Photoelectrochemical based Methods for hydrogen production

Abstract

The development of environmentally friendly fuels is essential for sustainable growth. Moreover, there is a huge demand for alternative energy resources which are renewable, low in cost and free from pollution. Hence, herein we report the production of biohydrogen from wastewaters generated during the processing of agricultural products. newlineMicrobial Electrolysis Cell (MEC) is an ecologically clean and inexpensive method to produce hydrogen. This research work presents the production of hydrogen from rice mill wastewater using Artificial Photo-Assisted MEC (APAMEC) consisting of an inexpensive anode prepared from sugar industry waste. Rhodobacter sphaeroides MTCC 8259 was used as a biocatalyst. Initially, experiments were carried out using rice mill wastewater. It was subjected to acid hydrolysis and the effect of acid concentration on hydrogen production was studied. The optimum acid concentration was found to be 1.5% and hydrogen production was maximum at pH 6. The maximum hydrogen production rate achieved was 3.6 ± 0.4 ml/l/h. The cathodic hydrogen recovery (RH2) and overall systemic coulombic efficiency (CE) observed were 73% ~ 92% and 50% ~ 62%, respectively. The maximum gas collected at pH 6 after five days was 220 ml. At 0.7 V and with the LED light illumination, the yield obtained for pure culture was 0.79 mole hydrogen per mole carbohydrate. newlineHydrogen production using a mixed culture of Rhodobacter sphaeroides and Enterobacter aerogenes was studied using APAMEC. Due to the antagonism effect between photoheterotrophic bacteria and facultative bacteria, hydrogen production in the mixed culture was not better than the pure culture. Hydrogen production was maximum at pH 6. newline