Granular carbon electrodes

A number of carbon materials are ideal for the construction of three-dimensional electrodes for metal ion removal, and commercial cells have been marketed based on beds of granular carbon [120], reticulated vitreous carbon [121], and carbon felt [122]. Details of the cell designs and examples of then-performance have been described previously [4,116,117]. 

Rayon-based ACFs are used in the adsorption of many volatile organic compounds including formaldehyde (80), methyl ethyl ketones (81), and benzene (81). ACFs are also finding uses in natural gas storage (82), electrodes for batteries (83), catalyst supports (84), and NO removal (85). Stabilized rayon fibers are carbonized and then activated with air (80), steam (86), or carbon dioxide (87), much as in granular carbon activation. The extent of pyrolysis governs the pore structure, carbon yield, and surface area of the fiber, while activation impacts the presence of functional groups on the pore surface (12). Properties of some commercial ACFs are summarized in Table 6. 

Calcined coke is the main raw material for the manufacture o/poly granular, carbon and polygranular graphite products (e.g. carbon and graphite, electrodes). 

High-surface-area three-dimensional electrodes (e.g., beds of granular activated carbon or carbon aerosols, graphite felts, and carbon fiber materials) have been used to adsorb organics from effluents [106, 107]. The potential of the carbon... 

Electrode materials for a BES require a high specific surface area in order to create a high volumetric current density 1.3 m g for granules (Mersen, Wemmel, Belgium) and 0.6 m g for felt materials (Alfa Aesar, Ward Hill, MA, USA) are commonly found in a BES. When reporting specific electrode surfaces, one has to keep in mind that most surface areas are determined by means of N2 gas adsorption. With three-dimensional electrodes, it is essential to determine the surface available for biological interaction instead of the surface available for N2 adsorption. Different types of carbon and stainless steel have mostly been used for both anode and cathode electrodes. Carbon materials that are frequently appHed are granular, felt, cloth, brushes, or solid blocks [9-12]. 

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