• Korean Chemical Engineering Research
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• v.49 no.5
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• pp.588-593
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• 2011

The porcine epidemic diarrhea virus(PEDV) production yield in spinner flask cultures using Vero cells immobilized on microcarriers was improved by the selective adsorption of ammonium ions in a Carberry type bioreactor which was equipped with Phillipsite-Gismondine synthetic zeolite. Though the apparent cell growth seemed to be lower than that of control due to the aggregation of microcarriers between impeller shaft and the adsorbent, zeolite was found to not to be toxic to Vero cell, considering estimated glucose and lactate changes. Zeolite was observed to remove ammonium ions effectively in both steps of cell growth and virus production. In virus production, the virus titer with zeolite was two times higher than that without zeolite. Consequently, zeolite was found to be an ideal adsorbent for higher production of virus vaccine with the effective removal of ammonium ions.

• Journal of the Korean GEO-environmental Society
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• v.15 no.12
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• pp.5-13
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• 2014

In this study, exfoliated vermiculite (EV) coated with glycerol was tested for its abiility to remove phosphorus in aqueous solution. The glycerol modified vermiculite (GS) was prepared with EV/glycerol ratio of 1/4 where glycerol contained 4 mol% $H_2SO_4$ and heated until designated temperature. GS heated at $380^{\circ}C$ showed that the specific surface area was $53.1m^2/g$ and mass loss due to oxidation of carbon was maximum from TGA analysis. Removal of phosphorus using GS heated at $380^{\circ}C$ was well explained by Langmuir isotherm model and maximum sorption capacity of 714.3 mg/kg is comparable or greater than those of other clay orignated sorbents for phosphorus.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.2
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• pp.193-200
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• 2010

This study evaluated treatability of soluble Mn(II) using multifunctional sand media simultaneously coated with iron and manganese. In the preparation of IMCS(Iron and Manganese Coated Sand), 0.05 M Mn(II) solution and Fe(III) solution was mixed with sand at pH 7. The mineral type of IMCS was identified as the mixture of ${\gamma}-MnO_2$, goethite and magnetite($F_{e3}O_4$). The contents of Mn and Fe coated onto sand were 826 and 1676 mg/kg, respectively. The $pH_{pzc}$ of IMCS was measured as 6.40. The removal of soluble Mn(II) using IMCS and oxidants such as NaOCl and $KMnO_4$ was investigated with variation of the solution pH, reaction time and Mn(II) concentration in a batch test. The removal of Mn(II) on IMCS was 34% at pH 7.4 and the removals of Mn(II) on IMCS in the presence of NaOCl(13.6 mg/L) at pH 7 and $KMnO_4$(4.8 mg/L) at pH 7.6 were 96% and 89%, respectively. The removal of Mn(II) using IMCS and oxidants followed a typical cationic type, showing a gradual increase of removal as the solution pH increased. The removal of Mn(II) was rapid in the first 6 hrs and then a constant removal was observed. The maximum removed amount of Mn(II) on IMCS-alone and IMCS in the presence of oxidants such as NaOCl(13.6 mg/L) and $KMnO_4$(4.8mg/L) were 833.3, 1428.6 and 1666.7 mg/kg, respectively. Mn(II) removal onto the IMCS in the presence of oxidants was well described by second-order reaction and Langmuir isotherm expression.

• Korean Journal of Environmental Agriculture
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• v.6 no.2
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• pp.46-52
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• 1987

This study of adsorption and column percolation was conducted to examine the utilization of natural zeolite for the removal of heavy metals from waste water to compare with that of absorption activated carbon. The adsorption of heavy metals by natural zeolite was conformed to the Freundlich isotherm (1/n values: $0.12{\sim}0.45$, K values: $18.77{\sim}59.48$) and natural zeolite was turned out to be an effective adsorbent of heavy metals. At the same particle size and percolation velocity, zeolite adsorbed a greater amount of heavy metals was adsorbed on natural zeolite than activated carbon. The smaller the particle size, the more heavy metals that were adsorbed. It was postulated that the most effective size as an adsorbent of heavy metals from waste water ranged from 0.5 to 2.0mm. The slower the percolation velocity that of the heavy metal solution in column, the more heavy metals were adsorbed. Natural zeolite in a single solution adsorbed more heavy metals than that in mixed solution, and the order of the adsorption amount on natural zeolite was Cu>Zn>Cd.

