• Membrane and Water Treatment
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• v.6 no.1
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• pp.1-13
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• 2015

The modification of ultrafiltration membranes with carbon nanotube (CNT) buckypaper on fouling control was investigated. Two types of commercially available flat-sheet membranes were used: PS35 and PES900C/D (PES) (the PS35 membranes were hydrophilic with a molecular weight cutoff of 20 kDa, and the PES membranes were hydrophobic with a molecular weight cutoff of 20 kDa). The CNT buckypaper modified ultrafiltration membranes were prepared by filtering a CNT suspension through the flat-sheet membrane in a dead-end ultrafiltration unit. After modification, the pure water flux of PES was significantly increased, while the pure water flux of PS35 was decreased. The properties of the CNT modified membranes were also investigated. Considering the antifouling properties, pure water flux of the modified membrane, and the stability of CNT buckypaper layer on the membrane surface, ethanol solution with a concentration of 50 wt.%, multi-walled carbon nanotubes (MWCNTs) with a larger diameter (30-50 nm), and the CNT loading with $7.5g/m^2$ was selected. The CNT buckypaper on the surface of ultrafiltration membranes can trap the pollutants in sewage effluent and prevent them reaching the surface of virgin membranes. Water quality analysis showed that the effluent quality of the modified membrane was obviously improved. The removal efficiency of humic acid and protein-like matters by the modified membrane was significant. These results indicate the potential application of the CNT buckypaper layer modified membranes in the field of wastewater reclaim.

• Journal of Sensor Science and Technology
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• v.33 no.5
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• pp.366-372
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• 2024

In this study, we present a novel approach to improve electrochemical heavy metal ion (HMI) sensing responses via post-synthetic modification of carbon nanotube-based metal-organic framework (MOF) nanocomposites with a Schiff base. UiO66-NH₂ was employed as the MOF and incorporated with multi-walled carbon nanotubes (MWCNT) through in-situ growth, enhancing the electrical conductivity of the MWCNT-UiO66-NH₂ composite. Subsequently, the Schiff base, which has been proven to be an excellent ligand for metal ion detection, was functionalized onto MWCNT-UiO66-NH₂ via post-synthetic modification to improve its HMI absorption capacity. To evaluate the effect of the Schiff base on HMI detection capacity, electrochemical sensing of Cd²⁺, Pb²⁺, Cu²⁺, and Hg²⁺ was performed in an aqueous solution utilizing the MWCNT-UiO66-Schiff modified electrode as well as the bare electrode. Individual differential pulse anodic stripping voltammetry results revealed that the modified electrode with MWCNT-UiO66-Schiff exhibited increased HMI sensing properties, especially with 1.82-fold improvement in average oxidation currents toward 10 µM of Cu²⁺ compared to that for a bare glassy carbon electrode. The selective Cu²⁺-sensing properties of MWCNT-UiO66-Schiff were reflected in the highly selective Cu²-binding affinity of the Schiff base-containing model molecules compared to those of Cd²⁺, Hg²⁺, and Pb²⁺. Our work provides a new strategy for improving the sensing properties of electrochemical HMI sensors by the post-synthetic modification of MWCNT-UiO66 with a Schiff base.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.11
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• pp.24-32
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• 2005

The object of this study is to design radar absorbing structures(RAS) with load-bearing ability in X-band. Glass/Epoxy plain-weave composites of excellent specific stiffness and strength, containing multi-walled carbon nanotubes(MWNT) added to induce dielectric loss were fabricated. The observation of microstructure and the permittivity of the composites confirmed that the materials are suitable to be used for radar absorbing material. Genetic algorithm and theory for reflection/transmission of electromagnetic waves in a multi-layered RAS were applied to conduct an optimal design of a RAS composed of the developed composites. We observed that the thickness per ply changes with the number of ply and MWNT contents. The fabrication process was proposed considering the problem and applied to fabricate a designed RAS and the theoretical and measured reflection loss of the RAS were also found in good agreement.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.9
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• pp.1209-1215
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• 2010

