Executive Summary : | Industries including petrochemicals, automotive, shipping, etc. produce large volumes of oily wastewater, of which significant amount ends up in water bodies posing a serious environmental threat. Therefore, effective treatment of oily water is one of the major challenges towards environmental protection. The traditional approaches for o/w separation suffer from various limitations such as low separation efficiency, long processing times, large sizes, generation of secondary pollutants, and high energy consumption. The development of materials with extreme wettability (superhydrophobic or superhydrophilic) is a promising approach for the treatment of oily water. A porous separator fabricated out of such materials can allow the wetting phase (either "oil" or "water") to permeate selectively with higher separation efficiencies and lower energy consumption compared to the conventional methods. However, utilizing separators with fixed wettability restricts their function only as "oil-removing" or "water-removing". This places a constraint of pre-selecting the separator type (-philic or -phobic) before operation based on the anticipated feed properties, in particular, the type and state of the o/w mixture (heavy or light o/w mixture, oil-in-water or water-in-oil emulsions). Moreover, a vast majority of the o/w separation has been demonstrated in a batch scale filtration assembly, with very few reports on the continuous operation. Addressing these challenges, this project aims to develop and optimize a scalable continuous flow o/w separator system with a smart and durable dual-functional separator which can switch on-demand between "oil-removing" and "water-removing" modes.
Specifically, a copper-copper oxide based porous dual-functional separator will be synthesized which can switch on-demand between superhydrophobic and superhydrophilic states using low-voltage electrical stimuli and consequently, can be used irrespective of the state and type of the o/w mixture. In this project, consistent testing protocols in-line with the o/w separation requirement will also be developed based on which the material properties will be optimized for the maximum effectiveness and performance. To achieve continuous o/w separation, a flow-field based system with a high contact area between the separator and feed mixture will be designed and fabricated. Studies will be conducted to elucidate the effects of different operating parameters, wetting states, operation modes ("oil-removing" and "water-removing") and durability under long-term operation. It is expected that the development of such a continuous o/w separation system can facilitate the lab-to-market transition. Moreover, employing a smart separator which is capable of switching the wettability on demand will ensure that the same material can be utilized irrespective of the feed compositions, thereby providing a singular material solution for the o/w separator. |