• 한국세라믹학회지
• /
• 제31권9호
• /
• pp.957-968
• /
• 1994

Manufacturing process of porous glass by the filler method was studied. Commercial soda-lime-silicate glass powder was mixed with inorganic salt as the filler such as KCl, K2SO4, Na2SO4. Sintering shrinkages of mixed powders with the variation of sintering temperature were compared, and the effects of the fillers to shrinkages of mixed powder were increased in the order of Na2SO4${\mu}{\textrm}{m}$ of pore diameter were manufactured when the filler sizes 100~200 ${\mu}{\textrm}{m}$. The open pore volume of porous glass is determined by the quantity of filler and porous glasses having open pore volume between 30 and 70 vol% are available. Available sintering temperature range for preparation of porous glass is from the softening temperature of the glass powder to eutectic melting temperature of DTA curve of mixed powder.

• 약학회지
• /
• 제35권4호
• /
• pp.277-282
• /
• 1991

Rheological, colloidal and micromeritical properties were followed to investigate aging mechanisms of hydrous aluminum oxide suspension using Zeta-meter systems, BET adsorption apparatus, Master sizer and electronmicroscope. The results indicate that hydrous aluminum oxide suspension revealed plastic flow with thixotropy. The viscosity, thixotropy and yield value were increased with increasing concentration. During aging process, the viscosity and thixotropic index were increased by an addition of glycerin, however, sorbitol stabilized aging process of the suspension being accompanied with growth of particle size and reduction in specific surface area, pore area and pore volume, and consistency. Diminution of adsorptive power of the particles was also protected by addition of sorbitol to hydrous aluminum oxide suspension. From these results, one of aging mechanism of hydrous aluminum oxide suspension assumed growth and/or crystallization of colloidal particles in aqueous suspension.

• 한국세라믹학회지
• /
• 제45권1호
• /
• pp.54-59
• /
• 2008

Hydrated sodium silicate with 25 wt% water contents was synthesized by hydrothermal reaction using anhydrous sodium silicate. The hydrated sodium silicate was expanded at $370^{\circ}C$ for 30 min. and then pulverized, classified (- 200 mesh) and press-formed. The samples were heat treated at $400{\sim}900^{\circ}C$ for 30 min. in order to study the expansion characteristics depending on heat treatment temperature. A porous body with closed pore was formed above $600^{\circ}C$. The volume expansion ratio and the pore size were increased and the specific gravity was decreased with increasing heat treatment temperature. However, the volume expansion ratio was decreased and the specific gravity was increased above $850^{\circ}C$ due to the softening of the sodium silicate.

• 한국염색가공학회지
• /
• 제14권6호
• /
• pp.305-312
• /
• 2002

In order to give a silk-like touch to PET fabrics, the PET fabrics were treated with NaOH alkaline solution in various conditions. In alkaline treatment, the liquor flow type pilot weight reduction apparatus with magnetostrictive ultrasonic transducer was used for the study. The effects of ultrasonic application, treatment time and temperature at NaOH 4% and 6"A solution on the decomposition rate of PET fabrics. From the results of the decomposition rate of PET fabrics, the qualitative and quantitative analysis of oligomer after decomposition of PET fabrics carried out by the HPLC. On the other hand, the surface pore characteristics of decomposition PET fabrics measured by porosimetery. The pore characteristics on the surface of treated PET fiber depended on the decomposition rate and did not depend on the ultrasonic cavitation. The pore diameter of alkaline untreated PET fiber were 15A and those of treated PET fibers were 5~6$\AA$ at the maximum pore volume. The average pore sizes of fiber before and after treatment were 141 h and 160h, respectively. Total amount of oligomer of the untreated PET fibers were 1.70wt% and 67.7% of total oligomer occupied with PET cyclic trimer and PET cyclic tetramer. Total amount of oligomer of fiber with 26.9% and 48.0% of weight loss without ultrasonic application were 1.78wt% and 1.79wt%, respectively. Also total amount oligomer of fibers which were reduced 27.7% and 48.2% of weight loss with ultrasonic application were 1.74wt%. This result showed that the removal rate of oligomer in the process of alkaline hydrolysis with ultrasonic higher than that of without ultrasonic application.tion.

