• Journal of Environmental Science International
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• v.30 no.1
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• pp.97-108
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• 2021

In the current study, MIL-101(Cr)-SO3H[HCl] as metal-organic frameworks (MOFs) was fabricated via a hydrothermal method. The physicochemical properties of the synthesized material were characterized using XRD, FT-IR, FE-SEM, TEM, and BET surface area analysis. The XRD diffraction pattern of the prepared MIL-101(Cr)-SO3H[HCl] was similar to previously reported patterns of MIL-101(Cr) type materials, indicating successful synthesis of MIL-101(Cr)-SO3H[HCl]. The FT-IR spectrum revealed the molecular structure and functional groups of the synthesized MIL-101(Cr)-SO3H[HCl]. FE-SEM and TEM images indicated the formation of rectangular parallelopiped structures in the prepared MIL-101(Cr)-SO3H[HCl]. Furthermore, the EDS spectrum showed that the synthesized material consisted of the elements of Cr, O, S, and C. The fabricated MIL-101(Cr)-SO3H[HCl] was then employed as an adsorbent for the removal of Sr2+ and Cs+ from aqueous solutions. The adsorption kinetics and adsorption isotherm models were studied in detail. The maximum adsorption capacities of MIL-101(Cr)-SO3H[HCl] for Sr2+ and Cs+ according to pH (3, 5.3~5.8, 10) were 35.05, 43.35, and 79.72 mg/g and 78.58, 74.58, and 169.74 mg/g, respectively. These results demonstrate the potential of the synthesized MOFs, which can be effectively applied as an adsorbent for the removal of Sr2+ and Cs+ ions from aqueous solutions and other diverse applications.

• Membrane Journal
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• v.22 no.6
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• pp.404-414
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• 2012

In order to investigate $SO_2$ removal, PEI hollow fiber membranes were produced by a dry-wet phase inversion method. The membrane support layer on surface was coated with PEBAX1657$^{(R)}$ and PEG blending materials. Modules were prepared for the single gas permeation characteristics of composite membrane according to temperature and pressure. As a result, $SO_2$ permeance and $SO_2/N_2$ selectivity were 220~1220 GPU and 100~506 through operating condition, respectively. Moreover, $SO_2/CO_2/N_2$ mixture gas was used to compare the performance of separation properties according to temperature, pressure and retentate flow rate difference. $SO_2$ removal efficiency was increased with pressure and temperature.

• Journal of Korean Society for Atmospheric Environment
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• v.16 no.4
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• pp.399-408
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• 2000

This study evaluated the SO2 adsorption characteristics using a continous moving bed system. Natural manganese oxide (NMO) reaction condition such as L/D the starting time of the NMO feed, feed rate, and flow rate of simulated flue gas, and NMO size were tested. The results showed that optimum L/D was 1.0 in this moving bed system. The higher the feeding rate was the higher the SO2 removal efficiency was and the higher the flow rate of simulated flue gas was the shorter the time to reach the euqilibirum concentration was. The final SO2 con-centration when it reaches the equilibrium concentration was not affected by the starting time of the NMO feed.

• Fashion & Textile Research Journal
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• v.2 no.4
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• pp.339-345
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• 2000

The effects of protease and/or lipase on the removal of protein soil and oily soil were investigated in this study. Cotton, rayon, nylon, and PET fabrics were soiled by padding of fresh bovine blood and spotting of mixed artificial sebum evenly. The soiled fabrics were aged at $130^{\circ}C$ for 30 minutes. The fabrics were washed by using Terg-O-Tometer at various conditions. Protease and/or lipase were added in the alcohol ethoxylate (AE) detergent solution. The removal efficiency was evaluated by analysis of protein and/or oil on the fabrics before and after washing, respectively. The detergency of protein and/or oil on the fabrics was discussed with enzyme concentration, washing time, washing temperature, pH of washing solution and fiber characteristics. The hydrolysis of protease improved effectively the removal of oil as well as protein by increasing removal of protein-oil mixed soil at the same time. The effect of lipase added detergent solution was slightly shown on the removal of oil and/or protein. The removal of mixed soils from cotton fabrics was very low because of large amount of residual soils caused by the physical characteristics of cotton fiber.

