Sensitivity of nanoparticles’ stability at the point of zero charge (PZC)

엄하늬,김영훈 한국공업화학회 2014 Journal of Industrial and Engineering Chemistry Vol.20 No.5

Since bare-nanoparticles (NPs) without stabilizers in aqueous phase are stabilized by electrostatic forces, pH control is easily used to influence the surface charge and hence the formation of aggregates or agglomerates. Therefore, herein, the sensitivity of bare-NPs’ stability in aqueous phase was analyzed close to the point of zero charge (PZC) using six model NPs. The results demonstrated that the sensitivity of NPs’ agglomeration/aggregation could be estimated by the diameter ratio (RD) between the primary and secondary particle sizes. Namely, if the primary particle size was almost identical to the hydrodynamic diameter (HDD), the agglomeration proceeded aggressively.

Spectroscopic and microscopic studies of vesicle rupture by AgNPs attack to screen the cytotoxicity of nanomaterials

엄하늬,김영훈 한국공업화학회 2013 Journal of Industrial and Engineering Chemistry Vol.19 No.6

It is well-known that silver nanoparticles (AgNPs) with 1–10 nm of diameter attached to the surface of cell membrane were able to penetrate into the cell followed by rupturing of the cell. However, most studies for cytotoxicity used living organisms and were time-consuming. Therefore, in this study, we proposed a model method for fingerprinting of nanotoxicity of AgNPs in mimetic cell membranes using phosphor lipid. The vesicle rupturing mechanism by AgNPs attack was investigated using surface plasmon resonance (SPR) spectroscopy and atomic force microscopy (AFM).

Simple Analysis for Interaction between Nanoparticles and Fluorescence Vesicle as a Biomimetic Cell for Toxicological Studies

엄하늬,김영훈 대한화학회 2012 Bulletin of the Korean Chemical Society Vol.33 No.12

With continuing progress of nanotechnologies and various applications of nanoparticles, one needs to develop a quick and fairly standard assessment tool to evaluate cytotoxicity of nanoparticles. However, much cytotoxicity studies on the interpretation of the interaction between nanoparticles and cells are non-mechanistic and time-consuming. Here, we propose a simple screening method for the analysis of the interaction between several AgNPs (5.3 to 64 nm) and fluorescence-dye containing vesicles (12 μm) acting as a biomimetic cellmembrane. Fluorescence-dye containing vesicle was prepared using a fluorescence probe (1,6-diphenyl-1,3,5- hexatryene), which was intercalated into the lipid bilayer due to their hydrophobicity. Zeta potential of all materials except for bare-AgNPs (+32.8 mV) was negative (−26 to −54 mV). The morphological change (i.e., rupture and fusion of vesicle, and release of dye) after mixing of the vesicle and AgNPs was observed by fluorescence microscopy, and fluorescence image were different with coating materials and surface charge of x-AgNPs. In the results, we found that the surface charge of nanoparticles is the key factor for vesicle rupture and fusion. This proposed method might be useful for analyzing the cytotoxicity of nanoparticles with cellmembranes instead of in vitro or in vivo cytotoxicity tests.

나노폐기물 처리의 새로운 패러다임

엄하늬(Ha Nee Umh),이병천(Byoung-Cheun Lee),김영훈(Younghun Kim) 한국청정기술학회 2012 청정기술 Vol.18 No.3

최근 나노기술의 급격한 발전은 산업 및 바이오의약 등 다양한 분야에 새로운 활용 가능성을 제시하고 있다. 그러나 나노물 질과 나노소비재의 연간 생산량이 증가하고 있어서, 의도하지 않은 환경 노출이 야기되고 있다. 따라서 지속적인 나노기술의 발전을 위해서도 나노폐기물에 관한 효과적인 관리가 필요하다. 현재까지는 나노폐기물을 효율적으로 처리할 수 있는 기존의 처리시설이 없는 실정이다. 이에 본 총설에서는 몇 가지 주제에 관하여 기술하고자 한다. 국내외의 나노물질 및 나노 소비재 현황을 파악하고, 나노폐기물의 정의와 주요 발생원이 무엇인지 파악하였다. 또한 기존의 폐기물 처리시설로 나노 폐기물을 처리 가능한지를 살피고, 개발되고 있는 새로운 처리법을 조사하였다. 마지막으로 나노물질에 관한 환경 규제를 거론하고, 나노폐기물에 관한 책임 있는 관리에 관한 새로운 나노폐기물 패러다임을 제시하고자 하였다. Recent rapidly growth in nanotechnolgies is promised novel benefits through the exploitation of their unique industrial and biomedical applications. In addition, the production amount of these nanomaterials and nanoproducts has increased, and thus their uncontrolled release into the environment is anticipated to grow dramatically in future. Therefore, nanowaste streams must be effectively managed for sustainable nanotechnology. However, the effectiveness and capability of the current systems to handle nanowastes are yet to be established. In this review, we investigated several key topics for new paradigm of nanowaste treatment, (i) global and domestic production of nanomaterials and nanoproducts, (ii) definition and key resources of nanowaste, (iii) current and developing treatment method for nanowaste, and (iv) regulations for nanomaterials and nanoproducts.

