TY - JOUR
T1 - Enhanced ammonium removal and recovery from municipal wastewater by asymmetric CDI cell equipped with oxygen functionalized carbon electrode
AU - Pastushok, Olga
AU - Ramasamy, Deepika L.
AU - Sillanpää, Mika
AU - Repo, Eveliina
N1 - Publisher Copyright:
© 2021 Elsevier B.V.
PY - 2021/11/1
Y1 - 2021/11/1
N2 - Following the concept of sustainable development and circular economy, the Capacitive Deionization (CDI) was examined for the removal and recovery of ammonium (NH4+) ions from municipal wastewater towards prevention of eutrophication and obtaining a valuable component for fertilizers production. The electrosorption study was conducted in the symmetric CDI cell, composed of activated carbon (AC) electrodes, and an asymmetric CDI cell, equipped with oxygen functionalized AC (AC-ox) cathode. The asymmetric CDI cell was demonstrated the enhanced performance in terms of the removal efficiency towards ammonium ions (83%) and the related energy consumption (and 0.085 kWh/mmol NH4+), compared to the symmetric one with the following results: 30% removal of NH4+ ions and 0.215 kWh/mmol NH4+. The beneficial performance of the AC-ox electrode also has been observed in terms of NH4+ recovery: 20% recovered NH4+ ions, compared to 9% NH4+ recovered ions by AC pristine electrode. The presence of competitive ions hindered the electrosorption efficiency. Nevertheless, the time-dependent selectivity of the AC-ox electrode towards NH4+ ions was observed. The specific capacities of the symmetric and asymmetric cells at 5 mV/s were calculated to be 10.4 F/g and 18.3 F/g, respectively. Material characterization of AC before and after oxidation explained the enhanced CDI performance of the AC-ox electrode due to the increased hydrophilicity and additional oxygen functionalities on the electrode surface.
AB - Following the concept of sustainable development and circular economy, the Capacitive Deionization (CDI) was examined for the removal and recovery of ammonium (NH4+) ions from municipal wastewater towards prevention of eutrophication and obtaining a valuable component for fertilizers production. The electrosorption study was conducted in the symmetric CDI cell, composed of activated carbon (AC) electrodes, and an asymmetric CDI cell, equipped with oxygen functionalized AC (AC-ox) cathode. The asymmetric CDI cell was demonstrated the enhanced performance in terms of the removal efficiency towards ammonium ions (83%) and the related energy consumption (and 0.085 kWh/mmol NH4+), compared to the symmetric one with the following results: 30% removal of NH4+ ions and 0.215 kWh/mmol NH4+. The beneficial performance of the AC-ox electrode also has been observed in terms of NH4+ recovery: 20% recovered NH4+ ions, compared to 9% NH4+ recovered ions by AC pristine electrode. The presence of competitive ions hindered the electrosorption efficiency. Nevertheless, the time-dependent selectivity of the AC-ox electrode towards NH4+ ions was observed. The specific capacities of the symmetric and asymmetric cells at 5 mV/s were calculated to be 10.4 F/g and 18.3 F/g, respectively. Material characterization of AC before and after oxidation explained the enhanced CDI performance of the AC-ox electrode due to the increased hydrophilicity and additional oxygen functionalities on the electrode surface.
KW - Activated carbon electrode
KW - Ammonium ions
KW - Capacitive deionization
KW - Desorption
KW - Electrosorption
KW - Oxidation
UR - http://www.scopus.com/inward/record.url?scp=85108730436&partnerID=8YFLogxK
U2 - 10.1016/j.seppur.2021.119064
DO - 10.1016/j.seppur.2021.119064
M3 - Article
AN - SCOPUS:85108730436
SN - 1383-5866
VL - 274
JO - Separation and Purification Technology
JF - Separation and Purification Technology
M1 - 119064
ER -