• Clean Technology
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• v.27 no.3
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• pp.261-268
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• 2021

Equilibrium, kinetics, and thermodynamics of adsorption of acid black 1 (AB1) by coal-based granular activated carbon (CGAC) were investigated with the adsorption variables of initial concentration of dye, contact time, temperature, and pH. The adsorption reaction of AB1 by activated carbon was caused by electrostatic attraction between the surface (H⁺) of activated carbon and the sulfite ions (SO₃^-) and nitrite ions (NO₂^-) possessed by AB1, and the degree of reaction was highest at pH 3 (97.7%). The isothermal data of AB1 were best fitted with Freundlich isotherm model. From the calculated separation factor (1/n) of Freundlich, it was confirmed that adsorption of AB1 by activated carbon could be very effective. The heat of adsorption in the Temkin model suggested a physical adsorption process (< 20 J mol^-1). The kinetic experiment favored the pseudo second order model, and the equilibrium adsorption amount estimated from the model agreed to that given by the experiments (error < 9.73% ). Intraparticle diffusion was a rate controlling step in this adsorption process. From the activation energy and enthalpy change, it was confirmed that the adsorption reaction is an endothermic reaction proceeding with physical adsorption. The entropy change was positive because of an active reaction at the solid-liquid interface during adsorption of AB1 on the activated carbon surface. The free energy change indicated that the spontaneity of the adsorption reaction increased as the temperature increased.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 1997.10a
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• pp.65-66
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• 1997

우리나라의 대부분 하천과 인공댐의 경우 조류발생에 기여하는 영양염은 질소, 인 그리고 규소 등인데 특히 인이 생산제한 인자로 작용하고 있다. 따라서 인을 적절히 제거할 경우에는 조류 발생에 의한 수질의 악화와 수이용의 저해요인을 배제할 수 있어 이에 대한 연구가 많이 진행되어 왔다. 지금까지와 연구는 인의 화학적 응집 침전법, 생물학적 처리법에 대하여 수행되어 왔으나 설비자금, 운영비, 운전기술, 슬러지 생성 그리고 제거효율 등에서 만족스런 결과가 도출되지 못하여 현장 적용을 하지 못하고 있는 실정이다. 이러한 현실을 감안하여 우리의 자연 환경에서 쉽게 자할 수 있는 황토를 모재로하여 Al3-과 Fe3-, Ca2-을 적절히 배합하여, 주로 인을 선택적으로 제거하 고자 개발된 황토의 흡착능력 그리고 흡착 메카니즘에 대한 기본적인 연구를 하고자 (1) 등온흡착실험을 통하여 흡착용량을 평가하고 (2) 흡착제거속도를 평 가하였고 (3)파과시간 및 흡착특성을 파악하기 위해 column 흡착실험을 하였다 또한 (4) 황토내의 Al3-, Fe3-과 Ca2- 등이 인의 화학적 흡착에 기여하는 정도를 파악하여 흡착메카니즘을 규명하고자 하였다. 먼저 흡착용량실험을 위하여 PO3-4-P 농도 3ppm의 용액 200mf에 황토 0.2g, 0.5g, 1.0g, 2.0g을 각각 투여한 후 충분한 흡착평형이 일어나게 24시간 동 안 130rpm으로 $25^{\circ}C$ 등온반웅조에서 저어주어 흡착평형에 도달하면 상등액을 GF/C Filter로 여과한 후, 여액에 대해 PO3-4-P의 농도를 Ascrobic he건법으로 측정한 결파, Freundlich 등온흡착식에 의하면 K값은 17.34와 16.28이었으며 1/n 값은 1.32와 1.42로 인흡착 성능이 뛰어난 것으로 평가되었다. 둘째, 흡착속도 실험은 PO3-4-P 농도 1.5ppm의 용액 2f에 259의 황토를 투여하고 충분한 혼합이 일어날 수 있도록 170rpm으로 교반하면서 시간별 용액 의 농도 변화를 측정한 결과, 0.45mg/g/m교의 속도로 15분만에 94.3%의 인 제거 효율을 보였다. 셋째, 직경 12mm의 glass column에 황토를 209 채우고 1.5ppm의 PO34P 용액을 2.Sne11in의 유량으로 통수 시킨 후, 시간에 따른 농도 변화를 측정한 결과, 원수 농도의 50%에 해당하는 파과점까지 약 70시간 만에 도달하였다. 넷째, Al3-, Fe3-과 Ca2- 등이 화학적 흡착에 기여하는 정도를 파악하기 위 하여 황토 2g에 대하여 Hieltijes and Lijklema 방법에 의해 Adsorbed-p, Nonapatite inorganic-P(NAI-P), Apatite-p, Organic-P로 구분하여 분석하고, 총인(Total Phosphorus)을 Standard Methods에 따라 Persulfate digestion후 0.45 m membrane 여지 여과하여 여액에 대해 PO3-4-P의 농도를 Ascorbic Acid 법으로 측정한 결과, NAI-P가 가장 큰 비율을 차지하였고, 부원료로 첨가된 금속 양이온 중 Fe3-이온이 흡착에 기여하는 정도가 가장 큰 것으로 평가되었다.

