oa Efficient and fast separation of emulsified oil/water mixtures with a novel micro/nanofiber network membrane

Produced water is one of the largest waste streams emanating from oil and gas industries. If inadequately treated, emulsified oil droplets contained in produced water will contaminate the environment and subsequently pose severe threat to human health. Removal of tiny emulsified oil droplets in produced water is very challenging. In this study, we demonstrated a new concept for constructing oil/water separating membranes with ultra-long titanate nanofibers (over 30 μm in length) / cellulose microfibers. An integrated network membrane was achieved with these ultra-long micro/nanofibers. This new membrane demonstrates good mechanical flexibility, which are critical for practical applications. This membrane shows high separation efficiency (99.9%) for oil/water emulsions with oil droplet size down to 3 μm, and at the same time has high water permeation flux (6.8 ×  104 L m-2 h-1 bar-1) at low operation pressure. The high water flux is attributed to the interconnected porous structure throughout the whole membrane, while the nanoporous selective layer contributes to high oil separation. In addition, the low-cost materials and fabrication process for this membrane suggests its great potential for industrial scale-up.