Study of the physical and chemical characteristics of a range of chemically treated, lignite based carbons

1997 ◽  
Vol 35 (7) ◽  
pp. 21-27 ◽  
Author(s):  
Orna Duggan ◽  
Stephen J. Allen
Keyword(s):  
Activated Carbons ◽  
Copper Ions ◽  
Mercury Porosimetry ◽  
Metal Compounds ◽  
Surface Areas ◽  
Preferential Adsorption ◽  
Chemical Morphology ◽  
Red Dye ◽  
Langmuir Constants ◽  
Physical And Chemical

It is already known that activated carbons may be developed by chemically treating the adsorbent precursor to produce a carbon which displays improved adsorption characteristics and possibly preferential adsorption of one particular molecule over another. For the purposes of this study, a selection of carbons produced by the chemical treatment of N.I. lignite were studied. A range of transition metal compounds were used for the study as oxo-complexes of these metals have previously been associated with micropore widening in activated charcoal cloth. The adsorption of different concentrations of aqueous solutions of phenol, basic red dye and copper ions onto each carbon was examined. The adsorption equilibrium isotherms obtained for the carbons were plotted to obtain the Freundlich and Langmuir constants for each system. The adsorption capacity of each carbon was found to depend on its method of activation. In order to make a connection between the adsorptive behaviour of each carbon and its method of treatment, the physical and chemical morphology of the carbon was studied. Gas sorption on the Fisons instruments Sorptomatic 1900 and mercury porosimetry on the Fisons instruments Porosimeter 2000 were the methods used to study the micro-, meso- and macropore volumes, surface areas and pore radius distributions of the carbon samples. Infra-red spectroscopy showed that only minor changes occurred in the surface functional groups between the untreated lignite and the carbons and also between carbons themselves. Finally data obtained for these carbons was compared with the results of a previous study of untreated Northern Ireland lignite and lignite chars.

scholarly journals Waste biomass as sources for activated carbon production-A review

2013 ◽  
Vol 47 (4) ◽  
pp. 347-364 ◽  
Author(s):  
MS Islam ◽  
MA Rouf
Keyword(s):  
Activated Carbon ◽  
Process Parameters ◽  
Activated Carbons ◽  
Low Cost ◽  
Process Conditions ◽  
Waste Biomass ◽  
Active Carbons ◽  
Carbon Production ◽  
Surface Areas ◽  
Physical And Chemical

A review of the production of activated carbons from waste biomass has been presented. The effects of various process parameters on the pyrolysis stage have been reviewed. Influences of activating conditions, physical and chemical, on the active carbon properties have been discussed. Under certain process conditions several active carbons with BET surface areas, ranging between 250 and 2410 m2/g and pore volumes of 0.022 and 91.4 cm3/g, have been produced. A comparison in characteristics and uses of activated carbons from waste biomass with those of commercial carbons has been made. Waste biomass being highly efficient, low cost and renewable sources of activated carbon production. Bangladesh J. Sci. Ind. Res. 47(4), 347-364, 2012 DOI: http://dx.doi.org/10.3329/bjsir.v47i4.14064

The Varied Causes of Color in Glass

1985 ◽  
Vol 61 ◽  
Author(s):  
K. Nassau
Keyword(s):  
Chalcogenide Glasses ◽  
Water Ligand ◽  
Ligand Field ◽  
Energy Bands ◽  
Metal Compounds ◽  
Chemical Mechanisms ◽  
Doped Glasses ◽  
Blue Eyes ◽  
Physical And Chemical ◽  
Ice Water

ABSTRACTAll but two of the fifteen physical and chemical mechanisms which are necessary to explain all the varied causes of color apply in one way or another to glass. These fifteen causes of color derive from a variety of physical and chemical mechanisms and are summarized in five groups with concentration on those mechanisms that apply to glass and the related glazes and enamels. Vibrations and simple excitations explain the colors of incandescence (e.g. flames, hot glass), gas excitations (neon tube, aurora), and vibrations and rotations (blue ice, water, glasses based on water). Ligand field effect colors are seen in transition metal compounds (turquoise, chrome oxide green, glasses based on copper sulfate) and impurities (ruby, emerald, many doped glasses). Molecular orbitals explain the colors of organic compounds (indigo, chlorophyll, organic glasses) and charge transfer compounds (blue sapphire, lapis lazuli, “beer-bottle” brown and chromate glasses). Energy bands are involved in the colors of metals and alloys (gold, brass, glassy metals), of semiconductors (cadmium yellow, vermillion, chalcogenide glasses), doped semiconductors (blue and yellow diamond), and color centers (amethyst, topaz, irradiated glass). Geometrical and physical optics are involved in the colors derived from dispersive refraction (rainbow, green flash, glass prism spectrum), scattering (blue sky, blue eyes, red sunset, ruby gold and opal glasses), interference (soap bubbles, iridescent beetles, cracks in glasses, interference filters), and diffraction (the corona aureole, diffraction grating spectrum).

