Selection of anode materials and optimization of operating parameters for electrochemical water descaling

Abstract Electrochemical water descaling is acknowledged as a newfashioned active technology for recirculating cooling water quality stabilization. As the core component of electrochemical technology, anode material exerts direct influence on the technology efficiency and equipment cost. This study investigated the integrated performance in the electrochemical scale removal techniques of four kinds of typical titanium substrate metal oxide electrode (i.e. Ti-based Ir/Ru electrode, Ti-based Ir/Ta electrode, Ti-based PbO2 electrode and the Ti-based Ti4O7 electrode). Then Ti4O7 with titanium substrate electrode was elected as the anode martial of a continuous flow reactor for electrochemical waster descaling, so as to optimize the system operating parameters. The alkalinity removal rates of the water samples were always higher than the hardness removal rates in all experimental results, indicating that the strong acidic region in vicinity of anode is conducive to the removal of alkalinity ions in the water samples and plays a crucial role of scale inhibition, which provided a supplementary perception to the mechanism of electrochemical descaling. After the water samples were treated by electrochemical scale removal reactor, the scaling trend was alleviated prominently, supported by LSI and RSI data. The current density and hydraulic retention time directly affect the performance of descaling process, the volume of treated water and the temperature rise of water sample. After comprehensive consideration of removal rate, scale deposition amount per unit area, energy consumption per unit scale weight and temperature rise, 6 mA/cm2 was taken as the optimal current density value. Additionally, the practical engineering situation of electrochemical equipment and recirculating water treatment should be taken into consideration when determining a reasonable hydraulic retention time.