Impact of the oxygen functional group of nitric acid‑treated activated carbon on KOH activation reaction

Ji‑Hyun Kim,Sang Youp Hwang,Jung Eun Park,Gi Bbum Lee,Ho Kim,Seokhwi Kim,Bum Ui Hong 한국탄소학회 2019 Carbon Letters Vol.29 No.3

To prepare activated carbon with a high specific surface area, oxygen functional groups (OFGs) that can serve as useful electron donors during KOH activation were treated with nitric acid and incorporated into activated carbon. OFGs are incorporated differently according to the surface characteristics of starting materials. Up to 22.46% OFGs are incorporated into wood-based activated carbons (WACs), the C=O, COOH contents was 1.90, 17.05%, respectively. Whereas up to 12.82% OFGs are incorporated into coconut shell-based activated carbons, the C=O, COOH contents was 4.12, 6.15%, respectively. The OFGs used for increasing the specific surface area are the carbonyl group, and as the content of the functional group increases, the carbonyl group spreads to the carboxyl group. The specific surface area of activated carbons increased by 10–68% with an increase in the carbonyl group up to 6% (maximum point of carbonyl group). On the other hand, the specific surface area for WACs increased when the carboxyl group was 10% or below, but decreased by 6–15% when it increased to 10% or excess.

산으로 개질된 활성탄의 메틸 메르캅탄 흡착특성

김대중,김상채,서성규 國立麗水大學校 環境問題硏究所 2004 環境硏究論文集 Vol.6 No.-

Adsorption characteristics of methyl mercaptan on virgin activated carbon(VAC) and modified activated carbons with acidic chemicals have been investigated in the present work. CAC, NAC, AAC and SAC were activated carbons modified with HCl, HNO₃, CH₃COOH and H₂SO₄, respectively. The pore structures and surface characteristics of virgin activated carbon and modified activated carbons were evaluated using nitrogen isotherm, EA, pH of carbon surface and acid value from Boehm titration. respectively. The modification of activated carbon with acidic chemicals resulted in decrease in BET surface area, micropore volume and surface pH, but an increase in acid value. In case of adsorption of methyl mercaptan. The order of the adsorption capacity of activated carbons was NAC>AAC>SAC>CAC>VAC. and in agreement with that of acid value of activated carbons, whereas in disagreement with that of micropore volume of activated carbons. It appeared that chemical adsorption played an important role in methyl mercaptan on modified activated carbons with acidic chemicals compared to virgin activated carbon. These results suggest that the adsorption of methyl mercaptan depends on the surface chemistry rather than the pore structure in modified activated carbons.

열수가압탄화에 의해 제조한 폐목재 바이오차 (Bio-char) 활성탄의 특성화에 관한 연구

원민희,조우리,장진만,박지수,이재영 한국폐기물자원순환학회 2022 한국폐기물자원순환학회지 Vol.39 No.3

The market for activated carbon is growing due to environmental awareness and strengthening of environmental regulations. Biochar is a solid carbide that is produced through a hydrothermal carbonization (HTC) process. Wood is an ideal raw material for activated carbon and biomass waste wood because it has low energy consumption rates and does not require pre-treatment to remove moisture. The activated carbon samples in this study were prepared by a chemical activation process using KOH, which is mainly used for activation. The study analyzed the specific surface area, pore volume, pore size, and pore distribution by selecting four samples with high iodine adsorption capacity among the prepared activated carbon samples. The specific surface area for all four samples was between 1192.2 and 1387.1 m2/g, all of which were over 1,000 m2/g, and the pore volume was between 0.6510 and 0.8030 cm3/g. During this process, micropores with an average pore size of 21 to 25 Å were formed. SEM photography revealed that these pores were uniform and that the number of pores increased according to activation levels of the carbon samples. When the iodine adsorptivity and specific surface area of commercial activated carbon was compared with that of activated carbon prepared by waste wood biochar with KOH, the specific surface area was higher in the activated carbon samples prepared by waste wood biochar with KOH. These results indicate that the adsorption of activated carbon by waste wood biochar with KOH is successful when applied to activated carbon samples.

