Photoelectrochemical desalination systems under continuous flux

Abstract

The concern regarding water scarcity for human consumption is a driving force towards effective strategies on seawater desalination, therefore, contributing to the development of systems with low environmental impact and low energy cost. In this project, a photo-assisted electrochemical system for desalination is proposed for desalination under continuous flow conditions. The working principle of these devices, powered by solar and electrical energy, involves: (1) photo-assisted oxygen evolution (OER) reaction; (2) hydrogen evolution reaction (HER); (3) selective migration of ionic species through ion-exchange membranes; and (4) channels for the seawater circulation and low salinity water collection. These faradaic reactions promote a charge imbalance in solution leading to an ionic flux towards more concentrated saline solutions, according to the principle of electroneutrality. Heterostructures of molybdenum, cobalt, and niobium dichalcogenides will be synthesized and investigated as catalysts for HER. Hematite-based electrodes and cocatalysts will be used for an OER. Their catalytic activities will be investigated using techniques and models in time and frequency domains, concerning their structures, morphologies and compositions. The reaction mechanism proposal and electrochemical simulation will enable the determination of physical-chemical parameters. As for the ion exchange membranes, the conductivity and the ionic transference numbers will be measured, and correlated to their composition and porosity. Finally, these devices will be built and their energy consumption and desalination efficiency evaluated, as a proof of concept. (AU)