• 한국지구물리탐사학회:학술대회논문집
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• 한국지구물리탐사학회 2003년도 Proceedings of the international symposium on the fusion technology
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• pp.629-636
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• 2003

The retardation of heavy metals in a mixture of fly ash and bentonite was studied as a potential barrier material for a landfill. Column tests were conducted using synthetic leachate having 100 mg/L and 50 mg/L of lead (Pb) and cadmium (Cd), respectively. Results indicated that the mixture had obvious retardation ability for heavy metals. To investigate the retardation factor caused by adsorption, batch adsorption tests were conducted at various concentrations. Test results were correlated with both Langmuir and Freundlich isotherms. The adsorption of the lead ion was applicable to the Langmuir isotherm and the adsorption of the cadmium ion was applicable to the Freundlich isotherm. In addition, based on experimental results, the migration characteristics of heavy metals through the bed of fly ash and bentonite mixture were investigated using the PHREEQC, a reactive transport model, under the real conditions of the landfill liner.

• 대한화학회지
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• 제62권2호
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• pp.79-86
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• 2018

This study reported the adsorption of Cu(II) ions onto activated carbon prepared from Myristica Fragrans shell (MFS AC) over independent variables of contact time, activating chemical (NaOH) concentration, initial adsorbate concentration, initial pH of adsorbate solution and adsorption temperature. The MFS AC structure, morphology and total surface area were characterized by FTIR, SEM and BET techniques, respectively. The Cu(II) ions adsorption on the MFS AC (activated using 0.5 M NaOH) fitted best to Freundlich adsorption isotherm (FAI), and the FAI constant obtained was 0.845 L/g at $30^{\circ}C$ and pH 4.5. It followed the pseudo first order of adsorption kinetic (PFOAK) model, and the PFOAK based adsorption capacity was 107.65 mg/g. Thermodynamic study confirmed the Cu(II) ions adsorption should be exothermic and non-spontaneous process, physical adsorption should be taken place. The total surface area and pore volume based on BET analysis was $99.85m^2/g$ and 0.086 cc/g, respectively.

• 한국환경보건학회지
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• 제21권3호
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• pp.77-86
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• 1995

Lead(II) removal efficiency by natural kaolinite was investigated through laboratory experiments. This study was conducted in two phases-sorption and desorption. In the adsorption study, the influence of sorption kinetics and sorption isotherm and various parameters such as pH, temperature, coexisting other heavy metal ions on the lead adsorption was investigated. And desorption study was carried out in order to find the re-usability of kaolinite as an adsorbent. The results of the study are as follows. 1. Sorption kinetics was investigated under the condition of 2.5 mg/l adsorbent concentration, pH 6.5$\pm$0.05, temperature $30\pm 0.5\circ$C, initial lead(II) concentration 25 mg/l. Adsorption rate was initially rapid and the extent of adsorption arrived at adsorption equilibrium with 73% adsorption efficiency in an hour. 2. The sorption isotherm experiment was made with different initial lead(II) concentration. A linearized Freundlich equation was used to fit the acquired experimental data. As a result, Freundlich constants, the sorption intensity (1/n) was 0.47 and the measure of sorption (k) was 2.44. So, it was concluded that sorption of lead(II) by kaolinite is effective. 3. The effect of pH on lead(II) sorption by kaolinite shows that at a pH of 3, only 6% of the total lead(II) was adsorbed and at a pH 9, 97% of the lead(II) was removed. And the effect of temperature on lead(II) sorption by kaolinite shows that as the temperature increased, the amount of lead(II) sorption per unit weight of kaolinite increased. But the effect was minor (p<0.05). 4. Sorption isotherm of lead coexisting cadmium (II) or zinc (II) was lower than that of lead itself. It was caused by the result of competitive sorption to adsorption site. And there was no difference between the sorption isotherm of cadmium and zinc. 5. In desorption studies, only 5.12% desorption took place in distilled water, while 52.08% in 0.1 N hydrochloric acid. Consequently used kaolinite could be regenerated by hydrochoric acid.

• 공업화학
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• 제25권6호
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• pp.632-638
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• 2014

