Hydrogen recovery from the photovoltaic electroflocculation-flotation process for harvesting Chlorella pyrenoidosa microalgae

• Published in: International journal of hydrogen energy 2017-08, Vol.42 (31), p.19591-19596
• Main Authors: Rahmani, Abdellatif, Zerrouki, Djamal, Djafer, Lahcène, Ayral, André
• Format: Article
• Language: English
• Subjects: Chemical Sciences; Electro-flocculation; Harvesting; Hydrogen; Microalgae; Photovoltaic; Recovery
• ISSN: 0360-3199; 1879-3487
• DOI: 10.1016/j.ijhydene.2017.06.123

In this paper, an integrated process using photovoltaic power to harvest microalgae by electro-flocculation (EF) and hydrogen recovery is presented. It is mainly favorable in regions with high solar radiation. The electro-flocculation efficiency (EFE) of Chlorella pyrenoidosa microalgae was investigated using various types of electrodes (aluminum, iron, zinc, copper and a non-sacrificial electrode of carbon). The best results regarding the EFE, and biomass contamination were achieved with aluminum and carbon electrodes where the electrical energy demand of the process for harvesting 1 kg of algae biomass was 0.28 and 0.34 kWh, respectively, while the energy yield of harvested hydrogen was 0.052 and 0.005 kWh kg−1, respectively. The highest harvesting efficiency of 95.83 ± 0.87% was obtained with the aluminum electrode. The experimental hydrogen yields obtained were comparable with those calculated from theory. With a low net energy demand, microalgae EF may be a useful and low-cost technology. •Promising use of photovoltaic power to harvest C. pyrenoidosa by electro flocculation.•We report an integrated process for C. pyrenoidosa harvesting and hydrogen recovery.•The energy yield of generated hydrogen ranged from 10 to 19% of the energy demand of the EF process.