N‐Doped Activated Carbons from Polypyrrole – Effect of Steam Activation Conditions

In this study, activated polymer-based hard carbon using steam activation (APHS) with mesopore-rich pore structures were prepared for application as electrodes in electrical double-layer capacitors (EDLC). The surface morphologies and structural characteristics of APHS were observed using scanning electron microscopy and X-ray diffraction analysis, respectively. The textural properties were described using Brunauer-Emmett-Teller and Barrett-Joyner-Halenda equations with N2/77 K adsorption isotherms. APHS were prepared under various steam activation conditions to find optimal ones, which were then applied as electrode materials for the EDLC. The observed specific surface areas and total pore volumes of the APHS were in the range 1170–2410 m2/g and 0.48–1.22 cm3/g, respectively. It was observed that pore size distribution mainly depended on the activation time and temperature, and that the volume of pores with size of 1.5–2.5 nm was found to be a key factor determining the electrochemical capacity.

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Evaluation of Porous Carbon Adsorbents Made from Rice Husks for Virus Removal in Water

Water ◽

10.3390/w13091280 ◽

2021 ◽

Vol 13 (9) ◽

pp. 1280

Author(s):

Vu Duc Canh ◽

Seiichiro Tabata ◽

Shun Yamanoi ◽

Yoichi Onaka ◽

Toshiyuki Yokoi ◽

...

Keyword(s):

Porous Carbon ◽

Activated Carbons ◽

Carbon Adsorbents ◽

Rice Husks ◽

Porous Carbons ◽

Inorganic Pollutants ◽

Steam Activation ◽

Virus Removal ◽

Silica Removal ◽

Effective Removal

Porous carbons are well-known efficient adsorbents for a variety of organic and inorganic pollutants; however, they have difficulty in virus removal. In this study, novel porous carbons (NPCs) (NPC-A, NPC-B, and NPC-C) derived from rice husks were compared with commercially available activated carbons (ACs) for their ability to remove MS2 bacteriophages (MS2) in a batch experiment. NPC-A was produced by the silica removal process. NPC-B was prepared with an additional steam activation applied to NPC-A. NPC-C was obtained with an additional acid rinse applied to NPC-B. The NPCs (particularly NPC-C) exhibited effective removal of up to 5.3 log10 of MS2, which was greater than that of less than 2.7 log10 obtained by other ACs under 10 g/L during the same contact time (60 min). The pore size distribution of the porous carbon adsorbents was found to influence their virus removal performance. The adsorbents with a larger proportion of pores ranging from 200–4500 nm in diameter were able to achieve higher virus removal rates. Thus, NPCs (particularly NPC-C), which had a larger volume of pores ranging from 200–4500 nm in size, demonstrated the potential for use as efficient adsorbents for removing viruses during water purification.

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Thermodynamic Behaviors of Adsorbed Methane Storage Systems Based on Nanoporous Carbon Adsorbents Prepared from Coconut Shells

Nanomaterials ◽

10.3390/nano10112243 ◽

2020 ◽

Vol 10 (11) ◽

pp. 2243

Author(s):

Ilya Men’shchikov ◽

Andrey Shkolin ◽

Evgeny Strizhenov ◽

Elena Khozina ◽

Sergey Chugaev ◽

...

Keyword(s):

