Backwashable dynamic membrane made of anchored CNT on SiC microfiltration membranes applied to oil in water emulsion filtration

Produced water is the highest liquid stream generated by the petroleum industry. It is most of the time saline water extracted with the petroleum or gas which contains<30 ppm of emulsified oil. SiC membrane material seems promising to treat such industrial wastewater and remove oil droplets but its development is still hindered by fouling phenomena. The present study investigates the filtration performances at lab-scale of a commercial flat sheet SiC membrane (55 cm(2)) and the positive impact of CNTs synthesis by C-CVD process. The SiC pristine membrane exhibited a sharp flux decline of about 96 % for a low filtration volume (i;e : 4 L h(-1) m(-2) for 20 L m(-2)). Results demonstrate that well anchored CNTs were successfully synthesized and functionalized on the SiC material. The hydrid SiC-CNTs materials showed permeate flux improvement with a higher permeate flux during O/W emulsion separation (i.e: 45 L h(-1) m(-2) for the same filtration conditions). Whatever the considered membrane, rejection values were excellent and above 90 %. Results also showed that the hydrophobic properties of SiC-CNTs membrane might be easily tuned by CNTs surface coating (i.e: iron oxide coating). Moreover, the synthesized CNTs were well anchored and might be backwashed keeping their positive impact on deposited oil. However, results emphasized that irreversible fouling tended to accumulate at the CNTs surface due to oil adsorption despite intensive chemical cleaning.

Automated summary

Produced water is the highest liquid stream generated by the petroleum industry, containing small amounts of emulsified oil. Research shows that SiC membrane material and CNTs synthesis have a positive impact on water treatment, but fouling phenomena hinder their development.