• Journal of Wetlands Research
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• v.25 no.2
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• pp.145-158
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• 2023

Constructed wetlands (CWs) are effective technologies for urban wastewater management, utilizing natural physico-chemical and biological processes to remove pollutants. This study employed a bibliometric analysis approach to investigate the progress and future research trends in the field of CWs. A comprehensive review of 100 most-recently published and open-access articles was performed to analyze the performance of CWs in treating wastewater. Spain, China, Italy, and the United States were among the most productive countries in terms of the number of published papers. The most frequently used keywords in publications include water quality (n=19), phytoremediation (n=13), stormwater (n=11), and phosphorus (n=11), suggesting that the efficiency of CWs in improving water quality and removal of nutrients were widely investigated. Among the different types of CWs reviewed, hybrid CWs exhibited the highest removal efficiencies for BOD (88.67%) and TSS (95.67%), whereas VSSF, and HSSF systems also showed high TSS removal efficiencies (83.25%, and 78.83% respectively). VSSF wetland displayed the highest COD removal efficiency (71.82%). Generally, physical processes (e.g., sedimentation, filtration, adsorption) and biological mechanisms (i.e., biodegradation) contributed to the high removal efficiency of TSS, BOD, and COD in CW systems. The hybrid CW system demonstrated highest TN removal efficiency (60.78%) by integrating multiple treatment processes, including aerobic and anaerobic conditions, various vegetation types, and different media configurations, which enhanced microbial activity and allowed for comprehensive nitrogen compound removal. The FWS system showed the highest TP removal efficiency (54.50%) due to combined process of settling sediment-bound phosphorus and plant uptake. Phragmites, Cyperus, Iris, and Typha were commonly used in CWs due to their superior phytoremediation capabilities. The study emphasized the potential of CWs as sustainable alternatives for wastewater management, particularly in urban areas.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.26 no.1
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• pp.1-9
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• 2020

We evaluated the applicability of baking soda, charco'al, coffee, and green tea as a natural deodorant in Kimchi packaging. Moreover, to evaluate the potential usage of these deodorants in packaging materials and confirm their applicability in high-temperature melt-extrusion processing, the thermal stabilities of the deodorants were investigated, and heat-treated deodorants were evaluated in terms of the deodorizing function compared with non-treated deodorants. Aroma patterns were decreased after deodorizing treatment with all-natural deodorants. Dimethyl disulfide, methyl trisulfide, and diallyl disulfide, the most significant odorous Volatile organic compounds (VOCs) of Kimchi, decreased after treatment with the deodorants. In particular, baking soda and charcoal showed the highest efficiency in removing odorous compounds and VOCs from Kimchi, even after high-temperature processing. The acetic acid removal rates for both baking soda and charcoal were 99.9±0.0%. The heating process increases the deodorizing effects of baking soda. Sensory evaluation results showed that there is a significant increase (p < 0.05) in the overall preference for Kimchi samples packaged with charcoal and baking soda. This study provides useful information for the deodorization effects of natural deodorants for Kimchi smell and their applicability for packaging materials.

• Journal of Electrochemical Science and Technology
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• v.12 no.1
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• pp.92-100
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• 2021

In this study, the use of waste food grade aluminium foil and mild steel as a sacrificial electrode in an electrocoagulation system was developed to remove reactive red 111 from wastewater. The effect of different parameters like pH, current density, electrode material, and different electrode configurations was investigated. Optimum operating conditions for maximum COD removal were determined as, 6 mA/㎠ current density and 30 min at 5 pH for aluminium foil and 7 pH for mild steel. Maximum COD reduction obtained at optimum conditions using monopolar 4 electrodes, monopolar 2 electrodes and bipolar electrode configuration were 96.5%, 89.3%, and 90.2% for Mild steel as a sacrificial electrode and 92.1%, 84.2%, and 88.6% for aluminium foil as a sacrificial electrode. The consumption of electrode and energy for both the electrodes of different configurations were calculated and compared. Using batch experimental data, a continuous-flow reactor was developed. Sludge analysis using Fourier Transform Infra-Red Spectroscopy (FTIR) analysis was done. Different adsorption kinetic models and isotherms were developed and it was found that pseudo second-order model and Langmuir isotherm fit best with the experimental data obtained.

