• Carbon letters
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• v.10 no.1
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• pp.33-37
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• 2009

Activated carbon (AC) is one of the most effective adsorbents for organic compounds because of their extended surface area, high adsorption capacity, microporous structure and special surface reactivity. The composites of pH-sensitive hydrogel and activated carbon were prepared in order to improve the loading capacity of drug. The pH-sensitive hydrogel matrix swelled well in the basic condition to release the drug loaded in AC. The release of drug was controlled depending on both the pH due to the ionization of the carboxylic acid group and the AC due to the surface properties.

• Applied Chemistry for Engineering
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• v.2 no.1
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• pp.1-11
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• 1991

Xenon-129 NMR technique has been developed since 1980 as a new method for the characterization of microporous materials such as zeolites, activated carbons and alumina by using chemical shift and linewidth variations in $^{129}Xe$ NMR of adsorbed xenon gas. This NMR technique has been known to be very effective to probe the locational and the chemical changes of the supported metallic species as well as the physicochemical change of the support material. Recently, this method has been successfully applied for the characterization of amorphous materials such as activated carbons, silica and alumina. Basic principles, experimental techniques and recent applications of the $^{129}Xe$ NMR method for the study of heterogeneous catalysts are introduced in this paper.

• Carbon letters
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• v.11 no.3
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• pp.192-200
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• 2010

Common reed (Fragmites australis), a local invasive grass, was investigated as a possible feedstock for the production of activated carbon. Dried crushed stems were subjected to impregnation with phosphoric acid (30, 40 and 50%) followed by pyrolysis at $400{\sim}500^{\circ}C$ with final washing and drying. Obtained carbons were characterized by determining: carbon yield, ash content, slurry pH, textural properties and capacity to remove color bodies from factory-grade sugar liquor. Produced carbons possessed surface area up to 700 $m^2/g$, total pore volumes up to 0.37 $cm^3/g$, and proved to be microporous in nature. Decolorization of hot sugar liquor at $80^{\circ}C$ showed degrees of color removal of 60 up to 77% from initial color of 1100~1300 ICU, at a carbon dose of 1.0 g/100 ml liquor. No correlation seems to hold between synthesis conditions and % R but depends on the degree of microporosity. A commercial activated carbon N showed a comparative better color removal capacity of 91%. Common reed proved to be a viable carbon precursor for production of good adsorbing carbon suitable for decolorization in the sugar industry, as well as in other environmental remediation processes.

• Carbon letters
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• v.11 no.3
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• pp.224-234
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• 2010

Four activated carbons were produced by two-stage process as followings; semi-carbonization of indigenous biomass waste, i.e. cotton stalks, followed by chemical activation with KOH under various activation temperatures and chemical ratios of KOH to semi-carbonized cotton stalks (CCS). The surface area, total pore volume and average pore diameter were evaluated by $N_2$-adsorption at 77 K. The surface morphology and oxygen functional groups were determined by SEM and FTIR, respectively. Batch equilibrium and kinetic studies were carried out by using a basic dye, methylene blue as a probe molecule to evaluate the adsorption capacity and mechanism over the produced carbons. The obtained activated carbon (CCS-1K800) exhibited highly microporous structure with high surface area of 950 $m^2/g$, total pore volume of 0.423 $cm^3/g$ and average pore diameter of 17.8 ${\AA}$. The isotherm data fitted well to the Langmuir isotherm with monolayer adsorption capacity of 222 mg/g for CCS-1K800. The kinetic data obtained at different concentrations were analyzed using a pseudo-first-order, pseudo-second-order and intraparticle diffusion equations. The pseudo-second-order model fitted better for kinetic removal of MB dye. The results indicate that such laboratory carbons could be employed as low cost alternative to commercial carbons in wastewater treatment.

• Tribology and Lubricants
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• v.24 no.4
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• pp.179-185
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• 2008

Microporous polymer lubricants(MPLs) are solid polymer materials containing micropores which are filled with liquid lubricants, and which are molded or formed to suit rolling bearings or other machine parts requiring lubrication. MPLs can be effectively applied to provide long-term, maintenance-free lubrication of a variety of machine elements without fully replacing of oils and greases. The application of rolling bearings packed fully with an MPL could reduce or eliminate the problems such as grease deterioration, leakage, under-lubrication caused by insertion of water or foreign matters under severe operation conditions. This paper discuss the application of MPLs for lubrication of rolling ball bearings. Two different MPLs were synthesized and the features of MPLs were tested. Characteristics of the bearings which are packed fully with synthesized MPLs were investigated using SEM, TG/DSC, extents of oil leakage, OIT, and life time test. After these preliminary tests twelve MPLs were synthesized and evaluated by measuring extents of oil leakage and OIT values. Then synthesis conditions for the optimum MPL were selected by SSRED(Six Sigma Robust Engineering Design) pro gram using extents of oil leakage and OIT values respectively. The optimum MPL by means of OIT value showed higher performance such as long life time and application at higher temperature of $140^{\circ}C$ than previous temperature of $100^{\circ}C$.

