Effect of Nanoparticle Addition on Biohydrogen Production

Rapid population growth and consumption lead to an increased demand for energy. Fossil fuels as the most dominant resources used for energy production are depleting, and more importantly, their combustion leads to the release of carbon dioxide (CO 2 ), triggering global warming and climate change. Therefore, recent studies have been focusing intensively on increasing the production of green hydrogen as a clean alternative [1- 2].Parallel to these efforts, bio-hydrogen has also been gaining significant attention. In this study, high temperature (110°C for 10 minutes), acidic conditions (pH 2-5.5), and nanoparticle addition (magnetite nanoparticle; obtained from Ege University, Faculty of Science, Department of Biochemistry) methods were tested for enhancing the biohydrogen production. For this purpose, initially, the sludge was autoclaved at 110°C for 10 minutes. Following these pretreatment steps, four different trial sets (R1: pH 5.5, R2: pH 5.5 + 5mg/L Fe 3 O 4 NP, R3: pH 7, R4: pH 7 + 5mg/L Fe 3 O 4 NP) were established to investigate biohydrogen production. The reactors were operated under static conditions at 38°C with fed- batch using 2-4 g COD/day substrate load. The volumetric contents of the produced biogas were determined by sampling of headspace gases and analyzed using gas chromatography (GC). According to the results, while reactors R1 and R2 produced a maximum volumetric percentage of biohydrogen of 10-15%, reactors R3 and R4 reached levels of 30% (on day 11) and 32% (on day 7), respectively. These results indicated that the acidification pretreatment did not increase hydrogen yield; however, the addition of nanoparticles under neutral conditions significantly improved biohydrogen production (compared to the control group) at earlier stages.