Tae-Young Jeong

Yonsei University, Sŏul, Seoul, South Korea

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Publications (11)20.84 Total impact

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    ABSTRACT: The aim of this study was to investigate how basic adsorption isotherms could be applied to predict removal efficiency or required adsorbent mass under given sets of initial conditions. The intrinsic parameters of the Langmuir and Freundlich adsorption isotherms were experimentally obtained and subsequently utilized to predict removal efficiencies for other sets of initial solute concentrations, solution volumes, and adsorbent masses, or to estimate the adsorbent mass required to remove solute at a desired removal efficiency. This was accomplished by combining the isotherms with mass balance of solutes between liquid solution and solid adsorbent phases.
    Journal of Industrial and Engineering Chemistry 02/2015; DOI:10.1016/j.jiec.2015.02.021 · 2.06 Impact Factor
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    ABSTRACT: The precipitation reaction between the orthophosphate and Fe2+ ions was studied to describe the optimum condition for the removal of orthophosphate from the aqueous solution. The effects of pH, Fe:P molar ratio, and alkalinity were evaluated for the initial orthophosphate concentrations in the range from 1.55 to 31.00 mg/L - PO4(3-) -P. The optimum pH was found to be 8.0 in all orthophosphate concentration ranges. When the stoichiometric moles of Fe2+ were added, the removal efficiencies were significantly less than the theoretical values. It is likely that the precipitation of Fe(OH)2(s) is partially formed. For the initial orthophosphate concentration of 3.10 mg/L PO4(3-) -P or greater, the removal efficiencies with the Fe:P molar ratio of 3.0:1.0 approached to the theoretical values, yielding greater than 98.5%. If the molar ratio of Fe:P was great enough, the precipitation reaction was completed within 1 h. As the alkalinity increases, the experimental removal efficiencies were significantly greater than the theoretical values. This is because the formation of vivianite is favoured over FeCO3(s). Finally, it was demonstrated that the orthophosphate (1.40-6.80 mg/L PO4(3-) -P) in the secondary effluents from wastewater treatment plants was effectively removed by dosing sufficient amount of Fe2+ ions.
    Environmental Technology 08/2014; 35(13-16):1668-75. DOI:10.1080/09593330.2013.879495 · 1.20 Impact Factor
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    ABSTRACT: The removal of orthophosphate ions from aqueous solutions by the anion exchange resin in the form of ion was investigated to elucidate the ion exchange mechanism which depends on the forms of orhthophoshate ions. In addition, the effects of alkalinity and other common anions were studied. The results showed that the orhthophosphate ions with the oxidation state of 2 and 3 ( and ) were effectively removed by the anion exchange resin, whereas the part of the ion passed through the ion exchange column. This suggested that the affinity of to the ion exchange resin was comparable with that of ion. In all cases, the effluent pHs have shown to be much lower than the calculated values, indicating that more ions than the orthophosphate equivalents in the influent were eluded. As the alkalinity increases, the decrease in pH was minimized. When the alkalinity was 100 mg/L () or greater, 100 mg/L orthophosphate ions including were completely removed. The common anions such as and were also removed by the anion exchange resin, and thus decreased the ion exchange capacity for the removal of orthophosphate.
    01/2012; 34(3).
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    ABSTRACT: The inhibition of methane production in the continuous anaerobic degradation process for the treatment of sewage sludge containing sulfate was investigated. Also, the competition between sulfate-reducing bacteria (SRB) and methane-producing bacteria (MPB) with COD/sulfate ratio was explained in terms of electron flow. The methane production rate was 0.07, 0.13, 0.24, 0.31 and 0.33 l-CH4 g-COD−1 when the initial COD/sulfate ratio was 3.3, 5.0, 6.7, 10 and 20, respectively. The numbers of SRB and MPB were counted after the continuous reactor reached steady state and the two bacteria showed opposite growth behaviors with COD/sulfate ratio. The inhibition by sulfate compounds was found to follow the uncompetitive model and inhibition constants were 24.57 and 87.99 mg l −1 for SRB and MPB, respectively. These results can be useful data for the efficient treatment of sewage sludge in a continuous anaerobic degradation process.
