Tailored adsorbent

Physical Properties. Physical properties of importance include particle size, density, volume fraction of intraparticle and extraparticle voids when packed into adsorbent beds, strength, attrition resistance, and dustiness. These properties can be varied intentionally to tailor adsorbents to specific apphcations (See Adsorption liquid separation Aluminum compounds, aluminum oxide (alumna) Carbon, activated carbon Ion exchange Molecular sieves and Silicon compounds, synthetic inorganic silicates). 

Economy, J., Foster, K., Andreopoulos, A. and Jung, H., Tailoring carbon fibers for adsorbing volatiles, CHEMTECH, October 1992, 597 603. 

Activated carbon is an amorphous solid with a large internal surface area/pore strucmre that adsorbs molecules from both the liquid and gas phase [11]. It has been manufactured from a number of raw materials mcluding wood, coconut shell, and coal [11,12]. Specific processes have been developed to produce activated carbon in powdered, granular, and specially shaped (pellet) forms. The key to development of activated carbon products has been the selection of the manufacturing process, raw material, and an understanding of the basic adsorption process to tailor the product to a specific adsorption application. 

These factors, together with the rather slow thermal regeneration that was common in early applications, resulted in the adsorber being an unpopular option with plant designers. Since a greater variety of adsorbents has become available, each tailor-made for a specific application, the situation has changed, particularly as faster alternatives to thermal regeneration are often possible. 

The adsorbent is an alkali exchanged faujasite bound into a bead. Because m-xylene is by far the most basic of the four mixed xylene isomers, the selectivity of the zeolite is tailored for this chemical trait. 

The outstanding performance of ACs stems from a unique combination of geometrical and chemical characteristics. Nowadays carbon adsorbents with tailor-made surface area and pore hierarchy are commercially available [1-3]. Chemical treatment, in addition to impregnation or doping techniques, is often used to enhance the performance of porous carbons. Introduction of heteroatoms into the carbon skeleton renders the carbon surface more attractive to polar molecules [4]. 

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