Electrochemical harvesting process for microalgae by using nonsacrificial carbon electrode: A sustainable approach for biodiesel production

• Electrochemical harvesting of algae employing non-sacrificial carbon electrode.
• Anode depletion and accompanying metallic contamination can be completely avoided.
• Effect of operating condition on lipid recovery and composition are evaluated.
• Electrochemical process has no adverse effect on the lipid extraction process.
• Striking recovery at low energy consumption by applying non-sacrificial electrodes.

Microalgal biodiesel has to overcome a cost incurring harvesting bottleneck for its commercial scale production. In this study electrochemical harvesting (ECH) using Chlorella sorokiniana and Scenedesmus obliquus was investigated. Nonsacrificial carbon electrodes were used to overcome the cost and metallic contamination implications. The effect of applied current and addition of electrolyte on harvesting efficiency was investigated. Addition of electrolyte (NaCl) increased the recovery efficiency of C. sorokiniana from 65.99% to 94.52%. ECH process has not shown any deteriorating effect on the lipid extraction process as well as fatty acid composition. ECH process for C. sorokiniana with optimum conditions showed 94.52% recovery efficiency with energy consumption of 1.6 kWh kg−1. This study for the first time validates application of nonsacrificial carbon electrodes in ECH process of microalgae. Attractive high recovery efficiency, low energy consumption and use of nonsacrificial electrodes could make ECH a possible step in commercial microalgal biomass and biodiesel production.

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