Heterogeneous Catalytic Ozonation of Refinery Wastewater over Alumina-Supported Mn and Cu Oxides Catalyst

Abstract

An economical method was proposed to develop an efficient alumina-supported manganese (Mn) and copper (Cu) oxides (Mn-Cu-O/Al 2 O 3 ) catalyst with a high surface area, 184.06 cm 2 g −1 . The catalyst was utilized for degradation refinery wastewater by heterogeneous catalytic ozonation. The effects of various operating variables including pH, ozone and catalyst dosages, and temperature were systematically investigated in detail to obtain the optimized conditions for accelerated degradation of refinery wastewater. The optimum values were as follows: ozone dose 50.0 mg L −1 , catalyst dose 3.0 g L −1 , initial pH = 6.8, T = 17 • C. Refinery wastewater samples were analyzed by chemical oxygen demand (COD) and the results indicated that kinetics of COD followed a pseudo-first-order degradation. Moreover, hydroxyl radical mechanism rather than absorption was proposed, indicating that the surface hydroxyl groups were the active sites that played a significant role in catalytic ozonation.

Continuous Catalytic Ozonation of Antibiotics Using Mn and Cu Oxides on γ-Al2O3 Pellets in a Micropacked Bed Reactor

“…Al 2 O 3 catalyst (PDF 24-0735). The CuO phase (2θ = 35.39°a nd 38.64°) was observed in the XRD pattern of the CuO/γ-Al 2 O 3 catalyst (PDF 48-1548) 23. These results indicate that Mn and Cu oxides are successfully doped on alumina separately.The SEM images (Figure1b−d) show that γ-Al 2 O 3 , MnO 2 / γ-Al 2 O 3 , and CuO/γ-Al 2 O 3 catalysts all have porous surfaces.…”

“…The results also show that ozone could be adsorbed on the surface of the catalyst and decomposed into HO• rapidly due to the presence of hydroxyl and metal active sites (Mn or Cu) on the surface of the catalyst. 23,27 Of course, there is also a direct oxidation reaction led by ozone molecules in this catalytic process. Moreover, phosphoric acid was used to adjust the pH when studying the effect of initial pH on catalytic ozonation.…”

“…Compared to that with a single ozonation (35%), the chemical oxygen demand (COD) removal with γ-Al 2 O 3 increases to 75% within 5 h in a stirred batch reactor. Many studies showed that with alumina as the carrier and metal oxides (MnO 2 , 22 CuO, 23 Fe 2 O 3 , 24 and CeO 2 25 ) as the active components, the degradation efficiency of organic pollutants is significant. For example, Liu et al 26 found that the highest removal efficiencies for quinoline and total organic carbon (TOC) of 95% and 65%, respectively, were achieved after catalytic ozonation with the MnO 2 /Al 2 O 3 catalyst for 90 min.…”

Preparation of Mn/Mg/Ce Ternary Ozone Catalyst and Its Mechanism for the Degradation of Printing and Dyeing Wastewater

“…Ozone catalyst can improve the mass transfer efficiency and utilization of ozone and shorten the reaction time (Zhang et al, 2021;Mansouri et al, 2013). Under optimum conditions, the chemical oxygen demand (COD) removal efficiency can reach 96.3% in the catalytic ozonation of oil refining wastewater with aluminasupported manganese and copper oxides (Deng et al, 2015;He et al, 2021;Jiang et al, 2021). The COD removal rate reached 96% after 120 min when iron and nickel foam was used as the catalyst to catalyze the ozonation of organic pollutants in actual petrochemical wastewater.…”

Catalytic Ozonation of Dairy Farming Wastewater Using a Mn–Fe–Ce/γ-Al2O3 Ternary Catalyst: Performance, Generation, and Quenching of Hydroxyl Radicals

“…Compared to homogeneous catalysts, heterogeneous catalysts in solid form can decompose O 3 more efficiently to produce HO • as well as transform generally insoluble metal elements in the environment from a weak acid to a weak base, which have the advantages of easy separation and reusability. − Heterogeneous catalysts with a transition-metal oxide as the main active component have attracted wide attention because of their high activity, high stability, and low cost. , However, single-metal-supported catalysts such as MgO or MnO 2 cannot meet the demand of practical engineering despite their low price. In recent years, the development of composite-supported transition-metal catalysts has a research focus in heterogeneous catalytic ozonation. − …”