입상활성탄을 사용하여 new fuchsin 염료를 흡착하는데 필요한 흡착등온선과 흡착동역학 및 열역학 파라미터들에 대하여 조사하였다. 흡착평형은 Langmuir 흡착등온식이 가장 잘 맞았으며, 등온흡착평형관계로부터 Langmuir 식과 Freundlich 식의 분리계수를 평가한 결과, 분리계수값이 각각 $R_L$ = 0.023, 1/n=0.198로 입상활성탄에 의한 new fuchsin 염료의 흡착조작이 유효한 처리방법이 될 수 있음을 알았다. Dubinin-Radushkevich 식으로 구한 흡착에너지값(E = 0.002 kJ/mol)과 Temkin 식으로부터 구한 흡착열상수값(B = 1.920 J/mol)으로부터 흡착공정이 물리흡착공정임을 알았다. 흡착공정에 대한 동력학적 해석을 통해 흡착반응은 유사이차반응속도식이 유사일차반응속도식과 비교하여 일치도가 높은 것으로 나타났으며, 입자 내 확산이 흡착공정의 지배단계이었다. 열역학적 해석을 통해 평가된 엔탈피 변화값(92.49 kJ/mol)과 활성화에너지값(11.79 kJ/mol)으로부터 흡착공정이 흡열반응으로 진행되었다. 또한, 엔트로피 변화값이 313.7 J/mol K로 흡착공정의 무질서도가 증가하였다. 온도가 올라갈수록 자유에너지값이 감소하는 것은 활성탄에 대한 new fuchsin 염료의 흡착반응은 온도가 올라갈수록 자발성이 높아지는 것으로 판단되었다.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2000년도 춘계학술발표대회
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• pp.386-389
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• 2000

Polysaccharides are very effective adsorbents for heavy metals. In this study, the adsorption characteristics of various polysaccharides for heavy metal adsorption were investigated. Tested polysaccharides were homogeneous polysaccharides such as curdlan, chitin, starch, cellulose, Avicel, and Solka floc and heterogeneous polysaccharides such as zooglan, locust bean gum, ghatti gum, pectin, and xylan. Lead(II) adsoption characteristic on these polysaccharides followed Freundlich isotherm and the isotherm parameters were calculated. For adsorption of lead(ll), Avicel, starch, and zooglan were found to be good adsorbents.

• 한국환경과학회지
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• 제12권10호
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• pp.1061-1069
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• 2003

The adsorption behaviors of strontium and cesium ions on fly ash, natural zeolites, and zeolites synthesized from fly ash were investigated. The zeolites synthesized from fly ash had greater adsorption capabilities for strontium and cesium ions than the original fly ash and natural zeolites. The maximum adsorption capacity of synthetic zeolite for strontium and cesium ions was 100 and 154 mg/g, respectively, It was found that the Freundlich isotherm model could fit the adsorption isotherm. The distribution coefficients (K$\_$d/) for strontium and cesium ions were also calculated from the adsorption isotherm data, The distribution coefficients decreased with increasing equilibrium concentration of strontium and cesium ions in solution. By studying the removal of cesium and strontium ions in the presence of calcium, magnesium, sodium, potassium, sulfate, nitrate, nitrite, and EDTA (in the range of 0.01 - 5 mM) it was found that these coexistence ions competed for the same adsorption sites with strontium and cesium ions.

• Advances in environmental research
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• 제4권3호
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• pp.197-210
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• 2015

Hexavalent chromium [Cr (VI)] adsorption on lateritic soil and lateritic soil blended with black cotton (BC) soil, marine clay and bentonite clay were studied in the laboratory using batch adsorption techniques. In the present investigation the natural laterite soil was blended with 10%, 20% and 30% BC soil, marine clay and bentonite clay separately. The interactions on test soils have been studied with respect to the linear, Freundlich and Langmuir isotherms. The linear isotherm parameter, Freundlich and Langmuir isotherm parameters were determined from the batch adsorption tests. The adsorption of Cr (VI) on natural laterite soil and blended laterite soil was determined using double beam spectrophotometer. The distribution coefficients obtained were 1.251, 1.359 and 2.622 L/kg for lateritic soil blended with 10%, 20% and 30% BC soil; 5.396, 12.973 and 48.641 L/kg for lateritic soil blended with marine clay and 5.093, 8.148 and 12.179 L/kg for lateritic soil blended with bentonite clay respectively. The experimental data fitted well to the Langmuir model as observed from the higher value of correlation coefficient. Soil pH and iron content in soil(s) has greater influence on Cr (VI) adsorption. From the study it is concluded that laterite soil can be blended with clayey soils for removing Cr (VI) by adsorption.

• Korean Chemical Engineering Research
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• 제59권4호
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• pp.565-573
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• 2021

