Pulsed corona discharge oxidation of aqueous carbamazepine micropollutant

The anti-epileptic drug carbamazepine (CBZ) receives growing attention due to slow biodegradation and inherent accumulation in the aquatic environment. The application of a gas-phase pulsed corona discharge (PCD) was investigated to remove CBZ from synthetic solutions and spiked wastewater effluent from a municipal wastewater treatment facility. The treated water was showered between high voltage (HV) wires and grounded plate electrodes, to which ultra-short HV pulses were applied. CBZ was readily oxidized and 1-(2-benzaldehyde)-4-hydroquinazoline-2-one (BQM) and 1-(2-benzaldehyde)-4-hydro-quinazoline-2,4-dione (BQD) were identified as the most abundant primary transformation products, which, contrary to CBZ ozonation data available in the literature, were further easily oxidized with PCD: BQM and BQD attributed to only a minor portion of the target compound oxidized. In concentrations commonly found in wastewater treatment plant effluents (around 5 µg L⁻¹), up to 97% reduction in CBZ concentration was achieved at mere 0.3 kW h m⁻³ energy consumption, and over 99.9% was removed at 1 kW h m⁻³. The PCD application proved to be efficient in the removal of both the parent substance and its known transformation products, even with the competing reactions in the complex composition of wastewater.