scholarly journals Activated Carbons for Syngas Desulfurization: Evaluating Approaches for Enhancing Low-Temperature H2S Oxidation Rate

2021 ◽  
Vol 5 (2) ◽  
pp. 23
Author(s):  
Christian Frilund ◽  
Ilkka Hiltunen ◽  
Pekka Simell
Keyword(s):  
Activated Carbon ◽  
Low Temperature ◽  
Performance Test ◽  
Activated Carbons ◽  
Physical Adsorption ◽  
High Surface ◽  
Fixed Bed ◽  
Adsorption Rate ◽  
H2s Removal ◽  
H2s Oxidation

Its relatively low cost and high surface area makes activated carbon an ideal adsorbent candidate for H2S removal. However, physical adsorption of H2S is not very effective; therefore, methods to facilitate reactive H2S oxidation on carbons are of interest. The performance of H2S removal of non-impregnated, impregnated, and doped activated carbon in low-temperature syngas was evaluated in fixed-bed breakthrough tests. The importance of oxygen content and relative humidity was established for reactive H2S removal. Impregnates especially improved the adsorption rate compared to non-impregnated carbons. Non-impregnated carbons could however retain a high capture capacity with sufficient contact time. In a relative performance test, the best performance was achieved by doped activated carbon, 320 mg g−1. Ammonia in syngas was found to significantly improve the adsorption rate of non-impregnated activated carbon. A small quantity of ammonia was consumed by the carbon bed, suggesting that ammonia is a reactant. Finally, to validate ammonia-enhanced desulfurization, bench-scale experiments were performed in biomass-based gasification syngas. The results show that when the ammonia concentration in syngas was in the tens of ppm range, 40–160 ppm H2S oxidation proceeded rapidly. Ammonia-enhanced oxidation allows utilization of cheaper non-impregnated activated carbons by in situ improvement of the adsorption kinetics. Ammonia enhancement is therefore established as a viable method for achieving high-capacity H2S removal with unmodified activated carbons.

Removal of Gas-Phase Elemental Mercury by Bromine-Impregnated Activated Carbon

2011 ◽  
Vol 356-360 ◽  
pp. 1660-1663 ◽  
Author(s):  
Jiang Wu ◽  
Jie He Chen ◽  
Shuai Bo Zhang ◽  
Ping He ◽  
Ji Hui Fang ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Gas Phase ◽  
Removal Efficiency ◽  
Activated Carbons ◽  
Physical Adsorption ◽  
Fixed Bed ◽  
Elemental Mercury ◽  
Adsorption Ability ◽  
Bromine Concentration ◽  
Fixed Bed System

Br-impregnated activated carbon for gas-phase elemental mercury adsorption experiments were carried out at a fixed-bed system to get the suitable mass fraction of KBr impregnation solution. Hg removal efficiency of 1% wt KBr-ACs was 69.0%, while that of 10% wt KBr-ACs was 57.9%. Both of them were higher than that of the raw activated carbon, 42.2%. The removal efficiency of Hg0 was not proportional to bromine concentration. Under 80-180°C, Hg removal efficiency of 1% wt KBr-ACs were 68.3%-71.8%, and at 140°C it reached the highest due to the increasing chemical adsorption ability of the functional groups which was on the surfaces of activated carbons by impregnating. At 160°C, Hg removal efficiency was lower than that at 140°C due to desorption making physical adsorption decrease, so that the total adsorption decreased.

Production and Characterization of Activated Carbon from Waste Tire by H3PO4 Treatment for Ethylene Adsorbent Used in Active Packaging

2012 ◽  
Vol 506 ◽  
pp. 214-217 ◽  
Author(s):  
Athiwat Sirimuangjinda ◽  
Khanthima Hemra ◽  
Duangduen Atong ◽  
Chiravoot Pechyen
Keyword(s):  
Activated Carbon ◽  
Surface Area ◽  
Activated Carbons ◽  
Adsorption Property ◽  
High Surface ◽  
High Surface Area ◽  
Fixed Bed ◽  
Activation Process ◽  
Experimental Conditions ◽  
Waste Tire

