• 한국대기환경학회지
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• 제25권4호
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• pp.316-324
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• 2009

Carbon based sorbents for $CO_2$ adsorption were prepared by impregnation with alkali metals ($Li^+$, $K^+$) and alkaline earth metals ($Ca^{2+}$, $Mg^{2+}$). BET surface area of test sorbents was lower than the intrinsic activated carbon. In particular, impregnation of $Ca^{2+}$ or $Mg^{2+}$ resulted in lower surface area of specific adsorption sites than that of $Li^+$ or $K^+$. While the adsorption capacity for $CO_2$ was high in the sorbents containing $Ca^{2+}$ and $Mg^{2+}$, strong interaction with $CO_2$ would cause to drop the capacity after regeneration. The adsorption was found high relatively in the flow with a high concentration of $CO_2$ and in a low flow rate. The adsorption isotherm for the present modified AC sorbents fits well with the Freundlich model.

• Membrane and Water Treatment
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• 제6권6호
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• pp.439-449
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• 2015

Carbolic Acid which is called phenol is one of the important starting and/or intermediate materials in various industrial processes. However, its excessive release into environment poses a threat to living organisms, as it is a highly carcinogens and hazardous pollutant even at the very low concentration. Thus removal of phenol from polluted environments is very crucial for sustainable remediation process. We developed a low cost adsorption method for separating phenol from a model aqueous solution. The phenol adsorption was studied using two adsorbents i.e., Amber lite XAD-16 and Amber lite XAD-7 HP with a constant amount of resin 0.1 g at varying aqueous phenol concentrations ($50-200mgL^{-1}$) at room temperature. We compared the efficacy of two phenol adsorbents for removing higher phenol concentrations from the media. We investigated equilibrium and kinetics studies of phenol adsorption employing Freundlich, Temkin and Langmuir isotherms. Amberlite XAD-16 performed better than Amberlite XAD-7 HP in terms of phenol removal efficiency that amounted to 95.52%. Pseudo second order model was highly fitted for both of the adsorption systems. The coefficient of determination ($R^2$) with Langmuir isotherm was found to be 0.98 for Amberlite XAD-7 HP. However, Freundlich isotherm showed $R^2$ value of 0.95 for Amberlite XAD-16, indicating that both isotherms could be described for the isotherms on XAD-7 HP and Amberlite XAD-16, respectively.

• 한국식품저장유통학회지
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• 제17권4호
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• pp.513-518
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• 2010

멸치분말의 저장안정성을 알아보고자 80 mesh이상, 80-60 mesh, 60-40 mesh로 입자크기에 따라 분급하여 흡습특성을 조사하고 평형수분함량의 예측 모델식을 수립하였다. 평형수분함량은 수분활성도가 높아짐에 따라 빠르게 증가하는 양상이었으며, 높은 온도에서 낮은 함량을 나타내었다. 단분자층 수분함량은 BET식보다 GAB식이 더 높은 유의성을 보였으며 그 함량은 0.022-0.029 g $H_2O/g$ dry solid 였다. 수분활성도가 증가함에 따라 필요로 하는 흡습에너지가 낮아져 흡습엔탈피는 감소하여 흡습이 쉽게 이루어짐을 알 수 있었다. 등온흡습곡선의 적합도는 Kuhn 모델이 $R^2$ 0.94 이상으로 높은 적합도를 나타내었고, Halsey, Caurie, Oswin 모델순으로 적합도를 나타내었다. 흡습 중 평형상대습도 예측 모델을 수립하기 위해 온도와 수분활성도의 경우 일차함수, 시간의 경우 ln 함수가 높은 적합도를 보였으며, 수분활성도 예측모델식은 입자의 크기에 관계없이 상대습도와 시간으로 수립한 모델식의 적합도가 적절한 것으로 나타났다.

• Korean Chemical Engineering Research
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• 제57권5호
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• pp.679-686
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• 2019