• KSBB Journal
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• v.14 no.2
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• pp.141-145
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• 1999

The study was conducted for the efficient utilization of biomaterials such as Chestnut shell which was wasted tremendously as an agricultural by-products. This biomaterials were examined for their removal rate of heavy metal ions as adsorbents in wastewater by batch adsorption experiments. In this experiment, the heavy metal ions used were $\Cd^{2+},\;Fe^{2+},\;Cr^{6+},\;Mn^{2+},\;Cu^{2+}$ and $Pb^{2+}$. The range of time for the removal rates of heavy metal ions were observed about 10 min. The range of high pH for the removal rates of $\Cd^{2+},\;Fe^{2+},\;Mn^{2+},\;Cu^{2+}$ and $Pb^{2+}$ ere observed 7.0-9.0. The range of high pH for the removal rate of $Cr_{6+}$ was observed 2. In the case of raw chestnut shell, the removal rates of $\Fe^{2+},\;Mn^{2+},\;Cu^{2+}$ and $Pb^{2+}$ were above 70 percent. The removal rates of heavy metals in formaline pretreated chestnut shells except $Cd_{2+}$ were above 50 percent and in phosphorylating chestnut shells except $Cr_{6+}$ were above 60 percent. Chestnut shells pretreated by formaline and phosphorylating were not so good enough for improvement of removal rates with pH change in mixed heavy metal solution.

• Proceedings of the KIEE Conference
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• 1999.07e
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• pp.2007-2009
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• 1999

In this paper, discharge domain of wire-cylindrical plasma reactor was separated from a gas flow duct to avoid unstable discharge by aerosol particle deposited on discharge electrode and grounded electrode. The NOx, SOx removal was experimentally investigated by a reaction induced to ammonium nitrate, ammonium sulfate using a low price of aqueous NaOH solution and a small quantity of ammonia. Volume percentage of aqueous NaOH solution used was 20% and $N_2$ flow rate was 2.5[$\ell$/min] for bubbling aqueous NaOH solution. Ammonia gas(14.82%) balanced by argon was diluted by air and was introduced to a main simulated flue gas duct through $NH_3$ injection system which was in downstream of reactor. The $NH_3$ molecular ratio[MR] was determined based on $NH_3$ to [NO+$SO_2$]. MR is 1.5. The NOx removal rates increased in the order of DC, AC and pulse, but SOx removal rates was not significantly effected by source of electricity. The NOx removal rate slightly decreased with increasing initial concentration but SOx removal rate was not significantly effect by initial concentration, and NOx, SOx removal rates decreased with increasing gas flow rate.

• Applied Chemistry for Engineering
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• v.28 no.6
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• pp.607-618
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• 2017

Harmful air pollutants are exhausted from the various industrial facilities including the coal-fired thermal power plants and these substances affects on the human health as well as the nature environment. In particular, nitrogen oxides ($NO_x$) and sulfur dioxide ($SO_2$) are known to be causative substances to form fine particles ($PM_{2.5}$), which are also deleterious to human health. The integrated system composed of selective catalytic reduction (SCR) and wet flue gas desulfurization (WFGD) have been widely applied in order to control $NO_x$ and $SO_2$ emissions, resulting in high investment and operational costs, maintenance problems, and technical limitations. Recently, new technologies for the simultaneous removal of $NO_x$ and $SO_2$ from the flue gas, such as absorption, advanced oxidation processes (AOPs), non-thermal plasma (NTP), and electron beam (EB), are investigated in order to replace current integrated systems. The proposed technologies are based on the oxidation of $NO_x$ and $SO_2$ to $HNO_3$ and $H_2SO_4$ by using strong aqueous oxidants or oxidative radicals, the absorption of $HNO_3$ and $H_2SO_4$ into water at the gas-liquid interface, and the neutralization with additive reagents. In this paper, we summarize the technical improvements of each simultaneous abatement processes and the future prospect of technologies for demonstrating large-scaled applications.

