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        검색결과 7

        1.
        2020.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Effective processing and use of coal slime is of great significance to protect the environment and save resources. Different coal slimes (untreated with 43 wt% ash content, crushed and flotation treated with 10 wt% ash content, and pre-carbonized) were activated with KOH to prepare porous activated carbon. The results show the activated carbon prepared from coal slime with 10 wt% ash had high specific surface area (3037 m2/ g) and pore volume (1.66 cm3/ g), which was ascribed to the suitable contents of minerals as template and oxygen-containing functional groups. Electrochemical measurements exhibited the best specific capacitance of 220 F/g at 0.1 A/g and the cycle stability of over 100% capacitance retention after 1000 cycles at 5 A/g in 6 M KOH solution. Due to the high specific surface area, superior electrochemical performance, and facile and low cost, developing highly porous activated carbon for supercapacitors is one alternative way for effective use of coal slime waste.
        4,000원
        3.
        2016.09 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Activated carbons (ACs) have been used as EDLC (electric double-layer capacitor) electrode materials due to their high specific area, stability, and ecological advantages. In order to prepare ACs with high density and crystallinity, coal tar pitch (CTP) was activated by K2CO3 and the textural and electrochemical properties of the obtained ACs were investigated. Although the CTP ACs formed by K2CO3 activation had much smaller specific surface area and pore volume than did the CTP ACs formed by KOH activation, their volumetric specific capacitance (F/cc) levels as electrode materials for EDLC were comparable due to their higher density and micro-crystallinity. Structural characterization and EDLC-electrode performance were studied with different activation conditions of CTP/K2CO3 ratio, activation temperature, and activation period.
        4,000원
        4.
        2000.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Coal tar pitch was chemically modified with 10 wt% benzoquinone (BQ) to raise the softening point of isotropic pitch precursor and the precursor was melt-spun into pitch fibers, stabilized, carbonized and activated with steam at 900℃. The weight loss of carbon fiber-benzoquinone (CF-BQ) increased with the increase of activation time like other fibers, but was lower than those of Kureha fiber at the same activation time in spite of larger geometric surface area. Those adsorption isotherms fitted into 'Type I' according to Brunauer, Deming, Deming and Teller classification. However, there was very thin low-pressure hysteresis that lower closure points of the hysteresis are about 0.42-0.45. From the pore size distribution curves, there might be some micropores having narrow-necked bottle; a series of interconnected pore is more likely than discrete bottles. FT-IR studies showed that the functional groups such as carboxyl, quinone, and phenol were introduced to ACFs-BQ surface after steam activation. Methylene blue decolorization and iodine adsorption capacity of ACF-BQ increased linearly with the increase of specific surface area and was larger than that of ACF-Kureha at the same specific surface area.
        4,000원
        5.
        2013.09 KCI 등재 서비스 종료(열람 제한)
        The efficiency of coal-based activated carbon in removing methylene blue (MB) and phenol from aqueous solution was investigated in batch experiments. The batch adsorption kinetics were described by applying pseudo-first-order, pseudo-second-order, and first order reversible reaction. The results showed that the adsorption of MB and phenol occurs complexed process including external mass transfer and intraparticle diffusion. The maximum adsorption capacity obtained from Langmuir isotherm was 461.0 mg/g for MB and 194.6 mg/g for phenol, respectively. The values of activation parameters such as free energy (△G˚), enthalpy (△H˚), and entropy (△S˚) were also determined as -19.0∼-14.9 kJ/mol, 25.4 kJ/mol, and 135.2 J/mol K for MB and 51.8∼54.1 kJ/mol, -29.0 kJ/mol, and -76.4 kJ/mol K for phenol, respectively. The MB adsorption was found to be endothermic and spontaneous process. However, the CV adsorption was found to be exothermic and non-spontaneous process.
        6.
        2013.02 KCI 등재 서비스 종료(열람 제한)
        This is made of domestic and foreign coal activated carbon of five species, physicochemical adsorption efficient about sterilize products and micro harmful substances and is a result of the economic evaluation. The most well-developed micropores bed volume 123,409 of AC-1 activate carbon appeared to be the best next AC-2, AC-3, AC-4, AC-5 followed by activated carbon was investigated. PFOA and PFOS in the BV 96,000 when evaluating foreign types of adsorption activated carbon adsorption capacity was greater when more than PFOA, PFOS showed that the adsorption well. The economic evaluation of activated carbon usage in chloroform (CUR) was most excellent as a AC-1 4.3 g/day, the next AC-2, AC-3, AC-4, AC-5 there are two types of foreign economic order appears to have appeared, but the current domestic market when applying the price AC-1, AC-3, AC-2, AC-4, AC-5 order was investigated.
        7.
        2000.08 KCI 등재 서비스 종료(열람 제한)
        Activated carbons were prepared from Youngwall coal by steam activation in this study. The feasibility of the Youngwall coal to commercial activated carbon was examined. The variation of pore structures and the development of porosity in activated carbons were investigated by changing activation conditions in batch type apparatus. The values of BET surface area and adsorption capacity of iodine and methylene blue of the resulting activated carbons were obtained as high as 1,000㎡/g, 900㎎/g, 150㎖/g, respectively. Youngwall activated carbon prepared in this study showed much higher pore volume in pore diameter over l0Å than that of commercial reference activated carbon(Ningxia Taihua ZJ-15C) produced from China anthracite.