수용액으로부터 활성탄에 대한 아닐린 블루의 흡착 평형, 동역학 및 열역학적 특성을 초기농도, 접촉시간과 온도를 흡착변수로 하여 조사하였다. 아닐린 블루의 등온흡착은 Langmuir, Freundlich, Redlich-Peterson, Temkin 및 Dubinin-Radushkevich 모델을 통해 해석하였다. Langmuir 모델이 다른 모델들 보다 등온 데이터에 더 잘 맞았다. 평가된 Langmuir 분리계수($R_L=0.036{\sim}0.068$)는 활성탄에 의한 아닐린 블루의 흡착 공정이 효과적인 처리방법이 될 수 있음을 나타냈다. 흡착속도상수는 유사일차속도 모델, 유사이차속도 모델 및 입자내 확산 모델에 적용하여 구하였다. 활성탄에 대한 아닐린 블루의 흡착속도실험 결과는 유사이차 반응속도식에 잘 따랐다. 흡착 메카니즘은 입자내 확산 모델에 의해 경막 확산과 입자내 확산의 두 단계로 평가되었다. 흡착공정에 대한 깁스 자유에너지, 엔탈피 및 엔트로피 변화와 같은 열역학 파라미터들이 평가되었다. 엔탈피 변화(48.49 kJ/mol)은 흡착공정이 물리흡착이고 흡열반응임을 알려주었다. 깁스 자유 에너지는 온도가 올라갈수록 감소하였기 때문에 흡착반응은 온도가 올라갈수록 자발성이 더 높아졌다. 등량흡착열은 흡착제 표면의 에너지 불균일성 때문에 흡착제와 흡착질 사이에 상호작용이 있음을 나타내었다.

• 한국환경과학회지
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• 제27권2호
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• pp.83-90
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• 2018

In this study, zeolite (Z-C2) was synthesized using a fusion/hydrothermal method on coal fly ash (FA) discharged from a thermal power plant in the Ulsan area and then analyzed via scanning electron microscopy (SEM) and X-ray diffraction (XRD). The Z-C2 was characterized in terms of mineralogical composition and morphological analysis. The XRD results showed that its peaks had the characteristics of Na-A zeolite in the range of $2{\theta}$ of 7.18~34.18. The SEM images confirmed that the Na-A zeolite crystals had a chamfered-edge crystal structure almost identical to that of the commercial zeolite. The adsorption kinetics of Cu, Co, Mn and Zn ions by Z-C2 were described better by the pseudo-second-order kinetic model more than by the pseudo-first-order kinetic model. The Langmuir model fitted the adsorption isotherm data better than the Freundlich model did. The maximum adsorption capacities of Cu, Co, Mn and Zn ions obtained from the Langmuir model were in the following order : Cu (94.7 mg/g) > Co (77.7 mg/g) > Mn (57.6 mg/g) > Zn (51.1 mg/g). These adsorption capacities are regarded as excellent compared to those of commercial zeolite.

• 한국식품과학회지
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• 제35권2호
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• pp.211-216
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• 2003

열풍, 진공 및 동결건조한 생강분말의 흡습특성을 조사하고 저장 중 수분함량 예측모델식을 수립하였다. 단분자층 수분함량은 BET식보다 GAB식이 더 높은 유의성을 보였으며 등온흡습곡선은 sigmoid 형태로서 건조방법에 따른 차이는 없었으나 낮은 온도에서 평형수분함량이 높았다. 건조방법에 따른 흡습엔탈피는 큰 차이가 없었으나 수분활성도가 증가함에 따라 낮은 흡습에너지를 보였다. 등온흡습곡선의 적합도는 Caurie 모델이 $R^2\;0.99$ 이상으로 높은 적합도를 나타내었고 그 외 Henderson, Bradley 모델의 순으로 높은 적합도를 나타내었으며, 편차도 Caurie 모델이 $1.2{\sim}5.4%$로 가장 낮았다. 수분함량 예측을 위해 각 독립변수의 최적함수로 시간은 ln 함수, 수분활성도와 온도는 일차식을 선정하였으며 수분함량 예측모델식은 건조방법에 관계없이 시간과 수분활성도, 온도로 수립한 모델식의 적합도가 높았다.

• 한국환경과학회지
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• 제28권1호
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• pp.55-64
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• 2019

The adsorption properties of $Cs^+$ and $Cu^{2+}$ ions were evaluated by using a polysulfone scoria zeolite (PSf-SZ) composite with synthetic zeolite synthesized from Jeju volcanic rocks (scoria). In order to investigate the adsorption properties, various parameters, such as pH, contact time, reaction rate, concentration, and temperature in aqueous solutions, were evaluated by tests carried out in batch experiments. The adsorption capacities of $Cs^+$ and $Cu^{2+}$ ions increased between pH 2 but achieved equilibrium at pH 4 and above. The adsorption rate increased rapidly up to the initial 24 h, after which it plateaued ; the adsorption rate then sustained at equilibrium from 48 h. The adsorption kinetics of $Cs^+$ and $Cu^{2+}$ ions were described better by the pseudo-second-order kinetic model than the pseudo-first-order kinetic model. The Langmuir model fitted the adsorption isotherm data better than the Freundlich model. The maximum adsorption capacities of $Cs^+$ and $Cu^{2+}$ ions obtained from the Langmuir model were 53.8 mg/g and 84.7 mg/g, respectively. The calculated thermodynamic parameters showed that the adsorption of $Cs^+$ and $Cu^{2+}$ ions on PSf-SZ was feasible, spontaneous and endothermic reaction.

