Neutralization Pseudocapacitors: An Acid-Base Machine

Author(s)

Morais, William G. ; Gomes, Wellington J. A. S. ; Huguenin, Fritz

• Document type: Journal article
• Source: Journal of Physical Chemistry C; v. 120, n. 32, p. 17872-17877, AUG 18 2016.
• Web of Science Citations: 4

Abstract

This study proposes a thermodynamic machine that operates between acid and basic reservoirs in four stages. Two of these stages are buffered isothermal steps. The other two stages constitute an open system and allow the passage of acid and base. The machine consists of a neutralization pseudocapacitor that, after a full cycle, carries out work generated from partial change in entropy associated with a change in the hydrogen potential after the neutralization process. Thermodynamic formalism is presented under reversible stages. This presentation enables determination of the maximum efficiency, related to the difference between the hydrogen potential of the acid reservoir and of the resulting solution after neutralization in the machine. Hence, the hydrogen potential scale can be defined as a function of the efficiency of the reversible acid-base machine regardless of the electrochemical cell composition. Electroactive thin films formed from phosphomolybdic acid and poly(3,4-ethylenedioxythiophene) have been investigated as proof of concept in electrolytic solutions at several pH values; their efficiency was close to the efficiency predicted by the thermodynamic approach. Therefore, this model allows one to estimate the maximum energy harvesting of neutralization pseudocapacitors and financial return for the treatment of acid wastewater, contributing to sustainable growth. (AU)

• FAPESP's process: 15/16867-9 - Neutralization and Mixing Entropy Batteries
• Grantee: Fritz Cavalcante Huguenin
• Support Opportunities: Regular Research Grants