온실가스 저감을 위한 루테늄-철을 담지한 그래핀 전기화학적 촉매의 개발

엄하늬(Ha Nee Umh),여창원(Chang-Won Yeo),우은석(Eunseck Woo),임동하(Dong-Ha Lim) 한국에너지기후변화학회 2019 한국에너지기후변화학회 학술대회 Vol.2019 No.05

나노물질의 환경 매질별 노출 사례 조사

엄하늬 ( Ha Nee Umh ),노진규 ( Jin Kyu Roh ),이병천 ( Byoung Cheun Lee ),박수민 ( Su Min Park ),이종협 ( Jong Heop Yi ),김영훈 ( Young Hun Kim ) 한국화학공학회 2012 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.50 No.6

최근 나노기술의 급격한 발전은 산업 및 바이오의약 등 다양한 분야에 새로운 활용 가능성을 제시하고 있다. 나노 물질을 이용한 나노소비재의 증가와 함께 환경으로의 나노물질 노출 가능성이 제기되고 있으며, 최근 나노물질의 인 체 및 환경 영향이 주요 현안으로 떠오르고 있다. 환경 중에 비의도적으로 노출된 나노물질은 다양한 환경 매질에 축 적되고 언젠가는 우리들에게 재영향을 미치게 된다. 따라서, 환경 매질(대기, 수계, 토양)에 노출된 나노물질의 영향을 이해하기 위해서는 나노물질의 환경 내 거동을 이해하는 것이 중요하다. 이에 본 연구에서는 나노물질의 환경 매질별 노출 사례를 조사하고, 향후 연구 방향을 제시하고자 하였다. 작업장(실험실)에서는 주로 대기 노출이 지배적이지만, 환경중으로 노출될 경우 최종적으로 수계 및 토양으로 노출되는 것으로 파악되었다. 또한 기존의 하수처리장 설비로 는 완벽하게 나노물질을 제거하기가 어렵다는 것을 확인하여, 나노폐기물 처리에 관한 새로운 방법론 개발이 절실함을 확인하였다. 보다 다양하고 깊이있는 환경 노출 연구를 위해서는 현장 모니터링 장비의 개발이 필요함을 확인할 수 있었으며, 이에 추가적으로 다양한 분석법을 제안하였다. 본 총설에서 정리한 나노물질의 환경 매질별 노출 사례 연구 들은 향후 나노물질의 환경 거동 평가 및 나노폐기물의 적절한 처리방법 모색에 기본 자료로 활용될 것이다. Recent rapidly growth in nanotechnolgies is promised novel benefits through the exploitation of their unique industrial and biomedical applications. With increasing utilization of nanomaterials in consumer products, the potential release of nanomaterials into the environment and their impacts on the ecosystem and human health have been the issues of concern, Nanomaterials that was exposed unintentionally in environment might be accumulated in various environmental media, and finally it will be influenced to human and ecosystems. Therefore, it is important to understand the fate and behavior of nanoparticles for understanding effects on environmental media (air, water, and soil phase). Therefore, in this work, we investigated the several cases for environmental exposure of nanomaterials and suggested the direction of further research. In workplace, exposure to air media is dominant, but finally waste and wastewater was moved to the water and soil phase. In addition, we found the existing sewage treatment plant was not suitable to remove completely nanomaterials in wastewater flow. To deeper study, environmental monitoring tool must be developed additionally and we suggested the several analyzing method for aged and pristine physicochemical properties of nanomaterials exposed into environmental media. This review for nanomaterials` exposure to environmental media will be helpful to investigate the envrionmental fate of nanomaterials and define the suitable treatment method for nano-waste.

