Concurrent Desalination and Hydrogen Generation Using Microbial Electrolysis and Desalination Cells

By Luo, Haiping; Jenkins, Peter E. & Ren, Zhiyong
Published in Environmental Science & Technology NULL 2011

Abstract

The versatility of bioelectrochemical systems (BESs) makes them promising for various applications, and good combinations could make the system more applicable and economically effective. An integrated BES called microbial electrolysis and desalination cell (MEDC) was developed to concurrently desalinate salt water, produce hydrogen gas, and potentially treat wastewater. The reactor is divided into three chambers by inserting a pair of ion exchange membranes, with each chamber serving one of the three functions. With an added voltage of 0.8 V, lab scale batch study shows the MEDC achieved the highest H2 production rate of 1.5 m3/m3 d (1.6 mL/h) from the cathode chamber, while also removing 98.8% of the 10 g/L NaCl from the middle chamber. The anode recirculation alleviated pH and high salinity inhibition on bacterial activity and further increased system current density from 87.2 to 140 A/m3, leading to an improved desalination rate by 80% and H2 production by 30%. Compared to slight changes in desalination, H2 production was more significantly affected by the applied voltage and cathode buffer capacity, suggesting cathode reactions were likely affected by the external power supply in addition to the anode microbial activity.

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