scholarly journals Biogas Purification: A Comparison of Adsorption Performance in D4 Siloxane Removal Between Commercial Activated Carbons and Waste Wood-Derived Char Using Isotherm Equations

Processes ◽  
2019 ◽  
Vol 7 (10) ◽  
pp. 774 ◽  
Author(s):  
Papurello ◽  
Gandiglio ◽  
Kafashan ◽  
Lanzini
Keyword(s):  
Adsorption Capacity ◽  
Adsorption Isotherms ◽  
Activated Carbons ◽  
Biogas Production ◽  
Pollutant Emissions ◽  
Low Concentrations ◽  
Biogas Purification ◽  
Porous Volume ◽  
Trace Compounds ◽  
Isotherm Equations

Biogas production from organic waste could be an option to reduce landfill and pollutant emissions into air, water, and soil. These fuels contain several trace compounds that are crucial for highly efficient energy generators or gas injection into the grid. The ability of adsorbents to physically remove such adsorbates was investigated using adsorption isotherms at a constant temperature. We experimentally modelled isotherms for siloxane removal. Siloxanes were considered due to their high impact on energy generators performance even at low concentrations. Octamethylcyclotetrasiloxane was selected as a model compound and was tested using commercially available carbon and char derived from waste materials. The results show that recyclable material can be used in an energy production site and that char must be activated to improve its removal performance. The adsorption capacity is a function of specific surface area and porous volume rather than the elemental composition. The most common adsorption isotherms were employed to find the most appropriate isotherm to estimate the adsorption capacity and to compare the sorbents. The Dubinin-Radushkevich isotherm coupled with the Langmuir isotherm was found to be the best for estimating the adsorption capacity.

scholarly journals Experimental Analysis and Model Validation on the Performance of Impregnated Activated Carbons for the Removal of Hydrogen Sulfide (H2S) from Sewage Biogas

Processes ◽  
2019 ◽  
Vol 7 (9) ◽  
pp. 548 ◽  
Author(s):  
Davide Papurello ◽  
Marta Gandiglio ◽  
Andrea Lanzini
Keyword(s):  
Adsorption Capacity ◽  
Organic Waste ◽  
Activated Carbons ◽  
Biogas Production ◽  
Gas Mixture ◽  
Adsorption Model ◽  
Breakthrough Time ◽  
Power Generator ◽  
Langmuir Isotherm Model ◽  
Good Agreement

Organic waste exploitation is crucial for waste emissions restraint in air, soil and water. This type of waste can be exploited to produce biogas, a valuable fuel exploitable for energy purposes. A circular approach for energy production is much cleaner and more sustainable than the traditional linear approach. In this work, organic waste was used for biogas production to feed a highly efficient solid oxide fuel cell power generator, which requires an ultra-purified fuel. Commercial sorbents were experimentally studied in conjunction with a dynamic adsorption model to predict the breakthrough time and organize the material change-over. In the presence of 0.1% oxygen in the gas mixture, AirDep® CKC showed a marked increase in the adsorption capacity (from 3.91 to 84.87 mg/g), overcoming SulfaTrap® R8G (49.91 mg/g). The effect of several operating parameters on adsorption capacity was evaluated: inlet H2S concentration, filter geometry and gas mixture velocity. Experimental data revealed that adsorption capacity increases with initial H2S concentration, following the typical trend of the Langmuir isotherm. Model simulations were in good agreement compared to experimental results, with an average relative error lower than 7%. A sensitivity analysis on the adsorption capacity was accomplished considering parameters from operational and empirical correlations.

Adsorption kinetics and isotherm characteristics of selected endocrine disrupting compounds on activated carbon in natural waters

2009 ◽  
Vol 9 (1) ◽  
pp. 51-58
Author(s):  
A. Assoumani ◽  
L. Favier-Teodorescu ◽  
D. Wolbert
Keyword(s):  
Adsorption Isotherms ◽  
Adsorption Kinetics ◽  
Activated Carbons ◽  
Endocrine Disrupting Compounds ◽  
Langmuir Model ◽  
High Concentration ◽  
Acceptable Error ◽  
Low Concentrations ◽  
Kinetic Coefficients ◽  
Endocrine Disrupting

