Impact of pore size on competitive adsorption of phenolic compounds

2004 ◽  
Vol 4 (5-6) ◽  
pp. 1-7
Author(s):  
Q. Lu ◽  
G. Sorial
Keyword(s):  
Activated Carbon ◽  
Pore Size ◽  
Molecular Oxygen ◽  
Binary Systems ◽  
Activated Carbons ◽  
Average Pore Size ◽  
Adsorptive Capacity ◽  
Limiting Factor ◽  
Ideal Adsorbed Solution Theory ◽  
Solute Adsorption

Single and binary solute adsorption of phenol and o-cresol at 23°C on three activated carbons with different pore size were conducted in this study. One granular activated carbon (GAC) F400 and two activated carbon fibers (ACFs) were considered. Anoxic (absence of molecular oxygen) and oxic (presence of molecular oxygen) conditions were evaluated. For the single solute system, the three adsorbents studied have shown higher adsorptive capacities under oxic conditions as compared to anoxic conditions. The degree of adsorption enhancement was related to the pore size of the adsorbent. For binary adsorption on ACC-10, which has the least average pore size (1.76 nm), the oxic and anoxic adsorption isotherms overlapped, indicating no impact of the presence of molecular oxygen on the adsorptive capacity. Significant differences on adsorptive capacities were noticed for the binary solute adsorption on ACC-15 (2.10 nm) and F400 (2.48 nm). The Ideal Adsorbed Solution Theory (IAST) predicted well all binary systems for ACC-10 and anoxic isotherms on ACC-15 and F400. Poor model predictions for GAC and ACC-15 under oxic conditions were attributed to the oligomerization of the adsorbates on the surface of activated carbon. The unique pore size of ACFs has been shown to be a limiting factor in hampering the oligomerization under oxic conditions.

scholarly journals Low cost activated carbon prepared from Dipterocarpus alatus fruit

2020 ◽  
Vol 3 (SI3) ◽  
pp. first
Author(s):  
Yuvarat Ngernyen ◽  
Werawit Phiewruangnont ◽  
Narathorn Mahantadsanapong ◽  
Chantakorn Patawat ◽  
Ketsara Silakate ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Pore Size ◽  
Surface Area ◽  
Activated Carbons ◽  
Low Cost ◽  
Average Pore Size ◽  
Carbon Adsorbents ◽  
Average Pore ◽  
Maximum Surface ◽  
Dipterocarpus Alatus

Dipterocarpus alatus tree grows prolifically throughout Thailand and can be tapped to yield significant quantities of oil to be used as natural diesel. However, such practices lead to waste dried fruit dropping from the tree. At present, there is no utilization of this dropped fruit, therefore costeffective processes need to be applied to obtain higher value products from this waste. A possible to utilization is the conversion to activated carbon for adsorption applications including the removal of heavy metals, dyes, and other contaminants in water purification and other decontamination process. A major challenge of current commercial activated carbon is the high production cost and recently it has been shown that chemical activators comprise a significant proportion of these costs. This feasibility study investigates the use of Dipterocarpus alatus fruit as raw material to produce low cost activated carbon adsorbents. Activated carbon was prepared from Dipterocarpus alatus fruit: endocarp, mesocarp, and wing by chemical activation with ZnCl2, FeCl3, and KOH. Each part of the fruit was impregnated with 30 wt% activating agent at a ratio of 1:2 for 1 h and then carbonized at 500 oC for a further 1 h. The surface area, pore volume, and average pore size of the resulting carbons were characterized by nitrogen gas adsorption. Activation of mesocarp with ZnCl2, KOH, and FeCl3 gave activated carbons with the surface area of 447, 256, and 199 m2/g, respectively. In the same way, ZnCl2 activation gave a maximum surface area of 312 and 278 m2/g for wing and endocarp, respectively. All of the aforementioned samples have an average pore size of around 2 nm. In contrast, KOH and FeCl3 activation of wing and endocarp produced activated carbon with very low surface area (below 25 m2/g), but with an average pore size of 5- 14 nm. The maximum surface area of activated carbon prepared from Dipterocarpus alatus fruit was higher than some literature examples for activated carbon from other biomass. Consequently, Dipterocarpus alatus fruit demonstrated significant potential as a feedstock for the preparation of low cost activated carbons.