상전이법을 이용한 펠렛 활성탄 제조 최적화 연구

유혜선,여인설,박찬규 한국수처리학회 2023 한국수처리학회지 Vol.31 No.5

. Activated carbon has a high absorption capacity. So the consumption of activated carbon in Korea is increasing as it is utilized in the treatment process of environmental pollutants. However, Powdered activated carbon(PAC) is required to be molded into Granular activated carbon(GAC) due to difficulties in application to processes and industries. In this study, Three different Powdered activated carbons were molded pellet activated carbon using the Phase separation method : the Coconut-based powdered activated carbon, the Coal-based powdered activated carbon, the Wood-based powdered activated carbon. The pellet activated carbons were made by 10wt% PES, 16wt% PES, 27wt% PES, 35wt% PES due to the formation in the phase separation method depends on the ratio of binder, polar solvent, and non-solvent. 16wt% PES Coal-based pellet activated carbon had the best absorbency, and 35wt% PES Coal-based pellet activated carbon had the lowest absorbency. In addition, It was evaluated as economical in order of 16wt% PES, 10wt% PES, 35wt% PES, 27wt% PES. Finally, Considering the methylene blue adsorption capacity and economic feasibility evaluation, it was evaluated as efficient pellet activated carbon in order of 16wt% PES Coal-based pellet activated carbon, 27wt% PES Wood-based pellet activated carbon, 35wt% PES Wood-based pellet activated carbon, 16wt% PES Coconut shell-based pellet activated carbon, 27wt% PES Coal-based pellet activated carbon.

Pueraria Thunbergiana Cellulose를 이용한 분자체 탄소 제조

김동원,류해일,홍영관 충북대학교 과학교육연구소 2001 과학교육연구논총 Vol.17 No.1

The investigation of manufacturing activated carbon from a Pueraria Thunbergiana was lab-scale preliminary experiments, optimum experimental conditions in each step and were obtained by varying the experimental parameters such as oxidation temperature, carbonization temperature and reaction time. The activated carbon is amorphous and its intraparticle pores are well developed at the activation temperature of about 900℃. Physical properties and other characteristics of activated carbon produced in this experiment were measured according to the standardized test methods and compared with those of commercial activated carbon. According to the results from experiments to compare the properties of carbonization and activation by time, adsorption amount of the samples 4, 9, 10, 11, and 12 didn't depend on time, but absorbed more 600㎎/g of iodine, The samples 5, 6, 7, 8 treated with ZnCl_2 absorbed about 500㎎/g of iodine. The sample 4 had the most adsorption amount 812㎎/g of iodine on the condition of carbonization (500℃/3 hs) and activation(900℃/4 hs). Decolorization test of methyl blue was conducted on each sample. It led to great results on sample 3 catalytic conditions of 900℃ and 4 hours of activation independent of carbonization conditions. While samples 2, 4, 6, 8, 10, and 12 activated carbons decolorized in the 100-136 mg/g range of methylene blue, sample 1. 3, 5, 7, 9, and 11 only did 34-124㎎/g. It measured the specific surface area of activated carbons prepared. All the activated carbons have the specific surface area within 341-784㎡/g. The experiment was performed measurement of the adsorption value on methyl blue based on the specific surface area size. In the specific surface area increased form 300㎡/g to 800㎡/g, methylene blue was decolorized about 3 times more. The decolorization of activated carbons treated with N_2 separator was excellent. The micropore size distributed on activated carbons of Pueraria Thunbergiana measured by BET was identified in range of 19.46 Å-34.24 Å. According to the results of this experiment, it was proved that activated carbons of Pueraria Thunbergiana have micropore diameter. Judging from the experimental results on adsorption of iodine, decolorization of methyl blue, the specific surface area and pore size, activated carbons of Pueraria Thunbergiana produced on given different carbonization and activation condition did draw conclusion that it is possible to produce active carbons with quality even without chemical or physical catalysts.

