Selective electrochemical ammonium recovery with Prussian blue analogue materials
Journal
Desalination
Journal Volume
633
Start Page
120255
ISSN
00119164
Date Issued
2026-09-01
Author(s)
Kim, Kwiyong
Abstract
Ammonium (NH4+) recovery from wastewater is gaining attention as a strategy to convert a major pollutant into a reusable nitrogen resource, thereby supporting a circular nitrogen economy. Among emerging electrochemical approaches, Prussian blue analogues (PBAs) have recently attracted interest as redox-active host materials capable of selectively capturing NH4+ through Faradaic intercalation under low applied voltages. The objective of this review is to critically examine the current state of PBA-based electrochemical ammonium recovery and to clarify the material, mechanistic, and system-level factors that govern its performance. To this end, we first summarize the crystal chemistry, redox behavior, and ion-storage characteristics of PBAs relevant to NH4+ intercalation. We then discuss the physicochemical origins of NH4+ selectivity, with particular emphasis on ionic size compatibility, hydration energetics, host-guest interactions, and kinetic effects in competition with coexisting ions. Next, we review representative PBA-based recovery configurations, including rocking-chair battery-type cells, hybrid asymmetric systems, and multistage concentration processes, and compare their performance in terms of adsorption capacity, selectivity, energy consumption, and cycling stability. Recent advances, such as spontaneous ammonium uptake enabled by redox reservoirs, microbially powered systems, and PBA-modified ion-selective membranes, are also highlighted. Finally, PBA-based platforms are critically compared with other electrochemical ammonium recovery routes, including electrochemical stripping, electrodialysis, and capacitive deionization, to identify their advantages, current limitations, and practical challenges for scale-up. Overall, this review shows that PBAs offer a promising route for low-voltage and selective ammonium recovery, but further progress is needed in improving long-term stability, NH4+/K+ discrimination, standardized performance evaluation, and validation under realistic wastewater conditions.
Subjects
Ammonia
Intercalation
Nutrient recovery
Prussian blue analogues
Selectivity
Publisher
Elsevier B.V.
Type
journal article