Valorization of Cheese Whey by Electrohydrolysis for Hydrogen Gas Production and COD Removal
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- Kargi, F. & Uzunçar, S. Waste Biomass Valor (2013) 4: 517. doi:10.1007/s12649-012-9188-5
Diluted cheese whey (CW) solutions with different initial COD contents (4,800–25,000 mg l−1) were electro-hydrolyzed by application of constant DC voltage (3 V) for hydrogen gas production and COD removal. The highest cumulative hydrogen production (3,923 ml), hydrogen yield (1,719 ml H2 g−1 COD), hydrogen formation rate (699 ml d−1), and percent hydrogen (99.2 %) in the gas phase were obtained with the highest initial COD of 25,025 g COD l−1 with an energy conversion efficiency of 90.3 %. Hydrogen gas production in water and cheese whey controls were negligible indicating no significant H2 gas production by electrolysis of water and fermentation of cheese whey. Percent COD removals were between 18 and 20 % for initial CODs above 11,500 mg l−1. Major COD removal mechanism was anaerobic fermentation of carbohydrates producing volatile fatty acids (VFA) and CO2. Hydrogen gas was produced by reaction of (H+) ions released from VFAs and electrons provided by DC current. Electro-hydrolysis of CW solution was proven to be an effective method of H2 gas production with simultaneous COD removal.