하수슬러지의 물리적 화확적 활성에 따른 흡착특성

정동현 ( Dong Hyun Jung ),백원석 ( Won Seok Baek ),김승호 ( Seung Ho Kim ),전영남 ( Young Nam Chun ) 조선대학교 공학기술연구원 2008 공학기술논문지 Vol.1 No.1

This study produces absorbent through physical and chemical activation. Optimum activation conditions are established from changing the variables that are CO2 input amount, chemicals mixing rate, activated temperature and activated time. As result of this study, Physical activation method is confirmed in case of CO2 activation that CO2 input amount “80 ml/min”, activated temperature “700℃” and activated time “90 min”. At the time, iodine adsorptivity and specific surface area shown that 272.53 mg/g and 115.04 ㎡/g. Chemical activation method is confirmed with optimum condition among chemicals in case KOH activation that activated temperature “600℃”, KOH mixing rate “1:1”, activated time “90min”. At the time, iodine adsorptivity and specific surface area shown that 412.0 mg/g and 163.92 ㎡/g. Also, the pore development and characteristic was confirmed by nitrogen adsorption and SEM.

Formation of micro/mesopores during chemical activation in tailor-made nongraphitic carbons

Chun, Sang-Eun,Whitacre, J.F. Elsevier 2017 Microporous and mesoporous materials Vol.251 No.-

<P><B>Abstract</B></P> <P>The mechanism of chemical activation by potassium hydroxide (KOH) was studied in highly controlled non-graphitic carbon structures to explore the constituent reactions and the related pore formation processes involved in producing highly microporous activated materials. For this purpose, nongraphitic carbon was activated independently with intermediate species of either metallic potassium (K) or potassium carbonate (K<SUB>2</SUB>CO<SUB>3</SUB>) reduced from KOH (activating agent). Structural and morphological changes during activation were probed <I>ex situ</I> using X-ray diffractometry and Brunauer–Emmett–Teller (BET) nitrogen gas adsorption. Reduced K and K<SUB>2</SUB>CO<SUB>3</SUB> disordered the stacking graphene layers to different extents. While micropore features were induced upon K evaporation following infiltration, the existing micropores were expanded into mesopores by K<SUB>2</SUB>CO<SUB>3</SUB> gasification. Exclusive activation with K or K<SUB>2</SUB>CO<SUB>3</SUB> induced ultra-small micropores, as measured using cyclic voltammetry. This work explains why activation using a KOH solution develops the preferable porous texture for use in many devices by creating open microporous structures as a result of the synergistic activation of both K and K<SUB>2</SUB>CO<SUB>3</SUB>.</P> <P><B>Highlights</B></P> <P> <UL> <LI> In KOH activation of non-graphitic carbon, the constituent reactions and the related pore formation processes were explored to study the chemical activation mechanism. </LI> <LI> The micropores were induced upon K evaporation following infiltration in KOH activation. </LI> <LI> The existing micropores were expanded into mesopores by K<SUB>2</SUB>CO<SUB>3</SUB> gasification in KOH activation. </LI> <LI> The activation via KOH solution develops open microporosity as a result of the synergistic activation of both K and K<SUB>2</SUB>CO<SUB>3</SUB>. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

약품활성화와 가스활성화에 대한 왕겨로부터 활성탄의 제조

홍종철,김명수 명지대학교 대학원 1998 대학원논문집 Vol.2 No.-

A series of activated carbons was prepared from rice hulls by both chemical activation with KOH and physical activation with steam and carbon dioxide. The effect of process variables such as carbonization, activation temperature, and chemical ratio on the pore structure and activation yield of the carbons was studied. When the char produced by the carbonization of the rice hulls in a stream of nitrogen at 700 ℃ was well mixed with a concentrated solution of potassium hydroxide at a KOH:char ratio of 4:1 and then the mixture was activated for 3 hours in a stream of nitrogen, high-quality activated carbons with high surface area, high pore volume, and well-developed pore structure could be prepared. The surface area and micropore volume of the chemically activated carbon were 2∼3 times higher than those obtained by physical activation.

