Investigation and optimization of a new electrocoagulation reactor with horizontal bipolar electrodes: Effect of electrode structure on the reactor performances

The performances of a new electrocoagulation reactor with bipolar horizontal iron electrodes were investigated. These electrodes were piled up in the reactor in order to maintain a low gap between them and to increase the electroflotation process. Electrodes were perforated to allow the passage of gas and effluents, and adjacent ones were separated by grids of polyamide or polytetrafluoroethylene. The performances of the reactor were investigated thanks to the weight lost of the electrodes. These performances increased with the number of holes in the electrodes, the current intensity, and the flow rate of the effluent, and mainly in the absence of a gap between the electrode edges and the walls of the reactor. More important, when the electrodes were not sealed with a system of tightness a decrease of the current efficiency was observed, leading to higher voltage and contributing to increase considerably the energy consumption. The use of eight-hole electrodes and a high flow rate reduced significantly the voltage and increased the current efficiency. Moreover in the absence of a gap between electrode edges and reactor walls, the current efficiency reached 100%; the voltage was stable and did not vary anymore and the energy consumption was minimized. The results showed that the sealing between electrode edges and the walls of the reactor was the most determinant factor in the optimization of the investigated reactor.