Mn3O4/p(DCPD)HIPE nanocomposites as an efficient catalyst for oxidative degradation of phenol

Abstract

The increase in the amount of wastewater containing organic pollutants in various industrial processes creates serious problems for the environment. Sulfate radical-based advanced oxidation process (AOP) is an effective route to remove pollutants from wastewater. However, designing a new nano-based catalyst to generate sulfate radicals is an important factor for the AOP. For this vision, porous trimanganese tetraoxide-polydicyclopentadiene (Mn3O4/pDCPD) nanocomposite, having an open-cell structure, was successfully designed via high internal phase emulsion (HIPE) and ring-opening metathesis polymerization (ROMP) approaches. The effect of Mn3O4 nanoparticle concentration on the structure was investigated, and the resulting Mn3O4/p(DCPD)HIPE nanocomposites were fully characterized by FT-IR, XRD, FE-SEM, TEM, solid-state 13C CPMAS NMR, DSC, and TGA analysis. The selected nanocomposite containing 5 wt% of Mn3O4 was used as a model catalyst to mediate the heterogeneous oxidation of phenol in the presence of oxone. It is concluded that Mn3O4/p(DCPD)HIPE nanocomposite is a highly active catalyst to generate sulfate radicals for phenol degradation. Complete removal of 25 mg/L phenol was achieved in 30 min under the conditions of [catalyst] = 0.8 g/L, [oxone] = 2 g/L, and T = 25 °C. The phenol degradation followed the pseudo-first-order kinetic model, and the highest kinetic constant of 0.0611 min−1 was achieved. No significant loss in the activity of the catalyst was determined after four consecutive cycles.