Bisphenol A (BPA) and ethynylestradiol (EE2), two representative endocrine disrupting compounds (EDCs), were tested for their adsorbabilities onto two powdered activated carbons (PACs). The main aim of the study was to create a prediction tool for the determination of the EDCs adsorbabilities at low ng.L−1 level. Single solute solution adsorption isotherms at high concentrations, for prediction purposes, and low concentrations, for verification of the prediction, were performed for one EDC/PAC couple. Over the whole range of concentration, results showed that the Langmuir-Freundlich model better suits the adsorption phenomenon than the Freundlich or Langmuir model. Kinetics experiments were carried out on the same EDC/PAC couple. HSDM modelling of single solute adsorption kinetics at high concentration allowed determining the kinetic coefficients kf and Ds; both were shown to dominate the mass transfer mechanism. Competitive adsorption isotherms at high and low concentrations showed that downward extrapolation of low concentration adsorption capacities from solely high concentration information results in acceptable error compared to the total range isotherm. The IAST-EBC approach combined with the Langmuir-Freundlich single solute model, for the target compound, and the Langmuir model, for the EBC, appears as an acceptable global model.

scholarly journals Computer Analysis of the Porous Structure of Activated Carbons Derived from Various Biomass Materials by Chemical Activation

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4121
Author(s):  
Mirosław Kwiatkowski ◽  
Elżbieta Broniek
Keyword(s):  
Porous Structure ◽  
Adsorption Isotherms ◽  
Computer Analysis ◽  
Activated Carbons ◽  
Chemical Activation ◽  
Adsorbed Layer ◽  
Dry Mass ◽  
Mass Ratio ◽  
Adsorption Volume ◽  
Homogeneous Surface

In this study, the preparation of activated carbons from various materials of biomass origin by activation with potassium hydroxide and a comprehensive computer analysis of their porous structure and adsorption properties based on benzene (C6H6) adsorption isotherms were carried out. In particular, the influence of the mass ratio of the activator’s dry mass to the char mass on the formation of the microporous structure of the obtained activated carbons was analysed. The summary of the analyses carried out based on benzene adsorption isotherms begged the conclusion that activated carbon with a maximum adsorption volume in the first adsorbed layer and homogeneous surface can be obtained from ebony wood at a mass ratio of the activator to the char of R = 3. The obtained results confirmed the superiority of the new numerical-clustering-based adsorption analysis (LBET) method over simple methods of porous structure analysis, such as the Brunauer–Emmett–Teller (BET) and Dubinin–Raduskevich (DR) methods. The LBET method is particularly useful in the evaluation of the influence of the methods and conditions of production of activated carbons on the formation of their porous structure. This method, together with an appropriate economic analysis, can help in the precise selection of methods and conditions for the process of obtaining activated carbons at specific manufacturing costs, and thus makes it possible to obtain materials that can successfully compete with those of other technologies used in industrial practice and everyday life.

Adsorption Capacity of Y Zeolite Using Organic Solvents such as Adsorbates

2014 ◽  
Vol 805 ◽  
pp. 641-645
Author(s):  
Ana Paula Araújo ◽  
Aline Cadigena Lima Patrício ◽  
Anna Karoline Freires de Sousa ◽  
Mariaugusta Ferreira Mota ◽  
Meiry Glaúcia Freire Rodrigues
Keyword(s):  
Small Molecules ◽  
Adsorption Capacity ◽  
Selective Adsorption ◽  
X Ray Diffraction ◽  
Y Zeolite ◽  
High Adsorption ◽  
X Ray ◽  
Low Concentrations ◽  
Adsorption Of Nitrogen ◽  
Type Zeolite

The zeolites differ from traditional adsorbents for selective adsorption of small molecules, the high adsorption capacity at low concentrations and affinity for organic compounds and unsaturated polar molecules. In this work a Y-type zeolite was synthesized, characterized by x-ray diffraction, scanning electron microscopy and adsorption of nitrogen and subjected to test adsorption capacity where it was found that the Y zeolite has the potential adsorption capacity compared to other materials being studied and marketed.

