scholarly journals The Effect of Sulphur Dioxide Exposure under Controlled Environmental Conditions on the Challenge Performance of Copper and Chromate Impregnated Active Carbon against Hydrogen Cyanide

1997 ◽  
Vol 15 (7) ◽  
pp. 531-540 ◽  
Author(s):  
P.J.C. Anstice ◽  
J.F. Alder
Keyword(s):  
Activated Carbon ◽  
Numerical Analysis ◽  
Flow Rate ◽  
Active Carbon ◽  
Environmental Conditions ◽  
Sulphur Dioxide ◽  
Hydrogen Cyanide ◽  
Carbon Surface ◽  
Adsorption Model ◽  
Active Centres

An ASC/T (Cu2+, Cr6+, Ag and triethylenediamine impregnated) Whetlerite activated carbon sample was exposed to a flow rate of 1 l/min, 0.746 mg/l SO2 in 80% RH air at 22°C for up to 510 min. Samples were subsequently challenged with 2 mg/l HCN in an identical diluent gas stream. Increasing SO2 exposure resulted in accelerated HCN and (CN)2 bed penetration. The basic shapes of the breakthrough profiles were however essentially unchanged. This observation is in accordance with numerical analysis of these results using Hinshelwood's adsorption model, which suggested that the adsorption rate constant was not significantly affected by SO2 but rather the pollutant exposure resulted in the number of active centres on the carbon surface being reduced and the effective bed depth of the sample being shortened. This loss in active centres was thought most likely to result from the reduction of Cr6+ to Cr3+.

scholarly journals The influence of active carbon contaminants on the ozonation mechanism interpretation

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Lilla Fijołek ◽  
Joanna Świetlik ◽  
Marcin Frankowski
Keyword(s):  
Activated Carbon ◽  
Active Carbon ◽  
Alkali Metals ◽  
Activated Carbons ◽  
Carbon Surface ◽  
Bulk Solution ◽  
Ozone Decomposition ◽  
Reaction Products ◽  
Treatment Technology ◽  
Carbon Impurities

AbstractIn water treatment technology, activated carbons are used primarily as sorbents to remove organic impurities, mainly natural organic matter, but also as catalysts in the ozonation process. Commercially available activated carbons are usually contaminated with mineral substances, classified into two main groups: alkali metals (Ca, Na, K, Li, Mg) and multivalent metals (Al, Fe, Ti, Si). The presence of impurities on the carbon surface significantly affects the pHpzc values determined for raw and ozonated carbon as well as their acidity and alkalinity. The scale of the observed changes strongly depends on the pH of the ozonated system, which is related to the diffusion of impurities from the carbon to the solution. In an acidic environment (pH 2.5 in this work), the ozone molecule is relatively stable, yet active carbon causes its decomposition. This is the first report that indirectly indicates that contaminants on the surface of activated carbon (multivalent elements) contribute to the breakdown of ozone towards radicals, while the process of ozone decomposition by purified carbons does not follow the radical path in bulk solution. Carbon impurities also change the distribution of the reaction products formed by organic pollutants ozonation, which additionally confirms the radical process. The study showed that the use of unpurified activated carbon in the ozonation of succinic acid (SA) leads to the formation of a relatively large amount of oxalic acid (OA), which is a product of radical SA degradation. On the other hand, in solutions with purified carbon, the amount of OA generated is negligible.

Removal of the Endocrine Disrupting Chemicals Nonylphenol from Water by Activated Carbon

2012 ◽  
Vol 178-181 ◽  
pp. 520-525
Author(s):  
Xiao Dong Wang ◽  
Yu Feng Xiao
Keyword(s):  
Activated Carbon ◽  
Photoelectron Spectroscopy ◽  
Pore Volume ◽  
Ph Value ◽  
Absorption Capacity ◽  
Carbon Surface ◽  
Drinking Water Source ◽  
Adsorption Model ◽  
Average Pore ◽  
Endocrine Disrupting

Nonylphenol(NP) have endocrine disrupting effects and exist generally in drinking water source. Physical properties including surface area, average pore-diameter, and micro-pore volume and chemical structure of the activated carbon was characterized by N2 adsorption experiment and X-ray photoelectron spectroscopy (XPS). Pore volume could be the most important for adsorption. The high O content of carbon surface lead a negative effect to absorption capacity and low pH value, low temperature lead a positive effect to adsorption. The effect of humus in water to the removal was also studied and EDCs-humus bi-component adsorption model was established, it was found that there is strong competition between EDCs and humus. Due to the competition adsorption capacity of NP greatly decreased especially when the concentration of NP is very low. The adsorption kinetics test results indicated that the adsorption of NP followed the first-order kinetics and the smaller diameter GAC could increase adsorption velocity.

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.

