Electrochemical method for dissolved oxygen consumption on-line in tubular photobioreactor

A new electrochemical tubular photobioreactor is designed for the efficient cultivation of chlorella, alongside eliminating the inhibition of the growth of microalgae caused by the high dissolved oxygen content. With the aid of anion-exchange membrane alkaline fuel cell, the dissolved oxygen in the photobioreactor which is produced by the photosynthesis of microalgae can be consumed and the energy consumption of photobioreactor can be reduced. Besides, the effects of different components and operating parameters on the efficiency of dissolved oxygen removal and the cell performance have been detailed investigated. The experiment results are shown as follows. First, by applying the double-cylinder alkaline direct glucose fuel cell to consume the dissolved oxygen of the microalgae suspension in the tubular photobioreactor on-line, the dissolved oxygen content rapidly decreases from over 20.0 mg L⁻¹ to 10.72 mg L⁻¹ below within 45 min. Second, the efficiency of dissolved oxygen consumption and cell performance increase significantly by using the bimetallic catalyst Pt-Ru as the cathode catalyst in the double-cylinder alkaline direct glucose fuel cell compared with the mono-metallic cathode catalyst by adopting Pd and Pt. Third, it exists an optimal cathode catalyst loading (1.5 mg_PtRu·cm⁻²)to consume the dissolved oxygen with the fuel cell yielding the best performance.