• Resources Recycling
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• v.22 no.1
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• pp.55-63
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• 2013

Considering considerable contents of vanadium and tungsten in spent SCR DeNOx catalysts, separation and recovery of those metals are required. In this respect, commercial anion exchange resin (MP600) was employed to recover vanadium from the synthetic solution of ammonium metavanadate. Experimental results indicated that vanadium exist as anion under the acidic condition (pH 2 ~ 6) and adsorbed on the resin. Although the adsorption rate was increased with temperature, the maximum amount of adsorption was not affected by temperature. Desorption took place under either strong acidic (less than pH 1) or strong caustic (higher than pH 13) condition. However, desorption seldom took place under moderate conditions (pH 3~11). Furthermore, adsorption equilibrium results agreed well with Freundlich isotherm and pseudo-second-order reactions. And, adsorption energy was evaluated using Dubinin-Radushkevich and Temkin isotherm.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.9
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• pp.907-912
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• 2008

In order to reduce the availability of dissolved inorganic phosphorus in surface water, lakes, and estuaries, black shale and zero valent iron can be used as reacitve materials. Sorption of phosphate to sampled sediment, black shale, and zero valent iron was quantitatively evaluated in this research. Effect of coexistence of calcium was also tested, since coexisting ions can enhance the precipitation of phosphate. An empirical kinetic model with fast sorption(k$_t$), slow sorption(k$_s$), and precipitation(k$_p$) was well fitted to experiment data from this research. Langmuir and Freundlich sorption isotherms were also used to evaluated phosphate maximum sorption capacity. Calcium ions at 0, 1 and 5 mM affected the precipitation kinetic coefficient in empirical kinetic model but did not have impact on the maximum sorbed concentration.

• Journal of the Korean Electrochemical Society
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• v.4 no.1
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• pp.14-20
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• 2001

The Langmuir adsorption isotherms of the under-potentially deposited hydrogen (UPD H) and the over-potentially deposited hydrogen (OPD H) at the single crystal Pt(100)/0.5 M $H_2SO_4$ and 0.5 M LiOH aqueous electrolyte interfaces have been studied using the phase-shift method. The phase-shift profile $({-\varphi}\;vs.\;E)$ for the optimum intermediate frequency can be used as a useful method to estimate the Langmuir adsorption isotherm $(\theta\;vs.\;E)$ at the interfaces. The equilibrium constant (K) for the OPD H and the standard free energy $({\Delta}G_{ads})$ of the OPD H at the Pt(100)/0.5M $H_2SO_4$ aqueous electrolyte interface are $1.5\times10^{-4}$ and 21.8 kJ/mol, respectively. At the Pt(100)/0.5 LiOH aqueous electrolyte interface, K transits from 1.9(UPD H) to $6.8\times10^{-6}$(OPD H) depending on the cathode potential (E) and vice versa. Similarly, ${\Delta}G_{ads}$ transits -1.6 kJ/mol (UPD H) to 29.5 kJ/mol (OPD H) depending on E and vice versa. The transition of K and ${\Delta}G_{ads}$ is attributed to the two distinct adsorption sites of the UPD H and OPD H on the Pt(100) surface. The UPD H and the OPD H at the Pt(100) interfaces are the independent processes depending on the H adsorption sites rather than the sequential processes for the cathodic $H_2$ evolution reactions.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.7
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• pp.499-504
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• 2009

Erythrosine is used a food coloring, ink and dye, etc. but erithrosine is rarely used in United States due to its known hazards. The adsorption characteristics of erythrosine by granular activated carbon were investigated in the batch adsorber and the packed column. The adsorptivity of activated carbon for erythrosine were largely improved by pH control. When the pH was 11 in the sample, the erythrosine could be removed 98% of initial concentration. It was estabilished that the adsorption equilibrium of erythrosine on granular activated carbon was successfully fitted by Freundlich isotherm equation in the concentration range from 10mg/L to 1,000mg/L. The characteristics of breakthrough curve of activated carbon packed column depend on the design variables such as initial concentration, bed height, and flow rate.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2003.05a
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• pp.292-296
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• 2003