• Korean Chemical Engineering Research
• /
• 제53권3호
• /
• pp.382-390
• /
• 2015

Poly(methyl methacrylate) (PMMA) supports and amine additives were investigated to adsorb $CO_2$. PMMA supports were fabricated by using different ratio of pore forming agents (porogen) to control the BET specific surface area, pore volume and distribution. Toluene and xylene are used for porogens. Supported amine sorbents were prepared by wet impregnation of tetraethylenepentamine (TEPA) on PMMA supports. So we could identify the effect of the pore structure of supports and the quantity of impregnated TEPA on the adsorption capacity. The increased amount of toluene as pore foaming agent resulted in the decreased average pore diameter and the increased BET surface area. Polymer supports with huge different pore distribution could be fabricated by controlling the ratio of porogen. After impregnation, the support with micropore structure is supposed the pore blocking and filling effect so that it has low $CO_2$ capacity and kinetics due to the difficulty of diffusing. Macropore structure indicates fast adsorption capacity and low influence of amine loading. In case of support with mesopore, it has high performance of adsorption capacity and kinetics. So high surface area and meso-/macro- pore structure is suitable for $CO_2$ capture.

• 한국전기전자재료학회논문지
• /
• 제31권2호
• /
• pp.112-116
• /
• 2018

Electric double layer capacitors (EDLCs) are promising candidates for energy storage devices in electronic applications. An EDLC yields high power density but has low specific capacitance. Carbon material is used in EDLCs owing to its large specific surface area, large pore volume, and good mechanical stability. Consequently, the use of carbon materials for EDLC electrodes has attracted considerable research interest. In this paper, in order to evaluate the electrochemical performance, graphene is used as an EDLC electrode with flake sizes of 3, 12, and 60 nm. The surface characteristic and electrochemical properties of graphene were investigated using SEM, BET, and cyclic voltammetry. The specific capacitance of the graphene based EDLC was measured in a 1 M $TEABF_4/ACN$ electrolyte at the scan rates of 2, 10, and 50 mV/s. The 3 nm graphene electrode had the highest specific capacitance (68.9 F/g) compared to other samples. This result was attributed to graphene's large surface area and meso-pore volume. Therefore, large surface area and meso-pore volume effectively enhances the specific capacitance of EDLCs.

• Bulletin of the Korean Chemical Society
• /
• 제34권2호
• /
• pp.569-573
• /
• 2013

In this study, activated carbon fabric was prepared from a cellulose-based polymer (viscose rayon) via a combination of physical and chemical activation (mixed activation) processes by means of $CO_2$ as a gasifying agent and surface and adsorption properties were evaluated. Experiments were performed to investigate the consequence of activation temperature (750, 800, 850 and $925^{\circ}C$), activation time (15, 30, 45 and 60 minutes) and $CO_2$ flow rate (100, 200, 300 and 400 mL/min) on the surface and adsorption properties of ACF. The nitrogen adsorption isotherm at 77 K was measured and used for the determination of surface area, total pore volume, micropore volume, mesopore volume and pore size distribution using BET, t-plot, DR, BJH and DFT methods, respectively. It was observed that BET surface area and TPV increase with rising activation temperature and time due to the formation of new pores and the alteration of micropores into mesopores. It was also found that activation temperature dominantly affects the surface properties of ACF. The adsorption of iodine and $CCl_4$ onto ACF was investigated and both were found to correlate with surface area.

• 한국섬유공학회:학술대회논문집
• /
• 한국섬유공학회 2003년도 The Korea-Japan Joint Symposium
• /
• pp.33-34
• /
• 2003

Lyocell yarns were treated with NaOH, liquid ammonia, high pressure steam and polycarboxylic acids, and dyed with five reactive dyes. The water content of the samples was also measured by the centrifugal and chromatographic techniques. The total pore volume w as substantially increased by NaOH treatment, while decreased by high pressure steaming. The pore size distributions for the dyed samples were affected by the dyes used.

• Carbon letters
• /
• 제11권3호
• /
• pp.224-234
• /
• 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.

• 한국환경과학회지
• /
• 제24권11호
• /
• pp.1463-1471
• /
• 2015

The surface modified activated carbons (SMACs) were prepared with various $P_2O_5$ concentrations using two activated carbons (ACs: waste citrus peel-based activated carbon and coconut-based activated carbon). The characteristics and adsorptivity of bisphenol A (one of phenolic endocrine disrupting chemicals) were compared between ACs and SMACs. The contents of C, H and N of SMACs were similar to those of ACs, but the content of $P_2O_5$ for the former increased greatly than for the latter, due to the impregnation of $P_2O_5$ into the pores. The specific surface area, total pore volume, average pore diameter and iodine adsorptivity for the former decreased due to the impregnation of $P_2O_5$ into the pores, compared to those for the latter. The adsorptivity of bisphenol A for the former were higher than that for the latter, although specific surface area, total pore volume, average pore diameter and iodine adsorptivity for the former were lower than those for the latter.