• Journal of Korean Society of Environmental Engineers
• /
• v.35 no.7
• /
• pp.472-478
• /
• 2013

Cu and Cr as a base metal and Pt, Pd as a supportive metal were selected for improving adsorption capacity of activated carbon fiber in eliminating especially targeted VOCs. Preparing variables such as metal loading, loading temperature, loading hours and kinds of loaded metals were changed. Properties measurement was carried out by SEM (scanning electron microscope), XRF (x-ray fluorescence analysis) and EDX (Energy Dispersive X-ray spectrometer) and adsorption capacity evaluation were also performed by gas analyzer. Under this study, the adsorption capacity of complex metal loaded activated carbon fiber was improved positively than that of single metal loaded activated carbon fiber. And we found that the best conditions for metal loading were 5 hours loading time at $100^{\circ}C$ and the adsorption capacity was enhanced almost double compared with other condition based activated carbon fiber. Cu-Cr-Pt-Pd loaded activated carbon fiber showed the best adsorption capacity. Also we confirmed that more than 0.5 second is necessary for adsorbate diffusion and adsorption over activated carbon fiber.

• Journal of Korean Society of Environmental Engineers
• /
• v.35 no.1
• /
• pp.31-37
• /
• 2013

To acquire enhanced adsorption capacity for especially targeted VOCs, activated carbon fiber of which surface area was $1,100m^2/g$ was selected and active metals were loaded. After screening study, Cr and Cu were selected as a base metal for improving adsorption capacity of activated carbon fiber. For acquiring better performance, metal loading, loading temperature, loading hours and kinds of loaded metals were changed as preparing variables. Properties measurement and adsorption capacity evaluation were performed. We found that the best conditions for metal loading were 5 hours loading at $100^{\circ}C$ and the adsorption capacity was enhanced almost double. Also we confirmed that more than 0.5 seconds contact time is needed for best adsorbate diffusion and adsorption over activated carbon fiber.

• Proceedings of the KAIS Fall Conference
• /
• 2012.05a
• /
• pp.36-38
• /
• 2012

본 연구는 석탄계 핏치를 원료로 하여 구형 활성탄소를 제조하여 독성 물질인 Dimethyl Methlphosphonate, Hydrogen Chloride에 대한 흡착과파 특성을 연구하였다. 본 연구에서 적용된 구형활성탄 제조방법은 피치를 이용하여 제조하였다. 제조방법은 원료 핏치의 연화점을 상승시키는 전처리 과정, 상기 전처리된 원료 핏치 용융물을 수용액에 현탁시켜 구형입자로 성장시키는 구형화 과정, 구형입자를 산화, 탄화 및 활성화하는 과정으로 구성되며 첨착 활성탄소에 첨착되는 첨착물질의 성분 및 첨착방법의 변화에 따른 독성가스의 흡착성능을 관찰하기 위하여 Dimethyl Methlphosphonate와 Hydrogen Chloride 가스를 대상으로 열중량반응기를 이용하여 흡착실험을 수행하였다. 최적의 담지체 선정을 위하여 담지금속에 따른 흡착능을 시험하여 최적 금속과 함침량을 도출하였다.

• Korean Chemical Engineering Research
• /
• v.61 no.3
• /
• pp.472-478
• /
• 2023

In this study, the acetaldehyde removal characteristics of activated carbon (AC) for air purifier filters were investigated using metal catalysts-impregnation and functional group-modification method. The AC with a high specific surface area(1700 m²/g) and micropores was prepared by KOH activation of coconut charcoal and the efficiency of catalyst and functional group immobilization was examined by varying the drying conditions within the pores after immersion. The physical properties of the prepared activated carbon were analyzed by BET, ICP, EA, and FT-IR, and the acetaldehyde adsorption performances were investigated using gas chromatography (GC) at various impregnation and modified conditions. As the concentration of impregnation solution increased, the amount of impregnated metal catalysts increased, while the specific surface area showed a decreasing trend. The adsorption tests of the metal catalyst-impregnated and functional group-modified activated carbons revealed that excellent adsorption performance in compositions MgO10@AC, CaO10@AC, EU10@AC, and H-U3N1@AC, respectively. The MgO10@AC, which showed the highest adsorption performance, had a breakthrough time of 533.8 minutes and adsorption capacity of 57.4 mg/g for acetaldehyde adsorption. It was found that the nano-sized MgO catalyst on the activated carbon improved the adsorption performance by interacting with carbonyl groups of acetaldehyde.

• Journal of Korean Society of Environmental Engineers
• /
• v.28 no.4
• /
• pp.384-388
• /
• 2006

The adsorption ability of polar and toxic substance was greatly enhanced by treating activated carbon with acid solution and impregnating iron, copper, or silver by using in 0.1 M $FeSO_4{\cdot}7H_2O,\;CuSO_4{\cdot}5H_2O,\;AgNO_3$ 300 mL per activated carbon 50 g. Physical and chemical properties of the metal impregnated activated carbons were measured using specific surface area, pore volume and size distribution, scanning eletron microscope(SEM), adsorption isotherm. When activated carbon was treated with acid, the quantity of impregnated metal increased about 1.3 times since the micropores were converted to mesopores or macropores. Both the physical absorption by micropores and chemical absorption by metal ions could be achieved simultaneously with the metal impregnated activated carbon because the capacity of micro pores did not change even after metal ions were impregnated.