Effect of Base Material on the Pore Size Distribution and Surface Area of Activated Carbon

2009 ◽  
Vol 62-64 ◽  
pp. 352-356 ◽  
Author(s):  
O.O. Ojo
Keyword(s):  
Activated Carbon ◽  
Pore Size ◽  
Surface Area ◽  
Surface Properties ◽  
Activated Carbons ◽  
Palm Kernel ◽  
Adsorptive Capacity ◽  
Corn Cobs ◽  
Base Materials ◽  
Materials Used

Powdered activated carbons were produced from palm kernel shells, corn cobs and cow bones by carbonization, pulverization and activation. The resulting granule has a surface area of 430.04 m2/g, 4022.15 m2/g and 733.60 m2/g respectively with controlled pore size. The characterized surface area enables the carbon to absorb vapors from gases, and substances from liquids. The surface properties are function of the base materials used in the preparation. Determinations of their adsorptive capacities show that activated carbon prepared from corn cobs has the highest adsorptive capacity. The surface properties are function of the base materials used in the preparation. Determinations of their adsorptive capacities show that activated carbon prepared from corn cobs has the highest adsorptive capacity.

Preparation and Characterization of Single and Mixed Activated Carbons Derived from Coconut Shell and Palm Kernel Shell through Chemical Activation Using Microwave Irradiation System

2017 ◽  
Vol 889 ◽  
pp. 215-220 ◽  
Author(s):  
Siti Anis Mohd Amran ◽  
Khudzir Ismail ◽  
Azil Bahari Alias ◽  
Syed Shatir Asghrar Syed-Hassan ◽  
Ali H. Jawad
Keyword(s):  
Activated Carbon ◽  
Pore Size ◽  
Iodine Number ◽  
Average Pore Size ◽  
Palm Kernel ◽  
Coconut Shell ◽  
Activation Process ◽  
Average Pore ◽  
Palm Kernel Shell ◽  
Percentage Removal

Single and mixed coconut shell (CS) and palm kernel shell (PKS) were successfully converted to activated carbon by using potassium hydroxide (KOH) as activating agent. Mixed activated carbon was produced from coconut shell: palm kernel shell at different KOH concentrations of 30%, 40% and 50%. Activation process was performed in a conventional microwave oven at fixed power and time of 600W and 20 minutes respectively. The results showed that activated carbon produced from single and mixed biomass at 40% concentration of KOH exhibited higher adsorption capacity for iodine number and percentage removal of MB with comparison to 30% and 50% of KOH concentrations. The highest BET surface area of 441.19 m2/g was obtained by CSAc-40. Further both CSAc-40 and PKSAc-40 produced an average pore size diameter of less than 2.0 nm which is in the range of micropore region. On contrary, the mixed CSPKSAc-40 produced an average pore size diameter of 6.0 nm which is in the region of mesopore. All the CSAc-40, PKSAc-40 and mixed CSPKSAc-40 showed similar adsorption trend for iodine number and percentage removal of MB. Interestingly, this finding showed that in the mixed activated carbon some chemical reactions might have occurred during the activation process producing mesoporous instead of microporous as obtained by the single biomass activated carbon.

Relationship between the Activated Carbon Surface Area and Adsorption Model Coefficients for Removal of Phenol from Water

1995 ◽  
Vol 30 (2) ◽  
pp. 325-338 ◽  
Author(s):  
Peter Samaras ◽  
Evan Diamadopoulos ◽  
George P. Sakellaropoulos
Keyword(s):  
Mass Transfer ◽  
Activated Carbon ◽  
Surface Area ◽  
Activated Carbons ◽  
Carbon Surface ◽  
Adsorptive Capacity ◽  
Mineral Matter ◽  
Transfer Coefficients ◽  
Mass Transfer Coefficients ◽  
Commercial Carbon

