• 제목/요약/키워드: 흡착율

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Comparison of Selective Removal of Nitrate Ion in Constant Voltage and Constant Current Operation in Capacitive Deionization (축전식 탈염에서 정전압과 정전류 운전에 따른 질산 이온의 선택적 제거율 비교)

  • Choi, Jae-Hwan;Kim, Hyun-Ki
    • Korean Chemical Engineering Research
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    • v.53 no.3
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    • pp.269-275
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    • 2015
  • The adsorption characteristics of ions were evaluated for the nitrate-selective carbon electrode (NSCE) in accordance with power supply methods. The NSCE was fabricated by coating the surface of a carbon electrode with anion-exchange resin powders with high selectivity for the nitrate ion. Capacitive deionization (CDI) experiments were performed on a mixed solution of nitrate and chloride ion in constant voltage (CV) and constant current (CC) modes. The number of total adsorbed ions in CV mode was 15% greater than that in CC mode. The mole fraction of adsorbed nitrate ion showed the maximum 58%, though the mole fraction was 26% in the mixed solution. This indicates that the fabricated NSCE is highly effective for the selective adsorption of nitrate ions. The mole fraction of adsorbed nitrate was nearly constant value of 55-58% during the adsorption period in CC mode. In the case of CV mode, however, the values increased from the initial 30% to 58% at the end of adsorption. We confirmed that the current supplied to cell is important factor to determine the selective removal of nitrate.

Removal of Ammonia Nitrogen, Manganese and Arsenic in The Ion Exchanged Natural Zeolite (이온 치환된 천연 제올라이트를 활용한 암모니아성 질소, Mn, As의 제거)

  • Lee, Kyung-Han;Kil, Bo-Min;Ryu, Cheol-Hwi;Hwang, Gab-Jin
    • Membrane Journal
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    • v.29 no.5
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    • pp.237-245
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    • 2019
  • Ammonia nitrogen is well known as a substance that causes the eutrophication with a phosphorus in the water, because it is contained in the industrial wastewater, agricultural and the stockbreeding wastewater. In addition, manganese (Mn) and arsenic (As) are included in the mine treated water, etc., and are known as a source of water pollution. Natural zeolites are used to remove ammonia nitrogen in water but it have a low adsorption capacity. In order to improve the low adsorption capacity of the natural zeolite, ion substitution was carried out with $Na^+$, $Ca^{2+}$, $K^+$ and $Mg^{2+}$. The adsorption capacity and removal rate of ammonia nitrogen ($NH_4-N$) were the highest at 0.66 mg/g and 89.8% in $Na^+$ ion exchanged zeolite. Adsorption experiments of Mn and As were performed using ion exchanged zeolites. Ion exchanged zeolite with $Mg^{2+}$ showed high adsorption capacity and removal rates of Mn and As.

Removal Characteristics of Geosmin and MIB in BAC Process : Biodegradation and Adsorption (생물활성탄 공정에서 Geosmin과 MIB의 제거 특성 : 생물분해와 흡착)

  • Son, Hee-Jong;Lee, Jeong-Kyu;Kim, Sang-Goo;Park, Hong-Ki;Jung, Eun-Young
    • Journal of Korean Society of Environmental Engineers
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    • v.39 no.6
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    • pp.318-324
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    • 2017
  • We evaluated geosmin and MIB biodegradation and adsorption mechanism of biological activated carbon (BAC) and anthracite biofilter. In steady state of BAC process, the geosmin and MIB were completely removed at the 30 min empty bed contact time (EBCT) even though low water temperature ($9^{\circ}C$) in which the activity of attached bacteria decreased. When the water temperature was $26^{\circ}C$, the microbial biomass and activity were higher at the upper layer of the biofilm than at $9^{\circ}C$, and the microbial biomass and activity decreased as the depth was deeper. This is because when the water temperature is high, the biodegradable organic matter (BOM) removal rate in the upper layer is high and the BOM amount that can't be supplied to the lower layer. The Removal rate of geosmin and MIB by BAC process did not show a significant difference compare to activity-inhibited BAC by treated with azide and the biofilter also removed the geosmin and MIB by biological action. It means geosmin and MIB could be removed by competitive relationship between adsorption and biodegradation.

