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Safe and immediate access to clean water is important for public health and in order to achieve this, various water purification methods are used to improve the water supply. However, existing methods of filtration often prove to be slow, difficult, and expensive placing limitations on who and where has readily available drinking water on tap.
Now, a team of collaborative researchers from the University of Ulm, Germany and CISC-Universidad de Zaragoza, Spain, have developed a new purification technique using magnetic nanoparticles to remove contaminants including microplastics from the water.
The team set about devising their innovative approach acknowledging that there is a growing need for new cost-effective technologies for wastewater and water management. Microplastics in the water supply are becoming a cause for concern around the world as they can access the food chain when ingested by fish and other marine organisms.
According to the World Health Organization (WHO), by 2025, water-stress will affect almost 50 percent of the global population. Thus, the re-use of wastewater and the ability to recover nutrients and energy from water, is becoming a crucial strategy. In recent years, the WHO International Scheme to Evaluate Household Water Treatment Technologies and their collaboration with UNICEF on the WASH FIT scheme, has been investigating and supporting methods to provide a clean global water supply and improving water and sanitation in developing countries.
The team, led by Carsten Streb, Robert Güttel, and Scott G. Mitchell, coated nanoparticles in an ionic liquid that would help eliminate the diverse set of pollutants in a water sample. The coating developed for a nanoparticle with a magnetic iron oxide core and porous silicon shell, “explored the removal of water contaminants by developing so‐called polyoxometalate‐supported ionic liquid phases (POM‐SILPs).” This could allow the nanoparticles to bind with both organic and inorganic matter before being extracted from the contaminated water using a series of magnets.
Their proposal is that water purification using magnetic particles is a promising alternative to filtration which could be used in a wide-range of water treatment applications, including extraction of pollutants from large volumes of water. In principle, their method, as published in the journal Angewandte Chemie, states that additional infrastructure would not be required if particle removal can be achieved using, “simple permanent magnets.”
During tests, the nanoparticles proved to be effective in the removal of metals including chromium, cobalt, copper, lead, and nickel, as well as a ‘Patent Blue V’ dye which stood in place for organic impurities. The method also prevented the growth of various bacteria, in addition to the nanoparticles attaching themselves to polystyrene spheres ranging from 1 to 10 µm in diameter as a model for microplastics.
In the future, the team led by Streb, Güttel, and Mitchell will attempt to explore how optimization of the individual components can be utilized to enhance their method as well as investigating the coupling to industrial electromagnetic recovery systems for use in realistic operating conditions. If this can be achieved the potential for cost-effective and easy water purification is highly-promising and could prove to be a pioneering breakthrough for the team and for a clean water supply.