Renewable energies driven electrochemical wastewater/soil decontamination technologies: A critical review of fundamental concepts and applications

Electrochemical wastewater and soil treatments are exciting set of technologies that has been well-studied over the recent years as one of the most-effective remediation techniques for the removal of hazardous pollutants from liquids effluents and soil. The main requirement of these technologies is electricity and their sustainability can be largely improved if they are powered by renewable energy sources. Likewise, this green energy powering can help to apply these technologies in remote areas, such as rural communities in developing countries, where no electricity grid is available. This review presents a comprehensive discussion on fundamental concepts and applications of renewable energy driven electrochemical technologies for treating hazardous pollutants in wastewater and contaminated soils. In the first section, the fundamentals of different electrochemical remediation technologies are presented, whereas the next two sections focused on the most applied technologies for powering these electrochemical devices: the solar photovoltaic (PV) (Section 3) and the wind turbines (Section 4). After that, the non-near future is faced with the study of the principles of biomass energy production and how bioelectrochemical systems are starting to be evaluated for powering electrochemical technologies (Section 5). Then, new approaches in the renewable energy driven electrochemical technologies such as triboelectric nanogenerators and photocatalytic fuel cells are described in Section 6. The last section focused on the challenges expected for the near future, describing the most promising storage system and evaluating the scale-up, environmental and economic concerns of the technologies studied in this work.