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Friday, 05 December 2014 12:59

Publication - Enhanced Performance of Bioelectrochemical Hydrogen Production with a pH Control Strategy

The use of membranes in microbial electrolysis cells (MECs) is required to obtain high-purity hydrogen and to avoid consumption of hydrogen by undesired microorganisms. However, its utilization results in pH gradients across the membrane that contribute to potential losses and to reduce the efficiency of MECs. Several pH-controlled and non-controlled scenarios were evaluated in this work, evidencing that pH control is very beneficial for the MEC performance. The best results were obtained when the anodic and cathodic pH were controlled at 7.5 and 2.0, respectively, producing 0.58 m3 m-3 d 1 of hydrogen at an applied voltage of only 0.2 V. The energy efficiency respect to electrical input was increased up to 883%. Anodic pH control allowed maintaining a stable exoelectrogenic activity with practically constant current intensity, while controlling cathodic pH at 2.0 allowed a 5-fold decrease of required electrical input, opening up new opportunities for the economy of its full-scale application