Swansea University scientists produce superhydrophilic membrane to clean fluids for reuse
A new superhydrophilic filter has proven able to remove greater than 90 per cent of hydrocarbons, as well as all bacteria and particulates from contaminated water produced by hydraulic fracturing (fracking) operations at shale oil and gas wells, according to researchers at the Energy Safety Research Institute at Swansea University in collaboration with researchers at Rice University.
The Energy Safety Research Institute is positioned to discover and implement new technology for a sustainable, affordable, and secure energy future and is housed on Swansea University's new world class Bay Campus. ESRI provides an exceptional environment for delivering cutting edge research across energy and energy safety-related disciplines with a focus on renewable energy, hydrogen, carbon capture and utilization, as well as new oil and gas technologies.
Credit: ESRI at Swansea University
The work by Prof Andrew R Barron and his colleagues turns a ceramic membrane with microscale pores into a superhydrophilic filter that "essentially eliminates" the common problem of fouling.
The researchers determined one pass through the membrane should clean contaminated water enough for reuse at a well, significantly cutting the amount that has to be stored or transported.
The work is reported in Nature's open-access Scientific Reports.
The filters keep emulsified hydrocarbons from passing through the material's ionically charged pores, which are about one-fifth of a micron wide, small enough that other contaminants cannot pass through. The charge attracts a thin layer of water that adheres to the entire surface of the filter to repel globules of oil and other hydrocarbons and keep it from clogging.
A hydraulically fractured well uses more than 5 million gallons of water on average, of which only 10 to 15 per cent is recovered during the flow back stage, Barron said.
"This makes it very important to be able to re-use this water"
Not every type of filter reliably removes every type of contaminant, he said.
Solubilized hydrocarbon molecules slip right through micro filters designed to remove bacteria. Natural organic matter, like sugars from guar gum used to make fracking fluids more viscous, require ultra- or nanofiltration, but those foul easily, especially from hydrocarbons that emulsify into globules. A multistage filter that could remove all the contaminants isn't practical due to cost and the energy it would consume.
Frac water and produced waters represent a significant challenge on a technical level. If you use a membrane with pores small enough to separate they foul, and this renders the membrane useless. In our case, the superhydrophilic treatment results in an increased flux (flow) of water through the membrane as well as inhibiting any hydrophobic material - such as oil - from passing through. The difference in solubility of the contaminants thus works to allow for separation of molecules that should in theory pass through the membrane.
Barron and his colleagues used cysteic acid to modify the surface of an alumina-based ceramic membrane, making it superhydrophilic, or extremely attracted to water. The superhydrophilic surface has a contact angle of 5 degrees.
The acid covered not only the surface but also the inside of the pores, and that kept particulates from sticking to them and fouling the filter.
In tests with fracking flow back or produced water that contained guar gum, the alumna membrane showed a slow initial decrease in flux -- a measure of the flow of mass through a material -- but it stabilized for the duration of lab tests. Untreated membranes showed a dramatic decrease within 18 hours.
The researchers theorized the initial decrease in flow through the ceramics was due to purging of air from the pores, after which the superhydrophilic pores trapped the thin layer of water that prevented fouling.
"This membrane doesn't foul, so it lasts," Barron said. "It requires lower operating pressures, so you need a smaller pump that consumes less electricity. And that's all better for the environment."
"Fracking has proved highly controversial in the UK in part as a result of the pollution generated from produced waters", co-author Darren Oatley-Radcliffe, an associate professor, at Swansea University, said, "However, with this new super-hydrophilic membrane we can clean up this waste produced water to a very high standard and recycle all of the materials, significantly improving the environmental performance of the fracking process."
Rice alumnus Samuel Maguire-Boyle is lead author of the paper. Co-authors are Rice alumnus Joseph Huseman; graduate student Thomas Ainscough at Swansea University, Wales; and Abdullah Alabdulkarem, of the Mechanical Engineering Department, and Sattam Fahad Al-Mojil, an assistant professor and environmental adviser, at King Saud University, Riyadh, Saudi Arabia. Barron is the Sêr Cymru Chair of Low Carbon Energy and Environment at Swansea and the Charles W. Duncan Jr.-Welch Professor of Chemistry and a professor of materials science and nanoengineering at Rice.
The research was supported by the Welsh Government Sêr Cymru Program, FLEXIS, which is partially funded by the European Regional Development Fund, and the Robert A. Welch Foundation.
The University's 46-acre Singleton Park Campus is located in beautiful parkland with views across Swansea Bay. The University's 65-acre science and innovation Bay Campus, which opened in September 2015, is located a few miles away on the eastern approach to the city. It has the distinction of having direct access to a beach and its own seafront promenade. Both campuses are close to the Gower Peninsula, the UK's first Area of Outstanding Natural Beauty.
Swansea is ranked the top university in Wales and is currently The Times and The Sunday Times 'Welsh University of the Year' for 2017. It is also ranked within the top 300 best universities in the world in the Times Higher Education World University rankings.
The results of the Research Excellence Framework (REF) 2014 showed the University has achieved its ambition to be a top 30 research University, soaring up the league table to 26th in the UK, with the 'biggest leap among research-intensive institutions' (Times Higher Education, December 2014) in the UK.
The University has ambitious expansion plans as it moves towards its centenary in 2020, as it continues to extend its global reach and realising its domestic and international ambitions.
Janis Pickwick | EurekAlert!
Biologically inspired skin improves robots' sensory abilities (Video)
11.10.2019 | Technical University of Munich (TUM)
New electrolyte stops rapid performance decline of next-generation lithium battery
11.10.2019 | DOE/Argonne National Laboratory
A very special kind of light is emitted by tungsten diselenide layers. The reason for this has been unclear. Now an explanation has been found at TU Wien (Vienna)
It is an exotic phenomenon that nobody was able to explain for years: when energy is supplied to a thin layer of the material tungsten diselenide, it begins to...
Researchers at Ludwig-Maximilians-Universitaet (LMU) in Munich have explored the initial consequences of the interaction of light with molecules on the surface of nanoscopic aerosols.
The nanocosmos is constantly in motion. All natural processes are ultimately determined by the interplay between radiation and matter. Light strikes particles...
Particles that are mere nanometers in size are at the forefront of scientific research today. They come in many different shapes: rods, spheres, cubes, vesicles, S-shaped worms and even donut-like rings. What makes them worthy of scientific study is that, being so tiny, they exhibit quantum mechanical properties not possible with larger objects.
Researchers at the Center for Nanoscale Materials (CNM), a U.S. Department of Energy (DOE) Office of Science User Facility located at DOE's Argonne National...
A new research project at the TH Mittelhessen focusses on the development of a novel light weight design concept for leisure boats and yachts. Professor Stephan Marzi from the THM Institute of Mechanics and Materials collaborates with Krake Catamarane, which is a shipyard located in Apolda, Thuringia.
The project is set up in an international cooperation with Professor Anders Biel from Karlstad University in Sweden and the Swedish company Lamera from...
Superconductivity has fascinated scientists for many years since it offers the potential to revolutionize current technologies. Materials only become superconductors - meaning that electrons can travel in them with no resistance - at very low temperatures. These days, this unique zero resistance superconductivity is commonly found in a number of technologies, such as magnetic resonance imaging (MRI).
Future technologies, however, will harness the total synchrony of electronic behavior in superconductors - a property called the phase. There is currently a...
02.10.2019 | Event News
02.10.2019 | Event News
19.09.2019 | Event News
17.10.2019 | Physics and Astronomy
17.10.2019 | Physics and Astronomy
17.10.2019 | Life Sciences