• 한국물환경학회지
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• 제27권2호
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• pp.141-146
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• 2011

Loess, a natural clay, was evaluated as an adsorbent for the decolorization of Acid Orange II, an azo and reactive dye, from aqueous solution. Adsorption studies were performed at $30^{\circ}C$ and the effect of reaction time, loess dosage, initial concentration, loess particle size, pH, agitation rate were investigated to determine the optimum operation conditions. The removal efficiencies of color were measured to evaluate the effectiveness of loess. From this study, it was found that optimal reaction time was 10 min. Color removal efficiencies of Acid Orange II were increased as higher loess dosage, initial concentration and agitation rate. However, color removal efficiencies decreased when pH is high and loess particle becomes large. Adsorption of Acid Orange II fitted to the pseudo-second-order rate kinetics more than first-order rate kinetics. Langmuir and Freundlich adsorption isotherm constants and correlation coefficients were calculated and compared. It was concluded that the adsorption data of Acid Orange II onto loess fitted to the Freundlich model more than Langmuir model.

• 한국수처리학회지
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• 제26권6호
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• pp.143-152
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• 2018

The process parameters of ethyl violet from aqueous solution by activated carbon adsorption were carried out as a function of pH, temperature, contact time, initial concentration and temperature. The adsorption equilibrium data can be described well by the Langmuir and Freundlich isotherm models. Base on Langmuir constant ($R_L=0.0343{\sim}0.0523$) and Freundlich constant (1/n=0.1633~0.1974), This process could be employed as effective treatment for adsorption of ethyl violet. The kinetic experimental results showed that the adsorption process can be well described with the pseudo second order model. Based on the positive enthalpy (6.505 kJ/mol), the adsorption of ethyl violet onto granular activated carbon is endothermic. The negative Gibbs free energy (-1.169~-1.681 kJ/mol) obtained indicates that the adsorption process is spontaneous and physisorption.

• 산업기술연구
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• 제20권A호
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• pp.57-62
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• 2000

This experiment was done to investigate the leaching and adsorption properties of heavy metals on porphyry. The comparison with respect to the leachability of heavy metals from porphyry between the Korea Standard Leaching Test (KSLT) and the Toxicity Characteristic Leaching Procedure (TCLP) was carried out. The fractional composition of leachate and the total concentration of heavy metal of porphyry were studied through Sequential Extraction Procedure (SEP) and EPA Method 3050. Adsorption experiment of porphyry has pointed out that the optimum dosage of porphyry for 50ppm Pb was over 10g/L, the effective particle size for absorption was below 200 mesh and the optimum pH was about 7. From the Freundlich' adsorption equation, 1/n was 1.0722, and k was 0.0041. After adsorption, the fractional composition of Pb was changed. The exchangeable, carbonate, reducible fractions were increased, and the organic fraction was not changed, and the residual fraction was decreased.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2004년도 총회 및 춘계학술발표회
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• pp.380-383
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• 2004

Heavy metal release from wastewater is a serious environmental problem, and therefore, various wastewater treatment techniques have been developed. Among the techniques, sorption technique is most attractive. Considerable researches have been recently focused on finding out inexpensive sorbents, especially from various natural materials. In order to evaluate the applicability of the scoria taken from the Jeju Island, Korea to remove heavy metals (Pb, Cu, Zn, Cd) from aqueous solutions, equilibrium sorption experiments were conducted in this study. In equilibrium tests, powdered activated carbon (PAC), one of the most commonly used sorbents, was also tested to compare the effectiveness of the Jeju scoria with that of PAC. The Jeju scoria had larger adsorption capacity and affinity for metal ions (Pb(II), Cu(II), Zn(II), Cd(II)) than PAC. The sorption parameters of the two sorbents were evaluated by using both the Langmuir and Freundlich isotherms, and the sorption data were better fitted to the Freundlich isotherm. In addition, the sorption behavior of metal ions (Pb(II), Cu(II), Zn(II), Cd(II)) onto the scoria displayed a typical characteristic of the cation sorption. The removal of metal ions decreased at a lower pH condition due to competition with hydrogen ions for the sorption sites of Jeju scoria, while the removal increased at a high pH condition due to hydroxide precipitation.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2004년도 총회 및 춘계학술발표회
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• pp.125-130
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• 2004

