Electric-field enhanced microalgae inactivation using a flow-through copper ionization cell

[Display omitted] •A copper ionization cell (CIC) was designed for efficient microalgae inactivation.•The microalgae growth of C. vulgaris and M. aeruginosa were efficiently inhibited.•The 96 h-maximum quantum yield inhibitions of the microalgae reached 37.0 % and 70.9 %.•The CIC realized low energy consumption of 16.8 J/L with low Cu concentration.•The electric-field-enhanced CIC treatment promoted Cu utilization by microalgae. Using copper (Cu) to treat algal blooms is a commonly accepted method worldwide. However, the release of Cu may cause environmental and health risk. It is required to exploit an efficient way to reduce the Cu concentration but improve the algicidal effectiveness. Here, a Cu ionization cell (CIC) was designed and utilized in a flow-through system for inactivation of two bloom-forming microalgae species, Chlorella vulgaris and Microcystis aeruginosa. The results showed that the in-situ Cu release in the CIC treatment cause efficient microalgae inactivation. The 96 h-growth inhibition for C. vulgaris and M. aeruginosa reached 98.5 ± 3.1 % and 75.9 ± 2.0 % at a flow rate of 5 mL/min with the effluent Cu concentration of 554 ± 9 μg/L and 613 ± 17 μg/L, respectively. The maximum quantum yield (Fv/Fm) inhibitions of C. vulgaris and M. aeruginosa were 37.0 ± 1.6 % and 70.9 ± 2.1 %. The electric field enhanced CIC treatment has a locally higher Cu level because of the in-situ release. The CIC improved the microalgae inactivation performance by increasing the microalgae cell membrane permeability with excessive Cu uptake. The energy consumption was only 16.8 J/L. The in-situ Cu treatment in this work provides a microalgae inactivation method with the more environment-friendly and cost-effective prospect.