TY - JOUR
T1 - Reactive species and mechanisms of perfluorooctanoic acid (PFOA) degradation in water by cold plasma
T2 - The role of HV waveform, reactor design, water matrix and plasma gas
AU - Papalexopoulou, K.
AU - Huang, X.
AU - Ronen, A.
AU - Aggelopoulos, C. A.
N1 - Publisher Copyright: © 2024 Elsevier B.V.
PY - 2024/8/21
Y1 - 2024/8/21
N2 - The scope of this study was to optimize dielectric barrier discharge (DBD) plasma for the degradation of perfluorooctanoic acid (PFOA) in water by comparing several critical aspects such as pulsed-plasma waveform (nanosecond and microsecond high voltage (HV) pulses), reactor configuration (gas–liquid treatment and underwater plasma bubbles), water matrix and plasma gas. The physicochemical properties and species concentration of plasma-treated water, under the aforementioned conditions, were also determined and correlated with PFOA degradation. PFOA was more efficiently degraded by air–liquid DBD compared to DBD-based underwater air-plasma bubbles consistent with the surfactant nature of PFOA and the more intense plasma-liquid interaction and species formation prevailing during gas–liquid treatment compared to plasma bubbles treatment. After 30 min of gas–liquid DBD treatment, the degradation of PFOA in ultrapure water was >99.9, 98.8, 95.1 and 63% under air-, N2-, Ar- and O2-plasma respectively, whereas its degradation was almost equally effective in the whole range of its initial concentration (10 to 0.1 mg/L). Air was almost equally effective at degrading PFOA in ultrapure and tap water, while argon was much more effective at degrading PFOA in tap water (>99.9% after 20 min) possibly due to the prevailing alkaline conditions (pH ∼8.7) favoring its degradation. Faster PFOA degradation was achieved under HV micropulses compared to HV nanopulses. Nevertheless, in terms of energy requirements, HV nanopulses were superior to HV micropulses, with the lowest electrical energy per order achieved under nanopulsed-argon (∼23.6 kWh/m3). The results of this study could contribute important knowledge to the development of plasma-based treatment of PFOA-contaminated water.
AB - The scope of this study was to optimize dielectric barrier discharge (DBD) plasma for the degradation of perfluorooctanoic acid (PFOA) in water by comparing several critical aspects such as pulsed-plasma waveform (nanosecond and microsecond high voltage (HV) pulses), reactor configuration (gas–liquid treatment and underwater plasma bubbles), water matrix and plasma gas. The physicochemical properties and species concentration of plasma-treated water, under the aforementioned conditions, were also determined and correlated with PFOA degradation. PFOA was more efficiently degraded by air–liquid DBD compared to DBD-based underwater air-plasma bubbles consistent with the surfactant nature of PFOA and the more intense plasma-liquid interaction and species formation prevailing during gas–liquid treatment compared to plasma bubbles treatment. After 30 min of gas–liquid DBD treatment, the degradation of PFOA in ultrapure water was >99.9, 98.8, 95.1 and 63% under air-, N2-, Ar- and O2-plasma respectively, whereas its degradation was almost equally effective in the whole range of its initial concentration (10 to 0.1 mg/L). Air was almost equally effective at degrading PFOA in ultrapure and tap water, while argon was much more effective at degrading PFOA in tap water (>99.9% after 20 min) possibly due to the prevailing alkaline conditions (pH ∼8.7) favoring its degradation. Faster PFOA degradation was achieved under HV micropulses compared to HV nanopulses. Nevertheless, in terms of energy requirements, HV nanopulses were superior to HV micropulses, with the lowest electrical energy per order achieved under nanopulsed-argon (∼23.6 kWh/m3). The results of this study could contribute important knowledge to the development of plasma-based treatment of PFOA-contaminated water.
KW - Cold plasma
KW - Dielectric barrier discharge
KW - Nanosecond pulses
KW - PFOA
KW - Underwater plasma bubbles
KW - Water treatment
UR - http://www.scopus.com/inward/record.url?scp=85186768592&partnerID=8YFLogxK
U2 - https://doi.org/10.1016/j.seppur.2024.126955
DO - https://doi.org/10.1016/j.seppur.2024.126955
M3 - Article
SN - 1383-5866
VL - 342
JO - Separation and Purification Technology
JF - Separation and Purification Technology
M1 - 126955
ER -