This study has been assessed the influence of applying sewage sludge to soil amendments on the sorption properties, and leaching potential of three commonly used organophosphorus pesticides, Diazinon, Fenitrothion, and Chlorpyrifos. A sandy soil with a low content of organic carbon was treated with sewage sludge with a ratio sandy soil : sludge ratio of 30:1. The sorption was determined with the batch equilibrium technique. The sorption isotherms could be described by Freundlich equation. The Freundlich constant, K value which measures sorption capacity, were 3.97, 9.94, 22.48 for Diazinon, Fenitrothion, Chlorpyrifos in non-amended soil. But in amended soil, K value was 12.58, 28.47, and 61.21 for Diazinon, Fenitrothion, and Chlorpyrifos. The overall effect of sewage sludge addition to soil was to increase pesticides adsorption, due to the high sorption capacity of the organic matter. The effect of sludge on tile leaching of pesticides in the soil was studied using packed soil columns. Total recoveries of pesticides in soil and leachate with leaching in soil column, were in the range of about 73～84%, was reduced with the passage of time. Diazinon moved more rapidly than Chlorpyrifos in the unamended soil due to greater sorption and lower water solubility of Chlorpyrifos. Total amounts of pesticides leached from the sewage sludge amended soils were significantly reduced when compared with unamended soils. This reduction may be mainly due to and increase in sorption in amended soils, as a consequence of the increase in the organic matter content.

• 한국토양환경학회지
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• 제1권2호
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• pp.43-50
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• 1996

The adsorption charateristics of lead(II) ions on Aspergillus niger and Rhizopus arrhizus were investigated. Adsorption amount of A. niger and R. arrhizus was about 95 mg/g and 25 mg/g, respectively. These biomass was approached to adsorption equilibrium within reaction time of 1hr because of their high reactivity. The uptake of lead ion by A. niger was less sensitivity than it by R. arrhizus on the inhibition effect of alkali metals and the decreasing ratio of uptake of lead ion of A. niger and R. arrhizus by inhibition effect of alkali metals was 37% and 50%, respectively. In pre-treatment on these biomass, NaOH treatment was contributed high adsorption capacity to these biomass. Then, adsorption amount of A. niger and R. allhizus was increased about 25 mg/g and 10 mg/g, respectively. In isotherm for the adsorption of lead ion based on Freundlich equation, 1/n value of A. niger and R. ar고izus was calculated the range of 0.28-0.56 and 0.44-0.67, respectively.

• 한국식품과학회지
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• 제40권1호
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• pp.111-114
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• 2008

데옥시리보뉴클레오사이드(deoxyribonucleosides)의 혼합물을 크로마토그래피 공정을 사용하여 분리함에 있어 최적의 조건을 구하기 위하여 dUrd과 dCyd의 흡착 평형식을 구하여 서로 비교하여 보았다. 이동상과 고정상의 농도를 가장 적합한 흡착 평형식으로 표시하기 위하여 네 가지 모델의 평형식을 선정하고 회귀분석에 의해 각각의 매개변수 값과 실험치와의 표준편차를 구하였다. dUrd의 경우 Radke-Prausnitz 식을 적용하였을 때 표준편차가 가장 작았으며, dCyd의 경우에는 Sips식을 적용하였을 때 계산값과 실험값이 가장 잘 일치하였다.

• 공업화학
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• 제26권5호
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• pp.581-586
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• 2015

입상 활성탄을 사용하여 수용액으로부터 Safranin의 흡착에 대해 조사하였다. 회분식 실험은 흡착제의 양, 초기농도와 접촉시간과 온도를 흡착변수로 사용하여 수행하였다. 흡착평형자료는 Langmuir, Freundlich 및 Dubinin-Radushkevich식을 사용하여 해석한 결과 Freundlich식이 가장 좋은 일치도를 나타냈다. 평가된 Langmuir 분리계수, $R_L=0.183{\sim}0.254$와 Freundlich 분리계수, 1/n = 0.518~0.547로부터 이 흡착공정이 적절한 처리방법이 될 수 있음을 알았다. 흡착속도실험자료를 유사1차 및 유사2차 반응속도식에 적용해 본 결과는 유사2차반응속도식에 잘 맞는 것으로 나타났다. 음수값의 Gibbs 자유에너지(${\Delta}G=-3.688{\sim}-7.220kJ/mol$)와 양수값의 엔탈피(${\Delta}H=33.126kJ/mol$)는 흡착이 자발적이고 흡열공정으로 진행된다는 것을 나타냈다.