나노물질 생산시설의 환경노출 평가와 안전관리

엄하늬 ( Ha Nee Umh ),노진규 ( Jin Kyu Roh ),박준수 ( Jun Su Park ),곽병규 ( Byoung Kyu Kwak ),이병천 ( Byung Cheon Lee ),최경희 ( Kyung Hee Choi ),이종협 ( Jong Heop Yi ),김영훈 ( Young Hun Kim ) 한국화학공학회 2012 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.50 No.1

나노기술의 발전과 함께 나노물질을 포함한 소비재가 대중화되고 있다. 그러나 지난 10여년간 조심스럽게 제기되고 있는 나노물질의 잠재적 위해성으로 인해, 나노제품 사용을 불안해하고 있다. 특히 나노제품을 직접 취급하는 생산시설(연구소 및 업체)의 작업자는 직접적인 인체 노출을 초래하게 된다. 따라서 이들에 대한 인체 및 환경 노출 안전관리를 위하여, 직접적인 노출평가가 필요하다. 본 연구에서는 기상 및 액상 반응을 통해 나노물질을 생산하는 두 곳의 업체를 현장 방문하여 나노물질의 주요 노출대상 공정과 노출원을 파악하고 SMPS를 이용한 실시간 현장 모니터링을 실시하였다. 분석 결과, 액상 공정도 기상으로의 나노입자 노출이 심각하게 발생하고 있음을 확인하였다. 가장 문제가 되는 점은 나노물질의 잠재적인 위해성에 관한 인식의 부족으로 제대로 된 방호활동을 못하고 있다는 점이다. 따라서 보다 다양한 나노물질 취급 시설에 대한 환경노출 평가가 필요하고 이를 바탕으로 한 나노물질 취급 안전관리 방법이 제시되어야 한다.

Regeneration of aged-AgNPs via density gradient ultracentrifugal nanoseparation

심재훈,엄하늬,신현호,성화경,이병천,오승연,김영훈,Rengaraj Selvaraj 한국공업화학회 2014 Journal of Industrial and Engineering Chemistry Vol.20 No.5

To reuse aged-silver nanoparticles (AgNPs) and recover the mono-dispersed AgNPs separately, we attempted to recycle the aged-AgNPs with high polydispersity in particle size distribution using the density gradient ultracentrifugation rate (DGUR) separation with five media. Results for the microscopic and spectroscopic showed that Tween series media, which have low density compared to other media, are suitable for the application of DGUR separation for recycling aged-AgNPs. This method might be helpful to regenerate and recycle the precious metal nanoparticles with polydispersity due to long-term storage.

Development of Ni-La supported on hierarchical alumina as steam methane reforming catalyst for enhancing durability

우은석,엄하늬,박대원,임동하 한국공업화학회 2019 한국공업화학회 연구논문 초록집 Vol.2019 No.1

In recent years, hydrogen energy is considered as an alternative energy to solve the depletion of fossil fuel. Steam Methane Reforming (SMR) is widely known as cost-effective method for hydrogen production. Ni catalyst with best activity is widely used for SMR reaction. However, It has severe problems such as carbon coking and sintering at high reaction temperature resulting in reducing the SMR performance. In this study, we developed the Ni-La catalyst supported on hierarchically alumina to prevent catalyst deactivation for enhancing durability. The optimum content of La was added in Ni catalyst with best catalytic performance for high hydrogen production. The as-prepared Ni-La showed high mass transfer capacity and minimizing carbon coking and sintering of Ni, resulting in enhancing catalytic activity and durability.

Comparison of adsorptive features between silver ion and silver nanoparticles on nanoporous materials

심재훈,엄하늬,신현호,성화경,오승연,이병천,김영훈,Selvaraj Rengaraj 한국공업화학회 2014 Journal of Industrial and Engineering Chemistry Vol.20 No.5

The removal of Ag+ or AgNPs released from nano-products or effluent of WTP is important to reduce the potential risk of AgNPs. In this work, we prepared bimodal nanoporous silica (BNS) to compare the removal efficiency of Ag+ and AgNP with unimodal nanoporous silica (NS). To determine the adsorption capacity of Ag+ and AgNPs on NS and BNS, isotherm and kinetics studies was carried out at different concentrations. The results showed BNS with a bimodal nanoporous structure and a large external surface showed a higher uptake capacity and faster adsorption rate.