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        검색결과 137

        61.
        2014.09 KCI 등재 서비스 종료(열람 제한)
        Adsorption and desorption characteristics of the representative 10 kinds components consisting of gasoline vapor on activated carbon were investigated at the temperature range of -30℃∼25℃. The breakthrough curves of each vapors obtained by the Thomas model were well described the breakthrough experimental results of this study. The breakthrough times of each vapors were correlated with the molecular weight, density, and vapor pressure. The breakthrough times had greater correlation with boiling point than molecular weight and density. The slope of the breakthrough curve was a proportional relationship with the rate constant (k) of Thomas model expression. The higher the slope of the breakthrough curve, the rate constant was larger. The biggest slope vapor had the smallest adsorption capacity (qe). Adsorption and desorption characteristics of mixed vapor similar to the gasoline vapor were studied at room temperature (25℃). The mixed vapor consisting of 9 components; group A (pentane, hexene, hexane), group B (benzene, toluene), group C (octane, ethylbenzene, xylene, nonane) was examined. Group A was not nearly adsorbed because of substitution by group C, and the desorption capacity of group A was smaller than group C. The adsorbed substances were confirmed to be Group C.
        62.
        2014.09 KCI 등재 서비스 종료(열람 제한)
        PVA-D2EHPA/TOPO beads containing two extractants, di-(2-ethylhexyl) phosphoric acid (D2EHPA) and trioctylphoshine oxide (TOPO) were prepared for the removal of copper ions from aqueous solution. The prepared PVA-D2EHPA/TOPO beads were characterized by SEM and FT-IR. The removal characteristics of copper ions by PVA-D2EHPA/TOPO beads was investigated using batch and continuous systems. In batch experiments, the maximum removal capacity calculated from Langmuir isotherm model was 18.6 mg/g and the optimal pH was in the range of 4.5 ∼6. The continuous experiments showed that the removal capacity of copper ions increased with increasing inlet copper ion concentrations and bed heights, but decreased with increasing inlet flow rates.
        63.
        2014.07 KCI 등재 서비스 종료(열람 제한)
        In this study, PVC-LMO beads were prepared by immobilizing lithium manganese oxide (LMO) with poly vinyl chloride (PVC) diluted in dioxane solvent. XRD and SEM analysis confirmed that LMO was immobilized well in PVC-LMO beads. The diameter of PVC-LMO beads prepared by dioxane solvent was about 2 mm. The adsorption experiments of lithium ions by PVC-LMO beads were conducted batchwise. The optimum pH was pH 10. The adsorption characteristics of lithium ions by PVC-LMO beads was well described by the pseudo-second-order kinetic model. The maximum adsorption capacity obtained from Langmuir model was 24.25 mg/g. The thermodynamic parameters such as △H°, △S° and △G° were evaluated. The calculated ΔG° was between −6.16 and −4.14 kJ/mol (below zero), indicating the spontaneous nature of Li+ adsorption on PVC-LMO beads. Also, the results showed that PVC-LMO beads prepared in this study could be used for the removal of lithium ions from seawater containing coexisting ions such as Na+, K+, Mg2+ and Ca2+.
        64.
        2014.06 KCI 등재 서비스 종료(열람 제한)
        The solid phase extractant (PVC-D2EHPA bead) was prepared by immobilizing di-2-ethylhexyl-phosphoric acid (D2EHPA) with polyvinyl chloride (PVC). The prepared PVC-D2EHPA beads were characterized by using fourier transform infrared spectrometer (FTIR) and scanning electron microscopy (SEM). The removal experiments of Cu(II) by PVC-D2EHPA beads conducted batchwise. The removal kinetics of Cu(II) was found to follow the pseudo-second-order model. The equilibrium data fitted well with Langmuir isotherm model and the maximum removal capacity was 2.6 mg/g at 20℃. The optimum pH region was in the range of 3.5 to 6. and the standard free energy (△Go) was between –4.67 ∼–4.98 kJ/mol, indicating the spontaneous nature of Cu(II) removal by PVC-D2EHPA beads.
        65.
        2014.06 KCI 등재 서비스 종료(열람 제한)
        The photocatalytic decomposition characteristics of single n-pentane, n-pentane mixed with methyl ethyl ketone (MEK), and n-pentane mixed with ethyl acetate (EA) by cylindrical UV reactor installed with TiO2-coated perforated plane were studied. The effects of the residence time, the inlet gas concentration, and the oxygen concentration were investigated. The removal efficiency of n-pentane was increased with increasing the residence time and the oxygen concentration, but decreased with increasing the inlet concentration of n-pentane. The photocatalytic decomposition rates of single n-pentane, n-pentane mixed with MEK, and n-pentane mixed with EA fitted well on Langmuir-Hinshelwood kinetics equation. The maximum elimination capacities of single n-pentane, n-pentane mixed with MEK, and n-pentane mixed with EA were obtained to be 465 g/m3․day, 217 g/m3․day, and 320 g/m3․day, respectively. The presence of coexisting MEK and EA vapor had a negative effect on the photocatalytic decomposition of n-pentane and the negative effect of MEK was higher than that of EA.
