Optimization of the electrooxidation of aqueous ammonium sulfite for hydrogen production at near-neutral pH using response surface methodology

Raúl A. Márquez-Montes, Raúl E. Orozco-Mena, Alejandro A. Camacho-Dávila, Samuel Pérez-Vega, Virginia H. Collins-Martínez, Víctor H. Ramos-Sánchez

Research output: Contribution to journalArticlepeer-review

10 Scopus citations

Abstract

Sulfur-based thermochemical cycles, such as the hybrid sulfur-ammonia (HySA) cycle, offer a valuable approach in which hydrogen is produced by exploiting sulfur dioxide (potentially pollutant emissions) through the electrochemical oxidation of aqueous sulfite. In this study, the effect of pH on electrooxidation rate was assessed by comparing different reaction scenarios. Then, a Central Composite Design (CCD) combined with a Response Surface Methodology (RSM) was used to optimize batch electrooxidation of ammonium sulfite at near-neutral pH. Results show that the use of an anion exchange membrane (AEM) greatly improves sulfite electrooxidation rate while pH is effectively stabilized. Furthermore, a second-order model that relates applied potential and sulfite concentration with the normalized half-life of the reaction was obtained and verified experimentally at long-term batch electrooxidations. A good agreement between the model and experimental tests, adequate hydrogen recoveries and low sulfur crossover through the membrane demonstrate practical robustness of this approach.

Original languageEnglish (US)
Pages (from-to)13821-13831
Number of pages11
JournalInternational Journal of Hydrogen Energy
Volume45
Issue number27
DOIs
StatePublished - May 18 2020
Externally publishedYes

Keywords

  • Anion exchange membrane
  • Electrochemical reactor
  • Hydrogen production
  • Response surface methodology
  • Sulfite electrooxidation

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment
  • Fuel Technology
  • Condensed Matter Physics
  • Energy Engineering and Power Technology

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