in June and October 2003 were 47.2 and 164.6cm, respectively. The average number of stems was 10.2 stems/$m^2$ in June 2003 and 18.8 stems/$m^2$ in October 2003. Average temperature of influent and effluent ranged 23.4 and $24.2^{\circ}C$, respectively. The average TP concentrations of influent and effluent were about 1.31, 0.50mg/L, respectively. TP loading rate of influent into the wetland averaged 26.81mg/$m^2$, day and average TP loading rate of effluent was 10.04mg/$m^2$, day. Monthly average TP removal by the wetland during the warm growing season of cattails(June to September) ranged 16.28~19.57mg/$m^2$, day and during the cold senescent period (October to November) ranged 12.62~13.90mg/$m^2$, day. TP removal in the wetland continued during the cold winter months and was primarily done by sedimentation and precipitation of phosphorus rather than phosphorus absorption by cattails and microorganisms.

• Korean Journal of Environmental Agriculture
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• v.22 no.4
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• pp.251-254
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• 2003

Phosphorous removal rate and emergent plant growth were examined of a surface-flow constructed treatment wetland system, whose dimensions were 31 meter in length and 12 meter in width. The system was established on floodplain in the down reach of the Kwangju Stream in Korea in one and half months from May to June 2001. Cattails(Typha angustiflora) were transplanted in the system. They were dug out of natural wetlands and stems were cut at about 40 cm height from their bottom ends. Water of the Kwangju Stream were funneled into it via a pipe by gravity flow and its effluent were discharged back into it. The stems of cattails grew from 45.2 cm in July 2001 up to 186 cm in September 2001 and the number of cattail stems per square meter increased from 22 in July 2001 to 53 in September 2001. The early establishment of cattails was good. Volume and water quality of inflow and outflow were analyzed from July 2001 through December 2001. Inflow averaged $40\;m^3/day$ and hydraulic retention time was about 1.5 days. The concentration of total phosphorous in influent and effluent was 0.85 mg/L, 0.41 mg/L, respectively. The average removal rate of total phosphorous in the system was about 52%. The retention efficiency was slightly lower, compared with that in surface-flow wetlands operating in North America, whose retention efficiency was reported to be about 57%. The lower abatement rate could result from the initial stage of the system and inclusion of two cold months into the six-month monitoring period. Root rhizosphere in wetland soils and litter-soil layers on bottoms were not properly developed. Increase of standing density of cattails within a few years will establish both root zones and substrates beneficial to the removal of phosphorous, which may lead to increase of the phosphorous retention rate. The system was submerged one time by heavy storm during the monitoring period. The inundation, however, scarcely disturb its environment.

• Journal of Soil and Groundwater Environment
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• v.16 no.2
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• pp.6-11
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• 2011

In this report, we provide experimental evidence that heavy metal ions could be removed using Pachymeniopsis sp., particularly soluble arsenic in leachate from soil contaminated by arsenic. We performed pilot scale of soil washing process based on our results. The adsorption of arsenic by Pachymeniopsis sp. indicated that it could be described with the Langmuir Model and the maximum adsorption capacity increased with decreasing pH (pH 3: 102.48 mg/g, pH 5: 98.32 mg/g, pH 7: 57.70 mg/g, pH 9: 43.34 mg/g) and increasing temperature (10$^{\circ}C$ : 60.38 mg/g, 20$^{\circ}C$ : 76.39 mg/g, 30$^{\circ}C$ : 112.12 mg/g). Our results revealed that soluble arsenic in leachate was removed from 24.03 mg/L to 0.6 ${\pm}$ 0.1 mg/L by Pachymeniopsis sp. for 48hours on pilot scale of soil washing process.

• Journal of the Korean Ceramic Society
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• v.45 no.11
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• pp.651-657
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• 2008

In this study, CNT/$TiO_2$ composites were prepared using surface modified Multiwall carbon nanotube (MWCNT) and titanium n-butoxide (TNB) with benzene. The composites were characterized by nitrogen adsorption isotherms, scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive X-ray analysis (EDX), FT-IR spectra, and UV-vis absorption spectroscopy. The UV radiation induced photoactivity of the CNT/$TiO_2$ composites was tested using a fixed concentration of methylene blue (MB, $C_{16}H_{18}N_3S{\cdot}Cl{\cdot}3H_2O$) in an aqueous solution. Finally, it can be considered that the MB removal effect of the CNT/$TiO_2$ composites is not only due to the adsorption effect of MWCNT and photocatalytic degradation of $TiO_2$, but also to electron transfer between MWCNT and $TiO_2$.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.33 no.5
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• pp.448-454
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• 2000

