Harvesting of microalgae Chlorella sp using electrocoagulation and quantification of dissolved hydrogen gas

¹ Doctoral Program of Environmental Sciences, School of Postgraduate Studies, Diponegoro University, Semarang, Indonesia
² Center of Biomass and Renewable Energy (CBIORE), Chemical Engineering Department, Diponegoro University, Semarang, Indonesia
³ Graduate Program of Environmental Sciences, School of Postgraduate Studies, Diponegoro University, Semarang, Indonesia
⁴ Department of Environmental Engineering, Faculty of Engineering, Diponegoro University, Semarang - Indonesia 50275

^* Corresponding author: purwonopurwono@students.undip.ac.id

Abstract

Microalgae harvesting is the stage of any microalgae-based activity that is the most inhibiting, providing it with an interesting issue of investigation that could be used in the field. Electrocoagulation (EC) is an effective alternative harvesting method because EC produces high efficiency, ease of operation, fast harvesting, and adaptability. Furthermore, the harvesting of microalgae results in producing renewable hydrogen gas, an excellent option for generating clean energy and lowering greenhouse gas emissions. This study aims to assess the effectiveness of harvesting Chlorella sp microalgae by electrocoagulation using stainless still &iron electrodes. We measure optical density and quantification of dissolved hydrogen gas. Chlorella sp was harvested using EC by adjusting the electrolysis period for 30 minutes, voltage 15 V, and stirring at 400 rpm, Interestingly, the dissolved hydrogen gas in the initial Chlorella sp substrate was 0 ppb, then increased to 509 ppb after being electrolyzed for two minutes and 1214 ppb at 30 minutes. Statistically, electrolysis time significantly affected the increase in hydrogen gas concentration (α< 0.05). Electrolysis time of two minutes can harvest up to 90% Chlorella sp. Adding electrolysis time up to 30 minutes did not significantly increase harvesting efficiency.