Efficient ozonation of reverse osmosis concentrates from petroleum refinery wastewater using composite metal oxideloaded alumina.

Novel Mn-Fe-Mg- and Mn-Fe-Ce-loaded alumina (Mn-Fe-Mg/Al₂O₃ and Mn-Fe-Ce/Al₂O₃) were developed to catalytically ozonate reverse osmosis concentrates generated from petroleum refinery wastewaters (PRW-ROC). Highly dispersed 100-300-nm deposits of composite multivalent metal oxides of Mn (Mn²⁺, Mn³⁺, and Mn⁴⁺), Fe (Fe²⁺ and Fe³⁺) and Mg (Mg²⁺), or Ce (Ce⁴⁺) were achieved on Al₂O₃ supports. The developed Mn-Fe-Mg/Al₂O₃ and Mn-Fe-Ce/Al₂O₃ exhibited higher catalytic activity during the ozonation of PRW-ROC than Mn-Fe/Al₂O₃, Mn/Al₂O₃, Fe/Al₂O₃, and Al₂O₃. Chemical oxygen demand removal by Mn-Fe-Mg/Al₂O₃- or Mn- Fe-Ce/Al₂O₃-catalyzed ozonation increased by 23.9% and 23.2%, respectively, in comparison with single ozonation. Mn-Fe-Mg/Al₂O₃ and Mn-Fe-Ce/Al₂O₃ notably promoted .OH generation and .OH-mediated oxidation. This study demonstrated the potential use of composite metal oxide-loaded Al₂O₃ in advanced treatment of bio-recalcitrant wastewaters. [ABSTRACT FROM AUTHOR]