A Comparative Study on Adsorption Characteristics of PCBs in Transformer Oil Using Various Adsorbents (여러 흡착제를 이용한 변압기 오일 중의 PCBs 흡착특성에 관한 비교연구)

  • Ryoo, Keon Sang;Hong, Yong Pyo;Ahn, Chun Ju
    • Journal of the Korean Chemical Society
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    • v.56 no.6
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    • pp.692-699
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    • 2012
  • The aim of the present study is to explore the possibility of utilizing loess and fly ash as well as activated carbon for the adsorptive removal of PCBs in transformer oil. Here, we investigated the effect of various factors such as temperature (5, 25, 55), contact time (30 min-3 day) and adsorbent does (1, 2.5, 5, 10 g) in detail. It was found that PCBs adsorption rate from transformer oil by activated carbon is more favored than loess at the equilibrium time of 60 minutes. The equilibrium data for both activated carbon and loess is fitted well to the Freundlich isotherm model. The rate constant and activation energy of PCBs adsorption in transformer oil on each adsorbent was analyzed by fitting a kinetic model at 5, 25 and $55^{\circ}C$. From the thermodynamic parameters, the PCBs adsorption process for transformer oil/activated carbon and loess system is spontaneous and endothermic in nature.

Removal of As(III) and As(V) in Aqueous Phases by Fe and Mn Oxides Coated Granular Activated Carbon (철 및 망간 산화물로 코팅된 입자활성탄을 이용한 수용액 중 As(III) 및 As(V)의 제거)

  • Lee, Hee-Yong;Yang, Jung-Seok;Choi, Jae-Young;Lee, Seung-Mok
    • Journal of Korean Society of Environmental Engineers
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    • v.31 no.8
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    • pp.619-626
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    • 2009
  • The objective of this study was to evaluate the efficiency of Fe and Mn oxides coated granular activated carbons (FMOCGs) for the removal of arsenite and arsenate by oxidation and adsorption mechanisms using surface characterization and batch adsorption experiments. Within four manufactured adsorbents, Fe and Mn contents of FMOCG-1 was the highest (178.12 mg Fe/g and 11.25 mg Mn/g). In kinetic results, As(III) was removed by oxidation and adsorption with FMOCGs. Removal of arsenic by FMOCGs increased as pH value of the solution decreased. The adsorption isotherm results were well fitted with Langmuir isotherm. Adsorption amount of As(V) onto FMOCGs was higher than that of As(III) and the maximum adsorption capacities of FMOCGs for As(III) and As(V) were 1.38~8.44 mg/g and 2.91~9.63 mg/g, respectively.

A Comparative Study on Adsorption Behavior of Heavy Metal Elements onto Soil Minerals : Illite, Halloysite, Zeolite, and Goethite (토양광물에 대한 중-금속원소의 흡착특성 비교연구: 일라이트, 할로이사이트, 제올라이트, 및 침철석)

  • 추창오;성익환
    • Journal of Korea Soil Environment Society
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    • v.4 no.1
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    • pp.57-68
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    • 1999
  • Adsorption behavior of metal elements onto soil minerals such as illite, halloysite. zeolite(clinoptilolite). and goethite was comparatively investigated at $25^{\circ}C$ using pollutant water collected from a gold-bearing metal mine. Speciation of solutions reacted was determined by WATEQ4F program, indicating that most of metal ions exist as free ions and that there is little difference in chemical species and their relative abundances between initial soultion and reacted solutions. The experimental data exhibit that the adsorption extent of elements varies depending on mineral types and reaction time. The adsorption process practically took place within one hour, with Fe and As significantly removed from solutions. On the whole, halloysite is regarded as the most effective adsorbent among minerals used in the experiment. Adsorption properties of alkali elements do not consistent with a manner predicted from hydrated ionic radii.

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Equilibrium, Kinetic and Thermodynamic Parameter Studies on Adsorption of Acid Black 1 Using Coconut Shell-Based Granular Activated Carbon (야자각계 입상 활성탄의 Acid Black 1 염료 흡착에 대한 평형, 동역학 및 열역학 파라미터의 연구)

  • Lee, Dong-Chang;Lee, Jong-Jib
    • Applied Chemistry for Engineering
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    • v.27 no.6
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    • pp.590-598
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    • 2016
  • In this study, the adsorption behavior from aqueous solution as well as kinetic and thermodynamic parameters of Acid Black 1 were investigated through batch reaction using coconut shell based granular steam activated carbon. The effects of various adsorption parameters such as pH, initial concentration, contact time, temperature were studied. To confirm the effect of pH, pHpzc measurements were analyzed followed by measuring removal efficiencies of Acid Black 1 at the pH range from 3 to 11. Experimental equilibrium adsorption data were fitted using Langmuir, Freundlich, Temkin and Dubinin-Radushkevich adsorption isotherm. The conformity of adsorption reaction for pseudo first and second order model were evaluated through kinetic analysis. Values of enthalpy change and activation energy were also investigated through thermodynamic analysis and it was confirmed that the adsorption process was endothermic. The spontaneity of adsorption process was evaluated using the values of entropy and Gibbs free energy changes.

