Indirect electrochemical reduction of methemoglobin: Design of the process

Methemoglobin can be reduced on a platinum cathode using flavin mononucleotide as an oxido‐reduction mediator. The process requires the utilization of a filter‐press cell with compartments separated by a semi‐permeable membrane. Analysis of the various constraints imposed by the process itself and by the nature of the molecules involved shows that the electrolysis cell must operate at a low temperature, in strictly anaerobic conditions, in series with a storage tank, and with fluid circulation rates lower than approximately 0.8 m/s. A process has been designed that takes into account these imperatives and enables volumes of solution of the order of 200 cm 3 to be processed. It enables optimization of the flow rates used as well as of the methemoglobin/flavin ratio and is the forerunner of an industrial reactor.