Coconut char

The adsorptive properties of carbon were well known long before the terms active and activated had been coined. In the early literature, data on the adsorptive properties appear under many varied names blood char, coconut char, bone char, lignite char, and others. More recently references appear under deco/orizing-carbon and also under various brand names (Table 1 2). 

The great capacity of coconut char for adsorbing gases was reported by Hunter7 in 1865. Certain outstanding properties of coconut char have never been fully duplicated in any other char— and for some purposes coconut char is superior to all others. 

Although activated carbon had been manufactured for some years, the soft powdered types were not suitable for gas masks. Consequently new materials had to be selected and new processing equipment developed. Coconut char proved to be a suitable source material because of its great potential adsorptive capacity combined with the required resistance to abrasion. The rapid development of effective methods of production constitutes a brilliant episode in the annals of industrial chemistry. 

The process for the thermal activation of other carbonaceous materials is modified according to the precursor. For example, the production of activated carbon from coconut shell does not require the stages involving briquetting, oxidation, and devolatilization. To obtain a high activity product, however, it is important that the coconut shell is charred slowly prior to activation of the char. In some processes, the precursor or product is acid-washed to obtain a final product with a low ash content (23,25). 

In this work we developed a methodology to produce activated carbons of high adsorption capacity and with controlled pore size, based on the KOH catalysed gasification with CO2 of a coconut shell char. To study the effect of potassium in the activation step two series of activated carbons were prepared, with (CK1173) and without KOH (DC1173), The results obtained show that the size of the micropores is much smaller in the series CKl 173. 

As raw-material, we used a char obtained by carbonisation of Baba u coconut shell, which is abundant in Brazil (Orbygnia Phalerata) with a particle size of 1.40-1.65 mm. 

Activated carbon is prepared by (a) heating organic materials such as wood, coal char, almond, coconut, or walnut shells, as well as vinyl copolymers or recycled tires in a stoichiometric 02-deficient atmosphere, and (b) activating the product by exposure to a mild oxidizing gas (CO2 or steam, for example) at a high temperature. The activation... 

Blackwood and McCarthy showed that the fixed-bed differential reaction rate of hydrogen and carbon—coconut and wood chars as well as a char of Australian brown coal—tends to zero at the graphite equilibrium. This observation may not be relevant to the over-all kinetic situation when carbon is gasified by steam in a fluidized bed, in which... 

Chem. Descrip. Coconut/palm kernel oil triglyceride Uses Hard fat esp. for thin coatings Features Exc. consistency and meiting chars. 

The porous char of carbon is obtained by the destructive distillation of an organic material such as wood and coconut shells. The product can be activated by heating in steam or CO2 to increase the surface area and significantly increase the ability to adsorb liquids and gases. 

NaOH/coconut shell char 3/1 [weight] activation temperature 750 C flow rate 500 mL/min soaking time 1 h)... 

In the first of these procedures, the lignocellulosic precursor (coconut shells or peach stones) was acid washed to eliminate mineral matter as far as possible and then slowly carbonized. The char was activated thermally) with carbon dioxide at 750 °C (to ensure a slow gasification) to controlled bum-offs. 

Of the many carbonaceous materials that form active charcoal, only relatively few— coconut shells, fruit pits, and cohune and babassu nutshells—readily yield chars with all of the properties desired for gas-adsorbent use. Becau.se of the limited supply of these materials, special preparatory treatments have been developed to enable other base materials to be used for gas-adsorbent carbon. In its most common form, the pretreatment consists of pulverizing carbonaceous material, incorporating a suitable binder, and pelleting or extruding to form a dense, compressed material. ITie pellets or spaghetti-like extrusions are then carbonized at temperatures from 700° to 900°C. Various types of wood and coal have been found to be suitable base materials, and materials such as sugar, tar, and lignin can be used as binders. 

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