Effect of concentration and flow rate of electrolyte on electrochemical regeneration of activated carbon at pilot-plant scale

Few research has investigated the problem of regeneration of activated carbon once it has been saturated by organic and inorganic contaminants. Among the regeneration methods, electrochemical technology is one of the most advanced, demonstrating its effectiveness in pilot-plant scale experiments using samples obtained from drinking water treatment plants. In the present study, the optimization of a parallel plate electrochemical reactor with a capacity of 15 kg of activated carbon, has been achieved regarding the electrolyte concentration and flow rate. A regeneration efficiency of approximately 90% was achieved with a 0.25 M H₂SO₄ concentration, while lower concentrations resulted in a voltage exceeding the acceptable limits for this type of installation. In addition, higher flow rates imply a higher recovery of the porous texture of the regenerated activated carbon. This is, to the best of our knowledge, the first report where these two experimental variables are optimized in a pilot-scale process with real saturated activated carbon samples with different types of pollutants adsorbed in the activated carbon.