University of Sydney Chemical Engineering lecturer Dr Qianhong She (pictured) has been recognised as a young innovator for his research around membrane technology.
Dr She, from the Faculty of Engineering and Information Technologies, has been working on both membrane process development and membrane synthesis for the past decade, carrying out research into the use of membranes for water, food and renewable energy applications.
His model, known as osmotic-resistance filtration, is universally applicable to all osmosis-related membrane processes, including reverse osmosis (RO), forward osmosis (FO) and pressure-retarded osmosis (PRO).
The model has several advantages – it can help to identify the performance-limiting factors for [osmosis] processes; optimise the design of osmotic membranes; and develop strategies to make the best use of these membrane technologies.
This has the potential to revolutionise research into the use of membranes to filter contaminants from water and other fluids, and could help researchers develop new strategies to improve the design of membranes and optimise them as much as possible.
“One of the missions for a membrane scientist is to develop high-performance membranes and high-efficiency membrane processes for real applications,” Dr She said.
“A useful model can predict the right direction to go for membrane scientists for developing membrane technologies. It can provide guidance for optimal design of membranes and membrane processes under real operating conditions.”
Dr She said the model can also help to better understand the trade-off between membrane permeability and selectivity and the impact of a structural parameter, which would allow researchers to choose the optimal parameters when they are designing membranes.
Dr She’s model could lead to a significant real-world impact for various industries. For example, it could help companies to reduce the cost and energy consumption for clean water and value-added food production, recover resources and energy from wastewater, and tap new types of renewable energy.
One type of renewable energy application includes using the model to utilise pressure-retarded osmosis, which can be used to harvest energy that is generated when two waters with different salinities combine, such as when river water flows into seawater.
PRO works by allowing water through a semi-permeable membrane, while rejecting salt in the water. Osmotic pressure from this process can then be turned into electricity by turbines.
That difference in salt concentration has been said to have the potential to generate a vast amount of energy – possibly meeting up to 40 percent of global electricity demands – with pressure-retarded osmosis just one of the methods of capturing this energy.
In marine applications such as wastewater reuse, water purification and desalination, Dr She’s model refers to reverse osmosis and forward osmosis – Dr She said hybrid processes that utlise both PRO and RO can be used for simultaneous seawater desalination, wastewater reuse and renewable osmotic energy harvesting.
“With the aid of the model, we can better understand the performance-limiting factors such as reverse salt diffusion, internal concentration polarisation and membrane fouling, which will further help us to develop strategies to minimise the negative impact of those factors,” he said.
Other studies have also been carried out on using RO–PRO hybrid systems to alleviate water and energy demands.
For example, Humboldt State University and the University of Southern California have been involved in developing a portable, prototype RO-PRO system in Samoa, California, to help lower the cost of desalination and reduce its impact on the environment.
Dr She’s ultimate goal is to make the environment more sustainable, and he is now in the process of setting up his research in the School of Chemical and Biomolecular Engineering at the University of Sydney to explore new materials and methods to synthesise the next generation of osmotic membranes.
He will also be looking at developing integrated membrane processes for sustainable water, food and renewable energy production, as well as testing a new generation of membranes in the processes to demonstrate a proof of concept.
“I am exploring new materials that have high selectivity and stability for next generation of osmotic membranes,” Dr She said.
“I am also exploring new methods that can not only improve the membrane properties, but also can be used for large scale production of membranes.”
He was recently named a recipient of the 2017 North American Membrane Society Young Membrane Scientist Award for his work.