Treatment Of High COD Wastewater By Catalytic Oxidation

The composition of oily wasterwater is very complex,which lead to challenges for degradation.The treatment of oily wastewater by heterogeneous Fenton oxidation can avoid a lot of iron sludge produced by traditional Fenton method.It is potential for oily wastewater treatment.In this paper,the simulated oily wastewater and refirnery wastewater were processed by catalytic oxidation.The effect factors of heterogeneous Fenton oxidation and the kinetic characteristics of catalytic oxidation were systematically studied by using a kettle reactor and a tube reactor,respectively.The main results are as follows:High pressure digestion tank was used as kettle reactor.H₂O₂ high temperature oxidation method was employed for the treatment of the oily wastewater.The influence of four factors on the oxidation effect was determined by orthogonal test and they decrease in the order of reaction temperature>reaction time>initial COD>n?COD?:n?H₂O₂?ratio.The apparent reaction order of H₂O₂ catalytic oxidation of simulated oily wastewater was approximately 1;the activation energy of reaction is51.06kJ mol^-1.When pyrite,magnetite and Fe₂O₃ were used as catalysts,the activation energy of H₂O₂ high-temperature catalytic oxidation is 27.85kJ·mol^-1,64.96kJ·mol^-1and 60.76kJ·mol^-1,respectively.The tube reactor was used for the inverstigation of the dynamic reaction.It shows that the apparent reaction order of H₂O₂ catalytic oxidation of simulated oily wastewater using pyrite and activated carbon as catalysts was approximately 1 on the condition of flow rate was 5mL/h;reaction temperature 200?,initial COD 1000mg/L and n?COD?:n?H₂O₂?,1:1.The molecular compositon and its transformation of dissolved organic matter?DOM?were revealed by Fourer transform ion cyclotron resonance mass spectrometry?FT-ICR MS?.The compositon of refinery wastewater DOM is supercomplex,in which more than 50 class species were assigned in a single mass spectrum.H₂O₂ high temperature oxidation can effectively remove the DOM,especially for sulfur and nitrogen containing compounds.The H/C and O/C ratios of DOM were both increased and small molecular were produced in the process.