Development of new materials and methods for capacitive deionization

• Grant number: 21/11630-1
• Support Opportunities: Scholarships in Brazil - Doctorate
• Effective date (Start): April 01, 2022
• Effective date (End): July 31, 2025
• Field of knowledge: Physical Sciences and Mathematics - Chemistry - Physical-Chemistry
• Principal Investigator: Ernesto Chaves Pereira de Souza
• Grantee: Felipe Staciaki da Luz
• Host Institution: Centro de Ciências Exatas e de Tecnologia (CCET). Universidade Federal de São Carlos (UFSCAR). São Carlos , SP, Brazil
• Associated research grant: 13/07296-2 - CDMF - Center for the Development of Functional Materials, AP.CEPID

Abstract

Water is an essential resource for life and is considered a human right bu the UN. Despite the enormous amount of water presente on the planet, lesse than 3\% of this total is suitable for the consumption of human beings and animals. Furthermore, this water is unevenly distributed around the globe. Such factors, together with the exponential increase in population, lead to water scarcity in differente regions of the world, which results in a deepening of social and economic inequalities, leading to an accelerated degradation, of the enviroment. In this contextm techniques for the desalination of brackish ans sea water have been developed to meeth the demanda for drinking water for human and animal consumption. Different technological solutions have made it possible to propose efficient and sustainable desalination systems.Among the different processesm reverse osmosis, electrodialysis, multistage distillation and capacitive deionization stand out as technigques for this purpose develepod so far. The volume of desalinated water represents 0.01\% of all the water consumed in the wolrd on daily basis, and most of this volume is obtained by reverse osmosis. However, reverse osmosis has a significant energy expenditure due to the pressure required and the need to change the membranes increases the cost of the process. A promising alternative to this technique that has been studied in recent years is capacitive deionization. This water purification technology gained prominence for generating a smaller amount of effluents and using low-cost materials for the manufacture of electrodes. In addition, the energy required to operate the desalination system ($\leq 1.4$ V) makes it possible to supply it with renewable energy sources such as, for example, photovoltaic cells and wind energy. Considering these facts, we propose, in this project, to develop new materials for electrodes for the capacitive desalination process, modifying carbon-based materials such as graphene and carbon nitride regarding their surface structure (functionalization), due to the presence of clusters of compounds, segments containing functional groups and structural defects. Finally, to improve availability of active sites, we propose to increase the distance between layers of carbon compounds by introducing chemical spacer structures based on chalcogenides. Also with the objective of increasing the activity for adsorption/desorption, we propose the use of a dual energy source using, in addition to the electric field, an applied external magnetic field (using a permanent magnet). (AU)