• Journal of Korean Society for Atmospheric Environment
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• v.31 no.3
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• pp.302-314
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• 2015

There is an adsorption method using activated carbon as a typical method for removing elemental mercury. Physical characteristics of activated carbon such as specific surface area and volume of pore (micro and meso) have positive effect for mercury adsorption. Activated carbon is carbon-based material with a high specific surface area. This activated carbon can be manufactured through carbonization and activation process. In this process, physical characteristics of specific surface area and pore distribution are changed by controlling operating parameters like temperature, time and reagent of activation. In this study, we evaluated characteristics of activated carbons manufactured from pinewood and coal with the operating parameters. We evaluated mercury adsorption capacities of the activated carbons having excellent physical characteristics and compared those to the commercial activated carbon.

• Journal of Hydrogen and New Energy
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• v.17 no.4
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• pp.418-424
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• 2006

In order to improve the activation properties of the $AB_2$ type hydrogen storage alloys for Ni-MH battery, the alloy surface was modified by employing high energy ball milling. The $Zr_{0.54}Ti_{0.45}V_{0.54}Ni_{0.87}Cr_{0.15}Co_{0.21}Mn_{0.24}$ alloy powder was ball milled for various period by using the high energy ball mill. As the ball milling time increased, activation of the $AB_2$ type composite powder electrodes were enhanced regardless of additives. When the ball milling time was small discharge capacities of the $AB_2$ type composite powder electrodes increased with the milling time. On the other hand for large milling time it decreased with increasing milling time. The maximum discharge capacity was obtained by ball milling for 3-4 min.

• Carbon letters
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• v.12 no.1
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• pp.1-7
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• 2011

In the present study, the removal of Pb (II) ions on oxidized activated carbons (ACs) was investigated. ACs were derived from activation of indigenous cotton stalks waste with potassium hydroxide (KOH) in two-stage process. The KOH-ACs were subjected to liquid-phase oxidation with hot $HNO_3$ and one untreated sample was included for comparison. The obtained carbons were characterized by Fourier transform infrared (FTIR), slurry pH and $N_2$-adsorption at 77 K, respectively. Adsorption capacity of Pb (II) ions on the resultant carbons was determined by batch equilibrium experiments. The experimental results indicated that the oxidation with nitric acid was associated with a significant increase in mass of yield as well as a remarkable reduction in internal porosity as compared to the untreated carbon. The AC-800N revealed higher adsorption capacity than that of AC-800, although the former sample exhibited low surface area and micropore volume. It was observed that the adsorption capacity enhancement attributed to pore widening, the generation of oxygen functional groups and potassium containing compounds leading to cation-exchange on the carbon surface. These results show that the oxidized carbons represented prospective adsorbents for enhancing the removal of heavy metals from wastewater.

• Fashion & Textile Research Journal
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• v.11 no.4
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• pp.672-677
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• 2009

To reduce the dependence of wool dyeing on the temperature several solvents with different properties and structures were added to the dye bath of C. I. Acid Yellow 42. Nearly the same total solubility parameters(${\delta}_t$) of solvents as those of wool fiber and hydrophobic part of the dyestuff were needed to increase disaggregation of dye molecules, loosening the wool fiber and wickabilty of dyeing solution; besides, the large surface tension(${\gamma}$) value of the solvents and the well balanced values of the three-component Hansen solubility parameters such as dispersion(${\delta}_d$), polar(${\delta}_p$), and hydrogen(${\delta}_h$) bonding parameters were required. Among the added solvents dimethyl phthalate(DMP) and acetophenone(AP) were satisfied with these conditions and worked the most successfully in the low temperature wool dyeing. Their effectiveness proven by the dyeing rate and the activation energy ($E_a$) of the dyeing was in the order of DMP > AP > DBE > CH > M >NONE. In conclusion the total solubility parameters(${\delta}_t$), the three-component Hansen parameters and the surface tension(${\gamma}$) of DMP and AP could be the guidelines to select suitable solvents for low temperature wool dyeing.

• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.219.2-219.2
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• 2011

The oxyfluorination effects of electrospun carbon nanofibers (OFACFs) were investigated for $CO_2$ storage. Carbon nanofibers were prepared form poly acrylonitrile / N,N-dimethylformamide solution through electrospinning method and heat treatment. Chemical activation of carbon nanofibers were carried out in order to improve the pore structure. And the surface modification of activated carbon nanofibers was conducted by oxyfluorination to improve the $CO_2$ storage on effect of introduced functional groups. The samples were labeled CF (electrospun carbon nanofiber), ACF (activated carbon nanofibers), OFACF-1 ($F_2:O_2$ = 3:7), OFACF-2 ($F_2:O_2$ = 5:5) and OFACF-3 ($F_2:O_2$ = 7:3). The functional group of OFACFs was investigated by x-ray photoelectron spectroscopy analysis. The specific surface area, pore volume and pore size of OFACFs were calculated and pore shape was estimated by the BET equation. Through the adsorption isotherm, the specific surface area and pore volume significantly decreased by oxyfluorination.

• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.93.2-93.2
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• 2011

In this work, graphite nanofibers (GNFs) were prepared for using catalyst supports in fuel cells. The GNFs were chemically activated to obtain high surface area and small pore diameter with different potassium hydroxide (KOH) amounts, i.e., 0, 1, 3, 4, and 5 g as an activating agent. And then Pt-Ru was deposited onto activated GNFs (A-GNFs) by chemical reduction method. The characteristics of Pt-Ru catalysts deposited onto A-GNFs were determined by specific surface area and pore size analyzer, X-ray diffraction (XRD), transmission electron microscopy (TEM), and inductive coupled plasma-mass spectrometer (ICP-MS). The electrochemical properties of Pt-Ru/A-GNFs catalysts were also analyzed by cyclic voltammetry (CV) experiments. From the results, the A-GNFs carbon supports activated with 4 g of KOH (A4g-GNFs) showed that the highest specific surface areas. In addition, the A4g-GNFs led to uniform dispersion of Pt-Ru onto A4g-GNFs, resulting in the enhancement of electrochemical activity of Pt-Ru catalysts.

• Membrane and Water Treatment
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• v.11 no.2
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• pp.151-158
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• 2020

ACF preparation from different materials has been attached with great attention during these years. This study was conducted to prepare activated carbon fiber (ACF) from luffa through the processes i.e pre-treatment, pre-oxidation and carbonization activation. Besides, this study also characterizes the ACF and its effect, i.e effect of pre-oxidation time and temperature also activation time and temperature on the compressive strength of ACF were investigated. The results from SEM, BET, FTIR and XRD show that the ACF is very efficient. The products under the optimum conditions had a specific surface area of 478.441 m2 /g with an average pore diameter of 3.783nm, and a pore volume of 0.193 cm3 /g. The surface of the luffa fiber is degummed and exposed, which is beneficial to the subsequent process and the increase of product properties. The compressive strength of HP-ACF was prepared under the optimum conditions, which can reach 0.2461 MPa. ACF is rich in micro-pores and has a good application prospect in the field of environmental protection.

• Composites Research
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• v.31 no.5
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• pp.267-275
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• 2018

A facile method for the preparation of nitrogen-doped microporous carbon via the pyrolysis of poly(vinylidene fluoride) (PVDF) using polypyrrole (PPy) as a selective nitrogen source was developed. A PVDF/PPy-800 sample (carbonized at $800^{\circ}C$) with a 1:0.5 ratio of PVDF and PPy exhibited the highest micropore volume. The activated microporous carbon materials obtained from PVDF/PPy-800 prepared at $800^{\circ}C$ with KOH possessed a large specific surface area and narrow pore-size distribution. They were characterized using $N_2$ adsorption at 77 K and argon (Ar) adsorption at 87 K, which allowed for the characterization of the narrow microporosity of the prepared materials due to the absence of interactions between Ar and the sample surface. In addition, the activated microporous carbon material with a KOH/carbon ratio of 2:1 was found to exhibit the largest specific surface area ($1296m^2g^{-1}$ in $N_2$ at 77 K) and microporosity, and a high specific capacitance ($122.8F\;g^{-1}$).

• Journal of Adhesion and Interface
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• v.14 no.4
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• pp.197-211
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• 2013

Surfactants which have ability to decrease surface tension through surface activation between the interfaces are used as essential major raw materials for detergents and cosmetics. Typical synthetic detergents such as EO (ethylene oxide), LAB (linear alkylbenzene) are made from chemical surfactant derived from petrochemicals, therefore, they are responsible for major environment contaminations and ecosystem destruction, especially of rivers and also cause atopic dermatitis through strong skin stimulus of these small molecular's powerful permeability and lead to cancers if they get into organs through capillary. Now worldwide interest is increasing to develop new natural surfactants and biosurfactants as ecological, biodegradabl, harmless and multi-functional new amphiphillic materials which replace these synthetic surfactants.

• Journal of Korean Society for Atmospheric Environment
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• v.33 no.1
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• pp.1-10
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• 2017

Adsorption is a plausible technology using solid adsorbents for dry capture of carbon dioxide ($CO_2$). In general, narrow size distribution of tiny pores and surface chemical functionalities of solid adsorbents enhance the adsorption capacity of gaseous $CO_2$ molecules. In order to utilize the advantages of fibrous adsorbents, this work prepared activated carbon nanofibers (ACNFs) via the electrospinning process using a polymer precursor of polyacylonitrile (PAN). The spun fibers were 390 nm to 580 nm in thickness with an average surface area of $27.3m^2/g$. The surface structure was improved by a programmed thermal activation at $800^{\circ}C$ in $CO_2$ atmosphere. It was also found that the nitrogen-groups including pyrrole and pyridine were created during the activation facilitaing the selective adsorption as forming enhanced active sites. The finally obtained adsorption capacities were 2.74 mmol/g for pure $CO_2$ flow and 0.74mmol/g for 3000 ppm.