활성탄에 의한 Brilliant Green(BG), Quinoline Yellow(QY) 염료의 흡착에 대한 등온선, 동력학, 열역학적 특성치와 경쟁흡착을 흡착제의 양, pH, 초기농도, 접촉시간 및 온도를 변수로 하여 수행하였다. BG와 QY는 가지고 있는 atomic nitrogen 이온(N⁺)의 영향으로 pH 11에서 92.4%의 최고 흡착율을 나타내었고, QY는 sulfite 이온(SO₃^-)의 영향으로 pH3에서 90.9%의 최고 흡착률을 나타냈다. 등온흡착 데이터로부터, BG의 경우는 Freundlich 등온식에 잘 맞아서 다분자층 흡착이었고, QY는 Langmuir 등온식이 가장 높은 일치도를 나타내어 주로 단분자층흡착이었다. Freundlich 식과 Langmuir 식의 분리계수는 활성탄에 의해 이들 염료를 효과적으로 처리할 수 있는 공정임을 나타냈다. Temkin 등온식에 의해 평가된 흡착 에너지는 활성탄에 의한 BG와 QY의 흡착이 물리 흡착임을 확인시켰다. 동력학적 실험결과는 유사 이차 반응속도식이 유사일차 반응속도식보다 일치도가 높았고 평형흡착량에 대한 오차도 더 작았다. 입자내 확산식을 이용하여 도시한 그래프는 2단계의 직선으로 나타났는데 기울기가 낮은 입자내 확산이 율속단계임을 확인하였다. 흡착공정의 활성화 에너지와 엔탈피 변화는 흡착과정이 비교적 수월하게 일어나며 흡열반응임을 나타냈다. 엔트로피 변화는 활성탄에 대한 BG와 QY 염료의 흡착이 진행됨에 따라 흡착시스템의 무질서도가 증가함을 나타냈고, Gibbs 자유 에너지 변화로 부터 흡착반응이 온도가 높아질수록 자발성이 더 커진다는 것을 알았다. 혼합용액의 경쟁흡착 결과는 상대적으로 흡착률이 높은 QY가 BG에 의해 큰 방해를 받아 흡착률이 크게 감소하는 것으로 나타났다.

• 청정기술
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• 제18권1호
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• pp.76-82
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• 2012

폐수로 부터 유독한 말라카이트 그린 성분을 제거하는데 있어서 제올라이트의 활용가능성을 살펴보았다. 흡착실험은 298, 308 및 318 K에서 수행하였으며, 흡착에 대한 온도, 접촉시간과 초기농도의 영향을 조사하였다. 흡착자료를 기초로 Langmuir와 Freundlich 흡착등온식에 대한 적합성을 평가하였다. 흡착공정은 Freundlich 흡착등온식이 잘 맞았으므로 제올라이트 표면의 불균일한 에너지에 의해 선택적인 흡착이 이루어짐을 알았다. 계산된 흡착등온선의 상수 값으로부터 제올라이트에 의해서 말라카이트 그린의 효과적인 처리가 가능하다는 것을 알 수 있었다. 동력학적 실험으로부터, 흡착공정은 유사이차반응속도식에 잘 맞으며, 속도상수($k_2$) 값은 말라카이트 그린의 초기농도가 증가할수록 감소하였다. 활성화에너지, 엔탈피, 엔트로피 및 자유에너지변화와 같은 열역학 파라미터들은 흡착공정의 특성을 평가하기 위하여 조사하였다. 활성화에너지의 계산값은 제올라이트에 대한 말라카이트 그린의 흡착이 물리적 공정임을 나타냈다. 자유에너지변화값(${\Delta}G^{\circ}$ = -6.47~-9.07 kJ/mol)과 엔탈피변화값(${\Delta}H^{\circ}$ = +32.414 kJ/mol)은 흡착공정이 298~318 K 범위에서 자발적이고 흡열과정이라는 것을 나타냈다.

• 청정기술
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• 제19권4호
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• pp.430-436
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• 2013

본 연구에서는 국내에서 대표적으로 버려지는 폐벌목 중 잣나무에서 만든 활성탄을 이용하여 벤젠에 대한 정지(static)흡착 실험을 수행하였다. 7.999 kPa에 이르는 압력 범위 내에서 온도 조건을 변화시켜 가며 303.15, 318.15, 333.15 K에서 흡착실험을 진행하였다. 등온흡착곡선은 Langmuir 등온흡착식, Freundlich 등온흡착식, Toth 등온흡착식을 적용하여 비교하였다. 벤젠의 흡착량(q)을 측정한 결과 Langmuir 등온흡착식과 Toth 등온흡착식으로 적용한 등온흡착곡선의 정확도가 높은 것으로 나타났다. 그리고 Langmuir 등온흡착식의 $q_{max}$ 값을 이용하여 흡착제의 흡착량을 비교하였다. 또한, 폐벌목 활성탄과 상용활성탄의 세공 발달 여부를 비교하기 위해 주사전자현미경(scanning electron microscopy, SEM) 사진을 관찰하였다. SEM 사진 관찰 결과, 폐벌목 활성탄이 국내 외 상용활성탄(DARCO A.C., SPG-100 A.C.)에 비해 세공발달 정도가 우수하며, 벤젠흡착량(q)이 높은 것을 확인할 수 있었다. 본 연구 결과를 통해 폐벌목 활성탄의 상용화 가능성을 검증할 수 있었다.