• 한국전기화학회:학술대회논문집
• /
• 한국전기화학회 2004년도 춘계총회 및 학술발표회
• /
• pp.23-23
• /
• 2004

• Journal of Electrochemical Science and Technology
• /
• 제11권1호
• /
• pp.84-91
• /
• 2020

The PtBi/C and PtBiPd/C electrocatalysts were synthesized via the irreversible adsorption of Pd and Bi ions precursors on commercial Pt/C catalysts. XRD and XPS revealed the formation of an alloy structure among Pt, Bi, and Pd atoms. The current of direct formic acid oxidation (I_d) increased ~ 8 and 16 times for the PtBi/C and PtBiPd/C catalysts, respectively, than that of commercial Pt/C because of the electronic, geometric, and third body effects. In addition, the increased ratio between the current of direct formic acid oxidation (I_d) and the current of indirect formic acid oxidation (I_ind) for the PtBi/C and PtBiPd/C catalysts suggest that the dehydrogenation pathway is dominant with less CO formation on these catalysts.

• 한국환경과학회지
• /
• 제10권4호
• /
• pp.269-273
• /
• 2001

Biosorption of Pb was evaluated for plants, Persicaria chinensis, Oenanthe javanica and Salvinia natnas. The adsorption equilibrium was reached in about 1hr for Pb and the highest adsorption capacity was 150mg Pb/g biomass at S.natans. Pb adsorption process showed a pseudo second order irreversible reaction. The highest initial adsorption rate was 2000mg pb/g biomass/hr at O.javanica. In spite of pH variation, Pb adsorption capacity by was selection, Pb was selectively adsorved. The selectivity of mixture solution showed the adsorption order of Pb>Cu>Cr>Cd. The Pb adsorption capacity of P. chinensis pretreated with NaOH was increased by 30% in comparison with that of no treatment.

• Bulletin of the Korean Chemical Society
• /
• 제26권5호
• /
• pp.735-739
• /
• 2005

Presented is a voltammetric study of co-adsorption of irreversibly adsorbing Sb and Te on Pt(111). When a layer of Sb and Te was formed via simultaneous adsorption, the reduction peak of Te was observed at 0.30 V in the initial cathodic scan. In contrast, sequential adsorption of Sb followed by Te adsorption led to a Te reduction peak at 0.50 V in the initial scan. As the voltammetric scan was continued, in addition, the voltammogram of the simultaneously co-adsorbed layer changed, while that of the sequentially co-adsorbed layer did not. These observations are discussed in terms of formation of a homogeneously mixed layer and a layer consisting of heterogeneously separated domains of Sb and Te. Also, the difference in the adsorption strength of Sb and Te was observed.

• 한국환경보건학회지
• /
• 제32권4호
• /
• pp.336-341
• /
• 2006

The biological wastewater treatment system is known to have an important role in reducing the quantify of enteric virus in water environments. To clarify the roles of activated sludge microbes in decreasing the virus infectivity, the behavior of the virus in bacteria, protozoa, and metazoa was examined by pure or mixed culture system using poliovirus type 1(Lsc, 2ab strain). In the bacterial culture systems, the virus infectivity in the liquid phase decreased by a reversible adsorption of the virus to the bacteria or bacterial flocs. On the other hand, in the protozoa and the metazoa culture systems using T. pyriformis and P. erythrophthalma, respectively, with a variety of bacterial strains as prey, the main virus decrease mechanism of reversible adsorption in early stage was changed to irreversible predation, which was not eluted in this study. The virus decrease was more effective in the P. erythrophthalma culture system, which had high predation and floc forming abilities. However, in the mixed culture system of Z. ramigera and P. erythrophthalma, the more rapid reversible adsorption of virus to Z. ramigera flocs preceded the irreversible predation of P. erythrophthalma.

• Bulletin of the Korean Chemical Society
• /
• 제18권11호
• /
• pp.1175-1179
• /
• 1997

The adsorption of oxygen on ZnO was monitored by measuring the capacitance of two contacting crystals which have depletion layers originated from the interaction between oxygen and ZnO at 298 K-473 K. An admission of oxygen to the sample induced an irreversible increase in the depth and the amount of adsorbed oxygen was less than 0.001 monolayer in the experimental condition. The relation between pressure of oxygen and variation of the depth was tested from the view point of Langmuir or Freundlich isotherm. Using Hall effect measurement and kinetic experiment, a model equation on the adsorption process was proposed. From the results, it was suggested that oxygen adsorption depended on the rate of electron transfer from ZnO to oxygen while the amount of adsorbed oxygen was kinetically restricted by the height of surface potential barrier.

