• KSBB Journal
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• v.22 no.3
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• pp.162-167
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• 2007

Ammonia gas is one of the major pollutants which cause environmental pollution and damage to the human and the livestock. The objective of this study was to investigate the important parameters for the development of efficient removal of ammonia gas by Bacillius subtilis IB101 and to optimize the medium composition for the mass production of B. subtilis IB101. The ammonia gas removal efficiency was evaluated at different growth phases and by changing culture conditions (temperature, pH). The effect of $(NH_4)_2SO_4$ concentration in preculture medium was examined. Medium optimization for the mass production of B. subtilis IB101 was performed by using Plackett-Burman design and one factor at a time method. The removal of ammonia gas was more efficient at exponential phase by 20% than at stationary phase. The ammonia gas removal was the highest at pH 4 and 30 $^{\circ}C$. There was not any significant influence of concentration of $(NH_4)_2SO_4$ on the removal of ammonia gas. The components of optimized medium for the production of viable Bacillus subtilis IB101 was yeast extract 10 g/l, soluble starch 2.5 g/l, $MgSO_4$ 6 g/l, $CaCl_2$ 1.55 g/l, $(NH_4)_2SO_4$ 5 g/l, $KH_2PO_4$ 0.75 g/l, soy bean meal 8 g/l.

• 한국생물공학회:학술대회논문집
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• 2000.04a
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• pp.489-492
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• 2000

The rejection of hardness in a lactate fermentation broth was investigated by NTR-729 nanofiltration membrane. Firstly, a method for determining membrane surface charge was proposed on the basis of the rejection data for NaCl, $Na_2SO_4$, $MgCl_2$, $MgSO_4$ solutions. It was found that the NTR-729 membrane was negatively charged. The rejection of $Mg^{2+}$ ions in model solution of lactate was over 80% with lactate concentrations. But the rejection of $Mg^{2+}$ ions in fermentation broth of lactate was about 40 %. This results was caused by anions paired with $Mg^{2+}$ ions. It was found that the repulsive force of monovalent anions with membrane was almost few through an experiment of a mixed solution of NaCl/ $Na_2SO_4$. So the rejection of $Mg^{2+}$ ion in a fermentation broth was lower than that in a model solution because $Mg^{2+}$ ions permeated to the membrane with various monovalent anions.

• Journal of Industrial Technology
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• v.26 no.A
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• pp.181-188
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• 2006

In this study, we analyzed the effects of several process variables on the removal efficiencies of NO and $SO_2$ by the dielectric barrier discharge process combined with photocatalysts. The $TiO_2$ photocatalysts were coated onto the spherical-shaped glass beads as dielectric materials by the dip-coating method to analyze the effects of photodegradation reaction on the NO and $SO_2$ removal. As the voltage applied to the plasma reactor increases, or as the pulse frequency of applied voltage increases, the NO and $SO_2$ removal efficiencies increase. Also as the residence time increases, or as the initial concentration of NO decreases, the NO and $SO_2$ removal efficiencies increase. The higher the amount of $TiO_2$ particles coated onto the glass bead is, the larger the surface area of $TiO_2$ particles for the photodegradation reaction is and the NO and $SO_2$ are removed more quickly by the faster photodegradation reactions.

• Journal of the Korea Institute of Building Construction
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• v.23 no.2
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• pp.153-164
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• 2023

The objective of this study is to examine the removal rate of air pollutants, specifically sulfur oxides (SO_x) and nitrogen oxides(NO_x), using concrete permeable blocks containing zeolite beads coated with materials capable of eliminating these pollutants. Titanium dioxide(TiO₂) powder and coconut shell powder were utilized for the removal of SO_x and NO_x and were applied as coatings on the zeolite beads. Concrete permeable block specimens embedded with the coated zeolite beads were produced using an actual factory production line. Test results demonstrated that the concrete permeable block containing zeolite beads coated with coconut shell powder in the surface layer achieved SO_x and NO_x removal rates of 12.5% and 99%, respectively, exhibiting superior performance compared to other blocks. Additionally, the flexural strength and slip resistance were 5.3MPa and 65BPN or higher, respectively, satisfying the requirements specified in KS F 4419 and KS F 4561. Conversely, the permeability coefficient exhibited low permeability, with grades 2 and 3 before and after contaminant pollution, according to the standard for 'design, construction, and maintenance of pavement using permeable block'. In conclusion, incorporating zeolite beads coated with coconut shell powder in the surface layer enables simultaneous removal of SO_x and NO_x, irrespective of ultraviolet rays, while maintaining adequate flexural strength and slip resistance. However, the permeability is significantly reduced, necessitating further improvements.

• Analytical Science and Technology
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• v.9 no.1
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• pp.98-106
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• 1996

The concentration of sulfur dioxide in Wonju City was predicted using TCM (Texas Climatological Model). We have studied the transportation and wet deposition of $SO_2$ using the TCM and the analysis of rainfalls. The results are as follows : At the Hak-Sung Dong site in Wonju city, the correlation coefficient between the measured and calculated concentrations were 0.904. Sulfur dioxide was washed out by wet deposition. The wet deposition ratio to total amount of emitted sulfur dioxide was higher in summer than in autumn and winter seasons due to heavy rainfall in summer. The correlation coefficient between the precipitation and wet deposition of sulfur dioxide was 0.68. The months with greater rainfall showed that the measured concentrations of sulfur dioxide were much lower than the predicted ones. Although the amount of precipitation in April was smaller than in summer, the wet deposition ratio in April was much higher than any other months, due to the sulfur dioxide that was adsorbed on particulate matter and moisture was transported during the period of yellow sand phenomena from China.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2003.11a
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• pp.696-700
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• 2003

$H_2SO_4$ and citric acid had higher extraction efficiency of $^{137}Cs$ from soil than the other chemicals. Thus, $H_2SO_4$and citric acid were used as additives on remediation experiment by electrokinetic method to increase removal efficiency of $^{137}Cs$ from the radioactive soil being stored during a long time. An average velocity of effluent discharged from experimental column $2.0{\times}10^{-2}$/cm/min and a volume of the discharged soil wastewater for 10 days is 3.6 Pore Volume. The 54% of a total of $^{137}Cs$ in the column was decontaminated for 10 days. Furthermore, the predicted values of residual concentration by the developed model were quite similar to those obtained from experiments.