구리 촉매 담지 대나무 활성탄의 NO 가스 반응 특성

박영철(Young Cheol Bak),최주홍(Joo Hong Choi) 大韓環境工學會 2016 대한환경공학회지 Vol.38 No.3

대나무를 원료로 탄화 및 활성화 온도 900℃에서 대나무 활성탄을 만들고, 이 대나무 활성탄에 금속 구리와 금속 은을 담지시켜 금속 담지 대나무 활성탄을 제조하였다. 제조된 금속 담지 활성탄의 비표면적 및 세공분포 등의 물리적 특성을 분석하였다. 또한 폐 대나무 활성탄의 재활용을 위하여 대나무활성탄과 NO 기체의 반응 특성 실험을 열중량분석기를 사용하여 반응 온도 20~850℃, NO 농도 0.1~1.8 kPa 변화 조건에서 하였다. 실험 결과, 대나무 활성탄 특성 분석에서 구리 담지 대나무 활성탄에서는 구리 담지량이 증가할수록 세공 부피와 표면적이 감소하였다. 비등온과 등온 NO 반응에서는 전체적으로 구리 담지 대나무 활성탄[BA(Cu)]이 대나무 활성탄[BA]에 비하여 반응속도가 향상되는 것을 볼 수 있었다. 그러나 은 담지 대나무 활성탄[BA(Ag)]은 반응이 억제되는 것을 볼 수 있었다. NO 반응에서의 활성화에너지는 80.5 kJ/mol[BA], 48.5 kJ/mol[BA(Cu)], 66.4 kJ/mol[BA(Ag)]로 나타났고, NO 분압에 대한 반응차수는 0.63[BA], 0.92[BA(Cu)]이었다. The metal-impregnated activated carbon was produced from bamboo activated carbon by soaking method of metal nitrate solution. The carbonization and activation of raw material was conducted at 900℃. The specific surface area and pore size distribution of the prepared activated carbons were measured. Also, NO and activated carbon reaction were conducted in a thermogravimetric analyzer in order to use as de-NOx agents of used activated carbon. Carbon-NO reactions were carried out with respect to reaction temperature (20℃~850℃) and NO gas partial pressure (0.1 kPa~1.8 kPa). As results, the specific volume and surface area of bamboo activated carbon impregnated with copper were decreased with increasing Cu amounts of activated carbon. In NO reaction, the reaction rate of Cu impregnated bamboo activated carbon[BA(Cu)] was promoted to compare with that of bamboo activated carbon[BA]. But the reaction rate of Ag impregnated bamboo activated carbon[BA(Ag)] was retarded. Measured reaction orders of NO concentration and activation energy were 0.63[BA], 0.92[BA(Cu)], and 80.5 kJ/mol[BA], 48.5 kJ/mol[BA(Cu)], 66.4 kJ/mol[BA(Ag)], respectively.

Quality Comparison of Activated Carbon Produced From Oil Palm Fronds by Chemical Activation Using Sodium Carbonate versus Sodium Chloride

( Seri Maulina ),( Gewa Handika ),( Irvan ),( Apri Heri Iswanto ) 한국목재공학회 2020 목재공학 Vol.48 No.4

Using Na₂CO₃ versus NaCl as chemical activator, we compared the quality of activated carbon produced from oil palm fronds as raw material. These activators were selected for comparison because both are readily available and are environmentally friendly. In the manufacturing, we used Indonesian National Standard (SNI 06-3730-1995) parameters. For the quality comparison, we determined activated-carbon yield, moisture, ash, volatiles, and fixed-carbon contents; and adsorption capacity of iodine. The best characteristics, assessed by morphological surface analysis and Fourier transform infrared (FTIR) spectral analysis, were observed in the carbon activated by Na₂CO₃ at an activator concentration of 10% and carbonization temperature of 400 °C. The results were as follows: activated-carbon yield, 84%; water content, 8.80%; ash content, 2.20%; volatiles content, 14.80%; fixed-carbon content, 68.60%; and adsorption capacity of iodine, 888.51 mg/g. Identification using the FTIR spectrophotometer showed the presence of the functional groups O-H, C=O, C=C, C-C, and C-H in the Na₂CO₃-activated carbon.