Enhancement of polycyclic aromatic hydrocarbons removal during anaerobic treatment of urban sludge

2003 ◽  
Vol 48 (4) ◽  
pp. 53-60 ◽  
Author(s):  
E. Trably ◽  
D. Patureau ◽  
J.P. Delgenes
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Sewage Sludge ◽  
Aromatic Hydrocarbons ◽  
Agricultural Soils ◽  
Biogas Production ◽  
Bacterial Consortium ◽  
Anaerobic Treatment ◽  
Biological Degradation ◽  
Low Concentrations ◽  
Polycyclic Aromatic

Anaerobically stabilized sewage sludge has potential to partially substitute synthetic fertilizers. The main risk with the recycling of urban sludge on agricultural soils is the accumulation of unwanted products, such as trace metals and organic micropollutants. In this context, the polycyclic aromatic hydrocarbons (PAHs) are particularly monitored because of their toxic properties at low concentrations and their high resistance to biological degradation. The aim of the present study was to optimize PAHs removal during anaerobic digestion of contaminated sewage sludge. Thirteen PAHs were monitored in laboratory-scale anaerobic bioreactors under mesophilic (35°C) and thermophilic (55°C) methanogenic conditions. Abiotic losses were statistically significant for the lightest PAHs, such as fluorene, phenanthrene and anthracene. It was shown that PAH removal was due to a specific biological activity. Biological PAHs removal was significantly enhanced by an increase of the temperature from 35°C to 55°C, especially for the heaviest PAHs. Bioaugmentation experiment was also performed by addition of a PAH-adapted bacterial consortium to a non-acclimated reactor. Significant enhancement of PAHs removal was observed. It was finally shown that PAH removal efficiencies and methanogenic performances were closely linked. The rate of biogas production may be used as an indicator of bacterial activity on PAH removal.

scholarly journals Can hydrogen enriched biogas be used as domestic fuel? - Part II: Pollutants Emission from Combustion of Biogas/H2/air Fuel Mixture

2021 ◽  
Vol 28 (2) ◽  
pp. 68-74
Author(s):  
Udaya Kahangamage ◽  
Yi Chen ◽  
Quan Zhou ◽  
Chun Wah Leung
Keyword(s):  
Thermal Performance ◽  
Biogas Production ◽  
Fuel Mixture ◽  
Pollutant Emissions ◽  
Emission Characteristics ◽  
Environmentally Conscious ◽  
Performance And Emission ◽  
Wide Range ◽  
Pollutants Emission ◽  
Domestic Fuel

Biogas is considered a sustainable source of energy which is largely untapped owing to its inherent weaknesses such as low thermal performance and potentially harmful emissions. Its thermal performance and emission characteristics can be enhanced through the technique of enriching with higher grade fuel. In this research study, biogas enriched with hydrogen was tested for its emission characteristics. A synthetic biogas identified as BG60 (60% CH4 and 40% CO2) enriched with 20% hydrogen (80%BG60-20%H2) was used for the test. Experiments were carried out for combustion of the enriched gas for a wide range of Reynolds numbers and equivalence ratios. The results indicate that the enriched fuel emits less CO and NOx than commonly used domestic fuel LPG. It also has a better thermal and emission performance than BG60. The low pollutant emissions compared with LPG, use of renewable feedstock for biogas production, and competitive cost may make the blended 80%BG60-20%H2 an attractive sustainable alternative domestic fuel choice for environmentally conscious urban dwellers of modern cities.

scholarly journals Key Factors for Activated Carbon Adsorption of Pharmaceutical Compounds from Wastewaters: A Multivariate Modelling Approach

Water ◽  
2022 ◽  
Vol 14 (2) ◽  
pp. 166
Author(s):  
Rui M. C. Viegas ◽  
Ana S. Mestre ◽  
Elsa Mesquita ◽  
Miguel Machuqueiro ◽  
Marta A. Andrade ◽  
...  
Keyword(s):  
Adsorption Capacity ◽  
Activated Carbons ◽  
Univariate Analysis ◽  
Pharmaceutical Compounds ◽  
Pls Regression ◽  
Short Term ◽  
Latent Structures ◽  
The Impact ◽  
Inorganic Matrix ◽  
Modelling Approach