• Applied Chemistry for Engineering
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• v.10 no.1
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• pp.41-45
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• 1999

Simulated liquid waste containing 50 ppm cobalt ion was treated by precipitate flotation using the surfactant of sodium lauryl sulfate. The effects of initial cobalt ion concentration, pH, surfactant concentration, removal time, gas flow rate and foreign ions were estimated on removal efficiency. 35% $H_2O_2$ was added for pre-treatment stage before precipitate flotation. As the result of pre-treatment, optimum removal pH and the pH of treated water being discharged were lowed and optimum removal pH range was broadened. For the result of this experiment, 99.8% removal efficiency was obtained at the condition of 50ppm of initial cobalt ion concentration, pH 9.5, 70 mL/min of gas flow rate, and 30 min of removal time. Attraction between precipitate and surfactant was supposed to be influenced by solubility and chemical affinity among species in sloution as well as zeta potential. The influence of foreign ions such as, $NO_3{^-}$, ${SO_4}^{-2}$, $Na^+$, $Ca^{+2}$ on the removal efficiency was also observed. Removal efficiency by precipitate flotation containing 0.1 M of ${SO_4}^{-2}$ ion decreased to 90% due to the decrease of zeta potential and interruption of precipitation.

• Applied Chemistry for Engineering
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• v.18 no.5
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• pp.454-458
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• 2007

The removal characteristics of ionic species, such as $Ca^{2+}$, $Mg^{2+}$, $Sr^{2+}$, $SO{_4}^{2-}$, $NO{_3}^-$, and $Cl^-$ by adsorption on the alumina were investigated. Alumina precusor powders were prepared from $Al(NO_3)_3{\cdot}9H_2O$ and $NH_4OH$. Alumina materials prepared from the heat treatment in a furnace at $450{\sim}750^{\circ}C$ for 5 h were analysed using FT-IR and the Brunauer-Emmett-Teller (BET) method. The specific surface area of the product particles decreased significantly with treatment temperature. The adsorption capacities of $SO{_4}^{2-}$and $NO{_3}^-$ on alumina were 23 mg/g and 12.4 mg/g, respectively. But, removal efficiencies of $Cl^-$ were less than 4 mg/g. In general, the removal efficiencies of the anion species were decreased with increasing treatment temperature. The best anion removal efficiency was obtained when the alumina was treated under $450^{\circ}C$. Removal efficiencies of $Ca^{2+}$, $Mg^{2+}$, and $Sr^{2+}$ were increased with increasing treatment temperature.

• Analytical Science and Technology
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• v.18 no.2
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• pp.112-119
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• 2005

This study reports on the efficiency of cleaning enameled magnet wire using a sulfuric acid $H_2SO_4$ and removal of dissolved organic material using hydrogen peroxide $H_2O_2$ and nitric acid $HNO_3$ at $80^{\circ}C$. The method involves the addition of pure $H_2SO_4$ and $H_2O_2$ or $HNO_3$. Layers of enameled organic material were dissolved by 90% $H_2SO_4$ and the solution was maintained as 35% $H_2O_2$ or 60% $HNO_3$. $H_2O_2$ content in aqueous $H_2O_2$ was maintained as 8.8 : 1.0. An initial concentration of $H_2SO_4$ in dissolution conditions was accomplished within 15 min, with a stripping time of about 2 h. The concentrations of $H_2O_2$ and $HNO_3$ in the processing bath were relatively low, but sufficient enough to produce an effective amount of power in the bath for the removal of the enamel material. The cleaning effect of enameled organic material involves the dehydration by $H_2SO_4$ and the oxidation by $H_2O_2$ or $HNO_3$.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.2
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• pp.313-321
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• 2000

This research is to remove heavy metals from AMD(Acid Mine Drainage) using AFMR(Anaerobic Floating Media Reactor) process. Two AFMR were operated at HRT(hydraulic retention time) of 3 days. COD/sulfate ratio from 0.3 to 0.8, temperature from $30^{\circ}C$ to $35^{\circ}C$, and alkalinity of 1.000mg/l(as $CaCO_3$). At COD/sulfate($SO{_4}^{2-}$) ratio of 0.5 and temperature of $35^{\circ}C$, the ratio of reduced sulfate($SO{_4}^{2-}$)/removed COD(mg/mg) kept about 1 and the reactor achieved 99.99% of Cr, Pb anee Fe, 98% of Cd, and 90% of Mn removal efficiencies, respectively. Decreasing temperature to $30^{\circ}C$ increased the ratio of reduced sulfate($SO{_4}^{2-}$)/removed COD(mg/mg) to 1.37. Amount of sulfate reduction maximized at the temperature of $30^{\circ}C$ and the COD/sulfate ratio of 0.4 in the influent and then removal efficiencies of heavy metals were 99.99% of Fe, 99.99% of Pb, 99,99% of Cr, 97.3% of Mn, 99.9% of Zn, 99.9% of Cd and 99.9% of Cu.