Autoclaving처리를 하지 않은 키토산과 autoclaving처리한 키토산과의 중금속 흡착실험을 해 본 결과 다음과 같은 결과를 도출 할 수 있었다. 1) 먼저 중금속간의 흡착능을 고찰하기 위하여 Langmuir와 Freundlich 흉착등온식에 적용시켜 본 결과 Freundlich 흡착등온식 보다는 Langmuir 흡착등온식이 보다 적합한 것으로 나타났다. 2) 시간에 따라서 autoclaving 처리한 키토산의 중금속 제거 가능성과 그 효율을 검토하기 위하여 각 중금속간의 Langmuir 흡착등온식을 이용하여 $q_{max}$를 나타냈다. 15 min > 60 min > 0 min 순으로 모든 중금속 제거 실험에서 15 min 동안 autoclaving 처리한 키토산의 중금속 흡착량이 가장 높은 것으로 나왔다. 그러므로 기존의 키토산 보다는 15 min동안 autoclaving 처리한 키토산이 중금속 제거에 더 좋은 흡착제로써 역할을 할 수 있을 것으로 판단된다. 3) 키토산을 이용한 중금속 제거에서는 $Pb^{2+}$ > $Cd^{2+}$ > $Cu^{2+}$ > $Cr^{3+}$순서로 제거가 되었다. 여러 연구자들의 실험 결과를 종합해 볼 때 Pb$^{2+}$가 중금속 중에 제거가 잘 된다는 연구 결과가 많이 발표 되었으며, $Cd^{2+}$, $Cu^{2+}$, $Cr^{3+}$의 경우에는 흡착제의 종류에 따라서 제거되는 순서가 다르다는 연구 결과들이 보고 되고 있다. 그러나 어떠한 이유로 중금속의 제거에 차이가 있는지에 대해서는 명확한 결론이 내려져 있지 않는 실정이다. 이러한 중금속간의 경쟁적인 관계에 대해 더 많은 세밀한 연구가 이루어져야 할 것 같다.는 0.52mg/$\ell$~0.99mg/$\ell$~의 범위이었다. 신천에 금호강물을 혼합한 이후에도 부유물질, 생화학적산소요구량, 암모니아태 질소, 총인 등의 농도가 개선되지 않았다. 즉 금호강물의 혼합은 신천수질환경사업소에서 배출되는 방류수에 함유되어 있을 2차 오염물질의 희석이라는 이점외의 수질개선효과는 확인되지 않았다.l years and a new type of transfer crane has been developed. Design concepts and control methods of a new crane will be introduced in this paper.and momentum balance was applied to the fluid field of bundle. while the movement of′ individual material was taken into account. The constitutive model relating the surface force and the deformation of bundle was introduced by considering a representative prodedure that stands for the bundle movement. Then a fundamental equations system could be simplified considering a steady state of the process. On the basis of the simplified model, the simulation was performed and the results could be confirmed by the experiments under various conditions.뢰, 결속 등 다차원의 개념에 대한 심도 깊은 연구와 최근 제기되고 있는 이론

• Journal of the Korean Electrochemical Society
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• v.11 no.3
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• pp.159-164
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• 2008

We investigated chloride ion effects on anodic dissolution of copper using potentiodynamic method, cyclic voltammtery, chronoamperometry and chronocoulometry. The anodic dissolution reaction of copper in NaCl solution under argon atmosphere is $Cu+2Cl^{-}{\rightleftharpoons}{CuCl_2}^{-}+e^-$ and chloride ion adsorption process in copper surface can be explained by Temkin isotherm.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.11 no.6
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• pp.264-268
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• 2001

We manipulate properly the partition function of the surface system to evaluate an adsorption isotherm. We explain the dependence of strong interaction on the surface phase transition via analysis of the derived adsorption isotherm. Our theoritical results for adsorption well reflect to the experiments.

• Journal of the Korean Chemical Society
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• v.61 no.5
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• pp.238-243
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• 2017

In this study, water treatment sludge carbonized with $400^{\circ}C$ was tested as an adsorbent for the removal of Pb and Cd in water. The carbonized sludge was characterized by thermo-gravimetric analysis (TGA), scanning electron microscopy (SEM), X-ray fluorescence spectrometry (XRF), and surface area analysis. Carbonized sludge exhibited much higher specific surface area and total pore volume than water treatment sludge itself. In batch-type adsorption process, carbonized sludge represented better adsorption performance for Pb than Cd, achieving 90~98% at the concentrations conducted in the experiments. Equilibrium data of adsorption were analyzed using the Freundlich and Langmuir isotherm models. It was seen that both Freundlich and Langmuir isotherms have correlation coefficient $R^2$ value larger than 0.95. The results of studies indicated that carbonized water treatment sludge by heat treatment could be used as an efficient adsorbent for the removal of Pb and Cd from water.