A critical evaluation of the pH split and associated effects in bioelectrochemical processes

Typical reactions in bioelectrochemical systems (BESs) promote the phenomenon of the pH split between anode and cathode. The pH split results in an undesirable phenomenon which has stimulated several technological solutions to limit its effects, particularly for energy-producing bioelectrochemical systems (BESs). On the other hand, several applications of energy-consuming BESs exploited the pH split to integrate different operations using the bioelectrochemical reactions. Those additional operations, which are directly related to the electric field generated by the bioelectrochemical interphases, include target products extraction, concentration, and recovery. This review offers a comprehensive overview of the different bioelectrochemical applications in which the pH split is used for the integration of bioelectrochemical reactions with products concentration and recovery. By discussing the phenomenon of the pH split in BESs, this paper presents an alternative view to stimulate new niches of applications for the bioelectrochemical processes.