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PINES FROM THE LANDES REGION Acticarbone is a wood-based activated carbon. A type of pine-wood which grows along the Bay of Biscay coastline is used for this purpose; it is processed at CECA's Parentis factory, in the heart of the Landes region in South West France. This raw material's structure and purity largely contribute to Acticarbone's performance.

ACTIVATED CARBON Activated carbon is a carbon structure which has been given a particular porosity, with a resulting inner surface accessible to molecules of varying nature and size. This porosity is developed by the activation process, which creates a remarkable power of adsorp-tion, an indispensable process in industrial separation, purification, decolorisation and recovery techniques. Acticarbone's distinct characteristic is therefore its inner suiface which is accessible to organic molecules dissolved in gas or in aqueous and organic liquids. The configuration of its access network defines its eventual uses. Preliminary laboratory studies determine the Acticarbone grade which best suits the application.

ADSORPTION Adsorption is the physical phenomenon by which a solid attracts and fixes onto its surface organic molecules which are dissolved in a liquid or a gas. In the case of activated carbon, "surface" is to be understood less as the outer surface than the inner surface developed within the pores of this solid. Pore diameters in activated carbon range from 5 to 50 A. As a result of this large number of small diameter pores, the inner area is considerable, and, depending on the Acticarbone grades, ranges from 800 to 2,000 m2/g. The effective adsorption surface of just three grammes of Acticarbone, for example, is therefore equivalent to the area of a rugby pitch, the favourite sport in the Landes region. In the adsorption process, the adsorbed substance (adsorbate) is retained in a more or less solid state by Van der Waals forces. Gases and vapours behave like liquids on the pores' suiface, which leads to a significant adsorption of these subs tances. The term ad sorption should not be confused with ab sorption, which means the filling of a hollow substance with a liquid or a gas which is then retained through capillary forces (e.g. sponges, fabrics, etc.).

A natural and porous substance

ADSORPTION INTENSITY AND CAPACITY

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ADSORPTION ISOTHERMS ON ACTICARBONE AC 40 1000

Be n.ze ne

20 C 40 C

- 600 ( 10'-----~~----'--~~~-'-~~--'~~~~ 0.1 1000

(temperature, concentration, etc.). It is normally expressed as the number of grammes adsorbed for each 100 grammes of Acticarbone.

TYPICAL CUMULATIVE CURVE FOR POROSITY BREAKDOWN 100

ADSORPTION OF SINGLE SUBSTANCES

90

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10

R : 10-JOOA - BJH method R : 75-5. 10, A - Hg poroiimetry

AC 40 Total pore ~ol ume : 1,2 ml.g-1

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The adsorption of single substances is governed by a few general principles. Firstly, ac tivated carbon can easily adsorb any non-polar molecules which can be fo und in the liquids or gases being treated . Additionally, adsorption intensity generally increases with molecular weight. This phenomenon is particularly obvious w hen atoms o f oxygen ,

R Pore radius-A chlorine or nitrogen are added . However, adsorption also depends on the type of functional group being u sed . Introducing a nitrated group , for example, often enhances adsorption , whereas adding hydroxyl, amine or sulfonic groups lowers it. Variable results are also obtained w hen carboxylic, halogenated or do uble bond groups are being u sed. Furthermore, introducing a second or third substituent often increases adsorption . Finally, aromatics are clearly better adsorbed than aliphatics of equal m olecular size, and so are non- linear chain compounds compared to linear chain compounds.

ADSORPTION AND SOLUBILITY The less soluble impurities are in a given m edium such as air or water, the more easily they can be adsorbed in that medium. Vapours of maj or solvents such as toluene, xylene and chlorinated derivatives can therefore easily be fixed onto Acticarbone. By virtue of this solubili ty principle, Acticarbone traps, from vapours, the substances with the highest boiling points. In the manufac ture of pure gases, for example, Acticarbone eliminates methane from hydrogen. The operation takes place in two phases: adsorption, w hich takes place under pressure, followed by desorption, which takes place in a vacuum.

A range of products capable of adsorbing any substance

POWDER, GRANULE, EXTRUDATE Extrudates loo k like cylindrica l rods, and are especially used in gas purifi ca tion and solvent recove ry . G ranules can be used both in liquids and in gases. Their main advantage is their regeneration capabibty. The advantage of powders lies in their excellent effi ciency resulting from the inner contac t they crea te with the solutions to be treated . Powder

dosage ca n be adju sted to suit particular requirements, and tlus fl exibili ty is a bonu s to many users . CECA's Acticarbone range offers powders to suit every applica tion: their range of adsorption capacity depends on the specific surface and the type of porosity.