Comparisons of activated carbons produced from sycamore balls, ripe black locust seed pods, and Nerium oleander fruits and also their H2 storage studies

Osman ?ner,?nal Ge?gel,Tarık Avcu 한국탄소학회 2021 Carbon Letters Vol.31 No.1

Starting materials are very significant to produce activated carbons because every starting material has a different chemical structure; hence they affect the surface functional groups and surface morphologies of obtained activated carbons. In this study, sycamore balls, ripe black locust seed pods, and Nerium oleander fruits have been used as starting materials by ZnCl2 chemical activations for the first time. Firstly, activated carbons were obtained from these starting materials with ZnCl2 chemical activation by changing production conditions (carbonization time, carbonization temperature, and impregnation ratio) also affecting the structural and textural properties of the resultant activated carbons. Then, the starting materials and resultant activated carbons were characterized by utilizing diverse analysis techniques, such as TGA, elemental analysis, proximate analysis, BET surface areas, pore volumes, pore size distributions, N2 adsorption–desorption isotherms, SEM, FTIR spectra, and H2 adsorption isotherms. The highest surface areas were determined to be 1492.89, 1564.84, and 1375.47 m2/g for the activated carbons obtained from sycamore balls, ripe black locust seed pods, and N. oleander fruits, respectively. The yields of these activated carbons with the highest surface areas were calculated to be around 40%. As the carbonization temperature increased with sufficient ZnCl2 amount, N2 adsorption–desorption isotherms began to turn into Type IV isotherms given by mesoporous adsorbents with its hysteresis loops. Also, their hysteresis loops resembled Type H4 loop generally associated with narrow slit-like pores. Moreover, hydrogen uptakes under 750 mmHg at 77 K were determined to be 1.31, 1.48, and 1.24 wt% for the activated carbons with the maximum surface areas produced from sycamore balls, ripe black locust seed pods, and N. oleander fruits, respectively. As a result, the highest surface areas of the activated carbons with different structural properties produced in this study were obtained with different production conditions.

알칼리금속과 알칼리 토금속 촉매 담지 대나무 활성탄의 NO 가스 반응 특성

박영철 ( Young Cheol Bak ),최주홍 ( Joo Hong Choi ) 한국화학공학회 2016 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.54 No.5

대나무를 원료로 탄화 및 활성화온도 900 oC에서 대나무 활성탄을 만들고, 이 대나무 활성탄에 알칼리 금속(Na, K)과 알칼리토금속(Ca, Mg)을 담지 시켜 알칼리 담지 대나무활성탄을 제조하였다. 제조된 알칼리 담지 활성탄의 비표면적 및 세공분포 등의 물리적 특성을 분석하였다. 또한 폐 대나무활성탄의 재활용을 위하여 알칼리 담지 대나무활성탄과 NO 기체의 반응 특성 실험을 열중량분석기를 사용하여 비등온반응(반응온도 20~850 oC, NO 농도 0.1 kPa)과 등온반응(반응온도 600, 650, 700, 750, 800, 850 oC, NO 농도 0.1~1.8 kPa) 조건에서 하였다. 실험 결과, 대나무 활성탄 특성 분석에서 알칼리 담지 대나무 활성탄에서는 알칼리 담지량이 증가할수록 세공 부피와 표면적이 감소하였다. 비등온과 등온 NO 반응에서는 전체적으로 Ca금속담지 대나무활성탄[BA(Ca)]과 Na금속담지 대나무활성탄[BA(Na)], K금속담지 대나무활성탄[BA(K)], Mg금속담지 대나무활성탄[BA(Mg)]이 대나무활성탄[BA]에 비하여 반응속도가 향상되는 것을 볼 수 있다. BA(Ca)> BA(Na)> BA(K)> BA(Mg)> BA 순으로 촉매 활성이 유효하였다. NO 반응에서의 활성화에너지는 82.87 kJ/mol[BA], 37.85 kJ/mol[BA(Na)], 69.98 kJ/mol[BA(K)], 33.43 kJ/mol[BA(Ca)], 88.90 kJ/mol [BA(Mg)]로 나타났고, NO 분압에 대한 반응차수는 0.76[BA], 0.63[BA(Na)], 0.77[BA(K)], 0.42[BA(Ca)], 0.30[BA(Mg)] 이었다. The impregnated alkali metal (Na, K), and the alkali earth metal (Ca, Mg) activated carbons were produced from the bamboo activated carbon by soaking method of alkali metals and alkali earth metals solution. The carbonization and activation of raw material was conducted at 900 oC. The specific surface area and the pore size distribution of the prepared activated carbons were measured. Also, NO and activated carbon reaction were conducted in a thermogravimetric analyzer in order to use for de-NOx agents of the used activated carbon. Carbon-NO reactions were carried out in the nonisothermal condition (the reaction temperature 20~850 oC, NO 1 kPa) and the isothermal condition (the reaction temperature 600, 650, 700, 750, 800, 850 oC, NO 0.1~1.8 kPa). As results, the specific volume and the surface area of the impregnated alkali bamboo activated carbons were decreased with increasing amounts of the alkali. In the NO reaction, the reaction rate of the impregnated alkali bamboo activated carbons was promoted to compare with that of the bamboo activated carbon [BA] in the order of BA(Ca)> BA(Na)> BA(K)> BA(Mg) > BA. Measured the reaction orders of NO concentration and the activation energy were 0.76[BA], 0.63[BA(Na)], 0.77[BA(K)], 0.4 [BA(Ca)], 0.30 [BA(Mg)], and 82.87 kJ/mol[BA], 37.85 kJ/mol[BA(Na)], 69.98 kJ/mol[BA(K)], 33.43 kJ/mol[B (Ca)], 88.90 kJ/mol [BA(Mg)], respectively.

