Electroneutralization desalination with spontaneous chemoelectric power generation

Aishwarya Rani; Shu-Yuan Pan; Suraj Negi; Yu-I Lin

doi:10.1016/j.watres.2024.121720

Electroneutralization desalination with spontaneous chemoelectric power generation

Water Res. 2024 May 3:257:121720. doi: 10.1016/j.watres.2024.121720. Online ahead of print.

Authors

Aishwarya Rani¹, Shu-Yuan Pan², Suraj Negi¹, Yu-I Lin¹

Affiliations

¹ Department of Bioenvironmental Systems Engineering, College of Bioresources and Agriculture, National Taiwan University, No. 1, Section 4, Roosevelt Rd, Da'an District, Taipei 10617, Taiwan, PR China.
² Department of Bioenvironmental Systems Engineering, College of Bioresources and Agriculture, National Taiwan University, No. 1, Section 4, Roosevelt Rd, Da'an District, Taipei 10617, Taiwan, PR China; Agricultural Net-Zero Carbon Technology and Management Innovation Research Center, College of Bioresources and Agriculture, National Taiwan University, No. 1, Section 4, Roosevelt Rd, Da'an District, Taipei 10617, Taiwan, PR China. Electronic address: sypan@ntu.edu.tw.

PMID: 38728780
DOI: 10.1016/j.watres.2024.121720

Abstract

This study designs a novel electroneutralization desalination cell using reaction heat from acidic-alkaline wastewater neutralization to desalinate wastewater and generates chemoelectric power. Several key performance indicators are measured in terms of the energy, environmental and economic aspects of the system, including the ionic flux, the electrical energy produced, the electrical energy consumption for desalination, parasitic losses, overall energy conversion efficiency and desalination performance. The maximum peak power density is ∼31.5 mW/cm² at 83.5 mA/cm² and the desalination efficiency is 62 % using brine. The overall energy conversion efficiency is ∼81.8 % and the desalination followed the zero-order reaction. Assuming a 1.5 million litres per day treatment capacity integrated with reverse osmosis, the system has environmental and economic benefits, with 44.5 kg-CO₂eq greenhouse gas emissions per cubic meter of treated brine, and a discounted payback period of 4.2 years. This study demonstrates a pioneering electroneutralization technique for self-sufficient brine valorization and wastewater reclamation.

Keywords: Circular economy; Clean energy; Decarbonization; Net-zero; Water-energy-carbon nexus.