Simultaneous removal of cadmium ions and phenol from water solution by pulsed corona discharge plasma combined with activated carbon

In this paper, an integrated approach, the pulsed corona discharge plasma combined with granular activated carbon (PCDP/GAC), is used for the simultaneous removal of cadmium ions (Cd2+) and phenol in wastewater. Experimental results show that 69.0% Cd2+ and 87.3% phenol can be simultaneously removed from the PCDP/GAC treatment system after 60 mm. This removal efficiency is 27.2% and 11.4% higher than in the GAC adsorption system, respectively, and 65.8% and 60.6% higher than in the PCDP treatment system, respectively. An increasing pulsed voltage is favorable for removal of Cd2+ and phenol. The removal efficiency of Cd2+ and phenol is the highest with oxygen as the feeding gas. At the same input power and an increasing initial phenol concentration, the removal efficiency of Cd2+ and phenol decreases. Scanning electron microscopy and energy-dispersive X-ray spectroscopy show that Cd2+ amount produced on GAC by the discharge treatment in the PCDP/GAC system is higher than that in the GAC adsorption system. Fourier transform infrared spectroscopy shows that O-H, C-H, and C=C bonds on GAC are cleaved, whereas Ar-O-C and C=O groups increase during the PCDP treatment. A possible removal mechanism of Cd2+ and phenol in such a system is proposed. Crown Copyright (C) 2013 Published by Elsevier B.V. All rights reserved.