The Construction Of Novel Flow-through Electro-fenton Reactor And Its Highly Energy-Efficient Treatment For Organic Pollutants

As the new emerging force of advanced oxidation processes(AOPs), Electro-Fenton(EF) technology has drown great attention from all over the world. However, it exits a series of drawbacks in the traditional single batch system, like long residence time, low oxidation efficiency and difficulty in practical application. So it is necessary to develop a high-efficiency EF system. The research was to express the high-efficiency property of EF oxidation and the value in reality via the coupling of Adsorption-oxidation and sequential flow process technologies. The main contains includes the design of EF reactor, degradation of organic pollutants using the modification active carbon fiber(ACF) and graphite felt(GF), possible mechanism of the pollutants removal and optimization of operational parameters. The main conclusions follows below;1?Here, we design the flow-through reactor including in-out opening, electrodes, the titanium ring, the insulating rubber ring. The solution and gas flow through the reactor from below to up. The experiment proved primarily that the cathode was fixed below the DSA anode using flow-through system had greater pollution removal.2?OG was degraded in cyclic flow-through EF system. The ACF was modified by carbon black(CB) and polytetrafluoroethylene(PTFE). Lots of CB particle and PTFE were adhered to the fibers shown in the SEM figure. The OG removal reached above 98% with 300 m L 100 mg/L OG at CB:PTFE=1:3, J=7 m L/min, V=50 m L/min, C(Fe2+)=0.3 m M, p H=3, C(Na2SO4)=0.05 M at 120 min, and the TOC removal was 55.4%. The results revealed that the adsorption ability of cathode could enforce EF oxidation ability. The operational parameters such as current density and flow rate were optimized. ?OH was proved to be the main oxidant and the cathodic adsorption and anodic oxidation ability also made a contribution to the OG removal. The electrode especially the cathode could regenerate at home position.3 ? MB was regarded as the target pollutant and degraded in the highly energy-efficient flow-through EF system. The graphite felt modified by CB and PTFE had high H2O2 production with low energy consumption with the value of 5.2 k Wh/(kg H2O2). The modified cathode was characterized by scanning electron microscopy(SEM), nitrogen adsorption-desorption study and contact angle. The flow-through E-Fenton system was compared to the flow-by and regular one, and confirmed to be better MB removal and TOC degradation. The operational parameters such as current density, p H,Fe2+ concentration and flow rate were optimized. The MB of the effluents could continue above 90% and TOC removal efficiency could reach 57.9% and the energy consumption was 23.0 k Wh/kg TOC at a current density of 50 m A, p H=3, C(Fe2+)=0.3 m M, C(Na2SO4)=0.05 M, C0(MB)=50 mg/L, J=7 m L/min in the flow-through EF system. Five more organic pollutants including Orange II(OG), Tartrazine, Acetylsalicylic acid(ASA), Tetracycline(TC) and 2,4-Dichlorophen(2,4-DCP) were introduced and the values of electric energy consumption(EEC) were 29.6?49.4?28.6?83.3?49.8 k Wh/kg TOC respectively. That proved that the system had high pollutant mineralization ability compared with literatures. ?OH was proved to be the main oxidizing species in this system. After 5 times operation, the system, especially cathode, still showed good stability. Overall, all the results indicated the great potential of the novel system for degradation of organic pollutants.