This study was to examine the physicochemical characteristics of coagulation reaction between ignited oyster shell powder (IOSP) and red tide organisms (RTO), and its feasibility, in developing a technology for the removal of RTO bloom in coastal sea,IOSP was made from oyster shell and its physicochemical characteristics were examined for particle size distribution, surface characteristic by scanning electron microscope, zeta potential, and alkalinity and pH variations in sea water. Two kinds of RTO that were used in this study, Cylindrotheca closterium and Skeletonema costatum, were sampled in Masan bay and were cultured in laboratory. Coagulation experiments were conducted using various c(Incentrations of IOSP, RTO, and a jar tester. The supernatant and RTO culture solution were analyzed for pH, alkalinity, RTO cell number, IOSP showed positive zeta potentials of $11.1{\~}50.1\;mV\;at\;pH\;6.2{\~}12.7$, A positive zeta potential of IOSP slowly decreased with decreasing pNa 4,0 to 2,0. When pNa reached zero, the zeta potential approached zero, When a pMg value was decreased, the positive zeta potential of IOSP increased until pMg 3.0 and decreased below pMg 3.0. IOSP showed 4.8 mV of positive zeta potential while RTO showed -9.2 mV of negative zeta potential in sea water. A positive-negative EDL (electrical double-layer) interaction occurred between $Mg(OH)_2$ adsorption layer of IOSP and RTO in sea water so that EDL attractive force always worked between them. Hence, their coagulation reaction occurred at primary minimum on which an extreme attractive force acted because of charge neutralization by $Mg(OH)_2$ adsorption layer of IOSP. As a result, the coagulation reaction was rapidly processed and was irreversible according to DLVO (Deriaguin-Landau-Verwey-Overbeek) theory. Removal rates of RTO were exponentially increased with increasing both IOSP concentration and G-value. The removal rates were steeply increased until 50 mg/l of IOSP and reached $100{\%}\;at\;400\;mg/l$ of IOSP. Removal rates of RTO were $70.5,\;70.5,\;81.7,\;85.3{\%}$ for G-values of $1,\;6,\;29,\;139\;sec^(-1)$at IOSP 100 mg/l, respectively. This indicated that mixing (i.e., collision among particles) was very important for a coagulation reaction.

• Proceedings of the Materials Research Society of Korea Conference
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• 2011.05a
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• pp.34.2-34.2
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• 2011

The demand for Ru has been increasing in the electronic, chemical and semiconductor industry. Chemical mechanical planarization (CMP) is one of the fabrication processes for electrode formation and barrier layer removal. The abrasive particles can be easily contaminated on the top surface during the CMP process. This can induce adverse effects on subsequent patterning and film deposition processes. In this study, a post Ru CMP cleaning solution was formulated by using sodium periodate as an etchant and citric acid to modify the zeta potential of alumina particles and Ru surfaces. Ru film (150 nm thickness) was deposited on tetraethylorthosilicate (TEOS) films by the atomic layer deposition method. Ru wafers were cut into $2.0{\times}2.0$ cm pieces for the surface analysis and used for estimating PRE. A laser zeta potential analyzer (LEZA-600, Otsuka Electronics Co., Japan) was used to obtain the zeta potentials of alumina particles and the Ru surface. A contact angle analyzer (Phoenix 300, SEO, Korea) was used to measure the contact angle of the Ru surface. The adhesion force between an alumina particle and Ru wafer surface was measured by an atomic force microscope (AFM, XE-100, Park Systems, Korea). In a solution with citric acid, the zeta potential of the alumina surface was changed to a negative value due to the adsorption of negative citrate ions. However, the hydrous Ru oxide, which has positive surface charge, could be formed on Ru surface in citric acid solution at pH 6 and 8. At pH 6 and 8, relatively low particle removal efficiency was observed in citric acid solution due to the attractive force between the Ru surface and particles. At pH 10, the lowest adhesion force and highest cleaning efficiency were measured due to the repulsive force between the contaminated alumina particle and the Ru surface. The highest PRE was achieved in citric acid solution with NaIO4 below 0.01 M at pH 10.

• Environmental Engineering Research
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• v.22 no.2
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• pp.203-209
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• 2017

Innovations in the biofiltration process can provide effective solutions to overcome crucial water pollution problems. The elimination of pollutants is a result of the combined effects of biological oxidation, adsorption and filtration processes. This research aims to evaluate the performance of quartz sand biofiltration for removing total suspended solids, turbidity, color, organic matter, and ammonium from polluted river water and develop an empirical model for designing quartz sand biofilters for the treatment of polluted river water. Experiments were conducted using two biofilter units filled with quartz sand as filter media. A set of experiments were performed to evaluate the effect of hydraulic retention time on biofilter performance in removing water contaminants. The kinetics of organic matter removal were also determined to describe the performance of the biofilter. The results show that biofiltration can significantly remove river water pollutants. Removal efficiency depends on the applied hydraulic retention time. At a hydraulic retention time of two hours, removal efficiencies of total organics, ammonium and total suspended solids were up to 78%, 82%, and 91%, respectively. A model for designing quartz sand biofiltration has been developed from the experimental data.

