Preparation and Characterization of Activated Carbons Based on Lignocellulosic Residues

2013 ◽  
Vol 856 ◽  
pp. 69-73 ◽  
Author(s):  
Cibele C.O. Alves ◽  
Pablo D. Rocha ◽  
Adriana S. Franca ◽  
Leandro S. Oliveira
Keyword(s):  
Activated Carbons ◽  
Press Cake ◽  
Lignocellulosic Residues ◽  
Adsorption Mechanisms ◽  
Corn Cobs ◽  
Adsorption Capacities ◽  
Precursor Material ◽  
Coffee Grounds ◽  
Physical And Chemical

This paper presents a comparative evaluation of three lignocellulosic residues (corn cobs, spent coffee grounds and Raphanus sativus press cake) as precursor materials in the production of activated carbons (ACs). Results indicate that the precursor material has a significant effect in both physical and chemical aspects of the adsorbent as well as on the adsorption mechanisms. Highest and lowest values of iodine number and density were observed for ACs based on press cake and corn cobs, respectively. Regardless of the observed differences in surface chemical make-up and adsorption mechanisms, all employed materials were deemed adequate for adsorbent production, since the prepared ACs presented adsorption capacities similar or even higher than those of commercial ACs and other residue-based adsorbents.

Comparative Evaluation of Activated Carbons Prepared by Thermo-Chemical Activation of Lignocellulosic Residues Aiming at Phenol Removal

2014 ◽  
Vol 1016 ◽  
pp. 309-314 ◽  
Author(s):  
Cibele C.O. Alves ◽  
Adriana S. Franca ◽  
Leandro S. Oliveira
Keyword(s):  
Comparative Evaluation ◽  
Activated Carbons ◽  
Chemical Activation ◽  
Maximum Adsorption Capacity ◽  
Phenol Removal ◽  
Spent Coffee Grounds ◽  
Lignocellulosic Residues ◽  
Precursor Material ◽  
Coffee Grounds ◽  
Physical And Chemical

This paper presents a comparative evaluation of three lignocellulosic residues (coffee husks, spent coffee grounds and pequi husks) as precursor materials in the production of activated carbons (ACs). Results indicate that the precursor material has a significant effect in both physical and chemical aspects of the adsorbent, with the AC based on spent coffee grounds being the most effective for phenol removal, with maximum adsorption capacity comparable to commercial ACs.

scholarly journals Preparation and Characterization of Activated Carbons fromPartheniumbiomass by Physical and Chemical Activation Techniques

2010 ◽  
Vol 7 (4) ◽  
pp. 1314-1319 ◽  
Author(s):  
Rajeshwari Sivaraj ◽  
Venckatesh Rajendran ◽  
G. Sangeetha Gunalan
Keyword(s):  
Activated Carbons ◽  
Chemical Activation ◽  
Perennial Weed ◽  
Food Grains ◽  
Characteristic Features ◽  
Activation Conditions ◽  
Physical And Chemical ◽  
Efficient Adsorbent ◽  
Potential Use

Parthenium hysterphorous(Linn), a perennial weed of no known beneficial use was introduced as a containment of food grains imported from US with P1480 scheme. The colonization efficiency of the weed was much higher than other indigenous weeds resulting in the reduction of cultivable areas of agricultural lands. Therefore, attention was focused to find out the potential use of its biomass. In the present study the preparation and characterization of activated carbons by physical and chemical activation methods are reported and aims to prepare relatively well developed porous activated carbons as well as study various conditions and parameters that were involved during the process. Among the carbons prepared Zncl2impregnated carbon at the ratio of 1 was found to possess the characteristic features of an efficient adsorbent. Experimental results showed that pyrolytic and activation conditions leading to various final average temperatures had significant effect on the properties of activated carbons prepared.