KOH를 이용한 PAN계 활성탄소섬유의 제조

김기원,정승훈,임연수 명지대학교 대학원 1998 대학원논문집 Vol.2 No.-

Activated carbon fiber(ACF) is a prospective adsorbent which has attracted much attention for several years. It has attractive properties such as high surface area, rapid adsorption/desorption rate and multi-using form. Chemical activation can be carried out at lower temperature, give higher yield and less devolatilization of raw materials than physical activation. Activated carbon fibers were prepared from stabilized PAN fibers by chemical activation with potassium hydroxide. Chemical activation was carried out by heat treatment of their fibers which were impregnated by dipping in water solution of KOH for 24 hours. The heat treatment temperatures were 500℃, 600℃, 700℃, 800℃ and 900℃, respectively. Yield, specific surface area and SEM micrograph of ACFs with the different activation conditions such as concentration of KOH and activation temperature were evaluated.

화학적 활성화로 제조된 활성탄 슈퍼커패시터에 대한 첨가제 영향

이종대 ( Jong-dae Lee ) 충북대학교 산업과학기술연구소 2018 산업과학기술연구 논문집 Vol.32 No.2

Several kinds of active carbons with high specific surface area and micro pore structure are prepared from the coconut shell charcoal by means of chemical activation. The results obtained confirm the importance of the activating chemical agents to charcoal ratio and the flow rate of gas during carbonization on the development of porosity. In addition, it shows that chemical activation can be successfully used to develop activated carbons with high surface area(1800~2500 m2/g) and, mean pore size(1.98~2.38 nm). Also, the electrochemical performances of super capacitor are studied using prepared active carbon as the electrode. Also the electrochemical behaviors of conductive materials were investigated by constant current charge/discharge test, cyclic voltammetry and leakage tests. The super capacitor using electrode with VGCF and Super-P has better capacitance than those of other conductive materials. In charge/discharge tests using VGCF(20%)+Super-P(80), super capacitor showed the best performance(0.452 F/cm2) in the electrolyte of TEABF₄dissolved in a PC(1M).

Surface structural characterization of highly porous activated carbon prepared from corn grain

Balathanigaimani, M. S.,Shim, Wang-Geun,Kim, Chan,Lee, Jae-Wook,Moon, Hee John Wiley Sons, Ltd. 2009 Surface and interface analysis Vol.41 No.6

<P>A novel corn grain precursor was used for the preparation of activated carbon by chemical activation. The detailed investigation of the porosity development in the prepared activated carbon was done by altering the various activation conditions such as the activation temperature, activation time and ratio between the powdered form of carbonized corn grain char and KOH. The surface characteristics including the surface roughness of all the activated carbon samples were evaluated from the analysis of nitrogen (N<SUB>2</SUB>) adsorption isotherm data. At the maximum of 2978 m<SUP>2</SUP>/g, a super surface area having the corn grain-based activated carbon (CG-AC) was synthesized by using the following conditions: 1/4 ratio of powdered form of carbonized corn grain char/KOH; 800 °C; and 4 h. The possibility of preparing highly porous activated carbons with controlled porosity by varying different activation conditions was found from the pore size distribution results. In particular, the domination of the ratio between the powdered form of carbonized corn grain char and KOH on the porosity development was high compared to the activation temperature and activation time. In addition, the surface roughness calculated from the surface fractal dimension indicates the decrease of surface roughness with increasing activation conditions. Copyright © 2009 John Wiley & Sons, Ltd.</P>