Pyrolysis is one form of energy recovery process which has the potential to generate oil, gas and char products. The char becomes an attractive by-product, with applications including production of activated carbons, which is useful as a ethylene sorbent for climacteric fruit packaging. In this work, activated carbon prepared from waste tire, produced as a by product of the bio-diesel extraction industry was prepared via chemical treatment with phosphoric acid (H3PO4) at three different char:H3PO4 ratios (1:1, 1:2 and 1:3) under fixed bed pyrolysis at 400, 500 and 600°C for 30 minutes in nitrogen (N2) flow rate of 1000 mL/min and heating rate of 20°C/min. Result shows that char pyrolyzed at 800°C contained high fixed carbon and low volatile content favorable for subsequent activation process compared to other cases.(data not show here) Under the experimental conditions investigated, impregnation ratio of 1:2 were found to be suitable for producing high-surface area activated carbon. It was shown that H3PO4 did work effectively as dehydration reagent at approximately 600°C. The obtained carbons were characterized by nitrogen adsorptiondesorption isotherms at-196 °C. The surface area of activated carbons, which were determined by application of the BrunauerEmmettTeller (BET) and t-plot methods, were achieved as high as 833.50 m2/g. The chemically activated carbons were found to be mainly type II carbons and high adsorption property (Methylene blue adsorption = 622 mg/g and Iodine number = 899 mg/g).

scholarly journals Preparation and characterization of activated carbons from albizia saman pod

2017 ◽  
Vol 36 (3) ◽  
pp. 44-53
Author(s):  
G. D. Akpen ◽  
M. I. Aho ◽  
N. Baba
Keyword(s):  
Activated Carbon ◽  
Surface Area ◽  
Activated Carbons ◽  
High Surface ◽  
High Surface Area ◽  
Volatile Matter ◽  
Sieve Analysis ◽  
Albizia Saman ◽  
Temperature Surface

Activated carbon was prepared from the pods of Albizia saman for the purpose of converting the waste to wealth. The pods were thoroughly washed with water to remove any dirt, air- dried and cut into sizes of 2-4 cm. The prepared pods were then carbonised in a muffle furnace at temperatures of 4000C, 5000C, 6000C ,7000C and 8000C for 30 minutes. The same procedure was repeated for 60, 90, 120 and 150 minutes respectively. Activation was done using impregnationratios of 1:12, 1:6, 1:4, 1:3, and 1:2 respectively of ZnCl2 to carbonised Albizia saman pods by weight. The activated carbon was then dried in an oven at 1050C before crushing for sieve analysis. The following properties of the produced Albizia saman pod activated carbon (ASPAC) were determined: bulk density, carbon yield, surface area and ash, volatile matter and moisture contents. The highest surface area of 1479.29 m2/g was obtained at the optimum impregnation ratio, carbonization time and temperature of 1:6, 60 minutes and 5000C respectively. It was recommended that activated carbon should be prepared from Albizia saman pod with high potential for adsorption of pollutants given the high surface area obtained.Keywords: Albizia saman pod, activated carbon, carbonization, temperature, surface area

Effect of Fractal Dimension of Powder Activated Carbon on SO2 Adsorption

2014 ◽  
Vol 955-959 ◽  
pp. 2169-2172 ◽  
Author(s):  
Bing Li ◽  
Jian Ming Xue ◽  
Yue Yang Xu ◽  
Hong Liang Wang ◽  
Chun Yuan Ma ◽  
...  
Keyword(s):  
Fractal Dimension ◽  
Activated Carbon ◽  
Adsorption Capacity ◽  
Activated Carbons ◽  
Fixed Bed ◽  
Fixed Bed Reactor ◽  
Removal Capacity ◽  
Powder Activated Carbon

Five kinds of powder activatedcarbons were studied to investigate the removal of SO2 from flue gasin a fixed bed reactor. The fractal dimension of activated carbon was determined by N2 adsorption isothermat 77Kand SO2 adsorptioncapacity was correlated with thefractal dimension. The results show thatthe activated carbons prepared from different precursors by differentactivation methods have different fractal dimension. Big differences in SO2 adsorption capacity are found between fivekinds of activated carbons. SO2 adsorption capacity increases with the fractaldimension increasing. The results indicate that the fractal dimension could be used as a indicator of SO2removal capacity on powder activated carbon.