Projection to Latent Structures (PLS) regression, a generalization of multiple linear regression, is used to model two datasets (40 observed data points each) of adsorption removal of three pharmaceutical compounds (PhCs), of different therapeutic classes and physical–chemical properties (carbamazepine, diclofenac, and sulfamethoxazole), from six real secondary effluents collected from wastewater treatment plants onto different powdered activated carbons (PACs). For the PLS regression, 25 descriptors were considered: 7 descriptors related to the PhCs properties, 10 descriptors related to the wastewaters properties (8 related to the organic matrix and 2 to the inorganic matrix), and 8 descriptors related to the PACs properties. This modelling approach showed good descriptive capability, showing that hydrophobic PhC-PAC interactions play the major role in the adsorption process, with the solvation energy and log Kow being the most suitable descriptors. The results also stress the importance of the competition effects of water dissolved organic matter (DOM), namely of its slightly hydrophobic compounds impacting the adsorption capacity or its charged hydrophilic compounds impacting the short-term adsorption, while the water inorganic matrix only appears to impact PAC adsorption capacity and not the short-term adsorption. For the pool of PACs tested, the results point to the BET area as a good descriptor of the PAC capacity, while the short-term adsorption kinetics appears to be better related to its supermicropore volume and density. The improvement in these PAC properties should be regarded as a way of refining their performance. The correlations obtained, involving the impact of water, PhC and PAC-related descriptors, show the existence of complex interactions that a univariate analysis is not sufficient to describe.

scholarly journals Dysprosium Removal from Water Using Active Carbons Obtained from Spent Coffee Ground

2019 ◽  
Author(s):  
Lorena Alcaraz ◽  
María Esther Escudero ◽  
Francisco J. Alguacil ◽  
Irene Llorente ◽  
Ana Urbieta ◽  
...  
Keyword(s):  
Adsorption Capacity ◽  
Activated Carbons ◽  
Chemical Study ◽  
Bet Surface Area ◽  
Maximum Adsorption Capacity ◽  
Solution Ph ◽  
Microporous Material ◽  
Physico Chemical ◽  
Spent Coffee Ground ◽  
Coffee Ground

This paper describes the physico-chemical study of the adsorption of dysprosium (Dy3+) in aqueous solution onto two types of activated carbons synthesized from spent coffee ground. KOH activated carbon is a microporous material with a specific BET surface area of 2330 m2·g-1 and pores with a diameter of 3.2 nm. Carbon activated with water vapor and N2 is a solid mesoporous, with pores of 5.7 nm in diameter and a specific surface of 982 m2·g-1. A significant dependence of the adsorption capacity on the solution pH was found, while it does not depend significantly neither on the dysprosium concentration nor on the temperature. A maximum adsorption capacity of 31.26 mg·g-1 and 33.52 mg·g-1 for the chemically and physically activated carbons, respectively, were found. In both cases, the results obtained from adsorption isotherms and kinetic study were better fit to a Langmuir model and a pseudo-second-order kinetics. In addition, thermodynamic results indicate that dysprosium adsorption onto both activated carbons is an exothermic, spontaneous and favorable process.

scholarly journals Exploratory study to assess the impact of chitosan /bentonite ratio on the metal removal capacity of chitosan modified bentonite clay

2016 ◽  
Vol 18 (2) ◽  
pp. 437-443 ◽  
Keyword(s):  
Physical Properties ◽  
Adsorption Capacity ◽  
Adsorption Isotherms ◽  
Exploratory Study ◽  
Metal Removal ◽  
Bentonite Clay ◽  
Settling Rate ◽  
Modified Bentonite ◽  
Removal Capacity ◽  
The Impact

<div> <p>Adsorption is one of the methods that can be used for metal removal. In this study five metals were used cadmium, chromium, lead, copper and Nickel (Cd, Cr, Pb, Cu, and Ni) over a concentration range from 0.8 to about 7 mg l<sup>-1</sup> for each metal. Adsorbents were prepared with increasing chitosan to bentonite ratio from 0 to 0.67 g chitosan/g bentonite. The study showed that adsorption of metals on plain bentonite and chitosan modified bentonite can fit well with Langmuir and Freundlich adsorption isotherms. Furthermore, the bentonite adsorption capacity will decrease with the increase of chitosan/bentonite ratio. This study concluded that bentonite is a good adsorbent. However, the applicability of bentonite as potential adsorbent may be limited by its physical properties such as slow settling rate and difficulty to use it as an adsorbent in adsorption columns. Despite the decrease of maximum theoretical adsorption capacity as a result of chitosan modification, the addition of small amount of chitosan can improve the physical characteristics of bentonite clay to be used as an adsorbent.&nbsp;</p> </div> <p>&nbsp;</p>

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