• 한국환경농학회지
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• 제34권3호
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• pp.155-160
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• 2015

왕겨 바이오차의 $N_2O$의 배출을 감소하기 위한 $NH_4-N$의 흡착제로서 가능성을 연구하기 위해 $NH_4-N$ 용액을 이용하여 왕겨 바이오차의 흡착 특성을 조사하였다. $NH_4-N$ 제거율은 왕겨 바이오차를 많이 첨가할수록 $NH_4-N$ 제거율이 증가하는 경향을 보이는 반면에, 바이오차 무게(g) 당 $NH_4-N$ 흡착량은 감소하는 경향을 보였다. 왕겨 바이오차를 이용한 흡착실험 결과를 Langmuir 흡착등온식에 적용하여 최대 단분자층 흡착량($q_m$), 흡착 친화도(b), 무차원 상수 $R_L$를 산출하였다. 그 결과 무차원 상수 $R_L$값이 0-1사이에 있어 Langmuir 흡착등온식을 잘 표현하였다. 따라서 왕겨를 소재로 제조한 바이오차는 흡착에 용이한 것으로 나타났다. 향후 이를 바탕으로 온실가스를 제어하기 위해 왕겨를 소재로 한 바이오차를 토양에 시용하였을 시 $N_2O$ 배출 감소를 위한 $NH_4-N$ 흡착 특성에 대한 연구가 필요한 것으로 판단된다.

• 한국산업융합학회 논문집
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• 제8권1호
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• pp.37-45
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• 2005

Adsorption equilibrium data of pure solvent vapors (n-Hexane, Toluene, MEK) as well as their binary mixtures on activated carbon (sorbonorit $B_4$) were experimentally determined in the range of 293.2~323.2 K and beyond saturated vapor pressure corresponding to experimental temperature. Langmuir, Freundlich, LRC, W-VSM, FH-VSM were estimated for the predication of single component as well as binary mixtuer systems. The isosteric heat of adsorption at infinite dilution of pure n-hexane, toluene, MEK on activated carbon were 45.18, 25.85, 34.62 Kcal/mol, respectively, also, n-hexane-toluene binary adsorption of activated carbon formed an azeotrope at 293.2 K and total pressure 5.1~10.3 mmHg.

• Journal of Electrochemical Science and Technology
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• 제7권2호
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• pp.153-160
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• 2016

The inhibition ability of N,N-bis(2,4-dihydroxyhydroxybenzaldehyde)-1,3-Propandiimine (DHBP) as a schiff base against the corrosion of API-5L-X65 steel in 1 M HCl solution was evaluated by electrochemical impedance spectroscopy, potentiodynamic polarization and scanning electron microscopy. Electrochemical impedance studies indicated that DHBP inhibited corrosion by blocking the active corrosion sites. The inhibition efficiency increased with increasing inhibitor concentrations. EIS data was analysed to equivalent circuit model and showed that the charge transfer resistance of steel increased with increasing inhibitor concentration whilst the double layer capacitance decreased. The adsorption of this compound obeyed the Langmuir adsorption isotherm. Gibbs free energy of adsorption was calculated and indicated that adsorption occurred through physical and spontaneous process. The corrosion inhibition mechanism was studied by potential of zero charge. Polarization studies indicated that DHBP retards both the cathodic and anodic reactions through adsorption on steel surface. Scanning electron microscopy was used to study the steel surface with and without inhibitor.

• 한국환경농학회지
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• 제10권1호
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• pp.27-31
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• 1991

국내산 천연(天然) zeolite의 $NH_4^\;+-N$ 제거제(除去劑)로서의 이용가능성(利用可能性)을 검정하기 위해 천연(天然) zeolite에 의한 $NH_4^\;^+-N$의 흡착능(吸着能)을 조사하였다. zeolite의 주구성점토광물(主構成粘土鑛物)은 clinoptilolite와 mordenite였다. Zeolite에 의한 $NH_4\;^+$의 흡착반응은 4시간 후에는 흡착평형(吸着平衡)에 도달하였다. $NH_4\;^+$ 흡착량은 zeolite의 입경(粒徑)에 의해 영향을 크게 받지 않았다. 치환성 양(陽)이온에 따른 $NH_4\;^+$ 흡착량은 Na-> Ca> K-zeolite의 순(順)이었다. 반응용액(反應溶液)의 pH가 높을수록 또 동일량(同一量)의 용액에 대한 시료량이 증가할수록 $NH_4\;^+-N$흡착량은 증가하였다. Zeolite에 의한 $NH_4\;^+$흡착등온곡선은 Langmuir 식(式)에 적용(適用)되었다.

• 한국토양비료학회지
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• 제48권5호
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• pp.413-420
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• 2015

Objective of this study was to investigate adsorption characteristics and kinetic models of $NH_4-N$ to biochar produced from rice hull in respective to mitigation of greenhouse gases. $NH_4-N$ concentration was analyzed by UV Spectrophotometer. For the experiment, the soil texture used in this study was sandy loam soil, and application rates of chemical fertilizer and pig compost were $420-200-370kgha^{-1}$ (N-P-K) and $5,500kgha^{-1}$ as recommended amount after soil test for corn cultivation. Biochar treatments were 0.2-5% to soil weight. Its adsorption characteristic was investigated with application of Langmuir isotherm, and pseudo-first order kinetic model and pseudo-second order kinetic model were used as kinetic models. Adsorption amount and removal rates of $NH_4-N$ were $39.3mg^{-1}$ and 28.0% in 0.2% biochar treatment, respectively. The sorption of $NH_4-N$ to biochar was fitted well by Langmiur model because it was observed that dimensionless constant ($R_L$) was 0.48. The maximum adsorption amount ($q_m$) and binding strength constant (b) were calculated as $4.1mgg^{-1}$ and $0.01Lmg^{-1}$ in Langmuir isotherm, respectively. The pseudo-second order kinetic model was more appropriate than pseudo-first order kinetic model for high correlation coefficient ($r^2$) of pseudo-second order kinetic model. Therefore, biochar produced from rice hull could reduce $N_2O$ by adsorbing $NH_4-N$ to biochar cooperated in sandy loam soil.