Removal of the Endocrine Disrupting Chemical Bisphenol A from Water by Activated Carbon

2013 ◽  
Vol 671-674 ◽  
pp. 2726-2731 ◽  
Author(s):  
Xiao Dong Wang ◽  
Yu Feng Xiao
Keyword(s):  
Activated Carbon ◽  
Photoelectron Spectroscopy ◽  
Ph Value ◽  
Micropore Volume ◽  
Absorption Capacity ◽  
Carbon Surface ◽  
Adsorption Model ◽  
Endocrine Disrupting Chemical ◽  
First Order Kinetics ◽  
Negative Effect

Physical properties including surface area, average porediameter, and micropore volume and chemical structure of the activated carbon was characterized by N2 adsorption experiment and X-ray photoelectron spectroscopy (XPS). The high O content of carbon surface lead a negative effect to absorption capacity and low pH value, low temperature lead a positive effect to adsorption. The effect of humus in water to the removal was also studied and EDCs-humus bi-component adsorption model was established, it was found that there is strong competition between EDCs and humus. Due to this competition adsorption capacity of BPA greatly decreased especially when BPA concentration is very low. The adsorption kinetics test results indicated that the adsorption of BPA followed the first-order kinetics and the smaller diameter GAC could increase adsorption velocity.

Study on Thermal Regeneration for Caffeine-Saturated Activated Carbon

2013 ◽  
Vol 781-784 ◽  
pp. 1941-1944 ◽  
Author(s):  
Zhao You Zhu ◽  
Li Li Wang ◽  
Wan Ling Wang ◽  
Ying Long Wang
Keyword(s):  
Activated Carbon ◽  
Carbon Layer ◽  
Carbon Surface ◽  
Optimum Conditions ◽  
Gas Velocity ◽  
Thermal Regeneration ◽  
Regeneration Time ◽  
Before And After ◽  
Carbon Regeneration ◽  
Carrier Gas Velocity

Waste activated carbon (AC) containing caffeine was produced during the process of the production for caffeine. The process of treatment caffeine-saturated AC using thermal regeneration was explored and factors on the regeneration of activated carbon were investigated. The optimum conditions obtained were: temperature is 650 °C, the regeneration time is 180 min, the carrier gas velocity is 0.002 m/s, carbon layer thickness is 0.1 m. Under these conditions, activated carbon regeneration efficiency reached 90.3%. In addition, the pore structure of activated carbon before and after regeneration was characterized and the activated carbon surface area and pore size distribution under optimum conditions were determined by the adsorption isotherms.

scholarly journals A Study of the Removal of Minor Amounts of H2S from Natural Gas by Activated Carbon

2002 ◽  
Vol 20 (10) ◽  
pp. 969-976 ◽  
Author(s):  
Li Zhou ◽  
Ping Chen ◽  
Ming Li ◽  
Yaping Zhou
Keyword(s):  
Activated Carbon ◽  
Natural Gas ◽  
Considerable Effect ◽  
Carbon Surface

Studies have been made of the removal of minor amounts of H2S from natural gas by activated carbon. The surface alkalinity of the carbon had a considerable effect on the H2S capacity, although this was not permanent. Thus, when the carbon surface became neutral, the H2S content remained constant after the initial cycles of the purification/regeneration operation. The presence of water in natural gas was found to be critical for the use of activated carbon as a means of sweetening natural gas. However, although it enhanced the H2S capacity of the carbon, it made regeneration of the latter very difficult.

scholarly journals Adsorption of Phenol from Aqueous Solution Using Activated Carbon prepared from Coconut Shell

2017 ◽  
Vol 29 (1) ◽  
pp. 9-13
Author(s):  
Masuma Sultana Ripa ◽  
Rafat Mahmood ◽  
Sabrina Khan ◽  
Easir A Khan
Keyword(s):  
Aqueous Solution ◽  
Activated Carbon ◽  
Adsorption Isotherm ◽  
Iodine Number ◽  
Chemical Engineering ◽  
Coconut Shell ◽  
Physical Activation ◽  
Batch Adsorption ◽  
Adsorption Model ◽  
Solution Ph

Adsorption separation of phenol from aqueous solution using activated carbon was investigated in this work. The adsorbent was prepared from coconut shell and activated by physical activation method. The coconut shell was first carbonized at 800°C under nitrogen atmosphere and activated by CO2 at the same temperature for one hour. The prepared activated carbon was characterized by Scanning Electron Microscope (SEM) and BET Surface Analyzer and by the determination of iodine number as well as Boehm titration. The iodine number indicates the degree of relative activation of the adsorbent. The equilibrium adsorption isotherm phenol from aqueous solution was performed using liquid phase batch adsorption experiments. The effect of experimental parameters including solution pH, agitation time, particle size, temperature and initial concentration was investigated. The equilibrium data was analyzed using Langmuir and Freundlich adsorption model to describe the adsorption isotherm and estimate the adsorption isotherm parameters. The results indicate the potential use of the adsorbent for removal of phenol from the aqueous solution.Journal of Chemical Engineering, Vol. 29, No. 1, 2017: 9-13

Sign in / Sign up

Export Citation Format

Share Document