국내탄을 이용한 활성탄의 제조와 흡착특성에 관한 연구

공성호,김재호 漢陽大學校 環境科學硏究所 2001 環境科學論文集 Vol.22 No.-

본 연구는 국내무연탄의 비연료 활용을 위해 국내무연탄을 원료로 하여 흡착제를 제조하는 것을 목적으로 하고 있다. 우선 활성탄 원료를 제조하기 위해서 중액선탄 방법으로 저회분 탄을 제조하였다. 파쇄탄과, 미분탄과 석탄 타르피치를 혼합하여 제조한 조립탄을 원료로 스팀과 CO_2로 활성화하여 활성탄을 제조하였다. 활성화 전에 알칼리로 처리하여 화학적 전처리의 영향을 고찰하였다. 활성탄의 흡착성능을 위해 액상으로는 페놀, 클로로포름을 중금속 시험으로는 Fe, Cr을, 그리고 기상용 실험으로는 벤젠, 사염화탄소 등을 사용하여 비교하였다. 활성화 결과 파쇄원탄으로 제조된 활성탄은 표면적 650㎡/g, 조립활성탄은 920㎡/g의 활성탄이 제조되었다. 파쇄원탄을 NaOH로 강한조건에서 화학적 처리한 결과 표면적이 650㎡/g에서 840㎡/g으로 증가하였으며 온순조건에서는 기공부피와 burn-off을 증가시키는 효과를 보였다. 화학적으로 처리된 파쇄활성탄과 CO₂로 활성화된 조립활성탄은 미세기공이 발달하여 기상용에 적합하였으며 스팀으로 활성화된 조립활성탄은 기공이 다양하게 발달하여 액상용으로 적합하였다. TPurpose of this study is development of activated carbons from domestic anthracite for non-fuel use. In order to obtain raw materials for activation, preparation of low ash coals by heavy media separation was conducted. Activated carbons were made with steam or CO₂ from crushed coals and granules made by mixing of pulverized coal and coal tar pitches. Treatment with alkali hydroxides was conducted prior to activation for the investigation of the effect of chemical pretreatment on the activation. Test for liquid phase organic compound removal, heavy metal removal and gas phase adsorption have been performed with phenol, chloroform, Fe, Cr, and with fumes of benzene and carbon tetrachloride. Activated carbons of surface area of 650㎡/g from crushed coals and of 920㎡/g from granules were produced. Chemical pretreatment has an effect on the surface area increase from 650㎡/g to 840㎡/g for the crushed raw coals at the strong pretreatment condition, and on the increase of pore size and burn-off by mild pre-treatment condition. It was found that the activated carbons from crushed coals by chemical pretreatment and from CO₂ activation have well developed microporosity, and that the activated carbons from granules by steam activation have wide ranges of porosity that are suitable for gas phase and liquie phase adsorption respectively.

해수중 화학원소의 거동과 생물활동

현상민,최영찬 제주대학교 해양연구소 1997 해양자원연구소연구보고 Vol.21 No.-

The concordant variation between chemical elements and biological activity in seawater is reviewed in this paper. The flux of the biogenic components in seawater is highly linked up with the flux of the lithogenic materials or vise versa. indicating that suspended clays. fine fractions and chemical elements are efficiently scavenged through the water column by sinking organic aggregates. Most of chemical elements in seawater are formed as complexation. suggesting that the biological activity in seawater plays an important role in becoming a complex form of chemical elements. Therefore, it is necessary to study the form of chemical elements and their behavior with respect to biological activity. Understanding the linkage between the biological activity and the behavior of chemical elements in seawater is the first step to explore oceanic environmental change including material cycles in sea water.

Correction to: Influence of mixed methods on the surface area and gas products of activated carbon

황상엽,이기범,김호,박정은 한국탄소학회 2020 Carbon Letters Vol.30 No.5

Upgraded activated carbons (ACs) are typically synthesized by mixed methods, such as solid–solid mixing and wet impregnation of low-grade ACs with KOH. This study compares the properties of upgraded ACs prepared by different methods using elemental analysis, X-ray photoelectron spectroscopy, N2 adsorption isotherms, and X-ray diffraction. In ACs produced by the solid–solid mixing, the ratio of potassium activator is proportional to the surface area and amount of gas produced. However, in wet impregnated ACs, the potassium ratio exhibits a zero or negative correlation. It is demonstrated that potassium ions in solution are not transferred to K2O and do not contribute to the surface area and pore size, generating less amount and different composition of gases. As such, impregnated ACs exhibit similar surface areas and large pores, regardless of the potassium ratio. The physical properties, such as specific surface areas and pore size distribution, of ACs using wet impregnation were similar to the ACs generated by the water physical activation. It indicated that the KOH does not efficiently act as a chemical activator in the wet impregnation method. Therefore, a certain amount and suitable mixing method of chemical activator play an important role in the property upgrade of ACs.

A study of activated carbons derived from chitosans for methane storage

이종훈,박수진 한국공업화학회 2019 한국공업화학회 연구논문 초록집 Vol.2019 No.0

In this study, activated carbons (AC) with high porosity were synthesized by chitosans which generally known as abundant polysaccharide. The precursors were carbonized at 900 °C, 1h, and N₂ flow conditions using chitosans as precursor. After carbonized, AC was synthesized by chemical activation. The effect of quantity of activation reagents was investigated by experience of AC/chemical reagent mass ratio. The structural information of the activated carbons was measured by X-ray diffraction (XRD) patterns and scanning electron microscopy (SEM). The N₂ adsorption-desorption isotherms were measured at 77 K and calculated by Brunauer-Emmett-Teller (BET) equation. Methane storage capacity was evaluated with a Model BEL-HP instrument (BEL Co., Ltd., Japan) at 298 K and 35 bar.