Intensification of degradation of Sunset Yellow using packed bed in a pulsed high-voltage hybrid gas-liquid discharge system: Optimization of operating parameters, degradation mechanism and pathways

Abstract

The degradation of Sunset Yellow simulated wastewater with a pulsed high-voltage hybrid gas-liquid discharge (PHVHGLD) method was investigated. Packed bed was introduced between two electrodes. Both conducting particles (copper beads and stainless steel beads) and non-conducting particles (activated carbon beads, activated alumina beads, silica gel beads, 3A molecular sieve beads, glass beads and ceramic alumina beads) were selected as the packed bed. The degradation efficiency with conducting particles as the packed bed was higher than that with non-conducting particles. Effects of discharge distance, Fe2+ concentration and several solution conditions on the degradation of Sunset Yellow were studied. Moreover, the effect of Fe2+ concentration on the Sunset Yellow degradation followed the Second-order-kinetics well. The degradation efficiency of simulated wastewater of Sunset Yellow could reach up to 93.8% under the optimal conditions. The degradation mechanism for Sunset Yellow and identification of by-products formed during the degradation process were investigated by UV–vis spectral, FTIR spectral, IC and GC–MS analyses of treated wastewater, based on which a possible degradation pathway for Sunset Yellow using PHVHGLD with a packed bed system was proposed. The PHVHGLD with a packed bed system is a promising technology for dye wastewater treatment.