Event: RO Membrane Is Not the Best Solution for Water Reclamation -- Nano Gives the Answer – organized by UST on 16 May 2013

RO Membrane Is Not the Best Solution for Water Reclamation -- Nano Gives the Answer –


Prof Darren Sun
School of Civil and Environmental Engineering 
Nanyang Technological University, Singapore

Date: 16 May 2013, Thursday
Time: 3:30 pm to 4:40 pm
Venue: Room 3574 (Lift 27/28), Civil Engineering Conference Room. The Hong Kong University of Science and Technology Clearwater Bay, Kowloon

Abstract

Drinking water and energy scarcities are today's most pressing challenges. Rapid industrialization and expanding population, coupled with more stringent environmental standards, are straining natural resources that are also affiliated with climate change. Cost effective water reclamation from seawater and wastewater has become the most viable means of meeting demand in many countries. Among various technologies, reverse osmosis (RO) membranes have been widely used for water reclamation. However, high external operational pressure used (above 75 bar for RO desalination while 25 bar for RO water recovery from wastewater) paints the image that RO membrane water reclamation process is energy intensive. In addition, these polymer-based membranes face high fouling problems that require additional pre-treatments (including MF/UF membrane filtration), resulting in even higher energy consumption for drinking water production. These obstacles paint an even worse image of ‘energy intensive’ in using RO membrane for water reclamation. It is well known that energy is one of the major barriers which hinder the economic development globally. High energy consumption is associated with the global warming as most of the energy is derived from fossil fuels that generate the global warming gas, CO2 as the final product. This is obviously against the Government’s efforts in reducing the CO2 emissions aiming to mitigate the global warming problem which affects Australia seriously. Osmosis is a natural phenomenon by utilizing the concentration gradient between two sides of the membrane. Forward osmosis (FO) is a natural process which exhibits unparalleled advantages of no external energy input, nearly complete rejection of contaminants and extremely low membrane fouling tendency. Today, FO is a well-recognized osmotic process for producing drinking water with brighter future as it uses this natural phenomenon and does not require any operational pressure in contrast with RO membrane process. Hence it saves large amount of energy by comparison. Thus it represents a tremendous and untapped opportunity with the potential to solve the global water and energy crisis. However, the biggest challenges facing the FO membrane water reclamation are (1) the lack of an ideal draw solute, which can be separated from water with a more energy-efficient process for reuse; and (2) the lack of an appropriate FO membrane with high water flux for large scale drinking water production. Tremendous efforts have been put in this area by our research group. This presentation will discuss the application of nanofibers and TiO2 for the fabrication of a novel nanocomposite FO membrane with the perspective in the use of FO membrane together with anaerobic reactor for concurrent drinking water and bio-energy production from wastewater. Finally, areas needed for further researches to improve the nanotechnology will also be discussed. Biography Darren Sun obtained his PhD degree in Chemical Engineering from The University of New South Wales, Australia in 1993. His research interests include (1) environmental applications and implication of nanomaterials, (2) membrane separation for desalination, water reclamation and water quality control, (3) engineered hybrid multifunctional membrane for sustainable production of water and energy. Darren has published more than 200 scientific publications on various prestigious journals with high impact – Energy & Environmental Science, Nano Letters, Advanced Materials, Advanced Functional Materials, Journal of American Chemical Society (JACS) etc.. His TiO2 nanofiber research was highlighted in the October 2006 issue of Nature. Darren was also the recipient of the IWA Innovation Award 2008 (East Asia and Pacific) from International Water Association (June 2008), Prestigious Engineering Achievement Award 2008 from Institute of Engineering Singapore (Sept 2008) for excellence in pilot scale water research using hybrid nanostractured TiO2 microsphere and membrane system, Nanyang Award for Innovation and Research 2009 from Nanyang Technological University (Feb 2010) for excellence in fabrication of flexible TiO2 nanofiber/tube/wire membrane and Distinguished Award 2011 from Singapore Accreditation Council (June 2011), Fellow of Renaissance Engineering Programme (REP) and President Award of Tokyo University of Science, Japan (March 2013). Externally, Darren is a Chair for International Water Associate (IWA) Specialist Group on Chemical Industries, Editors for Water Science and Technology, Journal of Photocatalysis Science and Journal of Chemistry. Darren is also a Shimizu Visiting Professor at Environmental Engineering and Science Program, Stanford University, USA. For enquiries, please contact Ms Rebecca Yau at 2358 7164 For more information: http://www.ce.ust.hk/Web/EventDetail.aspx?EventId=302