Engineering Omniphobic Slippery Membrane Surface for Wetting and Fouling Prevention: The Expanded Application of Membrane Distillation for Resource Recovery from Wastewater
DescriptionThe unprecedented demand for water, energy, and food, coupled with the impact of climate change, has presented serious global challenges. The inextricable linkage among the water-energy- food nexus makes a vibrant research question for many scientists to explore innovative technologies for achieving global sustainable development. Hong Kong is no exception to this challenge and to strengthen the growing city’s water security, a new desalination plant has been commissioned. At the same time, considering the excessive concentration of nutrients in Hong Kong’s wastewater, many studies now focus on the development of new technologies with the potential to recover resource from wastewater.Nitrogen removal by conventional treatment methods requires substantial energy to release it only back to the atmosphere as gaseous nitrogen. In contrast, an emerging membrane distillation (MD) possesses several advantageous characteristics such as high rejection of inorganic ions and non-volatile compounds thus guaranteeing a high quality of permeate water; insensitivity to feed concentration and not rigid requirements on membrane mechanical properties. Moreover, MD poses as a viable option for Hong Kong, mainly because the existing facilities under operation by the city’s Drainage Service Department (DSD) can recover low grade heat to reduce energy consumption and MD can facilitate ammonia recovery by controlling the volatility and pressure of vapor transport across the membrane to concentrate ammonia in the permeate stream.Like many other membrane applications, MD also cannot be free from membrane fouling and wetting, which is one of the major issues that huddle MD’s long-term performance. Based on our preliminary study, membrane wetting and fouling are not only attributed to membrane hydrophobicity, but also the interaction between membrane surface charge and the foulants. To mitigate deleterious membrane fouling and wetting and to achieve maximum nutrient recovery, it is integral to develop robust omniphobic MD membranes with superior anti-wetting and anti-fouling properties. Therefore, we propose to fabricate an engineered membrane by controlling the polymeric microspheres and fluorous coating which is highly resistant to fouling and wetting, then, to conduct a systematic study on the relationship between the physicochemical properties of the membrane and foulants with different charges and surface tension in real time using optical coherence tomography. This much-needed study on the role of membrane surface in attaining omniphobic feature with anti-fouling and anti-wetting properties in MD membranes will invigorate further research in this direction, bringing MD commercialization closer within our reach.?
|Effective start/end date||1/01/18 → …|