Experimental study on reducing the viscosity of sewage containing PAM catalyzed by low temperature plasma synergistic AC/Mn + TiO2

With the wide application of polymer flooding technology in oil fields, wastewater containing PAM (polyacrylamide) is produced. Its high viscosity makes it difficult to degrade. In this paper, the low-temperature plasma produced by DBD (Dielectric Barrier Discharge) was studied to reduce the viscosity of wastewater containing PAM under the synergistic action of AC (Activated carbon)/Mn + TiO2 catalyst. The effects of different amount of AC/Mn + TiO2 catalyst, discharge voltage and initial concentration of solution on viscosity reduction were studied. The change of functional groups in wastewater containing PAM was detected by FTIR (Fourier transform infrared absorption spectrometer), and the mechanism of catalytic viscosity reduction was analysed. The AC/Mn + TiO2 catalysts were analysed by XPS (X-ray photoelectron spectroscopy), XRD (X-Ray Diffraction) and ESEM (Field emission electron microscopy). With the increase of discharge voltage, the effect of catalytic viscosity reduction is enhanced. After 10 min of discharge, the effect of catalytic viscosity reduction is significantly enhanced. The catalytic viscosity reduction is best when discharge voltage is 18 KV and discharge time is 30 min. The viscosity reduction of polyacrylamide solution by low-temperature plasma AC/Mn + TiO2 is significant. When the amount of AC/Mn + TiO2 catalyst added is 544 mg, the viscosity of polymer containing solution can be reduced from 1758 mPa·s to 11.9 mPa·s, and the shear rate can be changed from 0 1/sec to 30 1/sec after the discharge for 30 min. The functional groups in solution did not change significantly and the element composition of AC/Mn + TiO2 catalyst did not change before and after catalytic discharge.