media releases - Unisa files first successful patent for water purification inven

Every once in a while, a new field of science, which enables the development of a new generation of technology, emerges. One such field is the nanoscience and nanotechnology field - an interdisciplinary focus of science which has great potential to transform technology and change people’s lives. This technology is believed to be the primary driver of the 21^st century and new economy.

Nanoscience and nanotechnology involves studying and working with matter on an ultra-small scale. This field encompasses a range of techniques rather than a single discipline, and stretches across the whole spectrum of science, touching medicine, agriculture, information technology, physics, engineering and chemistry.

Using magnetic nanoparticles - a class of a nanoparticle which can be manipulated using magnetic field - Dr Wei Hua Ho from Unisa’s Mechanical and Industrial Engineering department and Professor Srinivasu Vallabhapurapu from Unisa’s Physics department collaborated with Professor Ivan Hofsajer from the University of Witwatersrand to create a water purification invention that could be mass produced with great commercial value.

The invention, which is a method and apparatus for treating a fluid, comes at a time when many nanomaterials are under active research and development as they offer potential solutions for treating surface water, groundwater and wastewater contaminated by toxic metal ions, organic and inorganic solutes and microorganisms.

Explaining the invention in more detail, Ho says the invention involves a novel method in the use of magnetic nanoparticles that are coated with a functional layer - a layer of materials to perform the task required - in this case to remove certain contaminants from water.

“The use of magnetic nanoparticles is not novel,” he said, “but the novelty in our invention is the way in which the cleaning takes place. Most current systems use the magnetic property to separate the particles from the water after the purification is done. However our idea is to use the magnetic property in the cleaning phase as well.”

The purification process, continues Ho, uses a chemical reaction and therefore some kind of physical excitation of the particles within the water is required. “Usually excitation of the container or the water (through the use of a stirrer or similar devices) is used. Our invention shows that a moving magnetic field can achieve the same effect.”

Speaking on the importance of this, Ho says, while the invention and method has been shown to work on a small prototype, if it can be extended to a larger commercial scale, the main advantage comes from two factors. “Firstly because there are no moving parts (as opposed to physically stirring or shaking the container), there is little to no wear and tear issues thus dramatically reducing the need for maintenance. Secondly because we are only exciting the particles and not the water or container, the energy required could be greatly reduced. The contaminants that can be removed depend on the functional layer.”

Vallabhapurapu adds: “We have developed an electro- magnetic technique to move the magnetic nanoparticles in water. This has a great implication that it substitutes the usual mechanical stirring of the particles in water in the water purification processes. Which means that the whole thing can be automated and can be upgraded to mass processing.  Thus this technique has great commercial value in the futuristic magnetic nanoparticle based water purification processes.”

The Unisa academics remark that the team is very excited to have filed a patent – especially since it is Unisa’s first patent. This accomplishment comes at an opportune time as Unisa celebrates its 140 years in South African and African academia. But more than that, Unisa also celebrates its future where it aims to be a leading global centre of excellence in science and research.

Ho adds: “As academics, it is always fulfilling to know that what we are interested in and researching on eventually materialises into products that help people. This is particularly true for engineers and the field of engineering which works towards solving practical problems. It is also very fulfilling for me personally to answer a ‘why can’t’ question and seeing the prototype worked.”  

Hofsajer said collaborating with colleagues from Unisa was a “great experience”.  “What started out as a discussion on magnetic fields ended up with an experiment that demonstrated much more complicated behaviour than we expected. It is always exciting to discover things working differently than what you expect. It greatly expands the boundaries of what you think is possible.”

With this invention, Unisa can certainly contribute to developmental projects in South Africa and Africa. Ho said those within Unisa’s Research and Innovation portfolio, as a new portfolio in the university, are proud.

“Having a patent filed so soon after the establishment of the portfolio will hopefully reduce and allay the apprehension some colleagues may have about the importance of ideas that they have … This is the one small step that will hopefully show our colleagues it is not impossible. The successful filing of this patent indicates that we, Unisa, are firmly on our way,” he concludes.

CAPTIONS

Prof. Srinivasu Vallabhapurapu (Unisa Physics department) and Dr Wei Hua Ho (Unisa Mechanical and Industrial Engineering department) discuss water purification. Together with Prof. Ivan Hofsajer (University of Witwatersrand), they filed Unisa’s first patent of a method and apparatus for treating a fluid.

Dr Wei Hua Ho (Unisa’s Mechanical and Industrial Engineering department).

Prof. Srinivasu Vallabhapurapu (Unisa Physics department).

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