Valorization of high-salinity effluents for CO2 fixation and hypochlorite generation

• Published in: Chemosphere (Oxford) 2021-12, Vol.285, p.131359-131359, Article 131359
• Main Authors: Acosta-Santoyo, Gustavo, León-Fernández, Luis F., Bustos, Erika, Cañizares, Pablo, Rodrigo, M.A., Llanos, Javier
• Format: Article
• Language: English
• Subjects: Absorption; Carbon dioxide fixation; Chloralkaline process; Electrolysis; Value-added products
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2021.131359

In this work, it is evaluated the fixation of carbon dioxide using the alkali generated in the chloralkaline process, as a new way to face the treatment of highly saline wastewater, in which it is aimed not to separate the wastewater into concentrated and diluted streams but to recover value-added products (VAPs) while contributing to minimize the carbon fingerprint of other processes. The electrolytic process is combined with a reactive absorption and with a crystallization, demonstrating the formation of pure nahcolite, hypochlorite (or chlorine) and hydrogen from the waste. Carbon dioxide is captured with a current efficiency over 90% and the energy required is around 0.65 kWh kg−1, which is very promising from the view point of sustainability, considering that the system can be easily powered with green energies. [Display omitted] •CO2 is electrochemically captured with a current efficiency of 93%.•The system is not mass transfer limited within the range of concentrations tested.•An almost pure NaHCO3 solid is obtained by cooling the CO2-enriched solution.•The energy cost of CO2 capture is estimated to be 0.65 kWh kg−1.•The efficiency hypochlorite production increases with current density.