Enhancement degradation of formaldehyde by MgO/γ-Al2O3 catalyzed O3/H2O2 in a rotating packed bed

Abstract

Abstract The MgO/γ-Al2O3 catalyzed O3/H2O2 process was proposed to improve the degradation of formaldehyde in a rotating packed bed (RPB) and solve the difficult recycling problem of catalysts. Spherical MgO/γ-Al2O3 catalyst was prepared by the deep coating method and then used as the packing of the RPB for degradation of formaldehyde in wastewater, and characterized by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), and energy dispersive analysis of X-rays (EDAX). The results show that MgO can be uniformly dispersed on the surface of γ-Al2O3, and the surface area is 207.167 m2/g. There are abundant active sites on surface of the prepared catalyst. And the removal rates of formaldehyde (2200 mg/L) and mineralization (TOC) are 99.85% and 97.37% after 60 min by using 3MgO/Al2O3, respectively, which meets the Grade 3 standard set in the Chinese National Standards for Integrated Wastewater (GB 8978-1996). Compared with the bubbling reactor (BR), the coupling of RPB and spherical MgO/γ-Al2O3 catalyst results in a 16.5% and 25.28% increase in the removal rate of formaldehyde and TOC, respectively. The removal rate is still as high as 87% for the catalyst after 6 cycles.