• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2006년도 하계학술발표대회 논문집
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• pp.607-612
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• 2006

A pressure-type rapid automatic filter of 2000mm diameter and 170 ton/h filtering capacity was fabricated. In case of no external impurity inflow, the turbidity removal efficiency on raw water was experimented and the numbers of impurities of each sizes were analyzed by particle counter. As the result of circulated filtering, the raw water of 40 NTU was filtered to 0.44 NTU and the numbers of impurities above $1{\mu}m$ were removed by approximately 95%. With the filtering efficiency experimented and the mathematical method, the turbidity change of circulation water were calculated according to the inflow rate of external impurity and water treatment method of blow-down or filtering. The cost of blow-down water was calculated from above results. And simple payback period for this filter is calculated as about one year. Nowadays, as the cost of water is continuously increasing and environment regulations will be more strict, the water quality control using this filter will be expected to satisfy the user requirement.

• Nuclear Engineering and Technology
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• 제53권9호
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• pp.2926-2936
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• 2021

Rare-earth (RE) industries generate a massive amount of radioactive residue containing high thorium concentrations. Due to the fact that thorium is considered a non-economic element, large volume of these RE processed residues are commonly disposed of without treatment. It is essential to study an appropriate treatment that could reduce the volume of waste for final disposition. To this end, this research investigates the applicability of carbon-based adsorbent in separating thorium from aqueous phase sulphate is obtained from the cracking and leaching process of solid rare-earth by-product residue. Adsorption of thorium from the aqueous phase sulphate by carbon-based electrodes was investigated through electrosorption experiments conducted at a duration of 180 minutes with a positive potential variable range of +0.2V to +0.6V (vs. Ag/AgCl). Through this research, the specific capacity obtained was equivalent to 1.0 to 5.14 mg-Th/g-Carbon. Furthermore, electrosorption of thorium ions from aqueous phase sulphate is found to be most favorable at a higher positive potential of +0.6V (vs. Ag/AgCl). This study's findings elucidate the removal of thorium from the rare-earth residue by carbon-based electrodes and simultaneously its potential to reduce disposal waste of untreated residue.

• Nuclear Engineering and Technology
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• 제53권5호
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• pp.1717-1722
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• 2021

This study is devoted to the ability of carbon fiber material samples impregnated with various amounts of barium iodide and triethylenediamine to remove radioactive methyliodide from air streams. The main sorption characteristics of impregnated UVIS® carbon fiber were determined and the use of this material for purifying of technological gas flows at nuclear power plants was evaluated. The methyliodide trapping efficiency by samples impregnated with barium iodide, TEDA, and their mixture was 83.4 ± 0.8%; 93.1 ± 0.6% and 93.5 ± 0.7% respectively, under the same conditions. The study established a significantly higher capacity (8.3 ± 0.07 mg/cm²) of samples impregnated simultaneously with both chemical compounds toward methyliodide. Under the same test conditions, the values of this parameter for the samples impregnated separately with TEDA and BaI₂ were 2.85 ± 0.05 mg/cm² and 0.86 ± 0.04 mg/cm², respectively.

• 실내환경 및 냄새 학회지
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• 제17권4호
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• pp.396-403
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• 2018

In this study, volatile organic compounds (VOCs) emitted from printing industries were analyzed, and an inorganic adsorbent, ${\gamma}-alumina$, was selected for the effective control of the VOC emissions. Printing processes commonly require inks, thinners, and cleaners, and they were mixed organic solvents containing aromatic compounds, ketones, and alcohols. Therefore, toluene, methyl ethyl ketone (MEK), and isopropyl alcohol (IPA) were selected as model compounds for this study. The adsorptive properties using ${\gamma}-alumina$ were determined for the model compounds. Both batch isotherm and continuous flow column tests demonstrated that the adsorption capacity of MEK and IPA was 3~4 times higher than that of toluene. The column test performed at an inlet toluene concentration of 100 ppm showed that an 80% breakthrough for toluene was observed after 3 hours, but both MEK and IPA were continuously adsorbed during the same time period. A numerical model simulated that the ${\gamma}-alumina$ could remove toluene at a loading rate of 0.4 mg/min only for a 4-hour period, which might be too short of a duration for real applications. Consequently, lifetime enhancement for ${\gamma}-alumina$ must be implemented, and ozone oxidation and regeneration would be feasible options.

• 한국환경과학회지
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• 제30권9호
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• pp.719-726
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• 2021

In this study, zeolitic materials were synthesized from Jeju Volcanic Rocks (JVR) using a fusion/hydrothermal method at NaOH/JVR ratios of 0.6 and 1.2. The crystallinities of the zeolitic materials at NaOH/JVR ratios of 0.6 and 1.2 were 25.5% and 59.0%, respectively. It was confirmed through the SEM image that the zeolitic materials covered the zeolite particle with a cube-shaped crystals. The Co ions adsorption by the zeolitic materials were to reach the adsorption equilibrium at 120 min. It could be better simulated in the pseudo-second order adsorption kinetic equation than in the pseudo-first order adsorption kinetic equation. The adsorption capacities (q_m) of Co ions could be to estimate Langmuir isotherm better than Freundlich isotherm. The maximum adsorption capacities (q_m) at NaOH/JVR ratios of 0.6 and 1.2 were 55.3 mg/g and 68.7 mg/g, respectively. It was found that there was a high correlation between the crystallinity of zeolitic materials and the adsorption capacity of Co ions adsorption.