• Journal of Environmental Health Sciences
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• v.23 no.2
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• pp.57-63
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• 1997

This study was carried out to find the adverse health effects of ozone by papers, the potential indoor sources of ozone by papers, and then the removal mechanism of ozone by experiments. The exposure of individuals to excessive levels of ozone both in the industrial and ambient environment is a continuing public health concern. Ozone indoors may play a role in generating secondary pollutants that may have adverse health effects. The removal efficiency of ozone was studied by (1) the effect of concentration on breakthrough time, (2) the effect of flow rate on breakthrough time, (3) the effect of adsorbent's weight on breakthrough time, (4) the effect of temperature on breakthrough time, (5) the application of Langmuir's isotherm equation in using activated carbon. The followings are the conclusions that were derived from this study. 1. In the effect of concentration on breakthrough time, the adsorption capacity of activated carbon was inversely proportional to ozone concentratuion (0.1, 0.2, 0.3 ppm). 2. In the effect of flow rate on breakthrough time, the service life of activated carbon was inversely proportional to flow rate (2, 8, 14l/min). 3. The difference in removal efficiency of ozone between weights(100 mg and 150 mg) was seen. And when weight of activated carbon was 100 mg and 150 mg, pressure loss was 4-5mmHg and 6-7mmHg, respectively. It is required to study relations among flow rate and adsorbent's weight and ventilation quantity, too. 4. Generally, Langmuir's equation, one of the oldest and most used frequently isotherm equation, applies to chemisorption. In case of ozone, when the weight of activated carbon was 70 mg and temperature 40, slope(1/a) was $6.25\times 10^{-1}$ and intercept(1/ab) was $1.9\times 10^{-4}$ (average r=0.94).

• Korean Journal of Environmental Agriculture
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• v.32 no.2
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• pp.108-116
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• 2013

BACKGROUND: Certain crop-based waste materials have been recognized as cost-effective and highly efficient adsorbents for removal and recovery of different kind of heavy metals from aqueous solutions. The ability is strongly attributed to the carboxyl functional group of some pectin substances such as galacturonic acid often found in fruit peels. The present manuscript was aimed at assessing the potential applicability of banana peel for metal removal from contaminated waters. METHODS AND RESULTS: As revealed by laboratory investigations, banana peel contains pectin (10-21%), lignin (6-12%), cellulose (7.6-9.6%), and hemicelluloses (6.4-9.4%). The pectin extraction is reported to have glucose, galactose, arabinose, rhamnose, xylose, and galactouroninc acid. Several studies conducted under different conditions proved that banana peel is capable of adsorbing 5.71, 2.55, 28.00, 6.88, 7.97, and 5.80 mg/g of $Cd^{2+}$, $Co^{2+}$, $Cu^{2+}$, $Ni^{2+}$, $Pb^{2+}$, and $Zn^{2+}$, respectively, from aqueous solutions. Adsorption capacity is, however, dependent upon several factors including solution pH, dose of adsorbent and metal concentration, contact time and shaking speed. CONCLUSION(S): Since the annual world production of banana exceeds 100 million tons, about 40 million tons of banana peel (40% of total weight of the fresh fruit) remains vastly unused. Exploring a sound technology with banana peel would therefore, not only address the much needed sustainable tool for cleaning contaminated waters, but of course bring an additional value to the banana industry worldwide.

• Fashion & Textile Research Journal
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• v.22 no.4
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• pp.534-539
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• 2020

Experimental research is needed to provide information on the removal of bloodstains since washing clothes contaminated with blood is necessary for medical related fields (such as ambulance workers and doctors) as well as for women of childbearing age. This study investigated efficient washing conditions for the removal of bloodstains with a focus on washing temperature, fiber type and blood ageing time. Polyester/cotton fabric showed the highest detergency from among three fabrics that were influenced by the composition of the fiber and the structure of the yarn and fabric. When examining the effect of detergent, it was concluded that the alkalinity over pH 10 was essential to remove bloodstains and that auxiliary agents such as soil antiredeposition agents and bleach had a significant effect on the removal of bloodstains. Washing temperature showed the highest detergency at 20℃ due to the activity of the enzyme without the denaturalization of blood. Blood-ageing influenced detergency by inducing changes in the adsorption area and chemical bond. A combination of methods such as quick removal after contamination, use of alkaline detergents including soil antiredeposition agents and bleach, and low-temperature washing could help remove bloodstains.