Biosorption of Pb and Cr by using Sargassum sagamianum (비틀대모자반, Sargassum sagamianum을 이용한 Pb 및 Cr 생체흡착 및 회수)

  • SUH Kuen-Hack;AHN Kab-Hwan;LEE Hack-Sung;LEE Hwae-Geon;CHO Jin-Koo;HONG Yong-Ki
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.32 no.4
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    • pp.399-403
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    • 1999
  • Biosorption of Pb and Cr to Sargassum sagamianum was evaluated in the various conditions. An adsorption equilibrium was reached in about 15 min. for Pb and Cr. The uptake capacity was 224.5 mg Pb/g biomass and 77.5 mg Cr/g biomass, respectively. The adsorption parameters for Pb and Cr were determined according to Langmuir and Freundlich model. Biosorption of Pb and Cr was increased with an increase in pH value. Pb and Cr adsorbed by S. sagamianum could be recovered by desorption process with 0.1M HCl, 0.1M $HNO_3$ and 0.1M EDTA and the efficiency of Pb desorption was above $90\%$, whereas the efficiency of Cr desorption was below $51\%$.

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Modeling of the Nitrate Adsorption Kinetics onto $ZnCl_2$ Treated Granular Activated Carbon (염화아연으로 표면개질된 입상활성탄의 질산성질소 흡착속도의 모델링 연구)

  • Ji, Min-Kyu;Jung, Woo-Sik;Bhatnagar, Amit;Jeon, Byong-Hun
    • Journal of Soil and Groundwater Environment
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    • v.13 no.3
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    • pp.21-26
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    • 2008
  • Nitrate adsorption from aqueous solutions onto zinc chloride ($ZnCl_2$) treated coconut Granular Activated Carbon (GAC) was studied in a batch mode at two different initial nitrate concentrations (25 and 50 mg/L). The rate of nitrate uptake on prepared media was fast in the beginning, and 50% of adsorption was occurred within 10 min. The adsorption equilibrium was achieved within one hour. The mechanism of adsorption of nitrate on $ZnCl_2$ treated coconut GAC was investigated using four simplified kinetic models : the rate parameters were calculated for each model. The kinetic analysis indicated that pseudo-second-order kinetic with pore-diffusion-controlled was the best correlation of the experimental kinetic data in the present adsorption study.

Effects of Humic Acid on the pH-dependent Sorption of Europium (Eu) to Kaolinite (PH 변화에 따른 카올리나이트와 유로퓸(Eu)의 흡착에 대한 휴믹산의 영향)

  • Harn, Yoon-I;Shin, Hyun-Sang;Rhee, Dong-Seok;Lee, Myung-Ho;Chung, Euo-Cang
    • Journal of Soil and Groundwater Environment
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    • v.14 no.4
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    • pp.23-32
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    • 2009
  • The sorption of europium (Eu (III)) onto kaolinite and the influence of humic acids over a range of pH 3 ~ 11 has been studied by batch adsorption experiment (V/m = 250 : 1 mL/g, $C_{Eu(III)}\;=\;1\;{\times}\;10^{-5}\;mol/L$, $C_{HA}\;=\;5{\sim}50\;mg/L$, $P_{CO2}=10^{-3.5}\;atm$). The concentrations of HA and Eu(III) in aqueous phase were measured by UV absorbance at 254nm (e.g., $UV_{254}$) and ICP-MS after microwave digestion for HA removals, respectively. Results showed that the HA sorption onto kaolinite was decreased with increasing pH and their sorption isotherms fit well with the Langmuir adsorption model (except pH 3). Maximum amount ($q_{max}$) for the HA sorption at pH 4 to 11 was ranged from 4.73 to 0.47 mg/g. Europium adsorption onto the kaolinite in the absence of HA was typical, showing an increases with pH and a distinct adsorption edge at pH 3 to 5. However in the presence of HA, Eu adsorption to kaolinite was significantly affected. HA was shown to enhance Eu adsorption in the acidic pH range (pH 3 ~ 4) due to the formation of additional binding sites for Eu coming from HA adsorbed onto kaolinite surface, but reduce Eu adsorption in the intermediate and high pH above 6 due to the formation of aqueous Eu-HA complexes. The results on the ternary interaction of kaolinte-Eu-HA are compared with those on the binary system of kaolinite-HA and kaolinite-Eu and adsorption mechanism with pH was discussed.