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]