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Researchers at the University at Buffalo (UB) have developed a novel 3D-printed scalable water-purifying graphene aerogel with the potential to be used in large industrial wastewater treatment plants.
Approximately 2 billion people around the world live in high water stress countries. By 2040, one in four children under 18 years old in the world is estimated to be living in areas of high water scarcity. Considerable research is being devoted to improving the shortage of clean drinking water globally, to which the 3D printed water-purifying graphene aerogel by UB is an attractive advancement.
When put into the water treatment systems, the graphene aerogel holds its structure and removes contaminants from water without releasing any problematic chemical residue.
The unique aerogel, which is composed of latticed graphene, an aerogel and two bio-inspired polymers, showed 100% efficiency in removing metals, organic solvents and dyes from drinking water. The material is also reusable, and able to be 3D printed larger.
Graphene as a Purifier
Due to its versatile properties of being the lightest, strongest, thinnest, and the best heat-and-electricity conducting material, graphene is revolutionizing whole industries as researchers work on many different graphene-based materials, each one with unique qualities for different applications.
The ability to simultaneously exert hydrophobic and electrostatic interactions and the high specific surface area and mean that these materials bear a promising future in absorbing water contaminants.
For water purification, new technologies and materials are continuously being explored to make them more efficient and cheaper, which led to the possibility of experimenting with graphene as a better solution for water treatment and eliminating bacteria and other contaminants.
Previously, Graph Air, a novel filtration system based on graphene, was introduced to produce clean drinking water from polluted water. Graphene’s hydrophobic nature provides a remarkable property needed for water treatment. With the thin membrane made up of graphene oxide, an accurate mesh with narrow pores can allow ultrafast separation of atomic species that enables super-efficient filtering.
This exposes the idea that the graphene filter can be impermeable to all gases and vapors except water, giving the idea of using it for water filtration and desalination.
Water Purifying Aerogels
The idea of synthesizing aerogel with different materials and using them as an efficient technique for filtration has attracted interest from scientists in the last decade. A postdoctoral student at Linköping University in Sweden created an inexpensive and highly porous aerogel, mainly composed of cellulose.
A thin sheet of the aerogel floating on the surface of polluted water absorbs water from below and solar heat from above. This heats the water quickly to turn to steam, at a rate that is four to five times higher than the sunlight. The condensed steam onto a plate located above the aerogel forms into droplets of purified liquid water.
The UB’s solution stands out incredibly as they expose versatile properties of graphene oxide powder by adding the bio-inspired polydopamine (PDA) and bovine serum albumin (BSA) and yielding a novel 3D-printed aerogel, applicable for water absorption without particle agglomeration.
During the testing phase, the team exposed their prototype to organic solvent loaded-water repeatedly, which successfully removed 100% of the solvents. The design was later iterated in order to eliminate heavy metals like chromium, lead and alloys.
3D Printed Purification Devices
With an enormous advantage of low cost, flexibility, and personalized items, 3D printing has given options in many fields to make accurate novel devices. The possibility of customizing products with small details to get required properties has put 3D printing on the radar to use the concept in producing devices to clean drinking water.
The Defense Advanced Research Projects Agency (DARPA) recently awarded GE Research $ 14.3 million to 3D print a device that creates water out of thin air. Cleaning drinking water has been a challenge to many developing countries. Keeping this in mind, the University of Cambridge spin-out Blue Tap 3D printed chlorine doser, which can be easily fitted to water systems in developing countries to make it safe to drink.
There are many different types of 3D printing techniques, which can be used according to the required outcome. The UB chose to use Direct Ink Writing (DIW) to print graphene aerogel as the technique is already established in creating thermal, energy, and biomedical graphene devices. The advantage of DIW is that it offers the users precise control over the size, shape, and architecture of the products, making them easy to scale up.
Future of 3D-Printed Graphene Aerogels
Once 3D-Printed graphene aerogels are developed further, the UB team is planning to work with the aerogel and nano-metal particles so that they can also destroy chemical contaminants. The scaled-up aerogels will have a vital contribution to potential applications at water filtration plants in the form of devices, such as adsorbents, reactors, or filters.
References and Further Reading
BlueTap. (n.d.). Who We Are. [Online] BlueTap: https://www.bluetap.co.uk/our-story (Accessed on 03 May, 2021)
Coxworth, B. (2020). Aerogel quickly and cheaply purifies water – by turning it to steam. [Online] New Atlas: https://newatlas.com/good-thinking/hydrogel-steam-water-purification/ (Accessed on 03 May, 2021)
Everett, H. (2021). GE RESEARCH AWARDED $14M TO 3D PRINT PORTABLE DEVICE THAT PRODUCES WATER OUT OF THIN AIR. [Online] 3D Printing Industry: https://3dprintingindustry.com/news/ge-research-awarded-14m-to-3d-print-portable-device-that-produces-water-out-of-thin-air-183892/ (Accessed on 03 May, 2021)
Fang, J., Solis, J., Lan, E., & Dunn, B. (2012). Carbon Aerogels for Wastewater Treatment. In M. Aparicio, A. Jitianu, & L. C. Klein, Sol-Gel Processing for Conventional and Alternative Energy.
Graphene-info The Graphene Experts. (2019). Graphene and water treatment: introduction and market status. [Online] Graphene-info The Graphene Experts: https://www.graphene-info.com/graphene-water-treatment (Accessed on 03 May, 2021)
Han, S., Ruoko, T.‐P., Gladisch, J., Erlandsson, J., Wågberg, L., Crispin, X., & Fabiano, S. (2020). Cellulose‐Conducting Polymer Aerogels for Efficient Solar Steam Generation. Advanced Sustainable Systems. doi:10.1002/adsu.202000004
Hanaphy, P. (2021). SCIENTISTS 3D PRINT GRAPHENE AEROGELS THAT PURIFY WATER AT SCALE. [Online] 3D Printing Industry: https://3dprintingindustry.com/news/scientists-3d-print-graphene-aerogels-that-purify-water-at-scale-188753/ (Accessed on 03 May, 2021)
Smith, B. (2020). Graph Air: Revolutionary Water Filtration Using Graphene. [Online] AZoM: https://www.azom.com/article.aspx?ArticleID=19275 (Accessed on 03 May, 2021)