Abstract The present study investigated the relationship between the activated carbon surface area, as measured by the BET nitrogen adsorption method, and its adsorptive capacity. Aqueous solutions of phenol at pH 7 were used. The activated carbons were produced in the laboratory from raw and demineralized lignite. Adsorption experiments took place under equilibrium or kinetic conditions and the results were simulated by mathematical modelling. Freundlich and Langmuir models were used to describe equilibrium, while the Peel-Benedek non-equilibrium model was applied for the kinetic study. The results showed that for activated carbons produced from different starting materials, the adsorptive capacities could not be solely explained by their BET surface area. While laboratory-made activated carbons with a surface area of 300 m2/g demonstrated similar capacities under equilibrium, their kinetic behaviour was different. Activated carbon produced from raw lignite showed faster kinetics, due to wider porosity, which was facilitated by the mineral matter during activation. These results were in agreement with the mass transfer coefficients in macropores and micropores estimated by the Peel-Benedek model. Comparison of a laboratory-made activated carbon, with a surface area of 500m2/g, with a commercial activated carbon having twice the surface area showed that the maximum adsorptive capacity under equilibrium of the commercial carbon was only 35% higher than that of the lab-made carbon. Yet, the mass transfer coefficients of the commercial carbon were one to two orders of magnitude higher than those of the laboratory-produced carbon. Finally, the use of the qualitative D-R plots has been suggested to elucidate the porous structure of the activated carbons.

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.

Microwave Preparation of Modified Activated Carbons for Phenol Adsorption in Aqueous Solution

2013 ◽  
Vol 726-731 ◽  
pp. 1883-1889
Author(s):  
Brim Stevy Ondon ◽  
Bing Sun ◽  
Zhi Yu Yan ◽  
Xiao Mei Zhu ◽  
Hui Liu
Keyword(s):  
Aqueous Solution ◽  
Activated Carbon ◽  
Adsorption Capacity ◽  
Activated Carbons ◽  
Microwave Energy ◽  
Adsorptive Capacity ◽  
Obvious Effect ◽  
Phenol Adsorption ◽  
Adsorption Capacities ◽  
Modified Activated Carbons

Microwave energy was used to prepare modified activated carbons (GAC, GAC/MW, GAC/Ni, and GAC/Cu). The modified activated carbons were used for phenol adsorption in aqueous solution. The adsorption conditions were optimized. Adsorption capacities of the different modified activated carbons were evaluated. The effect of microwave pretreatment of activated carbons was investigated. A comparative study on the activated carbons adsorption capacities was also investigated. Under optimal conditions the results showed that there was no obvious effect on activated carbons adsorption when rising temperature and pH during the adsorption process. Stirring has a very high effect on the activated carbons adsorption capacity. The adsorption capacity of the modified activated carbons reaches 95%. MW/GAC, GAC/Ni and GAC/Cu adsorptive capacity was higher compared to the Granulated Activated Carbon (GAC) used as received. GAC treated with microwave energy has highest adsorption capacity. The adsorption capacity of GAC loaded with ion Ni2+ is higher than the activated carbon loaded with Cu2+. The untreated GAC has the lowest adsorption capacity. These results can be explained by the effect of microwave irradiation on GAC.The activated carbon loaded with Ni2+ adsorbs more microwave energy than the GAC loaded with Cu2+.

Vitamin B3 Adsorbed onto Activated Carbons and their Release Kinetics in Different Media

2011 ◽  
Vol 233-235 ◽  
pp. 697-700
Author(s):  
Xia Yang ◽  
Tao Zhang ◽  
Yao Ding ◽  
Jun Bo Li ◽  
Jia Guo
Keyword(s):  
Activated Carbon ◽  
Activated Carbons ◽  
Release Kinetics ◽  
Gastric Fluid ◽  
Simulated Gastric Fluid ◽  
Adsorptive Capacity ◽  
Vitamin B ◽  
Simulated Intestinal Fluid ◽  
Mathematical Simulations ◽  
Release Processes

The adsorption of vitamin B3 (VPP) by activated carbons and their release processes in the distilled water, simulated gastric fluid and simulated intestinal fluid were investigated. The adsorptive capacity of the activated carbon for VPP was 94.91 mg/g. Simulated gastric fluid could promote the release of VPP adsorbed by the activated carbon, and the cumulative percentage of VPP released was 76.36%. Based on three commonly-used kinetic models for drug release, mathematical simulations were carried out. It was found that the release processes of VPP in three different media could be fitted well by the Higuchi model Q = kt1/2 + C.