Storage Tank ◽

Activated Carbons ◽

Storage System ◽

Nitrogen Adsorption ◽

Methane Adsorption ◽

Carbon Adsorbents ◽

X Ray ◽

Coconut Shells ◽

Activation Conditions ◽

Charge Discharge

The present work focused on the experimental study of the performance of a scaled system of adsorbed natural gas (ANG) storage and transportation based on carbon adsorbents. For this purpose, three different samples of activated carbons (AC) were prepared by varying the size of coconut shell char granules and steam activation conditions. The parameters of their porous structure, morphology, and chemical composition were determined from the nitrogen adsorption at 77 K, X-ray diffraction (XRD), small-angle X-ray scattering (SAXS), and scanning electron microscopy (SEM) measurements. The methane adsorption data measured within the temperature range from 178 to 360 K and at pressures up to 25 MPa enabled us to identify the most efficient adsorbent among the studied materials: AC-90S. The differential heats of methane adsorption on AC-90S were determined in order to simulate the gas charge/discharge processes in the ANG system using a mathematical model with consideration for thermal effects. The results of simulating the charge/discharge processes under two different conditions of heat exchange are consistent with the experimentally determined temperature distribution over a scaled ANG storage tank filled with the compacted AC-90S adsorbent and equipped with temperature sensors and heat-exchanger devices. The amounts of methane delivered from the ANG storage system employing AC-90S as an adsorbent differ from the model predictions by 4–6%. Both the experiments and mathematical modeling showed that the thermal regulation of the ANG storage tank ensured the higher rates of charge/discharge processes compared to the thermal insulation.

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Optimization of Activated Carbons Prepared byH3PO4and Steam Activation of Oil Palm Shells

Journal of Chemistry ◽

10.1155/2013/654343 ◽

2013 ◽

Vol 2013 ◽

pp. 1-10 ◽

Cited By ~ 7

Author(s):

Daouda Kouotou ◽

Horace Ngomo Manga ◽

Abdelaziz Baçaoui ◽

Abdelrani Yaacoubi ◽

Joseph Ketcha Mbadcam

Keyword(s):

Activated Carbon ◽

Oil Palm ◽

Activated Carbons ◽

Optimum Conditions ◽

Steam Activation ◽

Experimental Conditions ◽

Activation Temperature ◽

Impregnation Ratio ◽

Preparation Conditions ◽

Two Factors

In this study, activated carbons were prepared from oil palm shells by physicochemical activation. The methodology of experimental design was used to optimize the preparation conditions. The influences of the impregnation ratio (0.6–3.4) and the activation temperature between 601°C and 799°C on the following three responses: activated carbon yield (R/AC-H3PO4), the iodine adsorption (I2/AC-H3PO4), and the methylene blue adsorption (MB/AC-H3PO4) results were investigated using analysis of variance (ANOVA) to identify the significant parameters. Under the experimental conditions investigated, the activation temperature of 770°C and impregnation ratio of 2/1 leading to the R/AC-H3PO4of 52.10%, theI2/AC-H3PO4of 697.86 mg/g, and the MB/AC-H3PO4of 346.25 mg/g were found to be optimum conditions for producing activated carbon with well compromise of desirability. The two factors had both synergetic and antagonistic effects on the three responses studied. The micrographs of activated carbons examined with scanning electron microscopy revealed that the activated carbons were found to be mainly microporous and mesoporous.

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Adsorption of MIB by activated carbons produced using several activation techniques

Water Science & Technology Water Supply ◽

10.2166/ws.2002.0178 ◽

2002 ◽

Vol 2 (5-6) ◽

pp. 265-270

Author(s):

R. McCallum ◽

F. Roddick ◽

M. Hobday

Keyword(s):

