Document Type

Article

Publication Date

12-2018

DOI

10.1039/c8ra08101h

Publication Title

RSC Advances

Volume

8

Issue

68

Pages

38808-38817

Abstract

Electrolytic flocculation using non-sacrificial electrodes with flocculants added was studied on harvesting Scenedesmus sp. In order to optimize the operating conditions of the electrolytic flocculation process and to quantify the amount of flocculants added, aluminum electrodes were first used in the process. It was found that under optimal conditions, the microalgae removal efficiency using aluminum electrodes could reach 98.5%, while 34.2 mg L-1 of aluminum ions were released during the process. Different metal electrodes were also studied, but high microalgae removal efficiency was witnessed only using aluminum electrodes, indicating the influence of the aluminum ion in flocculation. When non-sacrificial graphite electrodes were used in the electrolytic flocculation process, the corresponding amount of aluminum sulfate was added so that the aluminum ion concentration in water was also equal to 34.2 mg L-1. The result showed that the microalgae removal efficiency of graphite electrodes could reach above 90% after aluminum sulfate was added. In contrast, using graphite electrodes alone and using the metal salt alone only yielded 22.9% and 7.1% of microalgae removal efficiency, respectively. These results indicated that the presence of metal ions is necessary in the electrolytic flocculation process. The energy consumption of the process was found to be 0.3 kW h m-3 or 0.88 kW h kg-1, which is considered to be low energy consumption. The total cost of the process, including energy and chemicals, was found to be $ 0.21 m-3, proving a cost competitive method in microalgae harvesting.

Comments

This Open Access Article is licensed under a Creative Commons Attribution-Non Commercial 3.0 Unported Licence.

© The Royal Society of Chemistry 2018

Original Publication Citation

Liu, S. H., Abu Hajar, H. A., Riefler, G., & Stuart, B. J. (2018). Investigation of electrolytic flocculation for microalga Scenedesmus sp using aluminum and graphite electrodes. RSC Advances, 8(68), 38808-38817. doi:10.1039/c8ra08101h

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