        66.
        2014.06 KCI 등재 서비스 종료(열람 제한)
        The adsorption experiments of lithium ions were conducted in the fixed bed column packed with activated carbon modified with nitric acid. Effect of inlet concentration, bed hight and flow rate on the removal of lithium ions was investigated. The experimental results showed that the removal and the adsorption capacity of lithium ions increased with increasing inlet concentration, and decreased with increasing flow rate. When the bed height increased, the removal and the adsorption capacity increased. The breakthrough curves gave a good fit to Bohart-Adams model. Adsorption capacity and breakthrough time calculated from Bohart-Adams model, these results were remarkably consistent with the experimental values. The adsorption capacity was not changed in the case of 3 times repetitive use of adsorbent.
        67.
        2014.05 KCI 등재 서비스 종료(열람 제한)
        In order to remove fluoride ions from aqueous solution, PVC-Al(OH)3 beads were prepared by immobilizing Al(OH)3 with polyvinyl chloride (PVC). The prepared PVC-Al(OH)3 bead was characterized by using SEM, EDS and Zeta potential. Dependences of pH, contact time and initial fluoride concentration on the adsorption of fluoride ions were studied. The optimal pH was in the range of 4~10. The adsorption was rapid during the initial 12 hr, and equilibrium was attained within 72 hr. The adsorption rate of fluoride ions by PVC-Al(OH)3 beads obeyed the pseudo-second-order kinetic model. The maximum adsorption capacity obtained from Langmuir isotherm model was found to be 62.68 mg/g.
        68.
        2014.02 KCI 등재 서비스 종료(열람 제한)
        The occurrence trends and moleculargenetic characteristics of noroviruses detected from gastroenteritis patients in Jeju from 2008 to 2010 were investigated. In addition, the norovirus contamination and its characteristics of groundwaters in Jeju were examined. The incidence caused by norovirus in viral gastroenteritis patients has increased every year and was higher in male than in female. The patients caused by norovirus occurred throughout all months. The incidences started to increase from November, were very high from December to February, started to decrease from March, and were very low from June to September. The patients caused by norovirus occurred throughout all ages, however, the infants below 5 years were the most susceptible to norovirus infection and the age group from teens to forties were the most insensitive to norovirus infection. The sequencing analysis showed that 18 genotypes (8 genogroup I (GI) and 10 genogroup II (GII)) were detected, the incidences caused by GI and GII were 11.5% and 88.5%, respectively, and predominant genotype was GII-4 (70.5%), which was the major genotype giving rise to norovirus incidences in Jeju, together with GII-3 (6.1%) and GI-4 (4.1%). Among 20 groundwaters sampled at 9 wells (4 non-drinking water wells and 5 drinking water wells), noroviruses were detected from 2 groundwaters sampled at one non-drinking water well and their genotypes were GI-5 and GI-8.
        69.
        2014.01 KCI 등재 서비스 종료(열람 제한)
        Adsorption of phenol on activated carbon in a fixed bed was studied. The effects of fixed-bed length, superficial velocity (flow rate) and particle size of adsorbent on fixed-bed performance were investigated. Some characteristic parameters such as the breakthrough time (t0.05), saturation time (t0.95), length of mass transfer zone (LMTZ), adsorptive capacity (W), and adsorption rate constant (Ka) were derived from the breakthrough curves. Adsorbent particle sizes significantly affected the shape of the breakthrough curve. Larger particle sizes resulted in an earlier breakthrough, a longer LMTZ and a lower adsorption rate. Superficial velocity was a critical factor for the external mass transfer during fixed-bed adsorption process. The external mass transfer resistance was dominant as increasing superficial velocity.
        70.
        2013.12 KCI 등재 서비스 종료(열람 제한)
        The adsorption of lithium ion onto zeolite was investigated depending on contact time, initial concentration, cation forms, pH, and adsorption isotherms by employing batch adsorption experiment. The zeolite was converted into different forms such K+, Na+, Mg2+, Ca2+, and Al3+. The zeolite had the higher adsorption capacity of lithium ion in K+ form followed by Na+, Ca2+, Mg2+, and Al3+ forms, which was in accordance with their elctronegativities. The lithium ion adsorption was explained using the Langmuir, Freundlich, and Dubinin-Radushkevich adsorption isotherms and kinetic models. Adsorption rate of lithium ion by zeolite modified in K+ form was controlled by pseudo-second-order and particle diffusion kinetic models. The maximum adsorption capacity obtained from Langmuir isotherm was 17.0 mg/g for zeolite modified in K+ form. The solution pH influenced significantly the lithium ions adsorption capacity and best results were obtained at pH 5-10.
