Synergistic degradation of polyacrylamide in polyacrylamide-containing wastewater via non-equilibrium plasma and Mn–Ce/AC composite catalyst

Abstract

Polyacrylamide (PAM), a major component of polymer-containing wastewater, is challenging to degrade due to its high viscosity. This study investigates the synergistic degradation of PAM using non-equilibrium plasma generated by a dielectric barrier discharge (DBD) reactor in combination with a Mn+Ce/AC composite catalyst. PAM solution was employed to simulate industrial wastewater, and degradation mechanisms were probed via Fourier Transform Infrared Spectroscopy (FTIR), X-ray Photoelectron Spectroscopy (XPS), and X-ray Diffraction (XRD) analyses. Results demonstrate that the Mn+Ce/AC catalyst significantly enhances reactive species generation, accelerating PAM removal while reducing energy consumption. Increasing catalyst dosage led to rapid decreases in pH and viscosity, alongside improvements in electrical conductivity and energy efficiency. Under optimal conditions (21 kV, 200 mL/min, 180 mg catalyst), degradation efficiency reached 94.4 % at 120 min, exceeding plasma-alone treatment by 10.3 %. The viscosity of the PAM solution was reduced by up to 93 % within 30 min, compared to 55.6 % in the control group. Characterization analyses confirmed that the catalyst retained its structural integrity and functional stability, which could be further enhanced by optimizing the Mn/Ce ratio. This work demonstrates that plasma-assisted Mn+Ce/AC catalysis offers an efficient, energy-saving, and scalable strategy for polymer-containing wastewater treatment, providing mechanistic insights into catalyst-assisted plasma degradation processes.