    Korean Journal of Chemical Engineering 09/2009; 26(5):1319-1322. DOI:10.1007/s11814-009-0229-0 · 1.24 Impact Factor
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    ABSTRACT: The effect of chemical oxygen demand/sulfate (COD/SO(4)(2-)) ratio on fermentative hydrogen production using enriched mixed microflora has been studied. The chemostat system maintained with a substrate (glucose) concentration of 15 g COD L(-1) exhibited stable H(2) production at inlet sulfate concentrations of 0-20 g L(-1) during 282 days. The tested COD/SO(4)(2-) ratios ranged from 150 to 0.75 (with control) at pH 5.5 with hydraulic retention time (HRT) of 24, 12 and 6h. The hydrogen production at HRT 6h and pH 5.5 was not influenced by decreasing the COD/SO(4)(2-) ratio from 150 to 15 (with control) followed by noticeable increase at COD/SO(4)(2-) ratios of 5 and 3, but it was slightly decreased when the COD/SO(4)(2-) ratio further decreased to 1.5 and 0.75. These results indicate that high sulfate concentrations (up to 20,000 mg L(-1)) would not interfere with hydrogen production under the investigated experimental conditions. Maximum hydrogen production was 2.95, 4.60 and 9.40 L day(-1) with hydrogen yields of 2.0, 1.8 and 1.6 mol H(2) mol(-1) glucose at HRTs of 24, 12 and 6h, respectively. The volatile fatty acid (VFA) fraction produced during the reaction was in the order of butyrate>acetate>ethanol>propionate in all experiments. Fluorescence In Situ Hybridization (FISH) analysis indicated the presence of Clostridium spp., Clostridium butyricum, Clostridium perfringens and Ruminococcus flavefaciens as hydrogen producing bacteria (HPB) and absence of sulfate reducing bacteria (SRB) in our study.
    Water Research 05/2009; 43(14):3525-33. DOI:10.1016/j.watres.2009.04.023 · 5.32 Impact Factor
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    ABSTRACT: Methane production using the mixed organic wastes of peel-type fruit wastes from apple or orange and sewage sludge was investigated in the batch anaerobic degradation process. When apple or orange peels with sewage sludge were used as mixed substrates, higher methane production was achieved under the condition of 3 : 7 (fruit peel : sewage sludge) mixing ratio. However, above the 3 : 7 mixing ratio, the pH of mixture was decreased from 8.0 to 4.5∼4.7 due to organic acid production from the fruit wastes. Subsequently, methane production was low. The results in this study could be effectively applied to the methane gas production system as a bioenergy in the mixed batch anaerobic digestion process using the peel-type fruit wastes and sewage sludge.
    Journal of the Korean Industrial and Engineering Chemistry 01/2009; 20(5).
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    ABSTRACT: The effect of varying sulfate concentration on continuous fermentative hydrogen production was studied using enriched mixed microflora in continuously fed reactor. Glucose was used as a model substrate for carbohydrates, and hydraulic retention time (HRT) was maintained at 1, 0.5, 0.25 day, respectively. Sulfate concentration was 020,000 mg/L and the operating pH was maintained at 5.5. The experimental results indicate that hydrogen production is not affected by high sulfate concentration and shorter HRT of 0.25 day enhance hydrogen production. At HRT 1, 0.5, 0.25 day, the hydrogen production rate and hydrogen yield were 2.6, 4.6, 9.4 L/day, and 2.0, 1.8, 1.6 mol /mol glucose, respectively. Residual sulfate content was 9698, 9597, and 9497% at HRT 1, 0.5, 0.25 day which show that no sulfate reduction occurred in the reactor during the experiments. Results of Fluorescence In Situ Hybridization (FISH) may indicate the presence of HPB (hydrogen producing bacteria) under all experimental conditions. However, SRB (sulfate reducing bacteria) were not found.
    01/2009; 31(6).
