Oxidation of aromatic components in water and seawater by a catalytic membrane process

Oxidation of organic components in dilute aqueous solutions was successfully accomplished by applying a catalytic membrane contactor with Pt as the catalyst, a process called WaterCatox, at temperatures as low as 60–80 °C. The principle of the process is innovative but simple: by leading the waste water along the surface of a nano-catalytic contactor with a well controlled gas/liquid interface, spontaneous oxidation of the waste substances present in the effluents is induced. To maintain the oxidation process, oxygen from air is supplied continuously through the porous contactor wall. The compactness of the WaterCatox process offers a potential for off-shore applications in order to treat produced water (PW). Mixture of key aromatic components in seawater was prepared to represent produced water and was treated by the catalytic membrane contactor. After 24 h of recycled flow over a membrane contactor, 97% of the C2-phenol was removed from the mixture. Catalytic oxidation has been found to be responsible for 72% of the removal, while evaporation contributed with 25%. Although by-product formation was found, no halogenated by-products were found in the treated solution. Pt catalyst deactivation was observed after treating solutions containing C2-phenol and other aromatic components. The catalytic activity was partially recovered by heat treating the membrane in hydrogen at 200 °C.

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► Successful application of a catalytic membrane contactor for produced water polishing.
► Formic acid oxidation in water at 80 °C, 1 bar.
► 2,4-dimethyl phenol oxidation in water and in sea water at 60 °C, 1 bar.
► Pt catalyst deactivation and regeneration.