        71.
        2013.12 KCI 등재 서비스 종료(열람 제한)
        In manufacturing of flatfish skin collagen peptide (FSCP) and flatfish protein hydrolysate (FPH) by reuse of dead flatfish from fish farm in Jeju island, the industrial process was optimized with the laboratory scale research and the on-field process. Segmented unit processes from raw material incoming to shipment were established to produce commercial product of FSCP and FPH. Total plate counts of FSCP were twenty five times of FPH, but food poisoning bacteria were not detected in two samples. FSCP and FPH were safe from heavy metal such as Pb(II), Cd(II) and Hg(II). The residual contents of antibiotics and disinfection matter in FSCP and FPH were not detected. The optimized process for mass production made the one-third of the running time and two times of the yield. From economic analysis, the production cost was estimated to 22,000 and 12,000 won/kg for FSCP and FPH, respectively. Therefore the product from the reuse of dead flatfish was expected to have a considerable competitive price and high added-value functional food material compared with other commercially available fish products.
        72.
        2013.11 KCI 등재 서비스 종료(열람 제한)
        To develop the protein materials by the reutilization of dead flatfish from fish farms in Jeju island, the physicochemical characteristics and the functional activities of collagen peptide extracts were investigated. Flatfish skin collagen peptide (FSCP) and flatfish protein hydrolysate (FPH) were manufactured from dead flatfish. The differences of pH, moisture and fat contents between FSCP and FPH were not significant, fat contents were analyzed less than 0.3%, and trans-fat, saturated fat and cholesterol were not detected in both samples. Protein contents of FSCP and FPH showed about 92% and 95%, respectively. In the analysis of amino acids, glycine and hydroxy proline content in FSCP was 24.22% and 6.15%, respectively, showed a typical characteristics of the collagen protein, but essential amino acids contents such as threonine, valine, methionine, isoleusine, leusine and phenylalanine were relatively higher than those of FPH. Average molecular weight of FSCP was measured as 1,102 which was almost equal value with that of tuna collagen peptide. The antioxidant activities and functional properties showed high but did not show significant difference between two samples.
        73.
        2013.11 KCI 등재 서비스 종료(열람 제한)
        The adsorption ability of wood-based activated carbon to adsorb methylene blue (MB) and crystal violet (CV) from aqueous solution has been investigated. Adsorption studies were carried out on the batch experiment at different initial MB and CV concentrations (MB=150 mg/L~400 mg/L, CV=50 mg/L~350 mg/L), contact time, and temperature. The results showed that the MB and CV adsorption process followed the pseudo-second-order kinetic and intraparticle diffusion was the rate-limiting step. Adsorption equilibrium data of the adsorption process fitted very well to both Langmuir and Freundlich model. The maximum adsorption capacity (qm) by Langmuir constant was 416.7 mg/g for MB and 462.4 mg/g for CV. The thermodynamic parameters such as ΔH°, ΔS° and ΔG° were evaluated. The MB and CV adsorption process was found to be endothermic for the two dyes.
        74.
        2013.09 KCI 등재 서비스 종료(열람 제한)
        The efficiency of coal-based activated carbon in removing methylene blue (MB) and phenol from aqueous solution was investigated in batch experiments. The batch adsorption kinetics were described by applying pseudo-first-order, pseudo-second-order, and first order reversible reaction. The results showed that the adsorption of MB and phenol occurs complexed process including external mass transfer and intraparticle diffusion. The maximum adsorption capacity obtained from Langmuir isotherm was 461.0 mg/g for MB and 194.6 mg/g for phenol, respectively. The values of activation parameters such as free energy (△G˚), enthalpy (△H˚), and entropy (△S˚) were also determined as -19.0∼-14.9 kJ/mol, 25.4 kJ/mol, and 135.2 J/mol K for MB and 51.8∼54.1 kJ/mol, -29.0 kJ/mol, and -76.4 kJ/mol K for phenol, respectively. The MB adsorption was found to be endothermic and spontaneous process. However, the CV adsorption was found to be exothermic and non-spontaneous process.
        75.
