Optimization of bio-hydrogen production in dark fermentation using activated sludge and date syrup as inexpensive substrate

摘要

Today, the destructive effects of fossil fuels have caused environmental pollution and serious risks for human and other organisms. Hence, scientists attempt to replace fossil fuels with clean fuels obtained from renewable and accessible resources. The biological production of hydrogen has attracted the attention of researchers in the last decade, since it is a renewable and non-polluting energy source. Therefore, the present paper studied the optimization of four effective factors for the production of hydrogen from activated sludge. The parameters of pH, temperature, fermentation time, and concentration of waste date syrup were examined at three levels. Dark fermentation was used for hydrogen production and, in order to optimize the effective parameters, 2(k) factorial design and RSM were employed. According to the results obtained in the optimal conditions of pH = 6.2422, temperature of 27.0909 degrees C, sugar concentration of 4 gr/l, and fermentation time of 36 h, the highest hydrogen production in the proposed theoretical model was obtained equal to 2.30 mol H-2/mol hexose. The proposed theoretical model was compatible with the obtained experimental data.