Optimization of gas–liquid hybrid pulsed discharge plasma for p-nitrophenol contaminated dredged sediment remediation

•Pulsed discharge plasma is employed for dredged sediment remediation.•The coupling of pulsed power supply and discharge plasma reactor is evaluated.•Feasibility and efficacy of p-nitrophenol degradation in sediment is studied.•High p-nitrophenol degradation efficiency and energy yield are obtained.

p-Nitrophenol (PNP) removal in dredged sediment during pulsed discharge plasma process was studied in terms of adjustable trim capacitance, electrode distance and gas-flow rate. PNP degradation efficiency reached up to 88.5% under the conditions of adjustable trim capacitance of 2.0 nF, electrode distance of 16 mm, and air flow rate of 0.8 L min−1. To a certain extent, increasing the adjustable trim capacitance and decreasing the electrode distance leaded to high PNP degradation efficiency. An appropriate air flow rate was determined for gaining relatively high PNP removal efficacy. PNP mineralization was analyzed by UV–Vis spectrum, COD, and TOC evolution.