• 한국환경과학회지
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• 제20권2호
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• pp.241-249
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• 2011

In this research, equilibrium of adsorption and kinetics of As(V) removal were investigated. The coal mine drainage sludge(CMDS) was used as adsorbent. To find out the physical and chemical properties of CMDS, XRD (X-ray diffraction), XRF (X-ray fluorescence spectrometer) analysis were carried out. The CMDS was consist of 70% of goethite and 30% of calcite. From the results, an adsorption mechanism of As(V) with CMDS was dominated by iron oxides. Langmuir adsorption isotherm model was fitted well more than Freundlich isotherm adsorption model. Adsorption capacities of CMDS 1 was not different with CMDS 2 on aspect of amounts of arsenic adsorbed. The maximum adsorption amount of two CMDS were respectively 40.816, 39.682 mg/g. However, the kinetic of two CMDS was different. The kinetic was followed pseudo second order model than pseudo first order model. Concentrations of arsenic in all segments of the polymer in CMDS 2 does not have a constant value, but the rate was greater than the value of CMDS 1. Therefore, CMDS 2, which is containing polymer, is more effective for adsorbent to remove As(V).

• 대한토목학회논문집
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• 제2권1호
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• pp.63-68
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• 1982

본(本) 연구(硏究)는 국산천연(國産天然) 제오라이트를 이용한 중금속(重金屬) 산업폐수(產業廢水) 처리공정(處理工程)을 개발(開發)할 목적(目的)으로 수행(遂行)되었으며 본 논문에서는 1차적으로 알카리 처리된 제오라이트를 이용하여 Batch Test를 통한 기초실험(基礎實驗) 결과(結果)를 수록하였다. 제오라이트에 의한 중금속 흡착(吸着)공정에 미치는 pH의 영향(影響), 흡착 Isotherm Model 결정, 흡착속도 및 온도(溫度)의 영향을 중점적으로 평가분석(評價分析)하였으며 그 결과 최적(最適) pH는 4~5이상, 카드미움 흡착은 BET Model이 적합하며, 반응시간(反應時間)은 10분 이상이 소요됨을 알았으며 또한 온도가 증가하면 비례하여 흡착능(吸着能)도 증가하므로서 단순한 물리흡착(物理吸着)만이 아닌 화학흡착(化學吸着)도 병행하여 일어나고 있다고 판단된다. 본 연구 결과로 판단컨대, 국산 천연 제오라이트를 이용한 중금속 폐수처리는 그 전망이 밝으며 앞으로 Column Test를 통하여 합성(合成)폐수는 물론 실제폐수의 처리도(處理度)를 실험하므로서 처리공정설계 조건을 도출할 수 없으며 이와 같은 공정의 개발로서 우리나라의 중금속 폐수처리에 획기적인 공헌이 기대된다.

• 한국환경과학회지
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• 제25권12호
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• pp.1623-1632
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• 2016

Zeolite (FZ) prepared using coal fly ash from an Ulsan industrial complex was immobilized with polysulfone (PS) to fabricate PS-FZ beads. The prepared PS-FZ beads were characterized by scanning electron microscopy and Fourier transform infrared spectroscopy. The optimum ratio for preparing PS-FZ beads was 1 g of PS to 2 g of FZ. The removal efficiencies of Sr and Cu ions by the PS-FZ beads increased as the solution pH increased and nearly reached a plateau at pH 4. A pseudo-second-order model morel fit the adsorption kinetics of both ions by the PS-FZ beads better than a pseudo-first-order model. The Langmuir isotherm model fit the equilibrium data well. The maximum adsorption capacities calculated from the Langmuir isotherm model were 46.73 mg/g and 62.54 mg/g for the Sr and Cu ions, respectively. Additionally, the values of thermodynamic parameters such as free energy (${\Delta}G^{\circ}$), enthalpy (${\Delta}H^{\circ}$) and entropy (${\Delta}S^{\circ}$) were determined. The results implied that the prepared PS-FZ beads could be interesting an alternative material for Sr and Cu ion removal.