• Journal of environmental and Sanitary engineering
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• v.20 no.2 s.56
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• pp.12-20
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• 2005

Most of sewage treatment plants in Korea is operated for the removal of organic material. Because of low C/N ratio of domestic wastewater it is very difficult to remove nitrogen and phosphorus from wastewater. Therefore C/N ratio is key factor for the removed of nitrogen and phosphorus. PSB(photosynthetic bacteria) can remove the nutrient materials, so this study is focused on PSB characterization of nutrient removal. PSB is possible to remove nitrogen, phosphorus in anaerobic and aerobic condition. This study try to find out condition of the PSB in SBR reactor, Batch reactor. It consists of three Mode. Mode 1, 2 is to apply activated sludge process and Mode 3 is that seeded PSB in the activated sludge process. As a result of SBR process, Mode 1, 2 which was activated sludge Process showed $79\~90\%,\;66\~90\%$ of SCODcr, $94.67\~95.89\%,\;95.76\~98.56\%$ of TKN, and Mode 3 has $84\~92\%$ of SCODcr, $95.39\~99.52\%$ of TKN removal efficiency, respectively. When comparison with Mode 1, 2 and 3, most of nitrogen and phosphorus is removed at the anaerobic condition in Mode 3. but Mode 1, 2 has just revealed activated sludge process characterization. It would because of characterization of PSB.

• Journal of Environmental Science International
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• v.8 no.5
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• pp.617-623
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• 1999

This study was carried out to obtain the optimal operating parameter on organic matters and nutrient removal of mixed wastewater which was composed of sewage and stable wastewater using SBR. A laboratory scale SBR was operated with An/Ae(Anaerobic/Aerobic) ratio of 3/3, 2/4 and 4/2(3.5/2.5) at organic loading rate of 0.14 to 0.27 kgBOD/$m^3$/d. TCOD/SCOD ratio of mixed wastewater was 3, so the important operating factor depended upon the resolving the particulate parts of wastewater. Conclusions of this study were as follows: 1) For mixed wastewater, BOD and COD removal efficiencies were 93-96% and 85-89%, respectively. It was not related to each organic loading rate, whereas depended on An/Ae ratio. During Anarobic period, the amount of SCOD consumption was very little, because ICOD in influent was converted to SCOD by hydrolysis of insoluble matter. 2) T-N removal efficiencies of mixed wastewater were 55-62% for Exp. 1, 66-76% for Exp. 2, and 67-81% for Exp. 3, respectively. It was found that nitrification rate was increased according to organic concentration in influent increased. Therefore, the nitrification rate seemed to be achieved by heterotrophs. During anoxic period, denitrification rate depended on SCOD concentration in aerobic period and thus, was not resulted by endogenous denitrification. However, the amount of denitrification during anaerobic period were 3.5-14.1 mg/cycle, and that of BOD consumed were 10-40 mg/cycle. 3) For P removal of mixed wastewater, EBPR appeared only Mode 3($3^＊$). It was found that the time in which ICOD was converted to VFA should be sufficient. For mode 3 in each Exp., P removal efficiencies were 74, 87, and 81%, respectively. But for 45-48 of COD/TP ratio in influent, P concentration in effluent was over 1 mg/L. It was caused to a large amount of ICOD in influent. However, as P concnetration in influent was increased, the amounts of P release and uptake were increased linearly.

• Journal of Korea Society of Waste Management
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• v.35 no.7
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• pp.653-659
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• 2018

In the industrial wastewater that occupies a large proportion of river pollution, the wastewater generated in textile, leather, and plating industries is hardly decomposable. Though dyeing wastewater has generally been treated using chemical and biological methods, its characteristics cause treatment efficiencies such as chemical oxygen demand (COD) and suspended solids (SS) to be reduced only in the activated sludge method. Currently, advanced oxidation technology for the treatment of dyeing wastewater is being developed worldwide. Electro-coagulation is highly adapted to industrial wastewater treatment because it has a high removal efficiency and a short processing time regardless of the biodegradable nature of the contaminant. In this study, the effects of the current density and the electrolyte condition on the COD removal efficiency in dyeing wastewater treatment by using electro-coagulation were tested with an aluminum anode and a stainless steel cathode. The results are as follows: (1) When the current density was adjusted to $20A/m^2$, $40A/m^2$, and $60A/m^2$ under the condition without electrolyte, the COD removal efficiency at 60 min was 62.3%, 72.3%, and 81.0%, respectively. (2) The removal efficiency with NaCl addition was 7.9% higher on average than that with non-addition at all current densities. (3) The removal efficiency with $Na_2SO_4$ addition was 4.7% higher on average than that with non-addition at all current densities.