• Environmental engineer
• /
• v.23 s.238
• /
• pp.26-33
• /
• 2006

• Applied Chemistry for Engineering
• /
• v.32 no.6
• /
• pp.671-678
• /
• 2021

Effects of nitric acid treatment of an activated carbon and impregnation of metal chlorides on the activated carbon were investigated to improve ammonia adsorption performance. It was confirmed that functional groups such as hydroxyl and carboxyl groups were introduced onto a surface of the activated carbon with nitric acid treatment. Then, each metal chloride (NiCl₂, MgCl₂, CuCl₂, MnCl₂ or CoCl₂) was impregnated onto the surface-modified activated carbon using an ultrasonic impregnation method. The physicochemical properties and ammonia adsorption performance of various impregnated activated carbons were observed. Metal chlorides were well dispersed by sonication and evenly distributed on the surface of the activated carbon. Despite the reduced specific surface area and pore volume, the surface-modified activated carbon impregnated with metal chlorides exhibited excellent ammonia adsorption performance. In particular, HNO₃-NiCl₂ AC prepared by impregnating NiCl₂ showed the best ammonia adsorption capacity of 3.736 mmol·g^-1, which was improved by about 57 times compared to that of an untreated activated carbon (0.066 mmol·g^-1).

• Applied Chemistry for Engineering
• /
• v.18 no.5
• /
• pp.467-474
• /
• 2007

The palladium and gold nanoparticles containing PAN-based active carbon fiber (ACF) with a high specific surface area were prepared. Using the BET, TEM, FE-SEM, and XPS, their specific surface area and pore volume, pore structure, and the change in surface oxygen groups with time were analyzed and $SO_2$ adsorption performances were investigated. Because of the impregnating process, the micropore volume was mostly decreased from 95.5% to 30.5~43.7% compared with the total pore volume. And the change in surface oxygen groups with time was higher for the metal salt than the nanoparticles. Also, $SO_2$ breakthrough time of PAN-ACFs impregnated with Au nanoparticles and metal salts did not change compared with that of the non-impregnated PAN-ACF. But the PAN-ACF impregnated with Pd nanoparticles (100 ppm) showed good $SO_2$ adsorption performance as the breakthrough time of 880 sec. These results indicated that the $SO_2$ adsorption performance depended on the change in surface oxygen groups with time and the moderate impregnation of Pd nanoparticles on the PAN-ACF caused the increase in the $SO_2$ adsorption performance by a catalytic action.

• Clean Technology
• /
• v.26 no.2
• /
• pp.137-144
• /
• 2020

Metal-impregnated activated carbons were prepared via ultrasonic-assisted impregnation method for regeneration and low ammonia concentration. Magnesium and copper were selected as metals, while chloride (Cl^-) and nitrate (NO₃^-) precursors were used to impregnate the surface of activated carbon. The physical and chemical properties of the prepared adsorbents were characterized by TGA, BET, and NH₃-TPD. The ammonia breakthrough test was carried out using a fixed bed and flowing ammonia gas (1000 mg L^-1 NH₃, balanced N₂) at 100 mL min^-1, under conditions of temperature swing adsorption (TSA) and pressure swing adsorption (PSA, 0.3, 0.5, 0.7, 0.9 Mpa). The adsorption and desorption performance of ammonia were in the order of AC-Mg(Cl) > AC-Cu(Cl) > AC-Mg(N) > AC-Cu(N) > AC through NH₃-TPD and TSA and PSA processes. AC-Mg(Cl) using MgCl₂ showed the average adsorption amount of 2.138 mmol/g at TSA process. Also, AC-Mg(Cl) showed the highest initial adsorption amount of 3.848 mmol/g at PSA 0.9 Mpa. When metal impregnated the surface of the activated carbon, it was confirmed that not only physical adsorption, but also chemical adsorption increased, making enhancement in adsorption and desorption performances possible. Also, the prepared adsorbents showed stable adsorption and desorption performances despite repeated processes, confirming their applicability in the TSA and PSA processes.

• Journal of Korean Society of Environmental Engineers
• /
• v.32 no.10
• /
• pp.936-941
• /
• 2010

This study was conducted to investigate formaldehyde removals by silver nano-particles attached on the surface of granular activated carbon (Ag-AC) and to compare the results to those obtained with ordinary activated carbon (AC). The BET analysis showed that the overall surface area and the fraction of micropores (less than $20{\AA}$ diameter) of the Ag-AC were significantly decreased because the silver particles blocked the small pores on the surface of the Ag-AC. The formaldehyde removal capacity of the Ag-AC determined using the Freundlich isotherm was higher than that of AC. Despite the decreased BET surface area and micropore volume, the Ag-AC had the increased removal capacity for formaldehyde, presumably due to catalytic oxidation by silver nano-particles. In contrast, the adsorption intensity of the Ag-AC, estimated by 1/n in the Freundlich isotherm equation, was similar to that of the ordinary AC, indicating that the surface modification using silver nano-particles did not affect the adsorption characteristics of AC. In a column experiment, the Ag-AC also showed a longer breakthrough time than that of the AC. Simulation results using the homogeneous surface diffusion model (HSDM) were well fitted to the breakthrough curve of formaldehyde for the ordinary AC, but the predictions showed substantial deviations from the experimental data for the Ag-AC. The discrepancy was due to the catalytic oxidation of silver nano-particles that was not incorporated in the HSDM. Consequently, a new numerical model that takes the catalytic oxidation into accounts needs to be developed to predict the combined oxidation and adsorption process more accurately.