Comparison Study on Adsorption and Removal of Antimony from Acidic Aqueous Solution by Activated Carbons and Machine-Made Charcoal

2013 ◽  
Vol 779-780 ◽  
pp. 1600-1606 ◽  
Author(s):  
Miao Jia ◽  
Ji Wei Hu ◽  
Jin Luo ◽  
Su Ming Duan ◽  
Zhi Bin Li ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Activated Carbon ◽  
Adsorption Capacity ◽  
Activated Carbons ◽  
Solution Concentration ◽  
Adsorptive Capacity ◽  
Acidic Aqueous Solution ◽  
Constant Rate ◽  
Methylene Blue Number ◽  
Relationship Of

Adsorption effects of three kinds of activated carbons and a type of machine-made charcoal on the removal of antimony from acidic aqueous solution were investigated and compared. With an initial antimony solution concentration of 1000 μgL-1, the antimony adsorption by selected adsorbents were found to descend in the following order: machine-made charcoal (52.4%) > coconut activated carbon (42.6%) > coal based activated carbon (31.1%) > apricot stone based activated carbon (24.6%). The machine-made charcoal has the best adsorption capacity with a maximum adsorption values of 523.76 μgL-1. Five kinetic models were used for the fitting of the process of antimony adsorption, including Elovich, parabola diffusion, second order, first order and double-constant. Results showed that parabola diffusion and double-constant rate equation were the most suitable models in describing the relationship of antimony adsorption with time in acidic aqueous solution, implying that the adsorption kinetics of the antimony by the selected adsorbents in water might be a surface diffusion. Three adsorptive capacity indicators (iodine number, methylene blue number and phenol number) were determined in this paper. However, machine-made charcoal, which has a relatively high adsorption capacity, is of the lowest levels of the adsorptive capacity indicators. Thus, some complex mechanisms might be involved for the antimony adsorption by the machine-made charcoal, consequently considering the mechanism for the adsorption of antimony by the charcoal has not been verified, a further study still needs to be done.

scholarly journals Representative Pores: An Efficient Method to Characterize Activated Carbons

2021 ◽  
Vol 8 ◽  
Author(s):  
Jose Carlos Alexandre de Oliveira ◽  
Ana Luisa Galdino ◽  
Daniel V Gonçalves ◽  
Pedro F. G. Silvino ◽  
Celio L. Cavalcante ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Pore Size ◽  
Large Scale ◽  
Activated Carbons ◽  
Size Analysis ◽  
Carbonaceous Materials ◽  
Structure Property ◽  
Property Relationship ◽  
Pore Size Analysis ◽  
Structure Property Relationship

We propose a pore size analysis methodology for carbonaceous materials that reduces complexity while maintaining the significant elements of the structure-property relationship. This method chooses a limited number of representative pores, which will constitute a simplified kernel to describe the pore size distribution (PSD) of an activated carbon. In this study we use the representative pore sizes of 7.0, 8.9, 18.5, and 27.9 Å and N2 isotherms at 77.4 K to determine the PSD which is later applied to predict the adsorption equilibrium of other gases. In this study we demonstrate the ability to predict adsorption of different gas molecules on activated carbon from the PSD generated with representative pores (PSDrep). The methodology allows quick solutions for large-scale calculations for carbonaceous materials screening, in addition to make accessible an easily understood and prompt evaluation of the structure-property relationship of activated carbons. In addition to the details of the methodology already tested in different fields of application of carbonaceous materials, we present a new application related to the removal of organic contaminants in dilute aqueous solutions.

scholarly journals Prediction of the phenol removal capacity from water by adsorption on activated carbon

2021 ◽  
Author(s):  
Ana Luísa Galdino ◽  
José C. A. Oliveira ◽  
Madson L. Magalhaes ◽  
Sebastião M. P. Lucena
Keyword(s):  
Activated Carbon ◽  
Phenolic Compounds ◽  
Pore Size ◽  
Predictive Models ◽  
Activated Carbons ◽  
The Other ◽  
Phenol Removal ◽  
Trial And Error ◽  
Removal Capacity ◽  
Predictive Approach

Abstract Despite the improvement in understanding the structure of the activated carbons, the procedure for developing new carbonaceous materials suitable for the removal of phenolic compounds is still largely based on trial and error. Until now there are no predictive models to assist in the selection or synthesis of these adsorbents. Here, we apply molecular simulation in order to better understand the pore size – adsorption relationship in activated carbons. We simulated a set of phenol isotherms for different carbon pore sizes (8.9, 18.5 and 27.9 Å), named representative pores. The pore size of 8.9 Å is the most efficient in removing diluted phenol in water being effective at concentrations of 1.6 × 10−5 mol/L. The other pores are effective for concentrations of 3 orders of magnitude above this. A predictive approach for phenol removal capacity, based in the representative pore methodology, was proposed and validated for commercial activated carbon. Moreover, we present evidences that this method can be extended to other phenolic compounds.

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