Effect of Activating Agent on the Preparation of Bamboo-Based High Surface Area Activated Carbon by Microwave Heating

2016 ◽  
Vol 35 (6) ◽  
pp. 535-541 ◽  
Author(s):  
Hongying Xia ◽  
Jian Wu ◽  
Chandrasekar Srinivasakannan ◽  
Jinhui Peng ◽  
Libo Zhang
Keyword(s):  
Activated Carbon ◽  
Microwave Heating ◽  
Surface Area ◽  
Pore Volume ◽  
Activated Carbons ◽  
High Surface ◽  
High Surface Area ◽  
Significant Proportion ◽  
Mixture Ratio ◽  
Activating Agent

AbstractThe present work attempts to convert bamboo into a high surface area activated carbon via microwave heating. Different chemical activating agents such as KOH, NaOH, K2CO3 and Na2CO3 were utilized to identify a most suitable activating agent. Among the activating agents tested KOH was found to generate carbon with the highest porosity and surface area. The effect of KOH/C ratio on the porous nature of the activated carbon has been assessed. An optimal KOH/C ratio of 4 was identified, beyond which the surface area as well as the pore volume were found to decrease. At the optimized KOH/C ratio the surface area and the pore volume were estimated to be 3,441 m2/g and 2.093 ml/g, respectively, with the significant proportion of which being microporous (62.3%). Activated carbon prepared under the optimum conditions was further characterized using Fourier transform infrared spectroscopy (FTIR) and scanning electron microscope (SEM). Activated carbons with so high surface area and pore volume are very rarely reported, which could be owed to the nature of the precursor and the optimal conditions of mixture ratio adopted in the present work.

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

1997 ◽  
Vol 15 (10) ◽  
pp. 803-814 ◽  
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.

A comparison of different activated carbon performances on catalytic ozonation of a model azo reactive dye

2012 ◽  
Vol 66 (1) ◽  
pp. 179-184 ◽  
Author(s):  
Ş. Gül ◽  
O. Eren ◽  
Ş. Kır ◽  
Y. Önal
Keyword(s):  
Activated Carbon ◽  
Surface Area ◽  
Activated Carbons ◽  
High Surface ◽  
High Surface Area ◽  
Reactive Dye ◽  
Catalytic Ozonation ◽  
Bet Surface Area ◽  
Solution Ph ◽  
Pore Properties

The objective of this study is to compare the performances of catalytic ozonation processes of two activated carbons prepared from olive stone (ACOS) and apricot stone (ACAS) with commercial ones (granular activated carbon-GAC and powder activated carbon-PAC) in degradation of reactive azo dye (Reactive Red 195). The optimum conditions (solution pH and amount of catalyst) were investigated by using absorbencies at 532, 220 and 280 nm wavelengths. Pore properties of the activated carbon (AC) such as BET surface area, pore volume, pore size distribution, and pore diameter were characterized by N2 adsorption. The highest BET surface area carbon (1,275 m2/g) was obtained from ACOS with a particle size of 2.29 nm. After 2 min of catalytic ozonation, decolorization performances of ACOS and ACAS (90.4 and 91.3%, respectively) were better than that of GAC and PAC (84.6 and 81.2%, respectively). Experimental results showed that production of porous ACs with high surface area from olive and apricot stones is feasible in Turkey.

scholarly journals Activated carbons for the removal of heavy metal ions: A systematic review of recent literature focused on lead and arsenic ions

2015 ◽  
Vol 13 (1) ◽  
Author(s):  
Eleni A. Deliyanni ◽  
George Z. Kyzas ◽  
Kostas S. Triantafyllidis ◽  
Kostas A. Matis
Keyword(s):  
Systematic Review ◽  
Activated Carbon ◽  
Photoelectron Spectroscopy ◽  
Activated Carbons ◽  
Thermal Analyses ◽  
High Surface ◽  
High Surface Area ◽  
Adsorption Removal ◽  
Bet Analysis ◽  
Removal Of Heavy Metals

