• Applied Biological Chemistry
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• 제28권3호
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• pp.124-130
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• 1985

두가지 성질(性質)이 다른 토양(土壤)과 이들에 과산화수소(過酸化水素)를 처리(處理)하여 유기물(有機物)을 분해(分解)시킨 후 N-methylcarbamte 계(系) 농약(農藥)과의 흡착실험(吸着實驗)을 습식진탕법으로 행(行)한 결과(結果) 다음과 같다. N-methylacrbamate계(系) 농약(農藥)은 12시간(時間)의 진탕으로 평충농도(平衝濃度)에 도달(到達)하였다. 또한 토성별(土性別)로는 sandy clay가 sandy loam보다 N-methylcarbamate계농약(系農藥)을 더 많이 흡착(吸着)하는 것으로 나타났다. 유기물(有機物) 함량(含量)을 달리했을 때 N-methylcarbamate계농약(系農藥)의 흡착(吸着)은 유기물함량(有機物含量)에 상당한 영향(影響)이 있음이 나타났다. N-methylcarbamate계(系) 농약(農藥)의 흡착현상(吸着現象)은 Freundlich 정온흡착방정식(定溫吸着方程式)에 잘 부합(符合)되었다. 토양(土壤) pH를 변화(變化)시켰을 때 N-methlycarbamate계(系) 농약(農藥)의 흡착량(吸着量)에는 변화(變化)가 없었으며 이는 토양표면(土壤表面)에 hydrophobic한 부분(部分)에 물리적(物理的)으로 Vander waals 힘에 의(依)해서 흡착(吸着)되는 것으로 사료(思料)된다.

• Bulletin of the Korean Chemical Society
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• 제35권8호
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• pp.2471-2476
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• 2014

The aim of the present study is to explore the possibility of utilizing loess for the adsorption of total phosphorous (T-P) and total nitrogen (T-N) in water. Batch adsorption studies were performed to evaluate the influences of various factors like initial concentration, contact time and temperature on the adsorption of T-P and T-N. The adsorption data showed that loess is not effective for the adsorption of T-N. However, loess exhibited much higher adsorption capacity for T-P. At concentration of $1.0mgL^{-1}$, approximately 97% of T-P adsorption was achieved by loess. The equilibrium data were fitted well to the Langmuir isotherm model. The pseudo-second-order kinetic model appeared to be the better-fitting model because it has higher $R^2$ compared with the pseudo-first-order and intra-particle kinetic model. The theoretical adsorption equilibrium $q_{e,cal}$ from pseudo-second-order kinetic model was relatively similar to the experimental adsorption equilibrium $q_{e,exp}$. The thermodynamic parameters such as free energy ${\Delta}G$, the enthalpy ${\Delta}H$ and the entropy ${\Delta}S$ were also calculated.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
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• pp.182-182
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• 2011

We investigated the adsorption structures of serine on a Ge(100) surface by core-level photoemission spectroscopy (CLPES) in conjunction with density functional theory (DFT) calculations. The adsorption energies calculated using DFT methods suggested that four of six adsorption structures were plausible. These structures were the "O-H dissociated-N dative bonded structure", the "O-H dissociation bonded structure", the "Om-H dissociated-N dative bonded structure", and the "Om-H dissociation bonded structure" (where Om indicates the hydroxymethyl oxygen). These structures are equally likely, according to the adsorption energies alone. The core-level C 1s, N 1s, and O 1s CLPES spectra confirmed that the carboxyl oxygen competed more strongly with the hydroxymethyl oxygen during the adsorption reaction, thereby favoring formation of the "O-H dissociated-N dative bonded" and "O-H dissociation bonded" structures at 0.30 ML and 0.60 ML, respectively. The experimental results were corroborated theoretically by calculating the reaction pathways leading to the two adsorption geometries. The reaction pathways indicated that the "O-H dissociated-N dative bonded structure" is the major product of serine adsorption on Ge(100) due to comparably stable adsorption energy.