ACTIVATION Two activation principles are used by CECA to develop the carbon's porosity:

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IODINE ADSORPTION ISOTHERMS

Chemical ocl1vohon - Phy:licoloctivohorl

Activation is called physical when the carbon is hit by steam through the reaction of gas in water. This process produce extremely pure activated carbon w hich owes to its microporosity -its outstanding adsorpti on p ro perties for small to medium sized molecules, even w hen these are diluted down to trace elements.

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0.1 I Concenlrolion lin mg/ I)

Activa tion is called chemical when the pine sawdust is thermally trea ted with phosphoric acid as a ca talyst. Since 1988, the Parentis factory has been rumung an entirely automated chenucal activation plant, producing activated ca rbon of very !ugh activi ty and purity, wluch , due to its mesoporosity, is particularly suitable fo r liquid decolorisation.

TAILOR-MADE PRODUCTS One of CECA's distinct advantages is that it accommodates both physical and chemical acti vation plants on the same site, and so the company is able to blend products with the resulting benefit of combined properties. H owever, more specific applica tions require additional properties to be fine- tuned wlu ch make up speciality products. CECA can , for example, offer Acticarbone in w hich the

acidity, measured by pH, has been adjusted . Rinsed products fea ture a very low ash co n.tent and the resulting degree of high purity required for pharmaceuticals and fine chenucals. Humidification makes Acticarbone powders easier to use by miilinusing loose du st w hen they are handled by custo mers. Finall y, particle size and abrasio n resis tance ca n be cont ro ll ed and adju sted to m ee t cu sto m ers' specifica tion s.

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A comprehensive range of products

FIXING IMPURITIES Acticarbone is the perfect answer to two major concerns of industry: obtaining increasingly purer products with enhanced quality, avoiding polluting the environment with gas, liquid or solid waste emissions . Acticarbone maximises the potential of products it

'--------------------' has treated, and it eliminates impurities at lesser cost arid destroys them during regeneration or eventual combustion. Acticarbone is a stable and neutral product, which does not trigger decomposition reactions with the products it is treating. Its high quality makes it an ideal product in industry as well as in the protection of the environment.

IN GASES Solvents are recovered by being trapped onto Acticarbone granules or extrudates, which feature the clear advantage oflow steam consumption during regeneration. For large scale production, adsorption takes place on activated carbon beds. This applies to a wide range of sectors, ranging from the rubber and leather industries to industrial cleaning, printing, and photographic film manufacture, etc. Acticarbone filters the air in public places through air conditioning systems, and, when used in safety face mask cartridges, provides protection for anyone potentially exposed to toxic fumes and gases, whether in industry or in the armed forces.

IN LIQUIDS The most common applications consist m adding Acticarbone powder to liquids such as water or sweetened solutions from which impurities have to be removed. Drinking water, for example, is systematically treated with activated carbon, which eliminates all micropollutants such as pesticides, as well as tastes and odours. Similarly, Acticarbone is used, in industry, to eliminate chlorine from the water used in the

manufacture of beverages, and to purify waste water which may contain harmful substances or may have been coloured by some manufacturing process.

,___ ________________ __,

In the case of glucose made from natural products, colour variations can occur. So, the answer to obtaining a syrup with a constant quality is to treat it with the right quantity and the right quality of Acticarbone. In broader terms, therefore, whenever the problem is one of purifying, decolorising, deodorising, recovering or eliminating any kind of substance, there is bound to be one Acticarbone grade to suit the application.

Applications in a pure state

Your car 's evaporation control canister traps petrol fum es. It has been filled with chemically activated A cticarbone SA 1817.

Acticarbone JS is used to purify pharmaceuticals: antibiotics, vitamins, aspirin, paracetamol, etc.

A cticarbone Eno and Eno Anticromos help adjust the colour of wines and vermouths.

Unique custom-designed products

Corrosive sulphur substances are removed from kerosene and other light fuels with

the help of Acticarbone BGP MX 10x30.

A cticarbone A C 40 4mm traps solvents used in printing and photogravure.