AbstractThis work is a systematic review of the literature over the past decade of the application of activated carbon (microporous or mesoporous) as adsorbents for the removal of heavy metals, focusing especially on lead (Pb) and arsenic (As) ions from the aqueous phase. Classical examples from our lab are also given. Activated carbon is known to provide a high surface area for adsorption. Generally, surface modification is typically required, such as oxidation, treatment with ammonia or even impregnation with ferric ion, etc. and the adsorbent material may originate from various sources. The pristine materials, after modification and those after batch-wise adsorption, were characterized by available techniques (BET analysis, Fourier transform infrared spectroscopy, scanning electron microscopy, thermal analyses, X-ray photoelectron spectroscopy). Adsorption isotherms, thermodynamics and kinetics of the process are also discussed. Selected studies from the literature are examined in comparison with other adsorbents. The role of chemistry in the metals adsorption/removal was investigated.

scholarly journals Activated Carbon Produced by Pyrolysis of Waste Wood and Straw for Potential Wastewater Adsorption

Materials ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2047 ◽  
Author(s):  
Katarzyna Januszewicz ◽  
Paweł Kazimierski ◽  
Maciej Klein ◽  
Dariusz Kardaś ◽  
Justyna Łuczak
Keyword(s):  
Activated Carbon ◽  
Surface Area ◽  
Activated Carbons ◽  
Chemical Activation ◽  
Fixed Bed ◽  
Fixed Bed Reactor ◽  
Physical Activation ◽  
Activation Process ◽  
Waste Wood ◽  
Carbon Production

Pyrolysis of straw pellets and wood strips was performed in a fixed bed reactor. The chars, solid products of thermal degradation, were used as potential materials for activated carbon production. Chemical and physical activation processes were used to compare properties of the products. The chemical activation agent KOH was chosen and the physical activation was conducted with steam and carbon dioxide as oxidising gases. The effect of the activation process on the surface area, pore volume, structure and composition of the biochar was examined. The samples with the highest surface area (1349.6 and 1194.4 m2/g for straw and wood activated carbons, respectively) were obtained when the chemical activation with KOH solution was applied. The sample with the highest surface area was used as an adsorbent for model wastewater contamination removal.

The Effect of Activated Carbon Properties on the Adsorption of Toxic Substances

1992 ◽  
Vol 25 (1) ◽  
pp. 153-160 ◽  
Author(s):  
E. Diamadopoulos ◽  
P. Samaras ◽  
G. P. Sakellaropoulos
Keyword(s):  
Activated Carbon ◽  
Fulvic Acid ◽  
Surface Area ◽  
Activated Carbons ◽  
High Surface ◽  
High Surface Area ◽  
Ash Content ◽  
Adsorptive Capacity ◽  
Toxic Substances ◽  
Carbon Loading

The objectives of this work were to relate the activated carbon properties to its adsorptive capacity. The activated carbon needed was produced in the lab from Greek lignite coal. Subsequently, adsorption studies were performed in order to evaluate the efficiency of the various activated carbons to remove toxic substances from water. Two organic substances were used. These were phenol and fulvic acid. Additionally, the adsorption of arsenic (V) was, also, investigated. It was found that the adsorptive capacity of the activated carbons depended primarily on the ash content and the compound. The capacity of the carbon to remove phenol, expressed as mg of phenol removed per g of activated carbon (carbon loading), decreased linearly as the amount of ash in the activated carbon increased. Ash-free activated carbons could adsorb 4 times as much phenol as the activated carbons with a high ash content. On the other hand, fulvic acid and arsenic adsorbed poorly on the ash-free activated carbons. Even for the high surface area activated carbons (over 1000 m2/g), the quantity of fulvic acid or arsenic adsorbed was significantly less than that exhibited by the high ash activated carbons (maximum surface area measured hardly exceeded 300 m2/g). As the amount of ash in the carbon increased, the carbon loading increased as well, up to a certain level, beyond which the amount of ash played no significant role. The beneficial role of ash was explained by the ability of the fulvic acid and arsenic to interact with metal oxides and metal ions, which constitute a significant fraction of the ash.

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