• Bulletin of the Korean Chemical Society
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• 제34권4호
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• pp.1055-1060
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• 2013

The adsorption structures of threonine on the Ge(100) surface were investigated using core-level photoemission spectroscopy (CLPES) in conjunction with density functional theory (DFT) calculations. CLPES measurements were performed to identify the experimentally preferred adsorption structure. The preferred structure indicated the relative reactivities of the carboxyl and hydroxymethyl groups as electron donors to the Ge(100) surface during adsorption. The core-level C 1s, N 1s, and O 1s CLPES spectra indicated that the carboxyl oxygen competed more strongly with the hydroxymethyl oxygen during the adsorption reaction. Three among six possible adsorption structures were identified as energetically favorable using DFT calculation methods that considered the inter- and intra-bonding configurations upon adsorption onto the Ge(100) surface. These structures were O-H dissociated N dative inter bonding, O-H dissociated N dative intra bonding, O-H dissociation bonding. One of the adsorption structures: O-H dissociated N dative inter bonding was predicted to be stable in light of the transition state energies. We thus confirmed that the most favorable adsorption structure is the O-H dissociated N dative-inter bonding structure using CLPES and DFT calculation.

• 분석과학
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• 제9권4호
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• pp.406-410
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• 1996

The adsorption behaviors of transition metal ions on the poly(N,N'-bispalmitoyl-1, 12-diaza-3, 4;9,10-dibenzo-5,8-cyclopentadecane) has been determined by adsorption process in aqueous solution. The order of concentration factor(CF) and the amount of adsorption were Cu(II)

• Korean Chemical Engineering Research
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• 제46권6호
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• pp.1087-1094
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• 2008

본 연구는 활성탄을 사용한 n-hexane의 흡착공정에 있어서 분자수준에서 시작하여 공정단계에 이르는 다중규모 모사에 관하여 기술한다. 분자모사에서는 GCMC(Grand Canonical Monte Carlo) 방법을 이용하여 활성탄에서 n-hexane의 등온흡착식을 예측하고, 2차원 전산유체역학(CFD; Computational fluid dynamics) 모사를 통하여 흡착컬럼 내 유체흐름에 대한 수력학적 특성을 파악한다. 공정모사단계에서는 분자모사 및 유체역학 모사에서 각각 얻은 등온흡착식과 축방향 확산계수값을 이용하여 n-hexane의 용출곡선을 얻는다. 이러한 3단계 다중규모 모사기법을 활용하여 얻은 공정모사 결과는 펄스응답의 실험결과와 비교해볼 때, 온도와 유량변화에 따른 1차 모멘트(평균 체류시간)에 관하여 약 20% 미만의 오차범위에서 일치함을 확인할 수 있다. 이 결과로부터 분자수준에서 시작하는 다중규모 모사는 필요한 실험횟수를 줄이면서 흡착공정 개발을 가속화할 수 있는 가능성을 보여준다.

• Korean Chemical Engineering Research
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• 제44권4호
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• pp.393-398
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• 2006

고농도의 1-부텐을 생산하기 위하여 흡착 분리제의 개발이 필수적인데, 본 연구에서는 메조포러스 실리케이트인 MCM-41을 지지체로 하여 $AgNO_3$를 함침시켜 흡착제를 제조한 후, 1-부텐과 n-부탄의 흡착 특성을 연구하였다. 또한, 열처리 조건에 따른 $Ag^+$ 이온의 형성 비율과 1-부텐의 결합 능력을 알아보았다. MCM-41 흡착제의 경우, 13X 제올라 이트에 비하여 매우 높은 흡착량을 보여주었으며, 은이 담지되었을 때, n-부탄의 흡착량은 감소하는 반면에 1-부텐의 흡착량은 증가함으로써 1-부텐과 n-부탄의 흡착 분리에 매우 좋은 성능을 갖음을 확인할 수 있었다. 또한, 진공 분위기에서 373 K로 열처리한 Ag/MCM-41의 경우 가장 높은 1-부텐/n-부탄 흡착비를 보였으며, 특히 저압에서 매우 높은흡착비를 보여주었다.

