Catalytic Ozonation Of Refractory Petroleum Refinery Wastewater Using Composite Metal Oxides Loaded Alumina

The newly issued Emission Standard of Pollutants for Petroleum Refining Industry?GB 31570-2015?upgrades the discharge standards for petroleum refinery wastewater.An efficient advanced treatment process is needed to meet the discharge standard.Catalytic ozonation processes?COPs?using various catalysts are the most promising treatment processes for PRW.However,the lack of commercially feasible catalysts hinders the full-scale application of COPs.In this study,a serial of composite metal oxides loaded alumina?Al₂O₃?catalysts were prepared and characterized.The potential for advanced treatment of refractory petroleum refinery wastewater?RPRW?in COPs and the catalytic mechanisms were investigated.?1?A novel composite Mg,Fe and Ce oxides loaded alumina?Mn-Fe-Ce/Al₂O₃?catalyst assisted COP for advanced treatment of a biological process effluent?EBP?was designed.Mn-Fe-Ce/Al₂O₃-COP enhances COD removal of EBP by approximately30% in comparison with a single ozonation and by 10-20% relative to Mn/Al₂O₃-COP,Fe/Al₂O₃-COP and Mn-Fe/Al₂O₃-COP.The evenly dispersed composite metal oxides on the catalyst surface significantly promote hydroxyl radical?·OH?mediated oxidation.The treated EBP meets the standard of GB31570-2015.?2?A novel composite Mn,Fe and Mg oxides loaded alumina?Mn-Fe-Mg/Al₂O₃?assisted COP for advanced treatment of a reverse osmosis concentrate?ROC?was designed.Mn-Fe-Mg/Al₂O₃-COP enhances COD removal of ROC by approximately27% relative to a single ozonation.The metal oxides,Mn?Mn2+,Mn3+ and Mn4+?,Fe?Fe2+ and Fe3+?and Mg?Mg2+?at a range of 100nm-300 nm are highly dispersed on the Al₂O₃ support.These metal oxides interact among each other or with support,which promote ·OH generation.The MnOOH and FeOOH are the main drivers of COP;and the MgO has a positive impact on ozonation of ROC.