Performance of ceramic foams as gas–liquid contactors for phenol wet oxidation in the trickle regime

Abstract

The scope of this work was to study the performance of a foam packed bed reactor for homogeneous wet oxidation of phenol, a relevant gas–liquid reaction in industrial wastewater treatment. The use of open-cell foams, macroporous structures constituted by interconnected channels with high bed porosity and surface area, largely enhances interfacial mass transfer rates, without significantly increasing pressure drop.Phenol (45mol/m3) was oxidized in the aqueous phase by oxygen dissolved from the gas (6bar), using Cu(II) salt (0.44mol/m3) as homogeneous catalyst. Experiments were performed in a continuous reactor with partial liquid recycle. The fresh feed and total reactor flow rates have been adjusted to obtain different space times (395–1177s) and liquid superficial velocities (0.84–3.5×10−3m/s). Temperature has also been varied within the range 110–140°C. Experimental phenol conversions are compared to that obtained from a simple perfect mixing model. Finally, the performance of the foam has been compared to that of a random packing bed made of spheres.