DESCRIPTION OF DIFFERENT SOLID ADSORBENT SURFACES ADSORPTION MECHANISMS BASED ON A SEQUENTIAL DECOMPOSITION OF ISOTHERMS

2013 ◽  
Vol 20 (02) ◽  
pp. 1350022 ◽  
Author(s):  
PABLO D. HUMPOLA ◽  
HECTOR S. ODETTI ◽  
ETHEL S. E. FLORES ◽  
JOSE LUIS VICENTE
Keyword(s):  
Activated Carbons ◽  
Behavior Changes ◽  
Step Method ◽  
Adsorption Mechanisms ◽  
Solid Adsorbent ◽  
Adsorption Capacities ◽  
Solid Substrates ◽  
Different Temperatures ◽  
Low Pressures ◽  
Sequential Decomposition

In order to analyze the adsorption capacities of different solid substrates, we present a multi-step method to separately study the isotherm at different pressure ranges (steps). The method is based on simple gas isotherm measurements (nitrogen, methane, carbon dioxide, argon, and oxygen) and is tested to describe the adsorption process and characterize a graphitized surface (GCB) and two different granular activated carbons (GAC). The GCB isotherms are described as a sum of Fowler-Guggenheim-Langmuir shifted curves; isotherm behaviors are quite similar at different temperatures, but change below a certain threshold. In GAC the first steps show the same adsorption characteristics at low pressures (Dubinin's description), but this behavior changes at higher pressure regimes, which allows one to elucidate how heterogeneous the surfaces are or how strong the interactions between adsorbed molecules are for this marginal adsorption to occur. We tested different approaches (from BET multilayer to Aranovich) and found quite different features. We finally conclude that if the description of the adsorption on complex substrates, such as those presented here, is carried using only one model, e. g. Dubinin in case of GACs, the resulting characteristics of the adsorbent would be very biased.

scholarly journals Adsorption of Metolachlor and Its Transformation Products, ESA and OXA, on Activated Carbons

2021 ◽  
Vol 11 (16) ◽  
pp. 7342
Author(s):  
Alicia Gomis-Berenguer ◽  
Pauline Sidoli ◽  
Benoît Cagnon
Keyword(s):  
Chemical Composition ◽  
Potassium Carbonate ◽  
Adsorption Process ◽  
Carbon Materials ◽  
Activated Carbons ◽  
Transformation Products ◽  
Lignocellulosic Residues ◽  
Adsorption Capacities ◽  
Commercial Carbon ◽  
Herbicide Metolachlor

Three activated carbons from lignocellulosic residues and a commercial carbon have been tested for the removal of the herbicide metolachlor and its two degradation transformation products, named ESA and OXA, in aqueous solutions. The kinetics and equilibrium adsorption were studied for the four materials, showing higher adsorption capacities for the three molecules on the carbon materials chemically activated by potassium carbonate, mainly associated with its greater porous development, especially in the range of microporosity. Additionally, the chemical composition of the adsorbents also highlighted their important influence on the ESA and OXA adsorption process. The efficient adsorption of both compounds—even at low initial concentrations—allows a removal efficiency of up to 80% to be reached, revealing promising perspectives for the use of biomass-derived carbon materials for the elimination of not only the herbicide metolachlor, but also its degradation compounds from contaminated wastewater.

scholarly journals Novel Correlations between Spectroscopic and Morphological Properties of Activated Carbons from Waste Coffee Grounds

Processes ◽  
2021 ◽  
Vol 9 (9) ◽  
pp. 1637
Author(s):  
Egle Rosson ◽  
Paolo Sgarbossa ◽  
Mirto Mozzon ◽  
Federico Venturino ◽  
Sara Bogialli ◽  
...  
Keyword(s):  
Solid State Nmr ◽  
Preparation Method ◽  
Activated Carbons ◽  
Chemical Characterization ◽  
Textural Properties ◽  
Morphological Properties ◽  
Experimental Conditions ◽  
Coffee Grounds ◽  
Adsorption Processes

Massive quantities of spent coffee grounds (SCGs) are generated by users around the world. Different processes have been proposed for SCG valorization, including pyrolytic processes to achieve carbonaceous materials. Here, we report the preparation of activated carbons through pyrolytic processes carried out under different experimental conditions and in the presence of various porosity activators. Textural and chemical characterization of the obtained carbons have been achieved through Brunauer–Emmett–Teller (BET), ESEM, 13C solid state NMR, XPS, XRD, thermogravimetric and spectroscopic determinations. The aim of the paper is to relate these data to the preparation method, evaluating the correlation between the spectroscopic data and the physical and textural properties, also in comparison with the corresponding data obtained for three commercial activated carbons used in industrial adsorption processes. Some correlations have been observed between the Raman and XPS data.