scholarly journals The Effects of Methane Storage Capacity Using Upgraded Activated Carbon by KOH

2018 ◽  
Vol 8 (9) ◽  
pp. 1596 ◽  
Author(s):  
Jung Park ◽  
Gi Lee ◽  
Sang Hwang ◽  
Ji Kim ◽  
Bum Hong ◽  
...  
Keyword(s):  
Surface Area ◽  
Storage Capacity ◽  
Activated Carbons ◽  
Chemical Activation ◽  
High Surface ◽  
Heat Of Adsorption ◽  
Low Grade ◽  
Surface Areas ◽  
Ch4 Adsorption ◽  
Ch4 Storage

In this study, a feasible experiment on adsorbed natural gas (ANG) was performed using activated carbons (ACs) with high surface areas. Upgraded ACs were prepared using chemical activation with potassium hydroxide, and were then applied as adsorbents for methane (CH4) storage. This study had three principal objectives: (i) upgrade ACs with high surface areas; (ii) evaluate the factors regulating CH4 adsorption capacity; and (iii) assess discharge conditions for the delivery of CH4. The results showed that upgraded ACs with surface areas of 3052 m2/g had the highest CH4 storage capacity (0.32 g-CH4/g-ACs at 3.5 MPa), which was over two times higher than the surface area and storage capacity of low-grade ACs (surface area = 1152 m2/g, 0.10 g-CH4/g-ACs). Among the factors such as surface area, packing density, and heat of adsorption in the ANG system, the heat of adsorption played an important role in controlling CH4 adsorption. The released heat also affected the CH4 storage and enhanced available applications. During the discharge of gas from the ANG system, the residual amount of CH4 increased as the temperature decreased. The amount of delivered gas was confirmed using different evacuation flow rates at 0.4 MPa, and the highest efficiency of delivery was 98% at 0.1 L/min. The results of this research strongly suggested that the heat of adsorption should be controlled by both recharging and discharging processes to prevent rapid temperature change in the adsorbent bed.

scholarly journals Sustainable Conversion of Agriculture and Food Waste into Activated Carbons Devoted to Fluoride Removal from Drinking Water in Senegal

2015 ◽  
Vol 8 (1) ◽  
pp. 8 ◽  
Author(s):  
Mohamad M. Diémé ◽  
Maxime Hervy ◽  
Saïdou N. Diop ◽  
Claire Gérente ◽  
Audrey Villot ◽  
...  
Keyword(s):  
Drinking Water ◽  
Activated Carbon ◽  
Activated Carbons ◽  
Public Health Problem ◽  
Calcium Content ◽  
Fluoride Removal ◽  
Carbonaceous Materials ◽  
Water Steam ◽  
Surface Areas ◽  
Fluoride Adsorption

<p>The objective of this study was to investigate the production of activated carbons (AC) from cashew shells, and millet stalks and their efficiency in fluoride retention. These agricultural residues are collected from Senegal. It is known that some regions of Sénégal, commonly called the groundnut basin, are affected by a public health problem caused by an excess of fluoride in drinking water used by these populations. The activated carbons were produced by a combined pyrolysis and activation with water steam; no other chemical compounds were added. Then, activated carbonaceous materials obtained from cashew shells and millet stalks were called CS-H<sub>2</sub>O and MS-H<sub>2</sub>O respectively. CS-H<sub>2</sub>O and MS-H<sub>2</sub>O show very good adsorbent features, and present carbon content ranges between 71 % and 86 %. The BET surface areas are 942 m² g<sup>-1</sup> and 1234 m².g<sup>-1</sup> for CS-H<sub>2</sub>O and MS-H<sub>2</sub>O respectively. A third activated carbon produced from food wastes and coagulation-flocculation sludge (FW/CFS-H<sub>2</sub>O) was produced in the same conditions. Carbon and calcium content of FW/CFS-H<sub>2</sub>O are 32.6 and 39.3 % respectively. The kinetics sorption were performed with all these activated carbons, then the pseudo-first equation was used to describe the kinetics sorption. Fluoride adsorption isotherms were performed with synthetic and natural water with the best activated carbon from kinetics sorption, Langmuir and Freundlich models were used to describe the experimental data. The results showed that carbonaceous materials obtained from CS-H<sub>2</sub>O and MS-H<sub>2</sub>O were weakly efficient for fluoride removal. With FW/CFS-H<sub>2</sub>O, the adsorption capacity is 28.48 mg.g<sup>-1 </sup>with r² = 0.99 with synthetic water.</p>

scholarly journals Impact of reaction vessel pressure on the synthesis of sliced activated carbon from date palm tree fronds