• Journal of information and communication convergence engineering
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• 제4권4호
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• pp.158-161
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• 2006

[ $Bi_2Sr_2Ca_nCu_{n+1}O_y(n{\geq}0)$ ] thin film is fabricatedvia two different processes using an ion beam sputtering method i.e. co-deposition and layer-by-layer deposition. A single phase of Bi2212 can be fabricated via the co-deposition process. While it cannot be obtained by the layer-by-layer process. Ultra-low growth rate in our ion beam sputtering system brings out the difference in Bi element adsorption between the two processes and results in only 30% adsorption against total incident Bi amount by layer-by-layer deposition, in contrast to enough Bi adsorption by co-deposition.

• 전기화학회지
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• 제3권2호
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• pp.104-108
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• 2000

전기화학에 있어서 전극 물질의 실제 거칠기(real roughness)를 아는 것은 매우 중요하다. 그러나 여러 가지 이유 때문에 전극 물질의 절대적인 거칠기를 아는 것은 불가능하다. 여기에서는 scanning tunneling microscopy (STM), 순환전압전류법을 이용하여 전기화학에서 자주 사용하는 다결정 금 전극의 거칠기를 구하여 Au(111), HOPG로부터 구한 거칠기와 비교해 보았다. STM으로부터 얻은 다결정 금전극의 거칠기는 $1.1(\pm0.1)$,산소의 탈착으로부터는 $2.4(\pm0.7)$, N-docosyl-N'-methyl viologen의 흡착으로부터 는 $1.6(\pm0.1)$이 얻어졌다.

• 한국토양비료학회지
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• 제29권2호
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• pp.107-112
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• 1996

토양의 규산 흡착기작을 밝히고자 continuous stirred-flow(연속진탕흘림) 법을 이용하여 시간 경과에 따른 규산 흡착량 변화에 대한 실험을 $25^{\circ}C$, pH 3수준(5, 6.5, 8)에서 실시하였다. 규산 흡착량은 실험기간내 최대 흡착량을 보이지 않고 계속 증가 하였다. 시간에 따른 규산의 흡착과정을 2단계로 구분 하였고, 1단계 반응과정은 아래의 지수함수식에서 고도의 유의성있는 상관관계를 보였다 $$R_{ad}=K_a*(Q_{OH}^S)^n$$ 여기서 $R_{ad}$는 규산흡착속도($Si\;{\mu}mal/min$), $Q_{OH}^S$는 알칼리 투여를 통하여 생성된 토양표면 음전하량, $K_a$와 n 은 상수이다. 1단계 반응과정의 n값은 1.1로 한자리 결합(monolantate ligand bonding)에 의한 흡착과정인 것으로 나타났다. 2단계 과정은 아래 식에서 고도의 유의성있는 상관관계를 보였다. $$R_{ad}=K_b*(pH)$$ 이때 $K_b$ 는 비례상수로, pH 증가에 따른 규산 흡착 속도의 증가 추세가 지수 함수적으로 감소하는 경향을 보였다.

• 한국전기전자재료학회논문지
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• 제24권11호
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• pp.929-934
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• 2011

The adsorption kinetic study of ruthenium complex, N3, onto nanoporous titanium dioxide ($TiO_2$) photoanodes has been carried out by measuring dye uptake in-situ. Three simplified kinetic models including a pseudo first-order equation, pseudo second-order equation and intraparticle diffusion equation were chosen to follow the adsorption process. Kinetic parameters, rate constant, equilibrium adsorption capacities and related coefficient coefficients for each kinetic model were calculated and discussed. It was shown that the adsorption kinetics of N3 dye molecules onto porous $TiO_2$ obeys pseudo second-order kinetics with chemisorption being the rate determining step. Additionally the heterogeneous surface and the pore size distribution of porous $TiO_2$ adsorbents were also discussed.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
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• pp.215-215
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• 2011

The bonding configuration and adsorption stability of alanine and leucine adsorbed on Ge(100)-2${\times}$1 surface were investigated and compared using core-level photoemission spectroscopy (CLPES) and density functional theory (DFT) calculations. The bonding configuration, stability, and adsorption energies were evaluated for two different coverage levels. In both cases, the C 1s, N 1s, and O 1s core-level spectra at a low coverage (0.30 ML) indicated that the carboxyl and amine groups participated in bonding with the Ge(100) surface in an "O-H dissociated-N dative bonded structure". At high coverage levels (0.60 ML), both this structure and an "O-H dissociation bonded structure" were present. As a result, we found that alanine adsorbs more easily (lower adsorption energy) than leucine on Ge(100) surfaces due to less steric hindrance of side chain.