• Textile Coloration and Finishing
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• v.17 no.4 s.83
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• pp.27-34
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• 2005

In order to prepare acetate nano filter for the adsorption of nicotine/tar in tobbaco, acetate nano fiber was fabricated by elecrospining from acetate solution dissolved in acetone/DMAc(2/1). Above a critical polymer concentration($15\%$), the nano fiber was formed. The average diameter of nano fiber was decreased with the applied voltage and increased with the feeding rate. Appropriate spinning condition was considered to be $15wt\%$ polymer concentration, 11.25kV applied voltage, 0.6ml/h feeding rate, and 13-15cm TCD. Using the nano fiber, acetate nano filter was fabricated. It showed good nicotine/tar adsorption ability compared with general tobbaco filter. It was considered that the increase of surface area and the development of microporous structure in filter was much affected to the adsorption of nicotine/tar.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2012.03a
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• pp.105-105
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• 2012

기능성 아웃도어 제품을 제조하기 위해서 사용되어지는 멤브레인은 크게 미세다공형과 친수무공형으로 구분할 수 있다. 최근에는 소비자들이 기능성 아웃도어에 쾌적성을 요구하고 있으며, 그 측면에서 본다면 미세다공형 멤브레인이 친수무공형보다 유리하다. 기존의 미세다공형 멤브레인은 고가이며, casting이 불가능한 단점을 가지고 있다. 본 연구에서는 분자구조 및 유화제 첨가에 따른 casting이 가능한 미세다공형 폴리우레탄 멤브레인의 특성에 대하여 연구하였다. Casting용 미세다공형 폴리우레탄은 soft segment와 hard segment의 비가 1/2일 때, 그리고 사용되는 용제가 MEK 단독일 때 안정적인 반응성과 이상적인 필름의 물성을 보이는 것을 확인 하였으며, 수지에 첨가되는 분산유화제의 양이 10%이상일 때 상분리 현상이 발생하지 않음을 확인 할 수 있었다. 개발된 수지의 적용성을 평가한 결과, J-knife를 이용하여 knife over roll 방식으로 25~35$g/m^2$ (dry add on)를 도포하여 $80/120/140^{\circ}C{\times}10m/min$의 다단건조 공정으로 진행했을 때 최적의 물성을 얻을 수 있었다.

• Membrane and Water Treatment
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• v.9 no.1
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• pp.53-62
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• 2018

In this study, vacuum membrane distillation (VMD) was used to treat high-salinity wastewater (concentration about 17%) discharged by chlor-alkali plant after resin regeneration. The feasibility of VMD for the treatment of real saline wastewater by using Polyvinylidene fluoride (PVDF) microporous plate membrane with a pore diameter of $0.2{\mu}m$ was investigated. The effects of critical operating parameters such as feed temperature, velocity, vacuum degree and concentration on the permeate water flux were analyzed. Numerical simulation was used to predict the flux and the obtained results were in good agreement with the experimental data. The results showed that an increase in the operating conditions could greatly promote the permeate water flux which in turn decreased with an increase in the concentration. When the concentration varied from 17 to 25%, the permeate water flux dropped marginally with time indicating that the concentration was not sensitive to the decrease in permeate water flux. The permeate water flux decreased sharply until zero due to the membrane fouling resistance as the concentration varied from 25 to 26%. However, the conductivity of the produced water was well maintained and the average value was measured to be $4.98{\mu}s/cm$. Furthermore, a salt rejection of more than 99.99% was achieved. Overall, the outcome of this investigation clearly indicates that VMD has the potential for treating high-salinity wastewater.

• Food Science and Preservation
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• v.17 no.2
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• pp.223-229
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• 2010

Anchovy soy sauce was fermented at ambient temperature in 20 L new Onggi, used Onggi, stainless steel, and plastic containers, and sauce quality was analyzed. Microporous insulated Onggi containers were found to promote fermentative microbial growth, thus creating desirable conditions for the preparation of good-quality anchovy soy sauce. The use of used Onggi containers yielded an anchovy soy sauce with high contents of total nitrogen and free amino acids, which afforded good sensory qualities with respect to odor, taste, and overall acceptability.

• Carbon letters
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• v.9 no.2
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• pp.115-120
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• 2008

Rubber reinforcing carbon black N330 was treated by physical activation under $CO_2$ to different degrees of burn-off. The mechanical properties indicating the reinforcement of SBR (Styrene-Butadiene Rubber) vulcanizates filled by activated carbon blacks, such as tensile strength, modulus at 300% strain and elongation at break were determined. During $CO_2$ activation of fresh carbon blacks, the development of microporous structure caused an increase of extremely large specific surface area and the porosity turned out to be an increasing function of the degree of burn-off. The tensile strength and modulus at 300% of activated carbon blacks filled rubber composites were improved at lower loading ratios of 20 and 30 phr, but decreased drastically after 30 phr, which is considered that it might be difficult to get a fully dispersed rubber mixture at higher loading ratios for fillers having very large specific surface areas. However, the Electromagnetic Interference (EMI) shielding effectiveness of SBR rubber composites having activated carbon black at 74% yield were improved at a large extent when compared to those having raw carbon black and increased significantly as a function of increasing loading ratio.