• 방사성폐기물학회지
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• 제19권1호
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• pp.39-49
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• 2021

The behaviors of various desorption agents were investigated during the desorption of cesium (Cs) from samples of clay minerals and actual soil. Results showed that polymeric cation exchange agents (polyethyleneimine (PEI)) efficiently desorbed Cs from expandable montmorillonite, whereas acidic desorption solutions containing HCl or PEI removed considerable Cs from hydrobiotite. However, most desorption agents could desorb only 54% of Cs from illite because of Cs's specific adsorption to selective adsorption sites. Cs desorption from an actual soil sample containing Cs-selective clay mineral illite (< 200 ㎛) and extracted from near South Korea's Kori Nuclear Power Plant was also investigated. Considerable adsorbed 137Cs was expected to be located at Cs-selective sites when the 137Cs loading was much lower than the sample's cation exchange capacity. At this low 137Cs loading, the total Cs amount desorbed by repeated washing varied by desorption agent in the order HCl > PEI > NH4+, and the highest Cs desorption amount achieved using HCl was 83%. Unlike other desorption agents with only cation exchange capabilities, HCl can attack minerals and induce dissolution of metallic elements. HCl's ability to both alter minerals and induce H+/Cs+ ion exchange is expected to promote Cs desorption from actual soil samples.

• Membrane and Water Treatment
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• 제10권6호
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• pp.405-415
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• 2019

Microcystins (MCs) are toxins produced by cyanobacteria causing a major environmental threat to water resources worldwide. Although several MCs have been reported in previous studies, microcystin-LR (m-LR) has been extensively studied as it is highly toxic. Among the several techniques employed for the removal of this toxin, adsorption with AC has been extensively studied. AC has gained wide attention as an effective adsorbent of m-LR due to its ubiquity, high sorption capacity, cost effectiveness and renewability. In this review, the adsorption of m-LR onto AC was evaluated using the information available in existing scientific literature. The effects of the pore volume and surface chemistry of AC on the adsorption of m-LR considering the structural and chemical properties of ACs were also discussed. Furthermore, we identified the parameters that influence adsorption, including natural organic matter (NOM), pH, and ionic strength during the m-LR adsorption process. The effect of these parameters on MCs adsorption onto AC from previous studied is compiled and highlighted. This review may provide new insights into future activated carbon-m-LR adsorption research, and broaden its application prospects.

• Korean Journal of Chemical Engineering
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• 제35권11호
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• pp.2191-2197
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• 2018

To remove tar and produce environment-friendly $H_2$, one of the promising routes is the sorption-enhanced steam reforming (SESR) process, in which the $CO_2$ sorbent is a key element. We prepared the $CO_2$ sorbents with $Ca_{12}Al_{14}O_{33}$ as carrier with various methods. Their characterizations were examined, and the sample prepared by solgel (SG) method showed the strongest CaO and $Ca_{12}Al_{14}O_{33}$ phases and the most excellent pore structure among all the samples. Then, a thermogravimetric experiment was conducted, and the results showed that the sample prepared by sol-gel (SG) method had the best $CO_2$ adsorption capacity and excellent long-term cyclic stability. Finally, the sorbent was used into the steam reforming experiments of tar. Under the action of the sorbent, the reforming reaction was enhanced in-situ, with the $H_2$ yield and concentration improved obviously, and especially, $H_2$ concentration can reach over 98.85%.

• Nuclear Engineering and Technology
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• 제54권6호
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• pp.1991-2003
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• 2022

The problem of water contamination by long-living cesium and strontium radionuclides is an urgent environmental issue. The development of facile and efficient technologies based on nanostructured adsorbents is a perspective for selective radionuclides removal. In this regard, current work aimed to obtain the nanostructured magnetic zeolite composites with high adsorption performance to cesium and strontium ions. The optimal conditions of hydrothermal synthesis were established based on XRD, SEM-EDX, N₂ adsorption-desorption, VSM, and batch adsorption experiment data. The role of chemical composition, textural characteristics, and surface morphology was demonstrated. The monolayer ionexchange mechanism was proposed based on adsorption isotherm modeling. The highest Langmuir adsorption capacity of 229.6 and 105.1 mg/g towards cesium and strontium ions was reached for composite obtained at 90 ℃ hydrothermal treatment. It was shown that magnetic characteristics of zeolite composites allowing to separate spent adsorbents by a magnet from aqueous solutions.

• Coupled systems mechanics
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• 제11권2호
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• pp.121-132
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• 2022

Wastewater treatment plants (WWTPs) are designed and built to remove contaminants from wastewater. WWTPs are composed of various facilities equipped with hydro-mechanical and electrical equipment. This paper presents a comparison of two different approaches for WWTPs modelling. Static modelling is suitable for determining the dimensions of facilities and equipment capacity. The special significance of this approach is for the design of new plants, i.e., when a very small number of input data on the quantities and composition of the influent wastewater is available. Dynamic modelling is expensive, time consuming and requires great expertise in the use of simulators, models and very good understanding of the treatment processes. Also, dynamic modelling is very important to use for optimization, consideration of future scenarios and also possible scenarios on the plant. The comparison of two approaches was made on the input data from the biggest and most important plant in Bosnia and Herzegovina (B&H)-WWTP Butila (Sarajevo). The main idea is to show the differences between two demanding accesses. It is important to know how to apply an adequate approach to research and solve the set task. The II phase of the plant Butila, which includes the removal of nutrients, is planned in several years and therefore the importance of research has increased.