The aim of this study was to develop a new pulsed switching peroxi-coagulation system to control hydroxyl radical(∙OH)production and to enhance 2,4-Dichlorophenoxyacetic acid(2,4-D)degradation.The system was constructed with a sacrifice iron anode,a Pt anode,and a gas diffusion cathode.Production of H_(2)O_(2) and Fe^(2+)was controlled separately by time delayers with different pulsed switching frequencies.Under current densities of 5.0 mA/cm^(2)(H_(2)O_(2))and 0.5 mA/cm^(2)(Fe^(2+)),the∙OH production was optimized with the pulsed switching frequency of 1.0 s(H_(2)O_(2)):0.3 s(Fe^(2+))and the ratio of H_(2)O_(2) to Fe^(2+)molar concentrations of 6.6.Under the optimal condition,2,4-D with an initial concentration of 500 mg/L was completely removed in the system within 240 min.The energy consumption for the 2,4-D removal in the system was much lower than that in the electro-Fenton process(686 vs.13610 kWh/kg TOC).The iron consumption in the system was~20 times as low as that in the peroxi-coagulation process(19620 vs.3940400 mg/L)within 240 min.The system should be a promising peroxi-coagulation method for organic pollutants removal in wastewater.
The aim of this study was to synthesize a novel lanthanum(La)doped catalyst and to investigate antipyrine removal in wastewater using the Fenton-like process with the catalyst.The La-doped Co-Cu-Fe catalyst was synthesized using the modified hydrothermal method.Results showed that the Ladoped catalyst had higher specific surface area and lower particle size than the catalyst without La doping(i.e.,the control)(267 vs.163 m2/g and 14 vs.32 nm,respectively).Under the conditions of catalyst dosage 0.5 g/L,H2O2 concentration 1.70 g/L,and NaHCO3 0.1g/L,the antipyrine removal within 60 min using the Fenton-like process with the La-doped catalyst was much higher than that with the control(95%vs.54%).The hydroxyl radical concentration with the La-doped catalyst within 60 min was two times higher than that with the control(49.2 vs.22.1 gg/L).The high catalytic activity of La-doped catalyst was mainly attributed to its high specific surface area based on the X-ray photoelectron spectroscopy result.Our La-doped catalyst should have great potential to remove antipyrine in wastewater using the heterogeneous Fenton-like process.