2015 ◽  
Vol 69 (5) ◽  
pp. 561-565 ◽  
Author(s):  
Muhammad Shoaib ◽  
Hassan Al-Swaidan
Keyword(s):  
Electron Microscopy ◽  
Flow Rate ◽  
Activated Carbons ◽  
Single Step ◽  
Reaction Vessel ◽  
Bet Surface Area ◽  
Palm Tree ◽  
Surface Areas ◽  
Transmission Electron ◽  
Co2 Flow

The effects of the reaction vessel pressure on the BET surface area, pore volume and pore size of the synthesis of sliced activated carbons (SAC) at 850?C starting from 0.10 to 0.40 bars were investigated. Other synthetic variables like dwell time, CO2 flow rate and heating ramp rate were kept constant during the whole study. Methodology involves a single step procedure using the mixture of gases (N2 and CO2). During activation flow rate of both gases are kept at 150 and 50ml/min respectively. The BET surface areas of the SAC prepared at 0.10, 0.15, 0.20, 0.25, 0.30, 0.35 and 0.40 bar after 30 minutes activation time are 666, 745, 895, 1094, 835, 658 and 625 m2/g, respectively. Scanning electron microscopy (SEM) for surface morphology, Energy dispersive spectroscopy (EDS), Transmission electron microscopy (TEM) for nano particle size were also carried out that also confirms the same trend.

Preparation and Application of Biochars for Organic and Microbial Control in Wastewater Treatment Regimes

2019 ◽  
pp. 19-34 ◽  
Author(s):  
Victor Odhiambo Shikuku ◽  
Wilfrida N. Nyairo ◽  
Chrispin O. Kowenje
Keyword(s):  
Organic Pollutants ◽  
Organic Contaminants ◽  
Activated Carbons ◽  
Low Cost ◽  
Microbial Control ◽  
Chemical Compositions ◽  
Preparation Methods ◽  
Factors Affecting ◽  
Surface Areas ◽  
Control Factors

Biochars have been extensively applied in soil remediation, carbon sequestration, and in climate change mitigation. However, in recent years, there has been a significant increase in biochar research in water treatment due to their stupendous adsorptive properties for various contaminants. This is attributed to their large surface areas, pore structures, chemical compositions, and low capital costs involved making them suitable candidates for replacing activated carbons. This chapter discusses the preparation methods and properties of biochars and their removal efficacy for organic contaminants and microbial control. Factors affecting adsorption and the mechanisms of adsorption of organic pollutants on biochars are also concisely discussed. Biochars present environmentally benign and low-cost adsorbents for removal of both organic pollutants and microbial control for wastewater purification systems.

Characterization of Surface Roughness

2000 ◽  
Vol 6 (S2) ◽  
pp. 916-917
Author(s):  
John C. Russ
Keyword(s):  
Surface Roughness ◽  
Chemical Deposition ◽  
Irregular Surfaces ◽  
X Ray ◽  
Surface Areas ◽  
Raster Scan ◽  
Vertical Displacements ◽  
Physical And Chemical ◽  
Deposition Techniques

Because of the session at this Microscopy and Microanalysis 2000 meeting concerned with the microanalysis of irregular surfaces, it seems appropriate to briefly review the methods used for the characterization of rough surfaces. This includes both mathematical tools for the concise description of surface roughness, and instruments used to acquire the necessary data. These methods are widely used in industry to characterize and specify the roughness of surfaces prepared by various machining, grinding, polishing, chemical etching, and physical and chemical deposition techniques, and to correlate the surface roughness with performance.Historically, surface roughness has been measured by performing a linear traverse with a mechanical stylus that is sensitive to vertical displacements of nm but with a lateral resolution on the order of pm, which is quite similar to the dimensions of the region analyzed by X-ray microanalysis. Recently, more comprehensive characterizations have been obtained using a raster scan over surface areas.

Sign in / Sign up

Export Citation Format

Share Document