• Bulletin of the Korean Chemical Society
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• v.34 no.5
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• pp.1513-1520
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• 2013

Novel chitosan (CS) based membrane networks were developed by solution casting and followed by crosslinking with different crosslinkers such as glutaraldehyde, urea-formaldehyde, and thiourea-formaldehyde. The developed membrane networks were designated as CS-GA, CS-UF and CS-TF. Crosslinking reaction of CS membranes was confirmed by Fourier transform infrared spectroscopy. Membrane rigidity and compactness were studied by the differential scanning calorimetry. The surface morphology of CS membranes was characterized by scanning electron microscopy. The sorption behaviour with respect to contact time, initial pH and initial metal ion concentration were investigated. The maximum adsorption capacity of CS-GA, CS-UF and CS-TF sorbents was found to be 1.03, 1.2 and 1.18 mM/g for $Cu^{2+}$ and 1.48, 1.55 and 2.18 mM/g for $Ni^{2+}$ respectively. Swelling experiments have been performed on the membrane networks at $30^{\circ}C$. Desorption studies were performed in acid media and EDTA and it was found that the membranes are reusable for the metal ion removal for three cycles. The developed membranes could be successfully used for the separation of $Cu^{2+}$ and $Ni^{2+}$ metal ions from aqueous solutions.

• Journal of Microbiology and Biotechnology
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• v.17 no.7
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• pp.1147-1151
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• 2007

Biodegradation of endocrine-disrupting bisphenol A was investigated with several white rot fungi (Irpex lacteus, Trametes versicolor, Ganoderma lucidum, Polyporellus brumalis, Pleurotus eryngii, Schizophyllum commune) isolated in Korea and two transformants of T. versicolor (strains MrP 1 and MrP 13). I. lacteus degraded 99.4% of 50 mg/l bisphenol A in 3 h incubation and 100% in 12 h incubation. which was the highest degradation rate among the fungal strains tested. T. versicolor degraded 98.2% of 50 mg/l bisphenol A in 12 h incubation. Unexpectedly, the transformant of the Mn-repressed peroxidase gene of T. versicolor, strain MrP 1, degraded 76.5% of 50 mg/l bisphenol A in 12 h incubation, which was a lower degradation rate than wild-type T. versicolor. The removal of bisphenol A by I. lacteus occurred mainly by biodegradation rather than adsorption. Optimum carbon sources for biodegradation of bisphenol A by I. lacteus were glucose and starch, and optimum nitrogen sources were yeast extract and tryptone in a minimal salts medium; however, bisphenol A degradation was higher in nutrient-rich YMG medium than that in a minimal salts medium. The initial degradation of endocrine disruptors was accompanied by the activities of manganese peroxidase and laccase in the culture of I. lacteus.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.33 no.5
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• pp.455-462
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• 2000

The objective of this study was to examine the physicochemical characteristics of coagulation reaction between loess and red tide organisms (RTO) and its feasibility, in developing a technology for the removal of RTO bloom in coastal sea. The physicochemical characteristics of loess were examined for a particle size distribution, surface characteristics by scanning electron microscope, zeta potential, and alkalinity and pH variations in sea water. Two kinds of RTO that were used in this study, Cylindrothen closterium and Skeietonema costatum, were sampled in Masan bay and were cultured in laboratory. Coagulation experiments were conducted using various concentrations of loess, RTO, and a jar tester. The supernatant and RTO culture solution were analyzed for pH, alkalinity, RTO cell number. A negative zeta potential of loess increased with increasing pH at $10^(-3)M$ NaCl solution and had -71.3 mV at pH 9.36. Loess had a positive zeta potential of +1,8 mV at pH 1.98, which resulted in a characteristic of material having an amphoteric surface charge. In NaCl and $CaCl_2$, solutions, loess had a decreasing negative zeta potential with increasing $Na^+\;and\;Ca^(+2)$ ion concentration and then didn't result in a charge reversal due to not occurring specific adsorption for $Na^+$ ion while resulted in a charge reversal due to occurring specific adsorption for $Ca^(+2)$ ion. In sea water, loess and RTO showed the similar zeta potential values of -112,1 and -9.2 mV, respectively and sea sand powder showed the highest zeta potential value of -25.7 mV in the clays. EDLs (electrical double-layers) of loess and RTO were extremely compressed due to high concentration of salts included in sea water, As a result, there didn't almost exist EDL repulsive force between loess and RTO approaching each other and then LVDW (London-yan der Waals) attractive force was always larger than EDL repulsive force to easily form a floe. Removal rates of RTO exponentially increased with increasing a loess concentration. The removal rates steeply increased until $800 mg/l$ of loess, and reached $100{\%}$ at 6,400 mg/l of loess. Removal rates of RTO exponentially increased with increasing a G-value. This indicated that mixing (i.e., collision among particles) was very important for a coagulation reaction. Loess showed the highest RTO removal rates in the clays.