• Korean Chemical Engineering Research
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• 제55권4호
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• pp.514-519
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• 2017

활성탄을 사용하여 흡착제의 양, pH, 초기농도, 접촉시간과 온도를 흡착변수로 acid green 27 염료의 흡착특성을 조사하였다. 흡착평형자료는 Freundlich와 Langmuir 등온식을 사용하여 해석하였는데, Freundlich 식이 더 좋은 일치도를 나타냈다. 평가된 Freundlich 분리계수(1/n=0.293~0.387)로부터 활성탄에 의한 acid green 27의 흡착조작이 효과적인 처리방법이 될 수 있음을 알았다. 흡착속도실험 결과는 유사이차 반응속도식에 잘 맞았으며, 유사이차속도상수($k_2$)값은 acid green 27 초기농도가 증가할수록 감소하였다. 활성화에너지값(10.457 kJ/mol)과 표준엔탈피변화값(76.946 kJ/mol)으로 흡착공정이 물리흡착이고 흡열반응임을 알았다. 298~318 K 범위에서 Gibbs 자유에너지값은 온도가 올라갈수록 감소하였기 때문에 흡착반응은 온도가 올라갈수록 더 자발적으로 일어났다.

• 한국환경농학회지
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• 제35권1호
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• pp.24-31
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• 2016

본 연구는 산업폐기물의 일종인 제강급랭슬래그의 중금속 폐수처리를 위한 여재로서의 활용도를 높이고자 단일 및 복합 중금속용액에 대한 제강급랭슬래그의 경쟁흡착특성을 조사하였다. Freundlich 등온흡착식을 이용한 Cd, Cu 및 Zn의 흡착능은 단일 용액일 때 각각 2.21, 2.56 및 0.89이었으며, 복합 용액일 때는 각각 0.31, 1.28 및 0.37이었으며, Langmuir 등온흡착식을 이용한 제강급랭슬래그의 최대흡착능은 단일 용액일 때 Cu(16.6 mg/g) > Cd(8.1 mg/g) > Zn(6.2 mg/g)순이었으며, 복합 용액일 때 Cu(14.5 mg/g) >> Zn(1.3 mg/g) > Cd(0.6 mg/g)이었다. Freundlich와 Langmuir 등온흡착식은 모두 동일한 경향으로 단일 용액에서 최대흡착능에 비해 복합 용액일 때 흡착능은 감소하는 경향이었다. 특히 Cu의 경우는 단일 용액에 비해 복합용액일때 흡착능이 12.6% 정도로 약간 감소하였으나, Cd 및 Zn의 경우는 단일 용액에 비해 복합 용액일 때 흡착능이 각각 92.6% 및 79.0% 정도로 현저하게 감소함을 알 수 있었다. 이상의 결과를 미루어 볼 때, Cd 및 Zn은 경쟁 이온이 없는 단일 용액에서는 흡착제에 대해 높은 흡착능을 보였으나, 복합용액에서는 경쟁관계인 Cu에 의해 상대적으로 흡착능이 감소한 것으로 판단된다. 제강급랭슬래그의 단일 및 복합중금속 용액에서 Cd, Cu 및 Zn의 흡착량은 전반적으로 Langmuir 등온흡착식이 Freundlich 등온흡착식에 비해 잘 일치하였으며, 또한 단일 및 복합중금속 용액에서 각 금속의 흡착패턴은 각 금속의 경쟁으로 인하여 서로 다른 패턴을 가지는 것을 알 수 있었다. 따라서 제강급랭슬래그는 중금속 폐수처리를 위한 여재로 충분히 활용이 가능할 것으로 판단된다.