Production of green hydrogen with simultaneous treatment of water contaminated with emerging pollutants

• Grant number: 24/18326-4
• Support Opportunities: Scholarships in Brazil - Program to Stimulate Scientific Vocations
• Start date: January 15, 2025
• End date: March 01, 2025
• Field of knowledge: Physical Sciences and Mathematics - Chemistry - Physical-Chemistry
• Principal Investigator: Edson Antonio Ticianelli
• Grantee: Juliana Prando
• Host Institution: Instituto de Química de São Carlos (IQSC). Universidade de São Paulo (USP). São Carlos , SP, Brazil

Abstract

Coupled water electrolysis is a promising strategy for green hydrogen production[1-2]. Pollutants are attractive raw materials for anodic reactions against the oxygen evolution reaction, with the advantages of converting waste to value-added products and reducing process costs [3-4]. In this work, a systematic evaluation of the coupled electrolysis of water with caffeine-containing wastewater is proposed. Caffeine (1,3,7-trimethylxanthine) is one of many emerging contaminants belonging to the pharmaceutical class and is a common ingredient in many foods, beverages, pharmaceutical drugs and PCPs. Consequently, caffeine accumulates in the environment, damaging biota and disturbing the fragile aquatic environment. For that reason, there is a need to develop new techniques to eliminate caffeine from wastewater to stop its accumulation in the aquatic ecosystem. Therefore, this work proposes to study the oxidation of caffeine in natural waters and simultaneously the electrochemical production of hydrogen [3-4]. For this, cell studies of two compartments separated by a Nafion® membrane will be carried out. Electrolyte solution containing KOH on the cathode side and caffeine solution on the anode side at basic pH will be used. Electrodes based on metal oxides and nickel cathodes will be used. Parameters that influence the process, such as cell potential and contaminant concentration, will be evaluated. The electrochemical degradation of caffeine will be evaluated through concentration decay analysis by high-performance liquid chromatography, total organic carbon analysis and kinetic calculations. The efficiency of the overall process will be evaluated through the rate of hydrogen production, energy consumption and caffeine degradation. The coupled electrolysis of water with refractory wastewater makes hydrogen a by-product with high added value to reduce operational costs from the vision of wastewater treatment. Therefore, this work may provide a reference for the systematic evaluation and selection of water electrolysis coupled to real wastewater. This work plan will offer the student the opportunity to learn and become familiar with electrochemical techniques, in a scientific topic that is highly relevant to the community and of global interest. (AU)