[1][2] Activated carbon beds vary in lifetime depending on the concentration of the pollutant(s) being removed, their associated adsorption isotherms, inlet flow rates and required discharge consents.
Activated carbon is often landfilled at the end of its useful life but sometimes it is possible to regenerate it restoring its adsorptive capacity allowing it to be re-used.
Ions generated at the electrodes can change local pH conditions in the divided cell which affect the adsorption equilibrium and have been shown to promote desorption of organic pollutants such as phenols from the carbon surface.
The cathode is the reducing electrode and generates OH− ions which increases local pH conditions.
An increase in pH can have the effect of promoting the desorption of pollutants into solution where they can migrate to the anode and undergo oxidation hence destruction.
The anode is the oxidising electrode and as a result has a lower localised pH during electrolysis which also promotes desorption of some organic pollutants.
Regeneration efficiencies of activated carbon in the anodic compartment are lower than that achievable in the cathodic compartment by between 5-20% for the same regeneration times and currents,[3][6] however there is no observed residual organic due to the strong oxidising nature of the anode.
[6] For the bulk of carbonaceous adsorbents regeneration efficiency decreases over subsequent cycles as a result of pore blockages and damage to adsorption sites by the applied current.
[7][8][9] Currently there are a very limited number of commercially available carbon based adsorption- electrochemical regeneration systems.