• Environmental Engineering Research
• /
• 제25권2호
• /
• pp.205-211
• /
• 2020

Chlorhexidine digluconate (CHD) in the aquatic environment causes irreversible change to microbes, making them resistant to biodegradation, which needs remediation other than biological process. Adsorption study was performed for the removal of CHD on fly ash (FA) as a function of pH and ionic strength. Experimental result has been validated by characterization using Scanning electron microscopy, Fourier Transform-Infrared Spectroscopy and Brunauer-Emmett-Teller. CHD adsorption with FA showed an increasing trend with an increase in pH. Variation in pH proved to be an influential parameter for the surface charge of adsorbent and the degree of ionization of the CHD molecules. The adsorption capacity of CHD decreased from 23.60 mg g-1 to 1.13 mg g-1, when ionic strength increased from to M. The adsorption isotherms were simulated well by the Freundlich isotherm model having R2 = 0.98. The Lagergren's model was incorporated to predict the system kinetics, while the mechanistic study was better explained by pseudo-second order for FA. On the basis of operational conditions and cost-effectiveness FA was found to be more economical as an adsorbent for the adsorption of CHD.

• 한국진공학회지
• /
• 제21권2호
• /
• pp.106-112
• /
• 2012

본 연구에서는 톨루엔 등의 휘발성 유기물의 흡착량을 정성, 정량적으로 연구할 수 있는 새로운 장비를 구축하였으며, 이를 이용하여 기존의 탄소를 기반으로 하는 다양한 흡착제와 원자층 증착으로 만든 $TiO_2$ 박막구조의 톨루엔 흡착에 대한 연구를 진행하였다. $TiO_2$ 박막구조의 흡착제가 기존의 탄소기반 흡착제보다 톨루엔 흡착량이 뛰어난 것을 입증하였으며, 이는 원자층증착으로 제조한 $TiO_2$ 박막 표면의 높은 농도의 OH 그룹의 높은 톨루엔 친화력과 연관성이 있는 것으로 나타났다. 또한 본장비를 이용하여 가역적인 흡착과 비가역적인 흡착을 구분할 수 있음을 보여주었다.

• 공업화학
• /
• 제9권2호
• /
• pp.311-316
• /
• 1998

물리 화학적인 특성이 다른 다공성 고분자 마이크로겔에 대한 bovine serum albumin (BSA-protein) 단백질의 흡착평형 특성을 연구하였다. 수용액 속에서 고분자와 단백질사이의 소수성 상호작용에 의하여 폴리부틸메타크릴레이트 (PBMA) 마이크로겔이 폴리비닐피리딘 (PVP)과 폴리아크릴로니트릴 (PAN) 마이크로겔보다 높은 흡착특성을 나타내었으며, PBMA 마이크로겔이 PVP와 PAN 마이크로겔보다 비가역적으로 흡착평형 특성을 나타내었다. 그러므로 고분자 마이크로겔의 물리적인 특성과 단백질-고분자 마이크로겔 사이의 정전기적 인력보다는 소수성 상호작용이 단백질의 흡착특성에 중요한 역할을 하고 있음을 알 수 있다. 또한 PBMA, PVP 및 PAN 마이크로겔 모두 Freundlich 흡착 등온식보다는 Langmuir 흡착 등온식에 잘 적용되었다.

• Korean Chemical Engineering Research
• /
• 제57권2호
• /
• pp.210-218
• /
• 2019

실로퓨트를 이용한 식물세포 Taxus chinensis 유래 주요 타르성분인 2-피콜린 흡착 실험을 수행하였다. 2-피콜린 초기농도, 흡착 온도 및 시간을 달리한 회분식 흡착 평형 데이터를 Langmuir, Freundlich, Temkin, Dubinin-Radushkevich 등온흡착식에 적용하였다. 실로퓨트를 이용한 2-피콜린의 흡착은 Langmuir 흡착등온식에 가장 적합함을 알 수 있었다. 흡착온도가 증가함에 따라 흡착용량이 감소하는 경향을 보였으며 실로퓨트를 이용한 2-피콜린 흡착 공정이 적합함을 알 수 있었다. 동역학적 해석을 통하여 본 흡착 공정은 유사 이차 반응속도식에 잘 따름을 알 수 있었으며, 입자 내 확산과 경계층 확산이 율속 단계에 거의 영향을 미치지 않았다. 열역학적 해석을 통해 흡착 과정이 발열이며, 비가역적 비자발적으로 수행되었다. 흡착량이 증가함에 따라 등량흡착열은 감소하는 경향을 보여 흡착제의 표면 에너지가 불균일함을 알 수 있었다.