• 한국환경과학회지
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• 제29권12호
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• pp.1261-1274
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• 2020

The characteristics of ammonia-nitrogen (NH4+-N) adsorption by a zeolitic material synthesized from Jeju scoria using the fusion and hydrothermal method was studied. The synthetic zeolitic material (Z-SA) was identified as a Na-A zeolite by X-ray diffraction, X-ray fluorescence analysis and scanning electron microscopy images. The adsorption of NH4+-N using Jeju scoria and different types of zeolite such as the Z-SA, natural zeolite, and commercial pure zeolite (Na-A zeolite, Z-CS) was compared. The equilibrium of NH4+-N adsorption was reached within 30 min for Z-SA and Z-CS, and after 60 min for Jeju scoria and natural zeolite. The adsorption capacity of NH4+-N increased with approaching to neutral when pH was in the range of 3-7, but decreased above 7. The removal efficiency of NH4+-N increased with increasing Z-SA dosage, however, its adsorption capacity decreased. For initial NH4+-N concentrations of 10-200 mg/L at pH 7, the adsorption rate of NH4+-N was well described by the pseudo second-order kinetic model than the pseudo first-order kinetic model. The adsorption isotherm was well fitted by the Langmuir model. The maximum uptake of NH4+-N obtained from the Langmuir model decreased in the order of Z-CS (46.8 mg/g) > Z-SA (31.3 mg/g) > natural zeolite (5.6 mg/g) > Jeju scoria (0.2 mg/g).

• Nuclear Engineering and Technology
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• 제56권3호
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• pp.812-818
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• 2024

The volume and toxicity of radioactive waste can be decreased by separating the components of high-level liquid waste according to their properties. An impregnated silica-based adsorbent was prepared in this study by combining N,N,N',N',N",N"-hexa-n-octylnitrilotriacetamide (HONTA) extractant, N',N'-di-n-hexyl-thiodiglycolamide (Crea) extractant, and macroporous silica polymer composite particles (SiO₂-P). The performance of platinum-group metals adsorption and separation on prepared (HONTA + Crea)/SiO₂-P adsorbent was then assessed together with that of co-existing metal ions by batch-adsorption and chromatographic separation studies. From the batch-adsorption experiment results, (HONTA + Crea)/SiO₂-P adsorbent showed high adsorption performance of Pd(II) owing to an affinity between Pd(II) and Crea extractant based on the Hard and Soft Acids and Bases theory. Additionally, significant adsorption performance was observed toward Zr(IV) and Mo(VI). Compared with studies using the Crea extractant, the high adsorption performance of Zr(IV) and Mo(VI) is attributed to the HONTA extractant. As revealed from the chromatographic experiment results, most of Pd(II) was recovered from the feed solution using 0.2 M thiourea in 0.1 M HNO₃. Additionally, the possibility of recovery of Zr(IV), Mo(VI), and Re(VII) was observed using the (HONTA + Crea)/SiO₂-P adsorbent.

• 한국환경과학회지
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• 제17권11호
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• pp.1255-1263
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• 2008

The efficiency of PP-g-AA and PP-g-St nonwoven fabric synthesized by photoinduced polymerization as an adsorbent for removal $NH_3-N$ from waste water was evaluated. The results evidently indicate that the adsorption capacities of $NH_3-N$ onto PP-g-AA nonwoven fabric were extremely superior to those onto sulfonated PP-g-St nonwoven fabric, PK and zeolite. PP-g-AA nonwoven fabric showed the maximum adsorption capacity of $NH_3-N$ at the degree of grafting of 80 wt.%. The adsorption behaviour of $NH_3-N$ onto PP-g-AA and sulfonated PP-g-St nonwoven fabric was controlled by an ion exchange reaction, and tended to be similar to both trends of Langmiur and Freundlish isotherm. Futhermore, PP-g-AA non-woven fabric could be regenerated more than 5 times by a simple washing with 0.1N HCl with no decrease of adsorption capacity and no degradation of physical properties. Also sulfonated PP-g-St nonwoven fabric could be regenerated by washing with 0.1N ${H_2}{O_4}$. However, their regeneration efficiency was significantly low because grafting layer acted as functional radical for adsorption was continuously desquamated in the adsorption or regeneration processes, which resulted in decrease of adsorption capacity and weight of adsorbent. All results obtained from this study indicate that the $NH_3-N$ removal capacity of PP-g-AA non-woven fabric was extremely superior to those of PP-g-St non-woven fabric, PK and zeolite.