은첨착 대나무 활성탄의 제조와 NO 가스 반응 특성

박영철 ( Young Cheol Bak ),최주홍 ( Joo Hong Choi ),이근림 ( Geun Lim Lee ) 한국화학공학회 2014 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.52 No.6

대나무를 원료로 탄화 및 활성화온도 900 ℃에서 대나무 활성탄을 만들고, 이 대나무 활성탄을 질산은 수용액에 침지시켜 은첨착 대나무활성탄을 제조하였다. 0.002~0.1 mol/L 농도의 질산은 수용액에서 농도변화와 시간 변화 조건에서 은첨착실험을 하였다. 제조된 첨착활성탄의 은첨착량, 비표면적 및 세공분포 등의 물리적 특성을 분석하였다. 또한 폐대나무활성탄의 재활용을 위하여 대나무활성탄과 NO 기체의 반응 특성 실험을 열중량분석기를 사용하여 반응온도20~850 ℃, NO 농도 0.1~1.8 kPa 변화 조건에서 하였다. 실험 결과, 첨착시간 2시간 내에 은첨착이 완료되었고, 질산은 수용액 농도가 0.002~0.1 mol/L로 증가됨에 따라 은첨착량은 1.95 mg Ag/g 활성탄(0.2%)~88.70 mg Ag/g 활성탄(8.87%)로 증가되었다. 대나무 활성탄 특성 분석에서 은첨착량이 증가할수록 세공 부피와 표면적은 은첨착 0.2%일 때 최대이고 은첨착량이 증가할수록 세공체적이 감소하였다. 비등온과 등온 NO 반응에서는 전체적으로 은첨착대나무활성탄[BA(Ag)]이 대나무활성탄[BA]에 비하여 반응이 억제되는 것을 볼 수 있다. NO 반응에서의 활성화에너지는 80.5kJ/mol[BA], 66.4 kJ/mol[BA(Ag)]로 나타났고, NO 분압에 대한 반응차수는 0.63[BA], 0.69l[BA(Ag)]이었다. The Ag-impregnated activated carbon was produced from bamboo activated carbon by soaking method of silver nitrate solution. The carbonization and activation of raw material was conducted at 900 oC. Soaking conditions are the variation of silver nitrate solution concentration (0.002~0.1 mol/L) and soaking time (maximum 24 h). The specific surface area and pore size distribution of the prepared activated carbons were measured. Also, NO and activated carbon reaction were conducted in a thermogravimetric analyzer in order to use for de-NOx agents of used activated carbon. Carbon-NO reactions were carried out with respect to reaction temperature (20~850 oC) and NO gas partial pressure (0.1~1.8 kPa). As results, Ag amounts are saturated within 2h, Ag amounts increased 1.95 mg Ag/g (0.2%)~ 88.70 mg Ag/g (8.87%) with the concentration of silver nitrate solution in the range of 0.002~0.1 mol/L. The specific volume and surface area of bamboo activated carbon of impregnated with 0.2% silver were maximum, but decreased with increasing Ag amounts of activated carbon due to pore blocking. In NO reaction, the reaction rate of impregnated bamboo activated carbon was retarded as compare with that of bamboo activated carbon. Measured reaction orders of NO concentration and activation energy were 0.63[BA], 0.69l[BA(Ag)] and 80.5 kJ/mol[BA], 66.4 kJ/mol[BA(Ag)], respectively.