scholarly journals Valorisation des coques de noyaux de Balanites aegyptiaca (L.) Del. et Hyphaene thébaica (L.) Mart. pour l’élaboration et caractérisation de Charbons Actifs; application pour l’élimination du chrome

2018 ◽  
Vol 14 (21) ◽  
pp. 195
Author(s):  
Sanda Mamane Ousmaila ◽  
Siragi Dounounou Boukari Maâzou ◽  
Malam Alma Maman Mousbahou ◽  
Natatou Ibrahim
Keyword(s):  
Specific Surface ◽  
Adsorption Process ◽  
Activated Carbons ◽  
Correlation Coefficients ◽  
Balanites Aegyptiaca ◽  
Adsorption Capacities ◽  
Calculated Parameter ◽  
Parameter Values

This paper focuses on the development and characterization of activated carbons to agro-food waste by activation with ortho phosphoric acid, and its application in the elimination of chromium in solution. The functions were determined by Bohem's method. The thermal analysis was carried out on the hulls of waste. The specific surface area and the pore volume are determined according to the method of Brunauer, Emmet and Teller and the method of Barret, Joyner and Halenda respectively. The Lagergren and Ho and McKay models were used for the kinetic study of chromium removal. Those of Langmuir and Freundlich have to do with the study of isotherms and the law of Van't Hoff and Gibbs in relation to the determination of thermodynamic parameters. The results obtained show that the surface functions are acidic in nature. Activated carbon from balanites aegyptiaca has developed a specific surface (1560.7401 m2 g -1 ) that exceeds that of Hyphaene thebaica (722.1510 m2 g -1 ). The pseudo-order 2 kinetics (Ho and McKay) better describe the adsorption with correlation coefficients close to unity. Adsorption capacities and rate constants prove rapid adsorption at the early stages. For the isotherms, the calculated parameter values are much more consistent with those of the Langmuir isotherm. ∆Gads 0 < 0 ; the adsorption process is spontaneous. Moreover, the values are in the range of a physisorption.

Characterization of defects in tabular silver halide grains

1990 ◽  
Vol 48 (4) ◽  
pp. 1046-1047
Author(s):  
C. Goessens ◽  
D. Schryvers ◽  
J. Van Landuyt ◽  
A. Verbeeck ◽  
R. De Keyzer
Keyword(s):  
Radiation Damage ◽  
Silver Halide ◽  
Chemical Characteristics ◽  
X Ray ◽  
Free Region ◽  
Central Defect ◽  
Crystallographic Defects ◽  
Physical And Chemical ◽  
Two Sides

Silver halide grains (AgX, X=Cl,Br,I) are commonly recognized as important entities in photographic applications. Depending on the preparation specifications one can grow cubic, octahedral, tabular a.o. morphologies, each with its own physical and chemical characteristics. In the present study crystallographic defects introduced by the mixing of 5-20% iodide in a growing AgBr tabular grain are investigated. X-ray diffractometry reveals the existence of a homogeneous Ag(Br1-xIx) region, expected to be formed around the AgBr kernel. In fig. 1 a two-beam BF image, taken at T≈100 K to diminish radiation damage, of a triangular tabular grain is presented, clearly showing defect contrast fringes along four of the six directions; the remaining two sides show similar contrast under relevant diffraction conditions. The width of the central defect free region corresponds with the pure AgBr kernel grown before the mixing with I. The thickness of a given grain lies between 0.15 and 0.3 μm: as indicated in fig. 2 triangular (resp. hexagonal) grains exhibit an uneven (resp. even) number of twin interfaces (i.e., between + and - twin variants) parallel with the (111) surfaces. The thickness of the grains and the existence of the twin variants was confirmed from CTEM images of perpendicular cuts.

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