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    ABSTRACT: A study on the effects of the COD/sulfate ratio on characteristics of sulfate-reducing bacteria (SRB) and methane-producing bacteria (MPB), using waste activated sludge (WAS), were performed in batch anaerobic digestion. The methane production rates of untreated and thermal treated WAS were 0.21–1.23, and 0.64–2.02 mL/day VSS, respectively. In the meantime, the hydrogen sulfide gas production rates of untreated and thermal treated WAS were 0–0.36, and 0–0.21 mL/day VSS, respectively. The methane production rate decreased as about 60% at the 11.6 of COD/sulfate ratio. In the case of high influent CODs, the methane production rate increased while the hydrogen sulfide rate decreased. It is thought that it is necessary to regulate the COD concentration in influent wastewaters in order to decrease the effects of SRB. The concentrations of various components such as sulfate should be properly controlled to reduce the methane production inhibition caused by the SRB in the anaerobic digestion using WAS.
    Journal of Industrial and Engineering Chemistry 09/2008; 14(5):693-697. DOI:10.1016/j.jiec.2008.05.006 · 2.06 Impact Factor
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    ABSTRACT: The characteristics of hydrogen production by four different hydrogen-producing bacteria (Clostridium beijerinckii, Rhodobacter sphaeroides, anaerobic bacteria isolated from sludge digester and Bacillus megaterium) were investigated quantitatively. The mathematical analysis using Gompertz equation showed that C. beijerinckii was the best hydrogen producer from glucose in terms of hydrogen-production potential and specific hydrogen-production rate. However, the bacteria required relatively long lag time at high-initial glucose concentration. The anaerobic bacteria showing the highest maximum hydrogen-production rate and relatively short lag time have a limit of low-hydrogen-production potential because they are mixed culture and produce some amount of methane gas. C. beijerinckii will be used in the actual system for hydrogen production from carbohydrate but the anaerobic bacteria may be a good choice for the production of hydrogen from wastewater containing innumerable compounds.
    Journal of Industrial and Engineering Chemistry 05/2008; 14(3):333-337. DOI:10.1016/j.jiec.2007.09.014 · 2.06 Impact Factor
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    ABSTRACT: The possibility and characteristics of hydrogen production from waste activated sludge were investigated using separation membrane acid fermentation reactor (AR) and photosynthetic reactor (PR). The AR used submerged and external separation membranes and it was followed by the PR. The COD removal efficiencies in the AR with submerged and external separation membrane were about 65% and 40%, respectively. More VFA was produced in the AR with external separation membrane than AR with submerged separation membrane. Hydrogen was produced in the PR but not in the AR and hydrogen productions in the PR connected with submerged membrane AR and external membrane AR were about 50.1 and 160.5ml H2/g T-VFA, respectively.
    International Journal of Hydrogen Energy 04/2007; 32(5):525-530. DOI:10.1016/j.ijhydene.2006.09.028 · 2.93 Impact Factor
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    ABSTRACT: The production and behavior of soluble microbial products (SMP) were investigated by employing a submerged MBR (membrane bio-reactor) process. The two types of bioreactors at different loading rates were conducted to understand the mechanism of bio-fouling and the behavior of SMP in a MBR process. Resultantly, the permeate flux of Run I (low loading rate) was maintained for 35days, while Run II (high loading rate) was maintained for 23 days. The filtration resistance values were similar because they were determined by the accumulated SMP concentration in the bioreactor. The production rate of SMP for Run II was measured as 0.0071 L/day, higher than for Run I (0.0056 L/day). After cleaning the membrane, the permeate flux showed on unstable and gradually decreased high SMP concentration in a short period. It is considered that the rate of accumulation of SMP relates to the biodegradability of utilization-associated products at different loading rate. From this research, we could determine that the volumetric loading rate affected to produce SMP, and SMP effected to not only membrane bio-fouling but also microbial activity.
    Desalination 03/2007; 207(1-3):107-113. DOI:10.1016/j.desal.2006.07.006 · 3.96 Impact Factor