Heat Treatment ◽

Activated Carbon ◽

Water Treatment ◽

Organic Compounds ◽

Activated Carbons ◽

Alkali Treatment ◽

Power Station ◽

Steam Activation ◽

Pre Treatment ◽

Physical And Chemical

Water treatment authorities use activated carbon as the best available technology to remove low molecular weight organic compounds from potable water. In Australia, pollutants of concern include secondary metabolites from bacterial and cyanobacterial blooms which are highly odorous and, in some cases, toxic. Of these compounds, 2-methylisoborneol (MIB) is one of the most common and its unpleasant musty earthy odour can be detected at or above approximately 10 ng/L. Difficulties in using activated carbon to target such small organic compounds arise when the water has high concentrations of natural organic matter (NOM), as these compounds also adsorb on activated carbon. The adsorption of NOM on activated carbon increases the cost of using this material in water treatment due to competition with the target organic compounds, reducing the capacity of the activated carbon for the latter. The surface of activated carbon can be tailored during production to provide physical and chemical characteristics that can either aid or hinder the adsorption of particular compounds. One source of activated carbon currently under investigation at RMIT University is brown coal char waste from power stations. This waste, currently disposed of to landfill, is potentially an option for activated carbon production. This material has the advantage that it has already been carbonised at around 500°C in the power generation process. This means that less energy is required to produce activated carbon from power station char compared to coal, making the final product cheaper to produce. Previous work at RMIT has shown that steam activated power station char can remove organic compounds from water. Production of a range of activated carbons from power station char (PSC) was undertaken using different activation methods, including steam activation, steam activation with acid pre-treatment, alkali heat treatment, and Lewis acid heat treatment. The different activation methods produced activated carbons with different pore size distributions, in particular, the acid pre-treatment increased the surface area and porosity significantly compared with steam activation, and the alkali treatment increased the microporosity. Adsorption of MIB on these activated carbons was evaluated to determine the relationship between physical and chemical interactions of the activated carbon and adsorption. Adsorption of MIB on these activated carbons was found to be dependent on the secondary micropore volume. Lewis acid treatment and alkali treatment was not involved in the generation of many of these secondary pores, hence carbons from these treatments did not perform well in adsorption tests. The best adsorption results were achieved with steam activated or acid treated steam activated samples which performed comparably to commercial products. Initial results showed that competition from NOM adsorption was lowest with the PSC activated carbons, allowing greater adsorption of MIB, compared with the commercial activated carbons.

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Impact of Biomass Derived Raw Material on Nitrogen Doped Porous Carbon Structure

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.762.99 ◽

2018 ◽

Vol 762 ◽

pp. 99-103

Author(s):

Ance Plavniece ◽

Aivars Zhurinsh ◽

Galina Dobele ◽

Aleksandrs Volperts

Keyword(s):

Activated Carbons ◽

Scientific Information ◽

Black Liquor ◽

Carbon Matrix ◽

Raw Material ◽

Carbon Structure ◽

Preparation Conditions ◽

Carbon Compounds ◽

Wood Char ◽

Activation Conditions

Carbon compounds with large surface area can be used as electrocatalytic cathodes for fuel cells. Nitrogen atoms largely determine the properties of doped activated carbon, such as hardness, wear resistance, electrical resistance etc., and therefore there is a need for new scientific information on the properties and structure of modified carbon matrix. Wood char and activated carbons based on wood char, cellulose, black liquor, and fine cellulose sludge were obtained in different activation conditions and doped with dicyandiamide. The obtained N-doped carbon materials porous structures were compared taking into account preparation conditions and raw material.

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Coal-Based Activated Carbons for the Removal of Sulphur Dioxide via Adsorption

Adsorption Science & Technology ◽

10.1177/026361749701501006 ◽

1997 ◽

Vol 15 (10) ◽

pp. 803-814 ◽

Cited By ~ 4

Author(s):

A.M. Youssef ◽

M.R. Mostafa ◽

E.M. Dorgham

Keyword(s):

Activated Carbon ◽

Low Temperature ◽

Zinc Chloride ◽

Sulphur Dioxide ◽

Activated Carbons ◽

Textural Properties ◽

Nitrogen Adsorption ◽

Carbon Surface ◽

Steam Activation ◽

Pore Widening

Zinc chloride-activated carbons and steam-activated carbons were prepared from Maghara coal. The textural properties were determined from low-temperature nitrogen adsorption. Zinc chloride activation is usually associated with the creation of new micropores while steam activation involves pore widening particularly when the percentage burn-off is high. The adsorption of SO2 on steam-activated carbon is high compared with ZnCl2-activated carbons. Steam activation develops surface basic groups which provide chemisorption sites for SO2. The adsorption of SO2 is enhanced in the presence of O2 and water vapour and involves the formation of sulphuric acid in this case. Sulphur dioxide adsorption is related to the chemistry of the carbon surface rather than to the extent of the surface area of the activated carbon.

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