        2013.09 KCI 등재 서비스 종료(열람 제한)
        Desorption characteristics of VOCs were investigated for the effective recovery of gasoline vapor. The adsorption capacity and desorption capacity were excellent at relatively low temperatures. The differences in the desorption capacity were not large in the condition; desorption temperature 25℃, desorption pressure 760 mmHg, inlet air flow rate 0.5 L/min, but were relatively great in the condition; desorption temperature 0℃, desorption pressure 60 mmHg, inlet air flow rate 1.0 L/min. The desorption ability of pentane was increased to about 81.4%, and the desorption ability of hexane was increased to about 102%, also the desorption ability of toluene was increased to about 156.7% by changes of temperature, pressure, inlet air flow rate in the experimental conditions. The optimum desorption condition for the effective recovery of VOCs was in the conditions; desorption temperature 0℃, desorption pressure 60 mmHg, inlet air flow rate 1.0 L/min.
        76.
        2013.01 KCI 등재 서비스 종료(열람 제한)
        The removal characteristics of composite odor and malodorous substances using 33 biofilters in sewage treatment facilities were investigated. The geometry mean values of composite odor and odor quotient were reduced by 52.7% and 59.2% at the outlet of the biofilters, respectively. The removal efficiencies of the biofiltes for the composite odor and odor quotient show a significant difference statistically(p=0.000<0.05). The median value of odor quotient of sulfur compounds was reduced by 69.1% at the outlet of the biofilter and the odor quotient of the sulfur compound at the inlet and outlet of the biofilter shows a significant difference statistically(p=0.000<0.05); on the other hand, those of the NH3 and trimethylamine, aldehydes, VOCs and alcohols, organic acids do not.
        77.
        2012.12 KCI 등재 서비스 종료(열람 제한)
        The purpose of this work is to study the desorption characteristics of water vapor on zeolites saturated with water vapor. Three kinds of zeolite; zeolite 3A, zeolite 4A, and zeolite 5A were used as adsorbent. The desorption experiments with several different temperatures in the range of 90∼150℃ and several different flow rates in the ranges of 0∼0.4 L/min on zeolite bed were carried out. The desorption ability of water vapor was most effective on zeolite 5A among the compared zeolites. The higher the desorption temperature of water vapor was, the faster the desorption velocity was. The desorption ability of water vapor with an air supply was higher than that without an air supply. The most appropriate air flow rate was considered as 0.1 L/min.
        78.
        2012.11 KCI 등재 서비스 종료(열람 제한)
        Odor from sewage treatment plants have the potential to cause significant annoyance and to impact the amenity. In this study, odor emission characteristics at unit process of 48 sewage treatment facilities in 39 plants were evaluated using composite odor concentration and hydrogen sulfide (H2S) concentration. The values of composite odor concentration (geometry mean) and H2S concentration (median) for sludge treatment processes are higher than those for the other treatment processes. The composite odor concentration and H2S concentration are distributed over a wide area in each process. Composite odor concentration (dilution ratio) was found to have the significant correlation with H2S concentration (p=0.000<0.05). The H2S concentration accounted for 67.1% of composite odor concentration.
        79.
        2012.10 KCI 등재 서비스 종료(열람 제한)
        The purpose of this work is to study the adsorption and desorption characteristics of acetone vapor and toluene vapor from adsorption tower in the VOCs recovery device. The six kinds of activated carbon with different pore structures were used and the adsorption and desorption characteristics were compared according to pore structure, desorption temperature, and adsorption method, respectively. Adsorption capacity of acetone vapor and toluene vapor by batch method was higher than that by dynamic method. Especially, activated carbon with medium-sized or large pores had more difference in adsorption capacity according to adsorption methods as a result of gradually condensation of vapors on relatively mesopore and large pores. Activated carbons with relatively large pores and relatively small saturated adsorption capacity had excellent desorption ability.
        80.
        2012.05 KCI 등재 서비스 종료(열람 제한)
        The adsorption behavior of Eosin Y on activated carbon (AC) in batch system was investigated. The adsorption isotherm could be well fitted by the Langmuir adsorption equation. The kinetics of adsorption followed the pseudo-second-order model. The temperature variation was used to evaluate the values of free energy (ΔG°), enthalpy (ΔH°) and entropy (ΔS°). The positive value of enthalpy change ΔH° for the process confirms the endothermic nature of the process and more favourable at higher temperature, the positive entropy of adsorption ΔS° reflects the affinity of the AC material toward Eosin Y and the negative free energy values ΔG° indicate that the adsorption process is spontaneous. With the increase of the amount of AC, removal efficiency of Eosin Y was increased, but adsorption capacity was decreased. And adsorption capacity was increased with the decrease of particle size. With the increase of the amount of AC, removal efficiency of Eosin Y was increased, but adsorption capacity was decreased. And adsorption capacity was increased with the decrease of particle size.
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