The effects of multi-walled carbon nanotube (MWCNT) content, carbon black (CB) content, atmospheric-pressure flame plasma (APFP) treatment, and acid treatment on the mechanical properties of elastomeric composites were investigated. For pure or filled rubbers with the given amount of CB (20 and 40 phr), the tensile strength and modulus of the elastomeric composites increase similarly with the MWCNT content. A composite with APFP-treated MWCNTs shows a hardening effect (high strength, high modulus, and high ductility) unlike the one with untreated MWCNTs. On the other hand, a composite with APFP-treated CB shows a softening effect (high strength, low modulus, and high ductility), which is unlike a composite with untreated CB. As the refluxing time increases from 1 h to 2 h and the sulfuric acid concentration increases from 60% to 90%, the tensile strength and modulus of a composite decrease. Thus, it is found that the MWCNT content, CB content, APFP treatment, sulfuric acid concentration, and refluxing time have an important effect on the mechanical properties of NBR composites.

• Proceedings of the Korean Vacuum Society Conference
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• 2007.02a
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• pp.169-169
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• 2007

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.3
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• pp.294-298
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• 2004

Carbon nanotubes(CNTs) were synthesized by thermal chemical vapor deposition(CVD) method. To fabricate CNT gas sensor, catalyst metal layer was deposited on microstructure. The CNT gas detecting layer was grown by thermal CVD method on the catalyst metal layer. In order to investigate the gas sensing characteristics of the fabricated CNT gas sensor, it was exposed in NO$_2$ gas and sensitivity, response, and recovery time were measured. As the result, this sensor has better reproductibility and faster recovery time than another CNT gas sensors.

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.849-851
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• 2003

After multi-walled carbon nanotubes (MWNT) powder was crushed with ball milling process, it was mixed with organic vehicles. And then CNT paste was printed on ITO coated glass substrate. The field emission characteristics of CNT pastes fired in air atmosphere was better than that of CNT paste fired in Ar ambient due to less organic residues after firing.

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.852-854
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• 2003

CNT paste was fabricated by mixture of multi-walled carbon nanotubes (MWNT) powder, organic vehicles and inorganic binder. Then firing process was performed at different temperature under air and $N_{2}$ atmosphere. It was found that emission property of CNT paste was changed by firing temperature and time due to interaction between remained resins and CNT powder. We obtained good emission property from CNT paste treated at $350^{\circ}C$ for 10 min.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.430-430
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• 2008

열화학기상 증착법으로 2원계 합금인 Invar 36(63wt% Fe, 37wt% Ni)을 이용하여 다중벽 탄소나노튜브를 360도의 저온에서 까지 합성이 가능함을 확인하였다. 촉매와 Si 기판과의 silicide형성을 막기 위한 Ti층의 두께가 증가함에 따라서 탄소나노튜브의 길이가 잘 자라는 것을 확인하였으며, 미량의 물이 첨가 되었을 경우 탄소나노튜브의 길이 성장에 큰 변화가 있음을 확인하였다. 또한 물을 포함하는 실험에서는 촉매인 Invar36의 두께가 0.5 nm 일 때에 비하여 0.25 nm 두께에서 물에 대한 영향이 더 크게 나타남을 SEM 사진을 통해 확인할 수 있었다.

• Proceedings of the Materials Research Society of Korea Conference
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• 2011.05a
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• pp.52.2-52.2
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• 2011

Flat form technology for constructing anticancer loaded multi-walled carbon nanotubes (mwCNTs) was introduced in this study. Conventional anticancer drugs, such as MTX (Methotrexate), cisplatin, DOX (Doxorubicin hydrochloride), DAU (Daunorubicin) and EPI (epirubicin) were bio-conjugated with folic acid (FA) for selective targeting tumor cells. Loading efficiencies of the used anticancer drugs on mwCNTs have shown different order of bindings depending on the molecular bind affinity of NH (amine) formation on mwCNTs. MTT assays have shown increased selective target efficiency of FA conjugated mwCNTs on breast cancer cell growth inhibition. All results collectively indicated promising application of mwCNTs as a smart inorganic nanomaterial for selective targeting drug delivery vehicle at tumor tissues.