Supercritical Fenton Oxidation: New Advanced Oxidation Technology

The roles of H2O2 in supercritical water oxidation (SCWO) were investigated. The results showed that some of the H2O2 could persist for a short time in SCW, and organic pollutants were mainly oxidized by the O2 generated from the H2O2 in SCWO. However, the introduction of Fe2+ into the SCWO system with H2O2 formed a new Fenton oxidation environment, i.e., supercritical Fenton oxidation (SCFO), which showed the cooperative effect of Fenton oxidation and SCWO. Comparative experiments of phenol and p-aminophenol (PAP) in SCWO and SCFO, respectively, were carried out. The results showed that, in the SCFO system, the CO2 yield from the oxidative degradation of phenol-simulated wastewater (766.0  mg/L) in 45s could reach 73.3%, much higher than that in the SCWO (49.2%) under the same conditions. After 8 min, the CO2 yield in SCFO (97.4%) was also significantly higher than that in SCWO (89.4%). The degradation efficiency of PAP-simulated wastewater (272.5  mg/L) in the SCFO system exceeded 94.3%, especially under acidic conditions, and the degradation efficiency reached 97.4%, much higher than that in the SCWO system (86.2%).